This augment the existing irradiance grid with a new visibility precomputation.
We store a small shadowmap for each grid sample so that light does not leak through walls and such.
The visibility parameter are similar to the one used by the Variance Shadow Map for point lights.
Technical details:
We store the visibility in the same texture (array) as the irradiance itself (in order to reduce the number of sampler).
But the irradiance and the visibility are not the same data so we must encode them in order to use the same texture format.
We use RGBA8 normalized texture and encode irradiance as RGBE (shared exponent).
Using RGBE encoding instead of R11_G11_B10 may lead to some lighting changes, but quality seems to be nearly the same in my test cases.
Using full RGBA16/32F maybe a future option but that will require much more memory and reduce the perf significantly.
Visibility moments (VSM) are encoded as 16bits fixed point precision using a special range. This seems to retain enough precision for the needs.
Also interpolation does not seems to be big problem (even though it's incorrect).
Before this patch, if one of the grid was updated (moved) only the subsequents evaluated grids had their level reset and had all their bounces recomputed.
There is no reason to have such a long function, it is really easy to break it
down into a smaller ones, and call them from where needed. Makes them smaller
and easier to follow. Also avoids use of confusing goto's.
For functions which will allocate requested data if it does not exist yet
"_ensure" is to be used instead of "_get". "_get" functions should return
NULL in cases when requested data does not exist yet.
This replaces dedicated flag which wasn't clean who sets it and who clears it,
and which was also trying to re-implement existing functionality in a way.
Flushing is not currently very efficient but there are ways to speed this up
a lot, but needs more investigation.
Previously the lighting of SSS material was not present in reflection probe or irradiance grid.
This does not compute the SSS correctly but at least output the corresponding irradiance power to the correct output.
This option prevent from automatically blurring the albedo color applied to the SSS.
While this is great for preserving details it can bleed more light onto the nearby objects since the blurring will be done on pure "white" irradiance.
This issue is to be tackled in a separate commit.
This cleanup removes the need of gigantic code duplication for each closure.
This also make some preformance improvement since it removes some branches and duplicated loops.
It also fix some mismatch (between cycles and eevee) with the principled shader.
The RenderResult struct still has a listbase of RenderLayer, but that's ok
since this is strictly for rendering.
* Subversion bump (to 2.80.2)
* DNA low level doversion (renames) - only for .blend created since 2.80 started
Note: We can't use DNA_struct_elem_find or get file version in init_structDNA,
so we are manually iterating over the array of the SDNA elements instead.
Note 2: This doversion change with renames can be reverted in a few months. But
so far it's required for 2.8 files created between October 2016 and now.
Reviewers: campbellbarton, sergey
Differential Revision: https://developer.blender.org/D2927
This adds the possibility to simulate things like red ears with strong backlight or material with high scattering distances.
To enable it you need to turn on the "Subsurface Translucency" option in the "Options" tab of the Material Panel (and of course to have "regular" SSS enabled in both render settings and material options).
Since the effect is adding another overhead I prefer to make it optional. But this is open to discussion.
Be aware that the effect only works for direct lights (so no indirect/world lighting) that have shadowmaps, and is affected by the "softness" of the shadowmap and resolution.
Technical notes:
This is inspired by http://www.iryoku.com/translucency/ but goes a bit beyond that.
We do not use a sum of gaussian to apply in regards to the object thickness but we precompute a 1D kernel texture.
This texture stores the light transmited to a point at the back of an infinite slab of material of variying thickness.
We make the assumption that the slab is perpendicular to the light so that no fresnel or diffusion term is taken into account.
The light is considered constant.
If the setup is similar to the one assume during the profile baking, the realtime render matches cycles reference.
Due to these assumptions the computed transmitted light is in most cases too bright for curvy objects.
Finally we jitter the shadow map sample per pixel so we can simulate dispersion inside the medium.
Radius of the dispersion is in world space and derived by from the "soft" shadowmap parameter.
Idea for this come from this presentation http://www.iryoku.com/stare-into-the-future (slide 164).
This was caused by 93936b8643
From GL spec :
GL_INVALID_OPERATION is generated if mask contains GL_DEPTH_BUFFER_BIT or GL_STENCIL_BUFFER_BIT and the source and destination depth and stencil formats do not match.
So blitting framebuffer with depth or stencil require the SAME FORMAT.
Samples : pretty self explanatory.
Jitter Threshold : Reduce cache misses and improve performance (greatly) by lowering this value. This settings let user decide how many samples should be jittered (rotated) to reduce banding artifacts.
How to use:
- Enable subsurface scattering in the render options.
- Add Subsurface BSDF to your shader.
- Check "Screen Space Subsurface Scattering" in the material panel options.
This initial implementation has a few limitations:
- only supports gaussian SSS.
- Does not support principled shader.
- The radius parameters is baked down to a number of samples and then put into an UBO. This means the radius input socket cannot be used. You need to tweak the default vector directly.
- The "texture blur" is considered as always set to 1
