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Learn about game development technology

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Website Changes

I want to streamline some of this website. We went through a lot of changes since the release on Steam in 2014 and learned what works and what does not. The "Marketplace" is just called the default "Downloads" name now, and that literally is what it is for. It's a place to keep a permanent copy of your files. Paid files are still supported, and any purchased items are still available to download, but I do not have any aspirations of building this up unless it just happens spontaneously. Ins

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Final Thoughts on Ultra App Kit

Breaking the new engine up into sub-components and releasing them in several stages is something new. The reason for trying this was twofold: Steam now incentives competition for digital shelf space, unlike when Leadwerks was first released on Steam in 2014, when I was trying to build up my quality of presence and promote one app ID on Steam. I would like to get some new software out early before the full engine is finished. The beautiful thing is that Ultra App Kit all con

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Project Launch Settings and Mod Support

The new editor is being designed to be flexible enough to work with any game, so it can be used for modding as well as game development with our new 3D engine. Each project has configurable settings that can be used to handle what the editor actually does when you run the game. In the case of a game like Quake, this will involve running a few executables to first compile the map you are working on into a BSP structure, then perform lightmaps and pre-calculate visibility. You can also

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AI-powered Texture Generation in Ultra Engine

Not long ago, I wrote about my experiments with AI-generated textures for games. I think the general consensus at the time was that the technology was interesting but not very useful in its form at the time. Recently, I had reason to look into the OpenAI development SDK, because I wanted to see if it was possible to automatically convert our C++ documentation into documentation for Lua. While looking at that, I started poking around with the image generation API, which is now using DALL-E 2. Ste

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GPU Voxel Downsampling with Compute Shaders

For downsampling of GI voxel data, I found that a compute shader offers the best performance. The first step was to add support for compute shaders into Ultra Engine.  I've never used these before but I was able to get them working pretty quickly. I think the user API will look something like this: //Load compute shader auto module = LoadShaderModule("Shaders/Compute/test.comp.spv"); auto shader = CreateShader(); shader->SetModule(module, SHADER_COMPUTE); //Create work group int wor

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A First Look at the New Editor

I've been wracking my brain trying to decide what I want to show at the upcoming conference, and decided I should get the new editor in a semi-workable state. I started laying out the interface two days ago. To my surprise, the whole process went very fast and I discovered some cool design features along the way. With the freedom and control I have with the new user interface system, I was able to make the side panel extend all the way to the top and bottom of the window client area. This g

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Sparse Voxel Octrees

Previously I noted that since Voxel global illumination involves calculation of direct lighting, it would actually be possible to do away with shadow maps altogether, and use voxels for direct and global illumination. This can eliminate the problems of image-based shadows like shadow acne and adjusting the shadow map size. I also believe this method will turn out a lot faster than shadow map rendering, and you know how I like fast performance.  The sparse voxel octree node structure consume

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Global Illumination with Voxel Cone Step Tracing

Finally, finally, finally, finally, for the first time since I started working on this feature several years ago, finally we have real-time global illumination with a second light bounce: Below you can see the direct light hitting the floor, bounding up to the ceiling, and then being reflected back down on the floor again. Performance is still good and I have not started fine-tuning optimization yet. I was just trying to get the effect working at all, which was quite difficult to do,

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Real-time Global Illumination: Introducing Latency

Since previously determining that voxels alone weren't really capable of displaying artifact-free motion, I have been restructuring the GI system to favor speed with some tolerance for latency. The idea is that global illumination will get updated incrementally in the background over the course of a number of frames, so the impact of the calculation per frame is small. The new GI result is then smoothly interpolated from the old one, over a period of perhaps half a second. Here's a shot of the r

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Building a single-file 4K HDR skybox with BC6 compression

HDR skyboxes are important in PBR rendering because sky reflections get dampened by surface color. It's not really for the sky itself, but rather we don't want bright reflections to get clamped and washed out, so we need colors that go beyond the visible range of 0-1. Polyhaven has a large collection of free photo-based HDR environments, but they are all stored in EXR format as sphere maps. What we want are cubemaps stored in a single DDS file, preferably using texture compression. We'

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Shadow Filtering

Happy Friday! I am taking a break from global illumination to take care of some various remaining odds and ends in Ultra Engine. Variance shadow maps are a type of shadowmap filter technique that use a statistical sample of the depth at each pixel to do some funky math stuff. GPU Gems 3 has a nice chapter on the technique. The end result is softer shadows that run faster. I was wondering where my variance shadow map code went, until I realized this is something I only prototyped in OpenGL a

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GPU Voxelization

After testing and some discussion with other programmers, I decided to try performing voxelization on the GPU instead of the CPU. The downside is the memory usage is much higher than a sparse voxel octree, but I found that sparse voxel octrees were very slow when it came to soft reflections, although the results of the sharp raycast were impressive: You can read the details of GPU voxelization here if you wish. Initially I thought the process would require rendering the

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Ultra Engine Compatibility with Leadwerks Game Engine

As the first release of Ultra Engine approaches, it seems clear that the best way to maximize its usefulness is to make it as compatible as possible with the Leadwerks game engine. To that end, I have implemented the following features. Native Loading of Leadwerks File Formats Ultra Engine loads and saves DDS, glTF, and OBJ files. Other formats are supported by plugins, both first and potentially third-party, for PNG, JPG, BMP, TGA, TIFF, GIF, HDR, KTX2, and other files. Additionally,

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Ultra App Kit beta updated with DPI scaling support

An update for Ultra App Kit beta on Steam is now available. This finishes the user interface scaling to support HD, 4K, 8K, and other resolutions. My original plan was to force an application restart if the scale setting was changed, but I found a way to dynamically resize the interface in a manner that gives natural results, so it now supports dynamic rescaling. That is, if the user changes the Windows DPI setting, or if a window is dragged to a monitor with a different DPI setting, the applica

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Finished Direct Lighting Step

While seeking a way to increase performance of octree ray traversal, I came across a lot of references to this paper: http://wscg.zcu.cz/wscg2000/Papers_2000/X31.pdf Funnily enough, the first page of the paper perfectly describes my first two attempted algorithms. I started with a nearest neighbor approach and then implemented a top-down recursive design: GLSL doesn't support recursive function calls, so I had to create a function that walks up and down the octree hierarchy with

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Sparse Voxel Octree Downsampling

I've moved on to one of the final steps for voxel cone step tracing, which is downsampling the lit voxels in a way that approximates a large area of rays being cast. You can read more about the details of this technique here. This artifact looks like a mirror that is sunken below the surface of some kind of frame. It was appearing because the mesh surface was inside the voxel, and neighboring voxels were being intersected. The solution was to move the ray starting point out of the voxel the

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Finalizing Direct Lighting

I have not used the engine outside the editor in a while, but I needed to for performance testing, so now I am back to real-time rendering. During the development of the GI system I broke most of the light types, so I had to spend a couple of days getting those to work again. While doing this, I decided to resolve some longstanding issues I have put off. First, the PBR lighting will use a default gradient in place of the skybox, if no reflection map is set for the world. This is based off t

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Sparse Voxel Octree Raycasting

I've got cone step tracing working now with the sparse voxel octree implementation. I actually found that two different routines are best when the surface is rough or smooth. For sharp reflections, and precise voxel raytracing works best: For rough surfaces, cone step tracing can be used. There are some issues to work out and I need to revisit the downsampling routine, but it's basically working: Here's a video showing the sharp raycast in motion. Performance is quite good

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Tightening up the graphics and tripling down on glTF

As I have stated before, my goa for this game enginel is not to build a marketplace of 3D models, but instead to just make sure our model loading code reliably loads all 3D models that are compliant with the glTF specification. I started testing more 3D models from Sketchfab, and found that many of them are using specular/gloss materials. At first I thought I could just fudge the result, but I wasn't getting very good results, and the Windows 10 3D Object Viewer was showing them perfectly. This

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Voxel Cone Step Tracing - Emission and Motion

Adding emission into the cascaded voxel cone step tracing global illumination and dynamic reflections system (SEO ftw) was simple enough: There's some slight trailing but it looks okay to me. There is a bit of a "glitch" in that when the emissive surface gets near the wall, the ambient occlusion kicks in, even though the sphere is self-illuminating. This happens because the emission color is mixed with the light voxel during the rasterization step. I could fix this by storing emis

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How to use gmax

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

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Better Voxelization

My initial implementation of mesh voxelization for ray tracing used this code. It was good for testing, but has some problems: It's slow, using an unnecessary and expensive x * y * z loop No support for per-voxel color based on a texture lookup There are mathematical mistakes that cause inaccuracy, and the math has to be perfect My solution addresses these problems and only uses an x * y loop to generate the voxels. It does this by identifying the major (largest magn

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Vulkan on AMD Graphics Cards

I have procrastinated testing of our new 3D engine on AMD hardware for a while. I knew it was not working as-is, but I was not too concerned. One of the promises of Vulkan is better support across-the-board and fewer driver bugs, due to the more explicit nature of the API. So when I finally tried out the engine on an R9 200 series card, what would actually happen? Would the promise of Vulkan be realized, or would developers continue to be plagued by problems on different graphics cards? Read on

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Voxel Cone Step Tracing - Cascaded Volumes

I had to spend several weeks just eliminating light leaks and other artifacts, and getting the results I wanted in a variety of scenes. The results are looking good. Everyone who tries implementing this technique has problems with light leaks but I have fortunately been able to avoid this with careful planning: Now that I have nice results with a single volume texture centered at the origin, it's time to add additional stages. The idea is to have a cascading series of volume textures

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Plugins and File Formats

At last I have been able to work the plugin system into the new editor and realize my dreams. The editor automatically detects supported file formats and generates thumbnails for them. (Thumbnails are currently compatible with the Leadwerks system, so Leadwerks can read these thumbnail files and vice-versa.) If no support for a file format is found, the program just defaults to the whatever icon or thumbnail Windows shows. The options dialog includes a tab where you can examine each pl

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