By Chris Vossen in Chris Vossen's Development Blog 6There 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:
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
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 2DPI 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 2Previously 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:
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.