Jump to content

Say Hello to Leadwerks 5 Shared Objects

Josh

1,187 views

All classes in Leadwerks are derived from a base Object class.  In Leadwerks 5 we separate simple and complex objects with the new SharedObject class.

Simple objects like a Vec3 ( a three-dimensional vector), an AABB (axis-aligned bounding box), and other items are all derived from the Object class.  Simple objects are created with constructors.  When we make one object equal to another the value is copied from one variable to another, but the two variables are still separate objects.  Below, A and B have the same value but are separate objects:

Vec3 a = Vec3(1,2,3);
Vec3 b = a;

Shared objects are things you don't want to copy, because they involve more than just some numbers.  These always use C++11 shared pointers and use a Create function.  Below, A and B refer to the same object:

shared_ptr<World> a = CreateWorld();
shared_ptr<World> b = a;

The SharedObject class has a couple of functions to make life easier.  Instead of casting pointers with some funny syntax we can use the Cast() method.  Here's an example of casting in Leadwerks 4:

Entity* entity = Model::Load("car.mdl");
Model* model = (Model*)entity;

And here's how it works in Leadwerks 5:

shared_ptr<Entity> entity = LoadModel("car.mdl");
shared_ptr<Model> model = entity->Cast<Model>();

Instead of using "this" inside a class method you can use Self() to get a shared pointer to the object itself:

class MyActor : public Actor
{
	void MyFunction()
	{
		//MyActor* me = this;
		shared_ptr<SharedObject> me = Self();
	}
}

Self() will always return a shared_ptr<SharedObject> value, so you can use Cast() if you need a specific type of object (and match the behavior of "this"):

class MyActor : public Actor
{
	void MyFunction()
	{
		//MyActor* me = this;
		shared_ptr<MyActor> me = Cast<MyActor>();
	}
}

Instead of calling delete or Release to destroy a shared object, all you have to do is set its variable to NULL:

shared_ptr<Model> model = LoadModel("car.mdl");
model = NULL;// poof!

And of course we can always use the auto keyword to make things really simple:

auto model = LoadModel("car.mdl");

Shared objects use automatic reference counting to give you the ease of use of a garbage-collected language, together with the blazing performance of modern C++.  These features are set to make Leadwerks Game Engine 5 the easiest and most cutting-edge development system in the history of game programming.



7 Comments


Recommended Comments

Quote

almost easier to use c++ now

I would imagine LUA is now being maintained only for backwards compatibility. It would still be advantageous to have LUA, obviously. I just don't think it should be the primary language for the engine's creative environment. Then again marketing the engine with LUA as its primary language bids well to the newbies.

I'm really happy to see the upgrades though, this engine will be super accessible and flexible to use in the near future.

Share this comment


Link to comment
On 9/16/2017 at 3:30 PM, jen said:

I would imagine LUA is now being maintained only for backwards compatibility. It would still be advantageous to have LUA, obviously. I just don't think it should be the primary language for the engine's creative environment. Then again marketing the engine with LUA as its primary language bids well to the newbies.

I'm really happy to see the upgrades though, this engine will be super accessible and flexible to use in the near future.

Lua will continue to be important because it is super convenient for entity scripts, and it's great for beginners.  Our implementation in Leadwerks 5 will work with shared pointers which will make everything a lot easier to manage.  With C++ in Leadwerks you have automatic reference counting that does everything except catch circular references.  Lua garbage collection is slower so I don't recommend it for VR or intensive code routines, but it does catch circular references.

Share this comment


Link to comment

Plus I believe you said some time ago that the vast majority of your customers are using Lua, not C++ (it was some high number like 90%).  I imagine that hasn't changed much since.

Share this comment


Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Add a comment...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Blog Entries

    • By Chris Vossen in Chris Vossen's Development Blog 6
      There are two types of days here at Leadwerks; days that we work and those that we werk. On werk days we hunker down at our desks, cups of caffeine in hand, and code (Unless you’re thinking… or pretending to think). Then there are work days, on these days we focus on business development: researching, planning, and occasionally field trips. So to kick off our intern hunt members of Leadwerks grabbed their sack lunches, kissed their monitors farewell, and ventured over to the Sacramento State University for some high octane presentations!
       



       
      These action packed presentations were given to students in both a game architecture course and a 3D modeling class, focusing on highlighting our four new internship openings:
       

      Programming Internship


      Assist the development team with core engine design
      Work with game development team to create a sample Leadwerks3D game
      Gain experience working in a professional software development environment
      C++ and Lua experience are a plus but not required

       

      3D Art internship


      Become proficient with the Leadwerks3D design tools
      Provide feedback to the development team to improve the art pipeline
      Assist game development team by producing 3D models, textures, animations, and game levels

       

      Web Development Internship


      Work with marketing to enhance our online identity
      Develop social features for our online community of game developers
      Foster online community relations

       

      Marketing Internship


      Author promotional materials for website, press releases, and newsletters
      Interact with the development team to communicate technical information to the public
      Enhance and promote our unique company brand

       
      We had a wonderful reception and have received an outpour of interest. The trip was well worth leaving our keyboards neglected for one day. A special thanks to everyone at Sac State and with any luck the Leadwerks intern family may be growing in the future!
    • By Josh in Josh's Dev Blog 2
      DPI scaling and the 2D drawing and GUI system were an issue I was a bit concerned about, but I think I have it worked out. This all goes back to the multi-monitor support that I designed back in September. Part of that system allows you to retrieve the DPI scale for each display. This gives you another piece of information in addition to the raw screen resolution. The display scale gives you a percentage value the user expects to see vector graphics at, with 100% being what you would expect with a regular HD monitor. If we scale our GUI elements and font sizes by the display scale we can adjust for screens with any pixel density.
      This shot shows 1920x1080 fullscreen with DPI scaling set to 100%:

      Here we see the same resolution, with scaling set to 125%:

      And this is with scaling set to 150%:

      The effect of this is that if the player is using a 4K, 8K, or any other type of monitor, your game can display finely detailed text at the correct size the user expects to see. It also means that user interfaces can be rendered at any resolution for VR.
      Rather than trying to automatically scale GUI elements I am giving you full control over the raw pixels. That means you have to decide how your widgets will be scaled yourself, and program it into the game interface, but there is nothing hidden from the developer. Here is my code I am working with now to create a simple game menu. Also notice there is no CreatePanel(), CreateButton(), etc. anymore, there is just one widget you create and set the script for. I might add an option for C++ actors as well, but since these are operating on the main logic thread there's not really a downside to running the code in Lua.
      local window = ActiveWindow() if window == nullptr then return end local framebuffer = window:GetFramebuffer() if framebuffer == nil then return end self.gui = CreateGUI(self.guispritelayer) --Main background panel self.mainpanel = CreateWidget(self.gui,"",0,0,framebuffer.size.x,framebuffer.size.y) self.mainpanel:SetScript("Scripts/GUI/Panel.lua", true) local scale = window.display.scale.y local w = 120 local h = 24 local sep = 36 local x = framebuffer.size.x / 6 local y = framebuffer.size.y / 2 - sep * 3 self.resumebutton = CreateWidget(self.mainpanel,"RESUME GAME",x,y,w,h) self.resumebutton:SetScript("Scripts/GUI/Hyperlink.lua", true) self.resumebutton:SetFontSize(14 * window.display.scale.y) y=y+sep*2 self.label2 = CreateWidget(self.mainpanel,"OPTIONS",x,y,w,h) self.label2:SetScript("Scripts/GUI/Hyperlink.lua", true) self.label2:SetFontSize(14 * window.display.scale.y) y=y+sep*2 self.quitbutton = CreateWidget(self.mainpanel,"QUIT", x,y, w,h) self.quitbutton:SetScript("Scripts/GUI/Hyperlink.lua", true) self.quitbutton:SetFontSize(14 * window.display.scale.y) w = 400 * scale h = 550 * scale self.optionspanel = CreateWidget(self.mainpanel,"QUIT", (framebuffer.size.x- w) * 0.5, (framebuffer.size.y - h) * 0.5, w, h) self.optionspanel:SetScript("Scripts/GUI/Panel.lua", true) self.optionspanel.color = Vec4(0.2,0.2,0.2,1) self.optionspanel.border = true self.optionspanel.radius = 8 * scale self.optionspanel.hidden = true  
    • By Josh in Josh's Dev Blog 2
      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.
×
×
  • Create New...