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 seems to be a correct implementation of the same diffusion profile as Cycles uses by default.
There are a few bias though:
- We consider _A_ the albedo to be 1 when evaluating _s_.
- We use a factor of 0.6 when computing _d_ to match more or less cycles results.
Note that doing per pixel jittering does bias the result even further (loss of energy).
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
This gets rid of the bottleneck of allocation / free of thousands of elements every frame.
Cache time (Eevee) (test scene is default file with cube duplicated 3241 times)
pre-patch: 23ms
post-patch: 14ms
It should behave like cycles.
Even if not efficient at all, we still do the same create - draw - free process that was done in the old viewport to save vram (maybe not really the case now) and not care about simulation's GPU texture state sync.
Engine is not stored in WorkSpaces. That defines the "context" engine, which
is used for the entire UI.
The engine used for the poll of nodes (add node menu, new nodes when "Use Nodes")
is obtained from context.
Introduce a ViewRender struct for viewport settings that are defined for
workspaces and scene. This struct will be populated with the hand-picked
settings that can be defined per workspace as per the 2.8 design.
* use_scene_settings
* properties editor: workshop + organize context path
Use Scene Settings
==================
For viewport drawing, Workspaces have an option to use the Scene render
settings (F12) instead of the viewport settings.
This way users can quickly preview the final render settings, engine and
View Layer. This will affect all the editors in that workspace, and it will be
clearly indicated in the top-bar.
Properties Editor: Add Workspace and organize context path
==========================================================
We now have the properties of:
Scene, Scene > Layer, Scene > World, Workspace
[Scene | Workspace] > Render Layer > Object
[Scene | Workspace] > Render Layer > Object > Data
(...)
Reviewers: Campbell Barton, Julian Eisel
Differential Revision: https://developer.blender.org/D2842
NODE_NEWER_SHADING was introduced in e868b459bb however it should have been
added as a bitflag.
BKE_scene_uses_blender_eevee() was used in gpu_shader_output() as a workaround
for compatibility being poorly used.
Anyways this fixes this situation. This is necessary for an upcoming patch, even
though this is considered temporary - since the other NODE_*_SHADING values are
legacy from Blender Internal drawing.
This bug (explained here https://github.com/dfelinto/opengl-sandbox/blob/downsample/README.md) is breaking eevee beyond the point it's workable.
This patch workaround the issue by making sure every fbo have mipmaps that are strictly greater than 16px. This break the bloom visuals a bit but only for this setup.
GSOC 2017 by Darshan Kadu, see: D2859.
This is a partial merge of some of the features from
the soc-2017-vertex_paint branch.
- Alpha painting & drawing.
- 10 new color blending modes.
- Support for vertex select in vertex paint mode.
This is really convenient for development. Either for profiling the
generated shaders or to check if the generated code is correct.
It writes the shaders to the temporary blender session folder.
You can change the amount of samples in the user preferences. You do not need to restart blender to see the effect in the new viewport.
This adds another Multisample Framebuffer and textures (so even more memory required).
It works by blitting the default_fb to the multisample_fb each time the renderer need to render one or more "wire" pass.
It it then blit back to the default_fb so that the rest of pipeline is working as expected.
We COULD lower the GPU memory / bandwidth usage to render everything to the same multisample fbo and change the logic depending on if MSAA is enabled or not, but I think it's a bit too much work for now.
This fix the crappy binding logic.
Note the current method is doing a lot of useless binding. We should somewhat order the texture so that reused textures are already bound most of the time.
This is in order to use the same texture on multiple sampler.
Also texture counter is reset after each shading group. This mimics the previous behaviour.
Although the problem was exposed in 9457715d9a, the problem was in the
original code that was copied over. To have:
```
} else { /* EXPECTED_VALUE */
```
Without an BLI_assert(value == EXPECTED_VALUE); is asking for troubles.
Yet another reason to favour switch statements with:
```
default:
BLI_assert(!"value not implemented or supported");
```
Instead of chained if/else if/else /* expected_value */.
