Re: Volume Shaders

Larry Gritz <l...@...>

Er, I'm not sure. I think this is exactly the kind of thing we will be working out over the next few weeks. When we actually implemented surface integrators, we discovered all sorts of issues we hadn't realized when we spec'ed it. The gist is what we imagined, but the little details are different, I expect the same will happen with volumes.

The "density" is already part of the volume's closure, in much the same way that opacity is already part of a surface closure (by virtue of its weighting of closure elements that know they are "transparency-like"). It's possible that we'll want the shader to also return some kind of hint about the frequency that it needs to be sampled (as part of, or in addition to, the closure). Or maybe that's strictly the job of the integrator. The integrator can itself have parameters set by the renderer, and there can be multiple integrators for very different volume situations that need different sampling strategies. Also, it should be obvious that when we add volumes, we will also add several volume scattering closures, as the set of surface closures will not be adequate.

Stay tuned, this will all be done very soon, and probably discussed in detail here as it's happening.

-- lg

On Jan 21, 2010, at 1:12 AM, Daniel wrote:

On 21 Jan., 08:33, Larry Gritz <l...@...> wrote:
OK, that is how I interpreted the spec.
The volume integrator will, presumably, need some information about
the density of the volume, right? Do you already have ideas for
specifying that in OSL? Or will volume density information simply be
part of the scene description so integrators can choose to do this in
a way that fits their scene format?

Larry Gritz

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