Caustics (Real-time Ray Tracing & Physics) 

Thanks! Happy to hear you like this one!

The physics are running on the CPU. My computer is fairly average: 8700K, RTX 2080. You’d get much better performance even on a current gen Threadripper and 2080 Ti build. And there is still room for optimizations moving it to DirectX 12 and taking advantage of multi-engine/async compute among other things. I imagine the new Nvidia and AMD cards will allow for further performance improvements as well but I don’t know anything the public doesn’t already know.

Thanks! I saw the price drop but I'm actually thinking of waiting for the next generation of CPUs & GPUs before upgrading my desktop. I may need to do a whole build, since I would have to replace the motherboard as well, and I currently have really slow memory (2400mhz). Regarding consoles, I'm hoping to get my game a little farther along and be able to apply to the ID@Xbox program in a month or two. Then I might be able to optimize directly on the devkit.

I'm planning on trying this out with the new Mesh Shaders feature that is available in DirectX 12 Ultimate. In addition to spheres, could also render actual geometric grass and other geometric blocks. And it will potentially introduce opportunities to optimize with frustum culling or LOD (render cubes from far away, upres to high-poly blocks up close).

Hi Pete! This is currently using DirectX 11.1. I started from the SimpleInstancing sample from Xbox-ATG. I modified it to take in the affine transformation matrices my simulation generates since the physics uses Affine Particle-in-Cell/MLS-MPM. This allows the particles to shear instead of just pure position and rotation. Then I added in the PBR shader from DirectXTK but still needed transparency. So I then started writing to UAVs to voxelize the particles into 3D textures at the same time as rasterizing them to position and normal buffers for later deferred rendering. Then I do some light propagation on these 3D UAVs/volume textures. Then I do the final pass, using the position and normal buffers to come up with reflection/refraction rays and then march them through the volume using techniques from the paper Eikonal Rendering. It's kind of like hybrid rasterization & raytracing but this doesn't really need RTX or DXR since I'm not tracing triangles. I can also use the volume mipmaps to simulate blurrier reflections/refractions. I have not had to deal with denoising or temporal light accumulation. I do plan on porting over to DX12U (still learning) to take advantage of other features though. I'm curious to see if I can improve the performance by stacking the rasterization and lighting compute on top of each other (multi-engine).

@@GrantKot Super cool! So, desktop C++ app, I assume (not an Xbox app (given the mouse/kb) or a UWP app)

@@Psychlist1972 Yeah, currently desktop C++, but definitely thinking about the new Xbox as well :) I'm planning to apply once my game concept is fleshed out a little more.

@@GrantKot What kind of game is it going to be ?

@@wasplay I have a few ideas but it's not fully settled yet. There will probably be a strong elemental bending component and you can choose what material you're attracting or dragging. There might be some combat and building (sharing of levels), and I am also currently exploring co-op or local multiplayer. I think the system will lend itself well to user created content, since everything is dynamic and there is no need to bake anything like shadows or global illumination. User level files will be pretty small, this "level" in the video is just 0.5MB and can probably be reduced even further with compression.