search

yt-project / yt_idv

Interactive volume rendering for yt
Other
9 stars 6 forks source link

Add initial particle point rendering #16

Closed matthewturk closed 3 years ago

matthewturk commented 3 years ago

This is not the end stage of where particle rendering should be -- as it just uses GL_POINTS -- but it is an incremental step.

The next phase is to use a geometry shader to expand the GL_POINTS into overlapping sets of quads/triangles and then properly integrate through them.

matthewturk commented 3 years ago

Next up is reducing the geometry shader overhead by determining the clip space vectors for the radius, without doing the 8 corner iteration.

This should be a matter of pulling columns out of the inverse matrix, I think...

matthewturk commented 3 years ago

The coordinates for the expanded particle views via the geometry shader are now computed via clip space vectors, applied in world space, and transformed back. There might be a way to do this with some matrix math that's consolidated at some point.

The particles are still just flat -- no attenuation or smoothing. The next step is to add a 1D texture with the pre-integrated smoothing in it, and then integrate that.

snap_0000

matthewturk commented 3 years ago

SPH kernel interpolation is now in, using the yt SPHKernelInterpolationTable class. What I'm seeing at present is that I have -- as per usual -- gotten confused with the smoothing lengths and half-smoothing lengths, and how to pass all of that in via UV coordinates. I'll dig in to this as I am able to.

The frame rate goes pretty far down when I zoom in, which doesn't actually make a lot of sense to me; I suspect this is a result of me not completely understanding where the time is being spend in the various parts of the pipeline.

matthewturk commented 3 years ago

I've done a bit of reading and I think I need to learn more about instanced rendering to see if it's possible to avoid the geometry shader here. I'm not completely sure it is, but it may very well be.