Added some extra seed to the hash, so it's now less likely to give repetitive
patters at values around zero.
This will change distribution of bricks for existing files. but it's something
inevitable.
Epsilon was quite arbitrary for GPU, replaced with checking for zero-sized faces.
It should solve both original report and the new one. After the release we can check
why GPU doesn't produce accurate math here and go to the root of the issue.
Disable Intel cards for until we'll go to the root of the issue of the crash.
This will take a bit, so being so close to the release we go safe and disable
unstable GPU, so blender at least doesn't crash.
This could be bypassed by setting OPENSUBDIV_ALLOW_INTEL environment variable.
Found a way to make AVX2 CPUs happy by reshuffling instructions a bit,
so now there's no weird precision errors happening in there.
This solves some render speed regressions on CPU, but unfortunately
this doesn't help for GPU rendering.
It can't be simply removed in cases when it's connected to input which is
different from Normal. This is because the input wouldn't be connected to
default Normal geometry input, possibly breaking shading setup.
The fix is not really ideal, but should work at least.
This fixes skin having too much glossy reflection in the file from T46013.
Initial idea was to optimize calculation a bit by skipping calculation of actual
triangle edges and use vector from ray origin to triangles. In practice this
optimization didn't quite work in cases when origin point is too close to the
triangle.
Let's do 2.76 with a bit more complicated calculation, still looking into exact
reasons why watertight intersections fails in certain cases, but actual fix might
bit be ready so soon.
This fixes wrong eyes on the lady from T46013.
The issue was caused by wrong detection whether number of verticies
changed or not. Basically, it wasn't working correct in cases when
number of verticies is increasing compared to the current frame.
This isn't really complete fix, complete fix would require calculating
derivatives via OIIO API, but supporting this will either end up with
some code duplication or will require some non really safe changes at
this release cycle.
The issue was caused by uninitialized ray used for composite and AO evaluation.
Can;t really think of "proper" ray configuration here, it's all a bit arbitrary
but think initializing the ray in a way so we look at the surface in a negative
normal direction is much better alternative to uninitialized ray.
Open for alternative suggestions tho.
This isn't a Blender issue and the same bug happens with official OpenSubdiv
examples. For until it's either worked around from OpenSubdiv side or fixed
in the driver we'll force disable GLSL Compute for AMD hardware.
Uniform block data layout was different on CPU and GPU which caused wrong
data being used from shader.
In theory using layout(std140) is what we need to do, but for some reason
such layout specifier is being ignored. This is probably caused by the way
how we exploit extensions from older version of glsl.
For until we've upgraded our glsl pipeline used different approach which
is basically about removing unused fields form the struct manual in hope
that it'll keep memory layout consistent for both CPU and GPU.
This seems to work so far for both NVidia GTX580 and AMD FirePro W8000
here in the studio.
This is a bit tricky one -- ideally viewport should detect whether alpha is used
in the shader tree and if so do separate viewport pass for that objects. But in
practice it's really tricky to detect whether alpha is affected by shader or not
without evaluating the tree for all possible input values. We also can't assume
that alpha might always be affected because it'll slow viewport drawing down.
For until some smart solution is found simply expose alpha blending mode used
by the viewport. It could be found below the Viewport Color settings.
It's hopefully no longer needed, at least not needed for as long as
single ptex face corresponds to a single patch which should be always
correct for uniform subdivisions as far as i know.
Implementation is less optimal compared to non-opensubdiv drawing but
it is now as good as we can do it without affecting on how patches are
being created by OpenSubdiv.
