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Josh

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Blog Entries posted by Josh

  1. Josh
    The GMF2 SDK has been updated with tangents and bounds calculation, object colors, and save-to-file functionality.
    The GMF2 SDK is a lightweight engine-agnostic open-source toolkit for loading and saving of game models. The GMF2 format can work as a standalone file format or simply as a data format for import and export plugins. This gives us a protocol we can pull model data into and export model data from, and a format that loads large data much faster than alternative file formats.
    Here is an example showing how to construct a GMF2 model and save it to a file:
    //Create a GMF file GMFFile* file = new GMFFile; //Create a model GMFNode* node = new GMFNode(file, GMF_TYPE_MODEL); //Set the orientation node->SetMatrix(1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1); //Set the object color node->SetColor(0,0,1,1); //Add one LOD level GMFLOD* lod = node->AddLOD(); //Create a triangle mesh and add it to the LOD. (Meshes can be shared.) GMFMesh* mesh = new GMFMesh(file, 3); lod->AddMesh(mesh); //Add vertices mesh->AddVertex(-0.5,0.5,0, 0,0,1, 0,0); mesh->AddVertex(0.5,0.5,0, 0,0,1, 1,0); mesh->AddVertex(0.5,-0.5,0, 0,0,1, 1,1); mesh->AddVertex(-0.5,-0.5,0, 0,0,1, 0,1); //Add triangles mesh->AddPolygon(0,1,2); mesh->AddPolygon(0,2,3); //Build vertex tangents (optional) mesh->UpdateTangents(); //Save data to file file->Save("out.gmf"); //Cleanup - This will get rid of all created objects delete file; You can get the GMF2 SDK on GitHub.
  2. Josh
    The Turbo Game Engine beta is updated! This will allow you to load your own maps in the new engine and see the speed difference the new renderer makes.

    LoadScene() has replaced the LoadMap() function, but it still loads your existing map files. To create a PBR material, insert a line into the material file that says "lightingmodel=1". Blinn-Phong is the default lighting model. The red and green channels on texture unit 2 represent metalness and roughness. You generally don't need to assign shaders to your materials. The engine will automatically select one based on what textures you have. Point and spot lights work. Directional lights do not. Setting the world skybox only affects PBR reflections and Blinn-Phong ambient lighting. No sky will be visible. Physics, scripting, particles, and terrain do not work. Variance shadow maps are in use. There are currently some problems with lines appearing at cubemap seams and some flickering pixels. Objects should always cast a shadow or they won't appear correctly with VSMs. I had to include glew.c in the project because the functions weren't being detected from the static lib. I'm not sure why. The static libraries are huge. The release build is nearly one gigabyte. But when compiled, your executable is small. #include "Leadwerks.h" using namespace Leadwerks; int main(int argc, const char *argv[]) { //Create a window auto window = CreateWindow("MyGame", 0, 0, 1280, 720); //Create a rendering context auto context = CreateContext(window); //Create the world auto world = CreateWorld(); //This only affects reflections at this time world->SetSkybox("Models/Damaged Helmet/papermill.tex"); shared_ptr<Camera> camera; auto scene = LoadScene(world, "Maps/turbotest.map"); for (auto entity : scene->entities) { if (dynamic_pointer_cast<Camera>(entity)) { camera = dynamic_pointer_cast<Camera>(entity); } } auto model = LoadModel(world, "Models/Damaged Helmet/DamagedHelmet.mdl"); model->Move(0, 1, 0); model->SetShadowMode(LIGHT_DYNAMIC, true); //Create a camera if one was not found if (camera == nullptr) { camera = CreateCamera(world); camera->Move(0, 1, -3); } //Set background color camera->SetClearColor(0.15); //Enable camera free look and hide mouse camera->SetFreeLookMode(true); window->HideMouse(); //Create a light auto light = CreateLight(world, LIGHT_POINT); light->SetShadowMode(LIGHT_DYNAMIC | LIGHT_STATIC | LIGHT_CACHED); light->SetPosition(0, 4, -4); light->SetRange(15); while (window->KeyHit(KEY_ESCAPE) == false and window->Closed() == false) { //Rotate model model->Turn(0, 0.5, 0); //Camera movement if (window->KeyDown(Key::A)) camera->Move(-0.1, 0, 0); if (window->KeyDown(Key::D)) camera->Move(0.1, 0, 0); if (window->KeyDown(Key::W)) camera->Move(0, 0, 0.1); if (window->KeyDown(Key::S)) camera->Move(0, 0, -0.1); //Update the world world->Update(); //Render the world world->Render(context); } Shutdown(); return 0; }
  3. Josh
    Not a lot of people know about this, but back in 2001 Discreet (before the company was purchased by Autodesk) released a free version of 3ds max for modding games. Back then game file formats and tools were much more highly specialized than today, so each game required a "game pack" to customize the gmax interface to support that game. I think the idea was to charge the game developer money to add support for their game. Gmax supported several titles including Quake 3 Arena and Microsoft Flight Simulator, but was later discontinued.
    I personally love the program because it includes only the features you need from 3ds max for hard surface modeling. It's basically a stripped down version of 3ds max with only the features you need.

    Gmax still survives today, apparently in the custody of Turbosquid. You can download it here. You need the gmax 1.2 installer and the Tempest game pack for Quake 3. You will also need to request a free registration key from Turbosquid. After installing gmax, you can simply find the MD3 export plugin ("md3exp.dle") in the Tempest game pack download and copy that to your "C:\gmax\plugins" directory to enable export. There is also an optional  There is also an optional MD3 import script by Chris Cookson which is uploaded here for safekeeping:
    q3-md3.ms
    With the plugin system in our new engine I was able to add support for loading Quake 3 MD3 models, so you can export your gmax models and load them up in the new engine. However, there are some restrictions. The MD3 file format uses compressed vertex positions, so your vertex positions have a limited range and resolution. Additionally, there are restrictions on what you can do with the gmax program, so take a look at the licensing terms before you do anything. Still, it's a fun program to have and this is a nice feature to play around with.
     
  4. Josh
    I wanted to get a working example of the plugin system together. One thing led to another, and...well, this is going to be a very different blog.
    GMF2
    The first thing I had to do is figure out a way for plugins to communicate with the main program. I considered using a structure they both share in memory, but those always inevitably get out of sync when either the structure changes or there is a small difference between the compilers used for the program and DLL. This scared me so I went with a standard file format to feed the data from the plugin to the main program.
    GLTF is a pretty good format but has some problems that makes me look for something else to use in our model loader plugins.
    It's text-based and loads slower. It's extremely complicated. There are 3-4 different versions of the file format and many many options to split it across multiple files, binary, text, or binary-to-text encoding. It's meant for web content, not PC games. Tons of missing functionality is added through a weird plugin system. For example, DDS is supported through a plugin, but a backup PNG has to be included in case the loaded doesn't support the extension. The GMF file format was used in Leadwerks. It's a custom fast-loading chunk-based binary file format. GMF2 is a simpler flat binary format updated with some extra features:
    Vertices are stored in a single array ready to load straight into GPU memory. Vertex displacement is supported. Compressed bitangents. Quad and line meshes are supported. LOD Materials and textures can be packed into the format or loaded from external files. PBR and Blinn-Phong materials Mesh bounding boxes are supported so they don't have to be calculated at load time. This means the vertex array never has to be iterated through, making large meshes load faster. I am not sure yet if GMF2 will be used for actual files or if it is just going to be an internal data format for plugins to use. GLTF will continue to be supported, but the format is too much of a mess to use for plugin data.
    Here's a cool five-minute logo:

    The format looks something like this:
    char[4] ID "GMF2" int version 200 int root //ID of the root entity int texture_count //number of textures int textures_pos //file position for texture array int materials_count //number of materials int materials_pos //file position for materials int nodes_count //number of nodes int nodes_pos //file position for nodes As you can see, it is really easy to read and really easy to write. There's enough complexity in this already. I'm not bored. I don't need to introduce unnecessary complexity into the design just so I can show off. There are real problems that need to be solved and making a "tricky" file format is not one of them.
    In Leadwerks 2, we had a bit of code called the "GMF SDK". This was written in BlitzMax, and allowed construction of a GMF file with easy commands. I've created new C++ code to create GMF2 files:
    //Create the file GMFFile* file = new GMFFile; //Create a model node = new GMFNode(file, GMF_TYPE_MODEL); //Add an LOD level GMFLOD* lod = node->AddLOD(); //Add a mesh GMFMesh* mesh = lod->AddMesh(3); //triangle mesh //Add a vertex mesh->AddVertex(0,0,0, 0,0,1, 0,0, 0,0, 255,255,255,255); mesh->AddVertex(0,0,1, 0,0,1, 0,0, 0,0, 255,255,255,255); mesh->AddVertex(0,1,1, 0,0,1, 0,0, 0,0, 255,255,255,255); //Add a triangle mesh->AddIndice(0); mesh->AddIndice(1); mesh->AddIndice(2); Once your GMFFile is constructed you can save it into memory with one command. The Turbo Plugin SDK is a little more low-level than the engine, so it includes a MemWriter class to help with this, since the engine Stream class is not present.
    As a test I am writing a Quake 3 MD3 import plugin and will provide the project and source as an example of how to use the Turbo Plugin SDK.

    Packages
    The ZIP virtual file system from Leadwerks is being expanded and formalized. You can load a Package object to add new virtual files to your project. These will also be loadable from the editor, so you can add new packages to a project, and the files will appear in the asset browser and file dialogs. (Package files are read-only.) Plugins will allow packages to be loaded from file formats besides ZIP, like Quake WADs or Half-Life GCF files. Notice we keep all our loaded items in variables or arrays because we don't want them to get auto-deleted.
    //Load Quake 3 plugins auto pk3reader = LoadPlugin("Plugins/PK3.dll"); auto md3loader = LoadPlugin("Plugins/MD3.dll"); auto bsploader = LoadPlugin("Plugins/Q3BSP.dll"); Next we load the game package files straight from the Quake game directory. This is just like the package system from Leadwerks.
    //Load Quake 3 game packages std::wstring q3apath = L"C:/Program Files (x86)/Steam/steamapps/common/Quake 3 Arena/baseq3"; auto dir = LoadDir(q3apath); std::vector<shared_ptr<Package> > q3apackages; for (auto file : dir) { if (Lower(ExtractExt(file)) == L"pk3") { auto pak = LoadPackage(q3apath + L"/" + file); if (pak) q3apackages.push_back(pak); } } Now we can start loading content directly from the game.
    //Load up some game content from Quake! auto head = LoadModel(world, "models/players/bitterman/head.md3"); auto upper = LoadModel(world, "models/players/bitterman/upper.md3"); auto lower = LoadModel(world, "models/players/bitterman/lower.md3"); auto scene = LoadScene(world, "maps/q3ctf2.bsp"); Modding
    I have a soft spot for modding because that is what originally got me into computer programming and game development. I was part of the team that made "Checkered Flag: Gold Cup" which was a spin-off on the wonderful Quake Rally mod:
    I expect in the new editor you will be able to browse through game files just as if they were uncompressed in your project file, so the new editor can act as a modding tool, for those who are so inclined. It's going to be interesting to see what people do with this. We can configure the new editor to run a launch script that handles map compiling and then launches the game. All the pieces are there to make the new editor a tool for modding games, like Discreet's old Gmax experiment.

    I am going to provide official support for Quake 3 because all the file formats are pretty easy to load, and because gmax can export to MD3 and it would be fun to load Gmax models. Other games can be supported by adding plugins.
    So here are some of the things the new plugin system will allow:
    Load content directly from other games and use it in your own game. I don't recommend using copyrighted game assets for commercial projects, but you could make a "mod" that replaces the engine and requires the player to own the original game. You could probably safely use content from any Valve games and release a commercial game on Steam. Use the editor as a tool to make Quake or other maps. Add plugin support for new file formats. This might all be a silly waste of time, but it's a way to get the plugin system working, and if we can make something flexible enough to build Quake maps, well that is a good test of the robustness of the system.
     
  5. Josh
    During development of Leadwerks Game Engine, there was some debate on whether we should allow multiple scripts per entity or just associate a single script with an entity. My first iteration of the scripting system actually used multiple scripts, but after using it to develop the Darkness Awaits example I saw a lot of problems with this. Each script used a different classname to store its variables and functions in, so you ended up with code like this:
    function Script:HurtEnemy(amount) if self.enemy ~= nil then if self.enemy.healthmanager ~= nil then if type(self.enemy.healthmanager.TakeDamage)=="function" then self.enemy.healthmanager.TakeDamage(amount) end end end end I felt this hurt script interoperability because you had to have a bunch of prefixes like healthmanager, ammomanager, etc. I settled on using a single script, which I still feel was the better choice between these two options:
    function Script:HurtEnemy(amount) if self.enemy ~= nil then if type(self.enemy.TakeDamage)=="function" then self.enemy.TakeDamage(amount) end end end Scripting in Turbo Game Engine is a bit different. First of all, all values and functions are attached to the entity itself, so there is no "script" table. When you access the "self" variable in a script function you are using the entity object itself. Here is a simple script that makes an entity spin around its Y axis:
    function Entity:Update() self:Turn(0,0.1,0) end Through some magic that is only possible due to the extreme flexibility of Lua, I have managed to devise a system for multiple script attachments that makes sense. There is no "component" or "script" objects itself, adding a script to an entity just executes some code that attached values and functions to an entity. Adding a script to an entity can be done in C++ as follows:
    model->AttachScript("Scripts/Objects/spin.lua"); Or in Lua itself:
    model:AttachScript("Scripts/Objects/spin.lua"); Note there is no concept of "removing" a script, because a script just executes a bit of code that adds values and functions to the entity.
    Let's say we have two scripts named "makeHealth100 and "makeHealth75".
    MakeHealth100.lua
    Entity.health=100 MakeHealth75.lua
    Entity.health=75 Now if you were to run the code below, which attaches the two scripts, the health value would first be set to 100, and then the second script would set the same value to 75, resulting in the number 75 being printed out:
    model->AttachScript("Scripts/Objects/MakeHealth100.lua"); model->AttachScript("Scripts/Objects/MakeHealth75.lua"); Print(entity->GetNumber("health")); Simple enough, right? The key point here is that with multiple scripts, variables are shared between scripts. If one scripts sets a variable to a value that conflicts with another script, the two scripts won't work as expected. However, it also means that two scripts can easily share values to work together and create new functionality, like this health regeneration script that could be added to work with any other scripts that treat the value "health" as a number.
    HealthRegen.lua
    Entity.healthregendelay = 1000 function Entity:Start() self.healthregenupdatetime = CurrentTime() end function Entity:Update() if self.health > 0 then if CurrentTime() - self.healthregenupdatetime > self.healthregendelay then self.health = self.health + 1 self.health = Min(self.health,100) end end end What about functions? Won't adding a script to an entity overwrite any functions it already has attached to it? If I treated functions the same way, then each entity could only have one function for each name, and there would be very little point in having multiple scripts! That's why I implemented a special system that copies any added functions into an internal table. If two functions with the same name are declared in two different scripts, they will both be copied into an internal table and executed. For example, you can add both scripts below to an entity to make it both spin and make the color pulse:
    Spin.lua
    function Entity:Update() self:Turn(0,0.1,0) end Pulse.lua
    function Entity:Update() local i = Sin(CurrentTime()) * 0.5 + 0.5 self:SetColor(i,i,i) end When the engine calls the Update() function, both copies of the function will be called, in the order they were added.
    But wait, there's more.
    The engine will add each function into an internal table, but it also creates a dummy function that iterates through the table and executes each copy of the function. This means when you call functions in Lua, the same multi-execution feature will be available. Let's consider a theoretical bullet script that causes damage when the bullet collides with something:
    function Entity:Collision(entity,position,normal,speed) if type(entity.TakeDamage) == "function" then entity:TakeDamage(20) end end If you have two (or more) different TakeDamage functions on different scripts attached to that entity, all of them would get called, in order.
    What if a function returns a value, like below?:
    function Entity:Update() if self.target ~= nil then if self.target:GetHealth() <= 0 then self.target = nil --stop chasing if dead end end end If multiple functions are attached that return values, then all the return values are returned.

    To grab multiple returned values, you can set up multiple variables like this:
    function foo() return 1,2,3 end a, b, c = foo() print(a) --1 print(b) --2 print(c) --3 But a more practical usage would be to create a table from the returned values like so:
    function foo() return 1,2,3 end t = { foo() } print(t[1]) --1 print(t[2]) --2 print(t[3]) --3 How could this be used? Let's say you had a script that was used to visually debug AI scripts. It did this by checking to see what an entity's target enemy was, by calling a GetTarget() function, and then creating a sprite and aligning it to make a line going from the AI entity to its target it was attacking:
    function Entity:UpdateDisplay() local target = self:GetTarget() self.sprite = CreateSprite() local p1 = self.entity:GetPosition() local p2 = target:GetPosition() self.sprite:SetPosition((p1 + p2) * 0.5) self.sprite:AlignToVector(p2 - p1) self.sprite:SetSize(0.1,(p2-p1):Length()) end Now let's imagine we had a tank with a main gun as well as an anti-aircraft gun that would ward off attacks from above, like this beauty I found on Turbosquid:

    Let's imagine we have two different scripts we attach to the tank. One handles AI for driving and shooting the main turret, while the other just manages the little machine gun. Both the scripts have a GetTarget() function, as the tank may be attacking two different enemies at once.
    We can easily modify our AI debugging script to handle multiple returned values as follows:
    function Entity:UpdateDisplay() local targets = { self:GetTarget() } --all returned values get put into a table for n,target in ipairs(targets) do local sprite = CreateSprite() self.sprites.insert(sprite) local p1 = self.entity:GetPosition() local p2 = target:GetPosition() sprite:SetPosition((p1 + p2) * 0.5) sprite:AlignToVector(p2 - p1) sprite:SetSize(0.1,(p2-p1):Length()) end end However, any scripts that are not set up to account for multiple returned values from a function will simply use the first returned value, and proceed as normal.
    This system supports both easy mix and match behavior with multiple scripts, but keeps the script code simple and easy to use. Scripts have easy interoperability by default, but if you want to make your function and variable names unique to the script it is easy to do so.
    Let me know if you have any other ideas for scripting in Turbo Game Engine.
  6. Josh
    With tessellation now fully implemented, I was very curious to see how it would perform when applied to arbitrary models. With tessellation, vertices act like control points for a Bezier mesh that is subdivided dynamically in screen space. Could tessellation be used to add new details to any low-poly model?
    Here is a low-res character model with a pointy head and obvious sharp edges all around his silhouette:


    When tessellation is enabled, the sharp edges go away and the mesh magically appears more detailed:


    Let's take a look at the "Doom Seeker" enemy model from Doom 3. The original model is 640 triangles:


    Tessellation gets rid of the blocky outline.

    And displacement adds new details to the model.


    What about other shapes? Can this technique be used to turn any low-poly model into a high-res version? Here is a tire model from "The Zone" DLC. Even with displacement set to zero on edge vertices, cracks still appear.

    So my conclusion on this is that tessellation is fantastic for closed organic shapes. In fact, I think it totally replaces separate LOD meshes for rocks, characters, and other organic shapes. However, it is not something you should use everywhere without any discretion.
  7. Josh
    Previously I talked about the technical details of hardware tessellation and what it took to make it truly useful. In this article I will talk about some of the implications of this feature and the more advanced ramifications of baking tessellation into Turbo Game Engine as a first-class feature in the 
    Although hardware tessellation has been around for a few years, we don't see it used in games that often. There are two big problems that need to be overcome.
    We need a way to prevent cracks from appearing along edges. We need to display a consistent density of triangles on the screen. Too many polygons is a big problem. I think these issues are the reason you don't really see much use of tessellation in games, even today. However, I think my research this week has created new technology that will allow us to make use of tessellation as an every-day feature in our new Vulkan renderer.
    Per-Vertex Displacement Scale
    Because tessellation displaces vertices, any discrepancy in the distance or direction of the displacement, or any difference in the way neighboring polygons are subdivided, will result in cracks appearing in the mesh.

    To prevent unwanted cracks in mesh geometry I added a per-vertex displacement scale value. I packed this value into the w component of the vertex position, which was not being used. When the displacement strength is set to zero along the edges the cracks disappear:

    Segmented Primitives
    With the ability to control displacement on a per-vertex level, I set about implementing more advanced model primitives. The basic idea is to split up faces so that the edge vertices can have their displacement scale set to zero to eliminate cracks. I started with a segmented plane. This is a patch of triangles with a user-defined size and resolution. The outer-most vertices have a displacement value of 0 and the inner vertices have a displacement of 1. When tessellation is applied to the plane the effect fades out as it reaches the edges of the primitive:

    I then used this formula to create a more advanced box primitive. Along the seam where the edges of each face meet, the displacement smoothly fades out to prevent cracks from appearing.

    The same idea was applied to make segmented cylinders and cones, with displacement disabled along the seams.


    Finally, a new QuadSphere primitive was created using the box formula, and then normalizing each vertex position. This warps the vertices into a round shape, creating a sphere without the texture warping that spherical mapping creates.

    It's amazing how tessellation and displacement can make these simple shapes look amazing. Here is the full list of available commands:
    shared_ptr<Model> CreateBox(shared_ptr<World> world, const float width = 1.0); shared_ptr<Model> CreateBox(shared_ptr<World> world, const float width, const float height, const float depth, const int xsegs = 1, const int ysegs = 1); shared_ptr<Model> CreateSphere(shared_ptr<World> world, const float radius = 0.5, const int segments = 16); shared_ptr<Model> CreateCone(shared_ptr<World> world, const float radius = 0.5, const float height = 1.0, const int segments = 16, const int heightsegs = 1, const int capsegs = 1); shared_ptr<Model> CreateCylinder(shared_ptr<World> world, const float radius = 0.5, const float height=1.0, const int sides = 16, const int heightsegs = 1, const int capsegs = 1); shared_ptr<Model> CreatePlane(shared_ptr<World> world, cnst float width=1, const float height=1, const int xsegs = 1, const int ysegs = 1); shared_ptr<Model> CreateQuadSphere(shared_ptr<World> world, const float radius = 0.5, const int segments = 8); Edge Normals
    I experimented a bit with edges and got some interesting results. If you round the corner by setting the vertex normal to point diagonally, a rounded edge appears.

    If you extend the displacement scale beyond 1.0 you can get a harder extended edge.

    This is something I will experiment with more. I think CSG brush smooth groups could be used to make some really nice level geometry.
    Screen-space Tessellation LOD
    I created an LOD calculation formula that attempts to segment polygons into a target size in screen space. This provides a more uniform distribution of tessellated polygons, regardless of the original geometry. Below are two cylinders created with different segmentation settings, with tessellation disabled:

    And now here are the same meshes with tessellation applied. Although the less-segmented cylinder has more stretched triangles, they both are made up of triangles about the same size.

    Because the calculation works with screen-space coordinates, objects will automatically adjust resolution with distance. Here are two identical cylinders at different distances.

    You can see they have roughly the same distribution of polygons, which is what we want. The same amount of detail will be used to show off displaced edges at any distance.

    We can even set a threshold for the minimum vertex displacement in screen space and use that to eliminate tessellation inside an object and only display extra triangles along the edges.

    This allows you to simply set a target polygon size in screen space without adjusting any per-mesh properties. This method could have prevented the problems Crysis 2 had with polygon density. This also solves the problem that prevented me from using tessellation for terrain. The per-mesh tessellation settings I worked on a couple days ago will be removed since it is not needed.
    Parallax Mapping Fallback
    Finally, I added a simple parallax mapping fallback that gets used when tessellation is disabled. This makes an inexpensive option for low-end machines that still conveys displacement.

    Next I am going to try processing some models that were not designed for tessellation and see if I can use tessellation to add geometric detail to low-poly models without any cracks or artifacts.
  8. Josh
    Now that I have all the Vulkan knowledge I need, and most work is being done with GLSL shader code, development is moving faster. Before starting voxel ray tracing, another hard problem, I decided to work one some *relatively* easier things for a few days. I want tessellation to be an every day feature in the new engine, so I decided to work out a useful implementation of it.
    While there are a ton of examples out there showing how to split a triangle up into smaller triangles, useful discussion and techniques of in-game tessellation is much more rare. I think this is because there are several problems to solve before this technical feature can really be made practical.
    Tessellation Level
    The first problem is deciding how much to tessellate an object. Tessellation should use a single detail level per set of primitives being drawn. The reason for this is that cracks will appear when you apply displacement if you try to use a different tessellation level for each polygon. I solved this with some per-mesh setting for tessellation parameters.
    Note: In Leadwerks Game Engine, a model is an entity with one or more surfaces. Each surface has a vertex array, indice array, and a material. In Turbo Game Engine, a model contains one of more LODs, and each LOD can have one or more meshes. A mesh object in Turbo is like a surface object in Leadwerks.
    We are not used to per-mesh settings. In fact, the material is the only parameter meshes contained other than vertex or indice data. But for tessellation parameters, that is exactly what we need, because the density of the mesh polygons gives us an idea of how detailed the tessellation should be. This command has been added:
    void Mesh::SetTessellation(const float detail, const float nearrange, const float farrange) Here are what the parameters do:
    detail: the higher the detail, the more the polygons are split up. Default is 16. nearrange: the distance below which tessellation stops increasing. Default is 1.0 meters. farrange: the distance below which tessellation starts increasing. Default is 20.0 meters. This command gives you the ability to set properties that will give a roughly equal distribution of polygons in screen space. For convenience, a similar command has been added to the model class, which will apply the settings to all meshes in the model.
    Surface Displacement
    Another problem is culling offscreen polygons so the GPU doesn't have to process millions of extra vertices. I solved this by testing if all control vertices lie outside one edge of the camera frustum. (This is not the same as testing if any control point is inside the camera frustum, as I have seen suggested elsewhere. The latter will cause problems because it is still possible for a triangle to be visible even if all its corners are outside the view.) To account for displacement, I also tested the same vertices with maximum displacement applied.
    To control the amount of displacement, a scale property has been added to the displacementTexture object scheme:
    "displacementTexture": { "file": "./harshbricks-height5-16.png", "scale": 0.05 } A Boolean value called "tessellation" has also been added to the JSON material scheme. This will tell the engine to choose a shader that uses tessellation, so you don't need to explicitly specify a shader file. Shadows will also be rendered with tessellation, unless you explicitly choose a different shadow shader.
    Here is the result:

    Surface displacement takes the object scale into account, so if you scale up an object the displacement will increase accordingly.
    Surface Curvature
    I also added an implementation of the PN Triangles technique. This treats a triangle as control points for a Bezier curve and projects tessellated curved surfaces outwards.
     
    You can see below the shot using the PN Triangles technique eliminates the pointy edges of the sphere.


    The effects is good, although it is more computationally expensive, and if a strong displacement map is in use, you can't really see a difference. Since vertex positions are being changed but texture coordinates are still using the same interpolation function, it can make texture coordinates appear distorted. To counter this, texture coordinates would need to be recalculated from the new vertex positions.
    EDIT:
    I found a better algorithm that doesn't produce the texcoord errors seen above.


    Finally, a global tessellation factor has been added that lets you scale the effect for different hardware levels:
    void SetTessellationDetail(const float detail) The default setting is 1.0, so you can use this to scale up or down the detail any way you like.
  9. Josh
    It is now possible to compile shaders into a single self-contained file that can loaded by any Vulkan program, but it's not obvious how this is done. After poking around for a while I found all the pieces I needed to put this together.
    Compiling
    First, you need to compile each shader stage from a source code file into a precompiled SPIR-V file. There are several tools available to do this, but I prefer GLSlangValidator because it supports the Google #include extension. Put your vertex shader code in a text file named "shader.vert" and your pixel shader code in a file called "shader.frag". Create a .bat file in the same directory with the following contents:
    glslangValidator.exe "shader.vert" -V -o "vert.spv" glslangValidator.exe "shader.frag" -V -o "frag.spv" Run the bat file and two .spv files will be saved.
    Linking
    Now we want to combine our two files representing different shader stages into a single file. This is done with the link tool from Khronos. Add the following lines to your .bat file to compile the two .spv files into one. It will also delete the existing files to clean things up a little:
    spirv-link "vert.spv" "frag.spv" -o "shader.spv" del "vert.spv" del "frag.spv" This will save a single file named "shader.spv" that you can load as one shader module and use for different stages in Vulkan.
    Here are the required executables and a .bat file:
    BuildShader.zip
    Parsing
    If you always use vertex and fragment stages then there is no problem, but what if the combined .spv file contains other stages, or is missing a fragment stage? We can easily account for this with a minimal SPIR-V file parser. We're not going to include any big bloated libraries to do this because we only need some basic information about what stages are contained in the shader. Fortunately, the SPIR-V specification is pretty simple and it doesn't take much code to extract the information we want:
    std::string entrypointname[6]; auto stream = ReadFile(L"Shaders/shader.spv"); // Parse SPIR-V data Assert(stream->ReadInt() == 0x07230203); int version = stream->ReadInt(); int genmagnum = stream->ReadInt(); int bound = stream->ReadInt(); int reserved = stream->ReadInt(); bool stages[6] = {false,false,false,false,false,false}; // Instruction stream while (stream->Ended() == false) { int pos = stream->GetPos(); unsigned int bytes = stream->ReadUInt(); int opcode = LOWORD(bytes); int wordcount = HIWORD(bytes); if (opcode == 15) { int executionmodel = stream->ReadInt(); Assert(executionmodel >= 0); if (executionmodel < 6) { stream->ReadInt(); // entry point stages[executionmodel] = true; entrypointname[executionmodel] = stream->ReadString(); } } stream->Seek(pos + wordcount * 4); } This code even retrieves the entry point name for each stage, so you can be sure you are loadng the shader correctly.
    Here are the different shader stages from the SPIR-V specification:
    0: Vertex 1: TessellationControl 2: TessellationEvaluation 3: Geometry 4: Fragment 5: GLCompute That's it! We now have a standard single-file shader format for Vulkan programs. Your code for creating these will look something like this:
    VkShaderModule shadermodule; // Create shader module VkShaderModuleCreateInfo shaderCreateInfo = {}; shaderCreateInfo.sType = VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO; shaderCreateInfo.codeSize = bank->GetSize(); shaderCreateInfo.pCode = reinterpret_cast<const uint32_t*>(bank->buf); VkAssert(vkCreateShaderModule(device->device, &shaderCreateInfo, nullptr, &shadermodule)); // Create vertex stage info VkPipelineShaderStageCreateInfo vertShaderStageInfo = {}; vertShaderStageInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; vertShaderStageInfo.stage = VK_SHADER_STAGE_VERTEX_BIT; vertShaderStageInfo.module = shadermodule; vertShaderStageInfo.pName = entrypointname[0].c_str(); VkPipelineShaderStageCreateInfo fragShaderStageInfo = {}; if (stages[4]) { // Create fragment stage info fragShaderStageInfo.sType = VK_STRUCTURE_TYPE_PIPELINE_SHADER_STAGE_CREATE_INFO; fragShaderStageInfo.stage = VK_SHADER_STAGE_FRAGMENT_BIT; fragShaderStageInfo.module = shadermodule; fragShaderStageInfo.pName = entrypointname[4].c_str(); } // Create your graphics pipeline...  
  10. Josh
    The Leadwerks 2 terrain system was expansive and very fast, which allowed rendering of huge landscapes. However, it had some limitations. Texture splatting was done in real-time in the pixel shader. Because of the limitations of hardware texture units, only four texture units per terrain were supported. This limited the ability of the artist to make terrains with a lot of variation. The landscapes were beautiful, but somewhat monotonous.
    With the Leadwerks 3 terrain system, I wanted to retain the advantages of terrain in Leadwerks 2, but overcome some of the limitations. There were three different approaches we could use to increase the number of terrain textures.
    Increase the number of textures used in the shader. Allow up to four textures per terrain chunk. These would be determined either programmatically based on which texture layers were in use on that section, or defined by the artist. Implement a virtual texture system like id Software used in the game "Rage". Since Leadwerks 3 runs on mobile devices as well as PC and Mac, we couldn't use any more texture units than we had before, so the first option was out. The second option is how Crysis handles terrain layers. If you start painting layers in the Crysis editor, you will see when "old" layers disappear as you paint new ones on. This struck me as a bad approach because it would either involve the engine "guessing" which layers should have priority, or involve a tedious process of user-defined layers for each terrain chunk.
    A virtual texturing approach seemed liked the ideal choice. Basically, this would render near sections of the terrain at a high resolution, and far sections of the terrain at low resolutions, with a shader that chose between them. If done correctly, the result should be the same as using one impossibly huge texture (like 1,048,576 x 1,048,576 pixels) at a much lower memory cost. However, there were some serious challenges to be overcome, so much so that I added a disclaimer in our Kickstarter campaign basically saying "this might not work"..
    Previous Work
    id Software pioneered this technique with the game Rage (a previous implementation was in Quake Wars). However, id's "megatexture" technique had some serious downsides. First, the data size requirements of storing completely unique textures for the entire world were prohibitive. "Rage" takes about 20 gigs of hard drive space, with terrains much smaller than the size I wanted to be able to use. The second problem with id's approach is that both games using this technique have some pretty blurry textures in the foreground, although the unique texturing looks beautiful from a distance.

    I decided to overcome the data size problem by dynamically generating the megatexture data, rather than storing in on the hard drive. This involves a pre-rendering step where layers are rendered to the terrain virtual textures, and then the virtual textures are applied to the terrain. Since id's art pipeline was basically just conventional texture splatting combined with "stamps" (decals), I didn't see any reason to permanently store that data. I did not have a simple solution to the blurry texture problem, so I just went ahead and started implementing my idea, with the understanding that the texture resolution issue could kill it.
    I had two prior examples to work from. One was a blog from a developer at Frictional Games (Amnesia: The Dark Descent and Penumbra). The other was a presentation describing the technique's use in the game Halo Wars. In both of these games, a fixed camera distance could be relied on, which made the job of adjusting texture resolution much easier. Leadwerks, on the other hand, is a general-purpose game engine for making any kind of game. Would it be possible to write an implementation that would provide acceptable texture resolution for everything from flight sims to first-person shooters? I had no idea if it would work, but I went forward anyway.
    Implementation
    Because both Frictional Games and id had split the terrain into "cells" and used a texture for each section, I tried that approach first. Our terrain already gets split up and rendered in identical chunks, but I needed smaller pieces for the near sections. I adjusted the algorithm to render the nearest chunks in smaller pieces. I then allocated a 2048x2048 texture for each inner section, and used a 1024x1024 texture for each outer section:

    The memory requirements of this approach can be calculated as follows:
    1024 * 1024 * 4 * 12 = 50331648 bytes
    2048 * 2048 * 4 * 8 = 134217728
    Total = 184549376 bytes = 176 megabytes
    176 megs is a lot of texture data. In addition, the texture resolution wasn't even that good at near distances. You can see my attempt with this approach in the image below. The red area is beyond the virtual texture range, and only uses a single low-res baked texture. The draw distance was low, the memory consumption high, and the resolution was too low.

    This was a failure, and I thought maybe this technique was just impractical for anything but very controlled cases in certain games. I wasn't ready to give up yet without trying one last approach. Instead of allocating textures for a grid section, I tried creating a radiating series of textures extending away from the camera:

    The resulting resolution wasn't great, but the memory consumption was a lot lower, and terrain texturing was now completely decoupled from the terrain geometry. I found by adjusting the distances at which the texture switches, I could get a pretty good resolution in the foreground. I was using only three texture stages, so I increased the number to six and found I could get a good resolution at all distances, using just six 1024x1024 textures. The memory consumption for this was just 24 megabytes, a very reasonable number. Since the texturing is independent from terrain geometry, the user can fine-tune the texture distances to accommodate flight sims, RPGs, or whatever kind of game they are making.

    The last step was to add some padding around each virtual texture, so the virtual textures did not have to be complete redrawn each time the camera moves. I used a value of 0.25 the size of the texture range so the various virtual textures only get redrawn once in a while.
    Advantages of Virtual Textures
    First, because the terrain shader only has to perform a few lookups each pixel with almost no math, the new terrain shader runs much faster than the old one. When the bottleneck for most games is the pixel fillrate, this will make Leadwerks 3 games faster. Second, this allows us to use any number of texture layers on a terrain, with virtually no difference in rendering speed. This gives artists the flexibility to paint anything they want on the terrain, without worrying about budgets and constraints. A third advantage is that this allows the addition of "stamps", which are decals rendered directly into the virtual texture. This allows you to add craters, clumps of rocks, and other details directly onto the terrain. The cost of rendering them in is negligible, and the resulting virtual texture runs at the exact same speed, no matter how much detail you pack into it. Below you can see a simple example. The smiley face is baked into the virtual texture, not rendered on top of the terrain:

    Conclusion
    The texture resolution problem I feared might make this approach impossible was solved by using a graduated series of six textures radiating out around the camera. I plan to implement some reasonable default settings, and it's only a minor hassle for the user to adjust the virtual texture draw distances beyond that.
    Rendering the virtual textures dynamically eliminates the high space requirements of id's megatexture technique, and also gets rid of the problems of paging texture data dynamically from the hard drive. At the same time, most of the flexibility of the megatexture technique is retained.
    Having the ability to paint terrain with any number of texture layers, plus the added stamping feature gives the artist a lot more flexibility than our old technique offered, and it even runs faster than the old terrain. This removes a major source of uncertainty from the development of Leadwerks 3.1 and turned out to be one of my favorite features in the new engine.
  11. Josh
    First, I was experiencing some crashes due to race conditions. These are very very bad, and very hard to track down. The problems were being caused by reuse of thread returned objects. Basically, a thread performs some tasks, returns an object with all the processed data, and then once the parent thread is done with that data it is returned to a pool of objects available for the thread to use. This is pretty complicated, and I found that when I switched to just creating a new return object each time the thread runs, the speed was the same as before. So the system is nice and stable now. I tend to be very careful about sharing data between threads and only doing it in a prescribed manner (through a command buffer and using separate objects) and I will continue to use this approach.
    Second, I added a built-in mouselook mode for cameras. You can call Camera::SetFreeLook(true) and get a automatic mouse controls that make the camera look around. I am not doing this to make things easier, I am doing it because it allows fast snappy mouse looking even if your game is running at a lower frequency. So you can run your game at 30 hz, giving you 33 milliseconds for all your game code to complete, but it will feel like 60+ hz because the mouse will update in the rendering thread, which is running at a faster speed. The same idea will be used to eliminate head movement latency in VR.
    Finally, I switched the instance indexes that are uploaded to the GPU from integers to 16-bit unsigned shorts. You can still have up to 131072 instances of a single object, because the engine will store instances above and below 65536 in two separate batches, and then send an integer to the shader to add to the instance index. Again, this is an example of a hard limit I am putting in place in order to make a more structured and faster performing engine, but it seems like the constraints I am setting so far are unlikely to even be noticed.
    Animation is working great, and performance is just as fast as before I started adding it, so things are looking good. Here's a funny picture of me trying to add things to the renderer to slow it down and failing :

    I'm not sure what I will tackle next. I could work on threading the physics and AI, spend some time exploring new graphics options, or implement lighting so that we have a basic usable version of Leadwerks 5 for indoors games. What would you like to see next in the Leadwerks Game Engine 5 Alpha?
  12. Josh
    The latest design of my OpenGL renderer using bindless textures has some problems, and although these can be resolved, I think I have hit the limit on how useful an initial OpenGL implementation will be for the new engine. I decided it was time to dive into the Vulkan API. This is sort of scary, because I feel like it sets me back quite a lot, but at the same time the work I do with this will carry forward much better. A Vulkan-based renderer can run on Windows, Linux, Mac, iOS, Android, PS4, and Nintendo Switch.
    So far my impressions of the API are pretty good. Although it is very verbose, it gives you a lot of control over things that were previously undefined or vendor-specific hacks. Below is code that initializes Vulkan and chooses a rendering device, with a preference for discrete GPUs over integrated graphics.
    VkInstance inst; VkResult res; VkDevice device; VkApplicationInfo appInfo = {}; appInfo.sType = VK_STRUCTURE_TYPE_APPLICATION_INFO; appInfo.pApplicationName = "MyGame"; appInfo.applicationVersion = VK_MAKE_VERSION(1, 0, 0); appInfo.pEngineName = "TurboEngine"; appInfo.engineVersion = VK_MAKE_VERSION(1, 0, 0); appInfo.apiVersion = VK_API_VERSION_1_0; // Get extensions uint32_t extensionCount = 0; vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, nullptr); std::vector<VkExtensionProperties> availableExtensions(extensionCount); vkEnumerateInstanceExtensionProperties(nullptr, &extensionCount, availableExtensions.data()); std::vector<const char*> extensions; VkInstanceCreateInfo createInfo = {}; createInfo.sType = VK_STRUCTURE_TYPE_INSTANCE_CREATE_INFO; createInfo.pApplicationInfo = &appInfo; createInfo.enabledExtensionCount = (uint32_t)extensions.size(); createInfo.ppEnabledExtensionNames = extensions.data(); #ifdef DEBUG createInfo.enabledLayerCount = 1; const char* DEBUG_LAYER = "VK_LAYER_LUNARG_standard_validation"; createInfo.ppEnabledLayerNames = &DEBUG_LAYER; #endif res = vkCreateInstance(&createInfo, NULL, &inst); if (res == VK_ERROR_INCOMPATIBLE_DRIVER) { std::cout << "cannot find a compatible Vulkan ICD\n"; exit(-1); } else if (res) { std::cout << "unknown error\n"; exit(-1); } //Enumerate devices uint32_t gpu_count = 1; std::vector<VkPhysicalDevice> devices; res = vkEnumeratePhysicalDevices(inst, &gpu_count, NULL); if (gpu_count > 0) { devices.resize(gpu_count); res = vkEnumeratePhysicalDevices(inst, &gpu_count, &devices[0]); assert(!res && gpu_count >= 1); } //Sort list with discrete GPUs at the beginning std::vector<VkPhysicalDevice> sorteddevices; for (int n = 0; n < devices.size(); n++) { VkPhysicalDeviceProperties deviceprops = VkPhysicalDeviceProperties{}; vkGetPhysicalDeviceProperties(devices[n], &deviceprops); if (deviceprops.deviceType == VkPhysicalDeviceType::VK_PHYSICAL_DEVICE_TYPE_DISCRETE_GPU) { sorteddevices.insert(sorteddevices.begin(),devices[n]); } else { sorteddevices.push_back(devices[n]); } } devices = sorteddevices; VkDeviceQueueCreateInfo queue_info = {}; unsigned int queue_family_count; for (int n = 0; n < devices.size(); ++n) { vkGetPhysicalDeviceQueueFamilyProperties(devices[n], &queue_family_count, NULL); if (queue_family_count >= 1) { std::vector<VkQueueFamilyProperties> queue_props; queue_props.resize(queue_family_count); vkGetPhysicalDeviceQueueFamilyProperties(devices[n], &queue_family_count, queue_props.data()); if (queue_family_count >= 1) { bool found = false; for (int i = 0; i < queue_family_count; i++) { if (queue_props[i].queueFlags & VK_QUEUE_GRAPHICS_BIT) { queue_info.queueFamilyIndex = i; found = true; break; } } if (!found) continue; float queue_priorities[1] = { 0.0 }; queue_info.sType = VK_STRUCTURE_TYPE_DEVICE_QUEUE_CREATE_INFO; queue_info.pNext = NULL; queue_info.queueCount = 1; queue_info.pQueuePriorities = queue_priorities; VkDeviceCreateInfo device_info = {}; device_info.sType = VK_STRUCTURE_TYPE_DEVICE_CREATE_INFO; device_info.pNext = NULL; device_info.queueCreateInfoCount = 1; device_info.pQueueCreateInfos = &queue_info; device_info.enabledExtensionCount = 0; device_info.ppEnabledExtensionNames = NULL; device_info.enabledLayerCount = 0; device_info.ppEnabledLayerNames = NULL; device_info.pEnabledFeatures = NULL; res = vkCreateDevice(devices[n], &device_info, NULL, &device); if (res == VK_SUCCESS) { VkPhysicalDeviceProperties deviceprops = VkPhysicalDeviceProperties{}; vkGetPhysicalDeviceProperties(devices[n], &deviceprops); std::cout << deviceprops.deviceName; vkDestroyDevice(device, NULL); break; } } } } vkDestroyInstance(inst, NULL);  
  13. Josh
    Shadow maps are now supported in the new Vulkan renderer, for point, spot, and box lights!

    Our new forward renderer eliminates all the problems that deferred renderers have with transparency, so shadows and lighting works great with transparent surfaces. Transparent objects even receive lighting from their back face automatically!

    There is some shadow acne, which I am not going to leave alone right now because I want to try some ideas to eliminate it completely, so you never have to adjust offsets or other settings. I also want to take another look at variance shadow maps, as these can produce much better results than depthmap shadows. I also noticed some seams in the edges of point light shadows.
    Another interesting thing to note is that the new renderer handles light and shadows with orthographic projection really well.

    A new parameter has also been added to the JSON material loader. You can add a scale factor inside the normalTexture block to make normal maps appear bumpier. The default value is 1.0:
    "normalTexture": { "file": "./glass_dot3.tex", "scale": 2.0 } Also, the Context class has been renamed to "Framebuffer". Use CreateFramebuffer() instead of CreateContext().
  14. Josh
    After about four days of trying to get render-to-texture working in Vulkan, I have everything working except...it doesn't work. No errors, no clue what is wrong, but the renderer is not even clearing the depth attachment, which is why the texture read shown here is flat red.

    There's not much else to say right now. I will keep trying to find the magic combination of cryptic obscure settings it takes to make Vulkan do what I want.
    This is very hard stuff, but once I have it working I think that gives me all the functionality I need to finish the Vulkan renderer. Post-processing effects are just another render-to-texture problem. Now, the Vulkan renderer is much more strict than OpenGL, and I think the way post-processing will work is with a an automatically created blur texture and a single post-process shader. It's very wasteful to render a bunch of different passes for each effect, so instead I think we will just have some different effects files and a shader that can include whatever effects you want. In fact, the post-process pass can probably be done as a third Vulkan subpass which would be very efficient.
  15. Josh
    Vulkan gives us explicit control over the way data is handled in system and video memory. You can map a buffer into system memory, modify it, and then unmap it (giving it back to the GPU) but it is very slow to have a buffer that both the GPU and CPU can access. Instead, you can create a staging buffer that only the CPU can access, then use that to copy data into another buffer that can only be read by the GPU. Because the GPU buffer may be in-use at the time you want to copy data to it, it is best to insert the copy operation into a command buffer, so it happens after the previous frame is rendered. To handle this, we have a pool of transfer buffers which are retrieved by a command buffer when needed, then released back into the pool once that command buffer is finished drawing. A fence is used to tell when the command buffer completes its operations.
    One issue we came across with OpenGL in Leadwerks was when data was uploaded to the GPU while it was still being accessed to render a frame. You could actually see this on some cards when playing my Asteroids3D game. There was no mechanism in OpenGL to synchronize memory, so the best you could do was put data transfers at the start of your rendering code, and hope that there was enough of a delay before your drawing actually started that the memory copying had completed. With the super low-overhead approach of Vulkan rendering, this problem would become much worse. To deal with this, Vulkan uses explicit memory management with something called pipeline barriers. When you add a command into a Vulkan command buffer, there is no guarantee what order those commands will be executed in, and pipeline barriers allow you to create a point where certain commands must be executed before other ones can begin.
    Here are the order of operations:
    Start recording new command buffer. Retrieve staging buffer from pool and remove from pool. Copy data into staging buffer. Insert command to copy from staging buffer to the GPU buffer. Insert pipeline barrier to make sure data is transferred before drawing begins. Execute the command buffer. When the fence is completed, move all staging buffers back into the staging buffer pool. In the new game engine, we have several large buffers to store the following data:
    Mesh vertices Mesh indices Entity 4x4 matrices (and other info) A list of visible entity IDs Visible light information. Skeleton animation data I found this data tends to fall into two categories.
    Some data is large and only some of it gets updated each frame. This includes entity 4x4 matrices, skeleton animation data, and mesh vertex and index data. Other data tends to be smaller and only concerns visible objects. This includes visible entity IDs and light information. This data is updated completely each time a new visibility set arrives. The first type of data requires data buffers that can be resized, because they can be very large, and more objects or data might be added at any time. For example, the vertex buffer contains all vertices that exist, in all meshes the user creates or loads. If a new mesh is loaded that requires space greater than the buffer capacity, a new buffer must be created, then the full contents of the old buffer are copied over, directly in GPU memory. A new pipeline barrier is inserted to ensure the data transfer to the new buffer is finished, and then additional data is copied.
    The second type of data is a bit simpler. If the existing buffer is not big enough, a new bigger buffer is created. Since the entire contents of the buffer are uploaded with each new visibility set, there is no need to copy any existing data from the old buffer.
    I currently have about 2500 lines of Vulkan-specific code. Calling this "boilerplate" is disingenuous, because it is really specific to the way you set your renderer up, but the core mesh rendering system I first implemented in OpenGL is working and I will soon begin adding support for textures.
     
  16. Josh
    Now that we have lights working in our clustered forward Vulkan renderer (same great technique the latest DOOM games are using) I am starting to implement shadow maps. The first issue that came up was managing render-to-texture when the texture might still be in use rendering the previous frame. At first I thought multiple shadowmaps would be needed per light, like a double-buffering system, but that would double the number of shadow textures and video memory. Instead, I created a simple object pool which stores spare shadowmaps that can be swapped around and used as they are needed.
    It turns out I already have pretty much all the code I need because Vulkan's swapchain creation works exactly the same way, by rendering to a series of images. I worked through the code slowly and came up with this by the end of the day, which runs successfully without throwing any validation errors:
    bool RenderBuffer::Initialize(shared_ptr<RenderContext> context, const int width, const int height, const int depth, const int colorcomponents, const bool depthcomponent, const int samples) { this->device = GameEngine::Get()->renderingthreadmanager->instance; int totalcomponents = colorcomponents; if (depthcomponent) totalcomponents++; std::fill(colortexture.begin(), colortexture.end(), nullptr); depthtexture = nullptr; //Create color images for (int i = 0; i < colorcomponents; ++i) { colortexture[i] = make_shared<RenderTexture>(); colortexture[i]->Initialize(VK_IMAGE_TYPE_2D, device->chaininfo.imageFormat, width, height, 1, 0, false, -1,-1,-1,-1,1, VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT); colorimages[i] = colortexture[i]->vkimage; } //Create depth image if (depthcomponent) { depthtexture = make_shared<RenderTexture>(); depthtexture->Initialize(VK_IMAGE_TYPE_2D, device->depthformat, width, height, 1, samples, false, -1, -1, -1, -1, 1, VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT); } //Create image views imageviews.resize(totalcomponents); VkImageViewCreateInfo createInfo = {}; createInfo.sType = VK_STRUCTURE_TYPE_IMAGE_VIEW_CREATE_INFO; createInfo.viewType = VK_IMAGE_VIEW_TYPE_2D; createInfo.components.r = VK_COMPONENT_SWIZZLE_IDENTITY; createInfo.components.g = VK_COMPONENT_SWIZZLE_IDENTITY; createInfo.components.b = VK_COMPONENT_SWIZZLE_IDENTITY; createInfo.components.a = VK_COMPONENT_SWIZZLE_IDENTITY; createInfo.subresourceRange.baseMipLevel = 0; createInfo.subresourceRange.levelCount = 1; createInfo.subresourceRange.baseArrayLayer = 0; createInfo.subresourceRange.layerCount = 1; // Create color image views for (size_t i = 0; i < colorcomponents; i++) { createInfo.image = colorimages[i]; createInfo.format = device->chaininfo.imageFormat; createInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT; VkAssert(vkCreateImageView(device->device, &createInfo, nullptr, &imageviews[i])); } //Create depth image view if (depthcomponent) { createInfo.image = depthtexture->vkimage; createInfo.format = depthtexture->format; createInfo.subresourceRange.aspectMask = VK_IMAGE_ASPECT_DEPTH_BIT; VkAssert(vkCreateImageView(device->device, &createInfo, nullptr, &imageviews[colorcomponents])); } //Create framebuffer VkFramebufferCreateInfo framebufferInfo = {}; framebufferInfo.sType = VK_STRUCTURE_TYPE_FRAMEBUFFER_CREATE_INFO; framebufferInfo.renderPass = device->renderpass->pass; framebufferInfo.attachmentCount = 2; framebufferInfo.pAttachments = imageviews.data(); framebufferInfo.width = width; framebufferInfo.height = height; framebufferInfo.layers = 1; VkAssert(vkCreateFramebuffer(device->device, &framebufferInfo, nullptr, &framebuffer)); return true; } The blog cover image isn't the Vulkan renderer, I just found a random image of Leadwerks shadows.
  17. Josh
    I am experimenting with a system for creating a sequence of actions using Lua coroutines. This allows you to define a bunch of behavior at startup and let the game just run without having to keep track of a lot of states.
    You can add coroutines to entities and they will be executed in order. The first one will complete, and then the next one will start.
    A channel parameter allows you to have separate stacks of commands so you can have multiple sequences running on the same object. For example, you might have one channel that controls entity colors while another channel is controlling position.
    function Script:Start() local MotionChannel = 0 local ColorChannel = 1 local turnspeed = 1 local colorspeed = 3 --Rotate back and forth at 1 degree / second self:AddCoroutine(MotionChannel, ChangeRotation, 0, 45, 0, turnspeed) self:AddCoroutine(MotionChannel, ChangeRotation, 0, -45, 0, turnspeed) self:LoopCourtines(MotionChannel)--keeps the loop going instead of just running once --Flash red and black every 3 seconds self:AddCoroutine(ColorChannel, ChangeColor, 1, 0 , 0, 1, colorspeed) self:AddCoroutine(ColorChannel, ChangeColor, 0, 0, 0, 1, colorspeed) self:LoopCourtines(ColorChannel)--keeps the loop going instead of just running once end There's no Update() function! Where do the coroutine functions come from? These can be in the script itself, or they can be general-use functions loaded from another script. For example, you can see an example of a MoveToPoint() coroutine function in this thread.
    The same script could be created using an Update function but it would involve a lot of stored states. I started to write it out actually for this blog, but then I said "ah screw it, I don't want to write all that" so you will have to use your imagination.
    Now if you can imagine a game like the original Warcraft, you might have a script function like this that is called when the player assigns a peasant to collect wood:
    function Script:CollectWood() self:ClearCoroutines(0) self:AddCoroutine(0, self.GoToForestAndFindATree) self:AddCoroutine(0, self.ChopDownTree) self:AddCoroutine(0, self.GoToCastle) self:AddCoroutine(0, self.Wait, 6000) self.AddCoroutine(0, self.DepositWood, 100) self:LoopCoroutines(0) end I wonder if there is some way to create a sub-loop so if the NPC gets distracted they carry out some actions then return to the sequence they were in before, at the same point in the sequence.
    Of course this would work really well for cutscenes or any other type of one-time sequence of events.
  18. Josh
    A new beta is available. In this build I cleaned up a lot of internal stuff. I removed some parts of the engine that I want to redesign in order to clean up the source.
    JSON material files loaded from MDL files are now supported.
    Added ActiveWindow() command. if the game window is not the foreground window this will return null.
    The Steamworks and all dependent classes are temporarily removed. There's a lot of stuff in there I don't intend to use in the future like all the Workshop functions, and I want to reintegrate it one piece at a time in a neater fashion. The good features like P2P networking will definitely be included in the future.
    File IO finished
    The file read and write commands are now 100% using global functions and internally using Unicode strings. You can still call functions with a regular std::string but internally it will just convert it to a wide string. The zip file read support is removed temporarily so I can rethink its design.
    Key and mouse event binding
    Since I am consciously making the decision to design the new engine for intermediate and expert users instead of beginners, it occurred to me that the MouseHit and KeyHit functions are flawed, since they rely on a global state and will cause problems if two pieces of code check for the same key or button. So I removed them and came up with this system:
    self:BindKey(KEY_E,self.Interact) self:BindKey(KEY_SPACE,self.Jump) self:BindMouseButton(MOUSE_LEFT,self.Throw) This works exactly as you would expect, by calling the entity script function when the key or mouse button is pressed. Naturally a key release event would also be useful. Perhaps a BindKeyRelease() function is the best way to do this? The KeyDown() / MouseDown() functions are still available, since they do not have the problems the Hit() commands do. The same technique will work with C++ actors though it is not yet implemented.
    This is undoubtedly more complicated than a simple MouseHit() command but it is better for people as their code gets more complex. Instead of hurting the experience for advanced users, I am going to force beginners to adjust to the correct way of doing things.
    This design is not final. I think there are other ways programmers might want to bind events. I would like to hear your ideas. I am willing to create a more complicated system if it means it is more useful. This is a big change in my idea of good design.
  19. Josh
    This is a good time to write about some very broad changes I expect to come about over the next year in our community as our new engine "Turbo" arrives. Turbo Game Engine, as the name suggests, offers really fast performance using a groundbreaking Vulkan-based renderer, which is relevant to everyone but particularly beneficial for VR developers who struggle to keep their framerates up using conventional game engines. I want to help get you onboard with some of the ideas that I myself am processing.
    Less emphasis on how-to tutorials, more emphasis on API documentation
    The new engine assumes you are either an artist or a programmer, and if you are a programmer you already know basic C++ or Lua. More attention will be paid to precisely documenting how commands behave. There will be a more strict division between supported and unsupported features. There will be less "guessing" what the user is trying to do, and more formal documentation saying "if you do X then Y will occur". For example, every entity creation function requires the world object be explicitly supplied in the creation command, instead of hiding this away in a global state. There will not be tutorials explaining what a variable is or teaching basic programming concepts.
    More responsiveness to user requests, especially for programming features
    Leadwerks 4 features have been in a semi-frozen state for a while now. Although many new features have been added, I have not wanted to create breaking changes, and have been reluctant to introduce things that might create new bugs, because I knew an entire new infrastructure for future development was on the way. With the new engine I will be more receptive to suggestions that make the engine better. One example would be an animation events system that lets users set a point in an animation where an event is called. These changes need to be implemented within the design philosophy of the new engine. For example, I would use an Actor class method to call the event function rather than a raw pointer. Emphasis should be placed on what is practical and useful for competent programmers and artists, and how everything fits into the overall design.
    Less attempts at hand-holding for new developers
    The new engine will not attempt to teach children to make their own MMORPG. Our marketing materials will not even suggest this is possible. The new engine will deliver performance faster than any other game engine in the world, period. Consequently, I think the community will gain a lot more advanced users, and though some of them will not even interact on the forum I do think you will see more organic creativity and quality. In its own way, the new engine actually is quite a lot easier to work with, but the sales pitch is not going to emphasize that, it will just be something people discover as they use it. I love seeing all the weird and cool creations that comes from people who are completely new to game development, but those people were new to game development and did well with Leadwerks had a lot of natural talent. Instead of trying to come up with a magic combination of features and tutorials to turn novices into John Carmack, we are going to rely on the product benefits to draw them and expect them to get up to speed quickly. Discussions should be about what is best for intermediate / experts, not trying to figure out what beginners want. Ease of use is subjective and I feel we have hit the point of diminishing returns chasing after this. If beginners want to jump in and learn that is great, but it is not our reason for existing.
    Stronger focus on the core essentials
    At the time of this writing, there are only eight entity types in the beta of the new engine. We can't win based on number of features, but we can do the core essentials much better than anyone else. Our new Vulkan renderer offers performance that developers (especially VR) can't live without. Models, lights, and rendering are the core features I want to focus on, and these can be expanded by the end user to create their own. For example, a custom particle system with support for all kinds of behaviors could easily be created with the model class and a few custom shaders, without breaking the performance that makes this engine valuable. Our new technology is very well thought out and will give us a stable base for a long time. I am planning on a plugin / extensions system because its best for this to be integrated in the core design, but you should not expect this to be very useful for a couple of years. Plugin systems require huge network effects to offer anything valuable. We can only reach that type of scale by offering something else unique that no one can match us on. Fortunately, we have something. It's right in the name.
    More formal support for good standards
    Vulkan has turned out to be a very good move. I don’t think anyone realizes how big a deal GLTF support is yet: you can download thousands of models from Sketchfab and other sources and load them right now with no adjustments. I may join the Khronos consortium and I have some ideas for additional useful GLTF extensions. I'm using JSON for a lot of files and it's great. DDS will be our main texture file format. There are more good standards today than there were ten years ago, and I will adopt the ones that fit our goals.
    Different type of new user appearing
    With Leadwerks, the average new user appears on the forum and says “hey, I want to make a game but I don’t really know how, please tell me what I need to know.” With the new engine I think it will be more like “hey, I’m more or less an expert already, I know exactly what I want to make, please tell me what I need to know.” I expect them to have less tolerance for bugs, undefined behavior, or undocumented features, and at the same time I think it will be easier to have frank discussions about exactly what developers need.
    In very general terms that is how I want to focus things. I think everyone here will adjust to this more strict and well-defined approach and end up liking it a lot better.
  20. Josh
    It's always fun when I can do something completely new that people have never seen in a game engine. I've had the idea for a while to create a new light type for light strips, and I got to implement this today. The new engine has taken a tremendous amount of effort to get working over two years, but as development continues I think I will become much more responsive to your suggestions since we have a very strong foundation to build on now.
    Using this test scene provided by @reepblue you can see how this new light type looks and behaves. They are great for placing along walls, but what really made me interested was the idea to calculate specular lighting not from a single point, but with a different way. I thought if I could figure out the math I would get a realistic reflection on the ground, and it worked!

    The reflection on the floor is actually the specular component of the light. We are used to thinking of specular reflections as a little white circle that moves around, but the light doesn't have to be coming from a single point. Some calculations in the shader can be used to determine the closest point to the light strip and use that for reflections. The net effect is that a long bar appears on the floor, matching the length of the light. This is not a screen-space effect or a cubemap. When you look down at the floor the specular component is still there shining back at you. Every surface is using the same exact equation, but it appears very different on the walls, the ceiling, and the floor due to the different angles.

    Even a surface facing opposite the light will correctly reflect it back to the camera.

    In this image, I created a small green strip light that looks like a laser. There is no visible laser beam, but if there was it would appear above the soft green lighting. The hard line on the ground is actually the specular reflection of the light. You can see it reflecting off the sphere as well.

    The new Vulkan renderer also supports box lights, which are a directional light with a defined boundary, and I have an idea for one more type of light.
  21. Josh
    A new update is available for beta subscribers.
    What's new
    Added support for strip lights. To create these just call CreateLight(world, LIGHT_STRIP). The entity scale on the Z axis will determine the length of the line, and the outer range will determine the radius in which light shows. Added new properties to the JSON material scheme. "textureScroll" is a float value that can animate a texture to make it smoothly move. "textureScrollRotation" is an angle to control which direction the texture moves. An example material is included. Renamed "albedoMap", "normalMap", "emissionMap", "displacementMap", and "brdfMap" to "baseTexture", "normalTexture", "emissionTexture", "displacementTexture", and "brdfTexture" in JSON material scheme.
  22. Josh
    A new update is available for beta subscribers. Transparent materials are now supported. Unlike the old deferred renderer, our new clustered forward renderer supports transparency really really well! You can add these in a JSON material file with a Boolean property called "transparent" set to true:
    "transparent": true There are no separate blend modes now, since pre-multiplied alpha allows alpha and additive blending in a single pass. This is actually a really simple technique but for some reason all the information about it online are these horrible academic examples that don't show any clear benefit. It wasn't until I thought "how do I make shiny glass?" that I actually started looking for a way to do this.
    The command Material::SetTransparent(true) replaces the old SetBlendMode(blendmode) function. GLTF materials with blending will be automatically loaded. Per-object Z-sorting is not yet supported, but transparent groups of objects will always be rendered on top of opaque objects automatically, so you don't actually need to enable sorting if you don't expect to have two layers of transparency visible anywhere..

    We haven't seen a lot of transparency in games since the mid-2000s, because at the time deferred rendering was the best lighting technique. I think the capabilities of our new renderer will open up a lot of possibilities to create games that look different from anything in the past.
    You can get access to the beta and private forum right now for just $5.
  23. Josh
    An update for the beta of the new engine is now available with the following changes:
    GLTF loader is now working for most models. A large collection of GLTF files are available online for free from many sources, and they can be loaded right into the engine without any adjustment for materials or textures. Single-file GLB files also work. Added support for GLTF extension KHR_materials_pbrSpecularGlossiness. Disabled PNG loader gamma correction. world->SetSkybox(texture) can now be used to make PBR reflections appear. (The sky will not yet be visible though.) I'm going to try to use a voxel GI system for further reflections, and not use environment probes at all. Window::GetWidth(), Window::GetHeight(), Context::GetWidth(), and Context::GetHeight() are removed. Use GetSize() instead. It will return an iVec2 object with x and y components. JSON material files are changed slightly. in order to accommodate additional per-texture settings. None of these work yet, but you can see where it is going: "albedoMap": { "file": "./Rough-rockface1_Base_Color.jpg", "filter": "linear", "tilingU": "repeat", "tilingV": "repeat" }, So before if you had this:
    "albedoMap": "./Rough-rockface1_Base_Color.jpg" Just change it to this:
    "albedoMap": {"file": "./Rough-rockface1_Base_Color.jpg"} And then it will work.
    The screenshot below is a GLTF loaded and rendered with Vulkan. Note that this model uses baked lighting that is already included in the model. But the fact I can download these things and have them appear correctly with no adjustments is great.

    You can get access to the beta and private forum right now for just $5.
  24. Josh
    A new beta update is available for subscribers. What's new?
    Lighting
    Point and spot lights are now supported in the new Vulkan renderer, with either PBR or Blinn-Phong lighting. Lighting is controlled by the shader in the material file. There are two main shaders you can use, "Shaders/PBR.spv" and "Shaders/Blinn-Phong.spv". See below for more details.

    JSON Materials
    Materials can now be loaded from JSON files. I am currently using the .json file extension instead of "mat", "mtl", or something else. If you load a scene and a JSON file is available with the same name as a material in that scene, the material will be loaded from a JSON file instead of the Leadwerks 4 .mat files. For example, you can create a JSON file named "brick01.json", place it in the same folder as "brick01.mat" and the new engine will load the JSON material if the brick material is used in a scene. However, it is not necessary to do this as the engine can also load Leadwerks 4 material files.
    A Turbo JSON material file looks like this. The string tokens are more or less locked in now and it is safe to start using them.
    { "turboMaterialDef": { "color": [ 1, 1, 1, 1 ], "emission": [ 0, 0, 0 ], "metallic": 0, "roughness": 0.6, "doubleSided": false, "blend": false, "albedoMap": "./concrete_clean_diff.tex", "normalMap": "./concrete_clean_dot3.tex", "metallicRoughnessMap": "", "emissionMap": "", "baseShader": "Shaders/PBR.spv", "shadowShader": "Shaders/Shadow.spv", "depthShader": "Shaders/DepthPass.spv" } } You can also indicate a shader for the new engine to use in an old Leadwerks 4 material file by adding a text line like this to the .mat file:
    baseshader="Shaders/myshader.spv" You do not need to specify a shader unless you are using a custom shader. JSON material files, by default, will use the PBR shader. Leadwerks 4 material files, by default, will use the Blinn-Phong shader.
    BC5 / BC7 Texture Compression
    A ton of new compression formats have been added, including the BC7 and BC5 formats, which provide better quality than DXT compression. Visual Studio 2019 actually has some good built-in DDS tools, although the BC7 compressor Is very slow. A sample material is provided using DDS textures (see "Materials/Rough-rockface1.json").
    Lua Commands
    A set of simple global Lua commands has been added.
    template<typename T> void LuaSetGlobal(const std::string& name, T var) template<typename T> void LuaPushObject(const std::string& name, T var) template<typename T> T LuaToObject(const int index = -1) int LuaCollectGarbage(const int what = LUA_GCCOLLECT, const int data = 0); void LuaPushString(const std::string& s); void LuaPushNumber(const double n); void LuaPushBoolean(const bool b); void LuaPushNil(); void LuaPushValue(const int index = -1); bool LuaIsTable(const int index = -1); bool LuaIsNumber(const int index = -1); bool LuaIsString(const int index = -1); bool LuaIsBoolean(const int index = -1); bool LuaIsObject(const int index = -1); bool LuaIsNil(const int index = -1); bool LuaIsFunction(const int index = -1); bool LuaToBoolean(const int index = -1); std::string LuaToString(const int index = -1); double LuaToNumber(const int index = -1); int LuaType(const int index = -1); int LuaGetField(const std::string& name, const int index = -1); int LuaGetTable(const std::string& name, const int index = -1); int LuaGetGlobal(const std::string& name); void LuaSetField(const std::string& name, const int index = -1); void LuaSetTable(const int index = -1); void LuaPop(const int levels = 1); void LuaRemove(const int index = -1); void LuaSetStackSize(const int sz); int LuaGetStackSize(); void LuaNewTable(); This makes our code simpler and more readable:
    #include "Turbo.h" using namespace Turbo; int main(int argc, const char *argv[]) { //Create a window auto window = CreateWindow("MyGame", 0, 0, 1280, 720); //Create a rendering context auto context = CreateContext(window); //Set some variables in the script environment LuaSetGlobal("mainwindow", window); LuaSetGlobal("maincontext", context); //Create the world auto world = CreateWorld(); //Load a scene auto scene = LoadScene(world, "Maps/start.map"); //Show off a PBR material auto sphere = CreateSphere(world); auto mtl = LoadMaterial("Materials/Rough-rockface1.json"); sphere->SetMaterial(mtl); sphere->Move(0, 1, 0); sphere->SetScale(2); while (window->KeyHit(KEY_ESCAPE) == false and window->Closed() == false) { world->Update(); world->Render(context); } return 0; } You can gain access to the beta and support development by subscribing for just $5.
  25. Josh
    The Vulkan renderer now supports new texture compression formats that can be loaded from DDS files. I've updated the DDS loader to support newer versions of the format with new features.
    BC5 is a format ATI invented (originally called ATI2 or 3Dc) which is a two-channel compressed format specifically designed for storing normal maps. This gives you better quality normals than what DXT compression (even with the DXT5n swizzle hack) can provide.
    BC7 is interesting because it uses the same size as DXT5 images but provides much higher quality results. The compression algorithm is also very long, sometimes taking ten minutes to compress a single texture!  Intel claims to have a fast-ish compressor for it but I have not tried it yet. Protip: You can open DDS files in newer versions of Visual Studio and select the compression format there.
    Here is a grayscale gradient showing uncompressed, DXT5, BC7 UNORM, and BC7 SNORM formats. You can see BC7 UNORM and SNORM have much less artifacts than DXT, but is not quite the same as the original image.





    The original image is 256 x 256, giving the following file sizes:
    Uncompressed: 341 KB DXT1: 42.8 KB (12.6% compression) DXT5, BC7: 85.5 KB (25% compression) I was curious what would happen if I zipped up some of the files, although this is only a minor concern. I guess that BC7 would not work with ZIP compression as well, since it is a more complicated algorithm.
    DXT5: 16.6 KB BC7 UNORM: 34 KB BC7 SNORM: 42.4 KB Based on the results above, I would probably still use uncompressed images for skyboxes and gradients, but anything else can benefit from this format. DXT compression looks like a blocky green mess by comparison.
    I was curious to see how much of a difference the BC5 format made for normal maps so I made some similar renders for normals. You can see below that the benefits for normal maps are even more extreme. The BC5 compressed image is indistinguishable from the original while the DXT5n image has clear artifacts.



    In conclusion, these new formats in the Vulkan renderer, when used properly, will provide compression without visible artifacts.
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