Hardware Ray Tracing

Hardware Ray Tracing leverages the GPU dedicated hardware to speed up ray triangle intersections. It is currently only used in POPs. It is currently not supported on MacOS and older hardware.

It first builds an acceleration structure, against which ray intersections are performed. It can currently be enabled on the Ray POP, Sprinkle POP volume mode (only for point generation, not for input attributes interpolation), and GLSL POP and GLSL Advanced POP.

The acceleration structure can be optimized for build time, if the geometry changes every frame and the acceleration structure needs to be rebuilt every frame, or trace time, good for static geometry.

Moreover, the geometry can be specified as Opaque. In that case only the first hit (which can be the closest hit or any hit) is returned. Opaque restricts some of the parameters on the Ray POP and is not available on the Sprinkle POP, since all intersections are needed to determine whether points are inside or outside the geometry (Similar to Inside attribute of Ray POP).

On the GLSL POP and the GLSL Advanced POP, specifying a POP on the Collisions page builds the acceleration structure and binds it to the shader. It also enable the Ray Query extension. See the RayQuery example (GLSL POP snippet glsl 1) for more detail.