Fast Voxel Raytracing with Vulkan
Entry posted by Josh ·
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PBR materials look nice, but their reflections are only as good as the reflection data you have. Typically this is done with hand-placed environment probes that take a long time to lay out, and display a lot of visual artifacts. Nvidia's RTX raytracing technology is interesting, but it struggles to run old games on a super-expensive GPU, My goal in Leadwerks 5 is to have automatic reflections and global illumination that doesn't require any manual setup, with fast performance.
I'm on the final step of integrating our voxel raytracing data into the standard lighting shader and the results are fantastic. I found I could compress the 3D textures in BC3 format in real-time and save a ton of memory that way. However, I discovered that only about 1% of the 3D voxel texture actually has any data in it! That means there could be a lot of room for improvement with a sparse voxel octree texture of some sort, which could allow greater resolution. In any case, the remaining implementation of this feature will be very interesting. (I believe the green area on the back wall is an artifact caused by the BC3 compression.)
I think I can probably render the raytracing component of the scene in a separate smaller buffer and the denoise it like I did with SSAO to make the performance hit negligible on this. Another interesting thing is that the raytracing automatically creates it's own ambient occlusion effect.
Here is the current state, showing the raytraced component only. It works great with our glass refraction effects.
Next I will start blending it into the PBR material lighting calculation a little better.
Here's an updated video that shows it worked into the lighting more:
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