This refactor was needed for some reasons:
- closure_lit_lib.glsl was unreadable and could not be easily extended to use new features.
- It was generating ~5K LOC for any shader. Slowing down compilation.
- Some calculations were incorrect and BSDF/Closure code had lots of workaround/hacks.
What this refactor does:
- Add some macros to define the light object loops / eval.
- Clear separation between each closures which now have separate files. Each closure implements the eval functions.
- Make principled BSDF a bit more correct in some cases (specular coloring, mix between glass and opaque).
- The BSDF term are applied outside of the eval function and on the whole lighting (was separated for lights before).
- Make light iteration last to avoid carrying more data than needed.
- Makes sure that all inputs are within correct ranges before evaluating the closures (use `safe_normalize` on normals).
- Making each BSDF isolated means that we might carry duplicated data (normals for instance) but this should be optimized by compilers.
- Makes Translucent BSDF its own closure type to avoid having to disable raytraced shadows using hacks.
- Separate transmission roughness is now working on Principled BSDF.
- Makes principled shader variations using constants. Removing a lot of duplicated code. This needed `const` keyword detection in `gpu_material_library.c`.
- SSR/SSS masking and data loading is a bit more consistent and defined outside of closure eval. The loading functions will act as accumulator if the lighting is not to be separated.
- SSR pass now do a full deferred lighting evaluation, including lights, in order to avoid interference with the closure eval code. However, it seems that the cost of having a global SSR toggle uniform is making the surface shader more expensive (which is already the case, by the way).
- Principle fully black specular tint now returns black instead of white.
- This fixed some artifact issue on my AMD computer on normal surfaces (which might have been some uninitialized variables).
- This touched the Ambient Occlusion because it needs to be evaluated for each closure. But to avoid the cost of this, we use another approach to just pass the result of the occlusion on interpolated normals and modify it using the bent normal for each Closure. This tends to reduce shadowing. I'm still looking into improving this but this is out of the scope of this patch.
- Performance might be a bit worse with this patch since it is more oriented towards code modularity. But not by a lot.
Render tests needs to be updated after this.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D10390
# Conflicts:
# source/blender/draw/engines/eevee/eevee_shaders.c
# source/blender/draw/engines/eevee/shaders/common_utiltex_lib.glsl
# source/blender/draw/intern/shaders/common_math_lib.glsl
This is a complete refactor over the old system. The goal was to increase quality
first and then have something more flexible and optimised.
|{F9603145} | {F9603142}|{F9603147}|
This fixes issues we had with the old system which were:
- Too much overdraw (low performance).
- Not enough precision in render targets (hugly color banding/drifting).
- Poor resolution near in-focus regions.
- Wrong support of orthographic views.
- Missing alpha support in viewport.
- Missing bokeh shape inversion on foreground field.
- Issues on some GPUs. (see T72489) (But I'm sure this one will have other issues as well heh...)
- Fix T81092
I chose Unreal's Diaphragm DOF as a reference / goal implementation.
It is well described in the presentation "A Life of a Bokeh" by Guillaume Abadie.
You can check about it here https://epicgames.ent.box.com/s/s86j70iamxvsuu6j35pilypficznec04
Along side the main implementation we provide a way to increase the quality by jittering the
camera position for each sample (the ones specified under the Sampling tab).
The jittering is dividing the actual post processing dof radius so that it fills the undersampling.
The user can still add more overblur to have a noiseless image, but reducing bokeh shape sharpness.
Effect of overblur (left without, right with):
| {F9603122} | {F9603123}|
The actual implementation differs a bit:
- Foreground gather implementation uses the same "ring binning" accumulator as background
but uses a custom occlusion method. This gives the problem of inflating the foreground elements
when they are over background or in-focus regions.
This is was a hard decision but this was preferable to the other method that was giving poor
opacity masks for foreground and had other more noticeable issues. Do note it is possible
to improve this part in the future if a better alternative is found.
- Use occlusion texture for foreground. Presentation says it wasn't really needed for them.
- The TAA stabilisation pass is replace by a simple neighborhood clamping at the reduce copy
stage for simplicity.
- We don't do a brute-force in-focus separate gather pass. Instead we just do the brute force
pass during resolve. Using the separate pass could be a future optimization if needed but
might give less precise results.
- We don't use compute shaders at all so shader branching might not be optimal. But performance
is still way better than our previous implementation.
- We mainly rely on density change to fix all undersampling issues even for foreground (which
is something the reference implementation is not doing strangely).
Remaining issues (not considered blocking for me):
- Slight defocus stability: Due to slight defocus bruteforce gather using the bare scene color,
highlights are dilated and make convergence quite slow or imposible when using jittered DOF
(or gives )
- ~~Slight defocus inflating: There seems to be a 1px inflation discontinuity of the slight focus
convolution compared to the half resolution. This is not really noticeable if using jittered
camera.~~ Fixed
- Foreground occlusion approximation is a bit glitchy and gives incorrect result if the
a defocus foreground element overlaps a farther foreground element. Note that this is easily
mitigated using the jittered camera position.
|{F9603114}|{F9603115}|{F9603116}|
- Foreground is inflating, not revealing background. However this avoids some other bugs too
as discussed previously. Also mitigated with jittered camera position.
|{F9603130}|{F9603129}|
- Sensor vertical fit is still broken (does not match cycles).
- Scattred bokeh shapes can be a bit strange at polygon vertices. This is due to the distance field
stored in the Bokeh LUT which is not rounded at the edges. This is barely noticeable if the
shape does not rotate.
- ~~Sampling pattern of the jittered camera position is suboptimal. Could try something like hammersley
or poisson disc distribution.~~Used hexaweb sampling pattern which is not random but has better
stability and overall coverage.
- Very large bokeh (> 300 px) can exhibit undersampling artifact in gather pass and quite a bit of
bleeding. But at this size it is preferable to use jittered camera position.
Codewise the changes are pretty much self contained and each pass are well documented.
However the whole pipeline is quite complex to understand from bird's-eye view.
Notes:
- There is the possibility of using arbitrary bokeh texture with this implementation.
However implementation is a bit involved.
- Gathering max sample count is hardcoded to avoid to deal with shader variations. The actual
max sample count is already quite high but samples are not evenly distributed due to the
ring binning method.
- While this implementation does not need 32bit/channel textures to render correctly it does use
many other textures so actual VRAM usage is higher than previous method for viewport but less
for render. Textures are reused to avoid many allocations.
- Bokeh LUT computation is fast and done for each redraw because it can be animated. Also the
texture can be shared with other viewport with different camera settings.
In Cycles the volume transmittance is already composited into the color
passes. In Eevee the volume transmittance pass was separate and needed
to be composited in the compositor. This patch adds the volume
transmittance pass direct in the next render passes:
* Diffuse Color
* Specular Color
* Emission
* Environment
This patch includes the removal of the volume transmittance render pass.
It also renames the volume render passes to match Cycles. The setting
themselves aren't unified.
Maniphest Tasks: T81134
Cryptomatte is a standard to efficiently create mattes for compositing. The
renderer outputs the required render passes, which can then be used in the
compositor to create masks for specified objects. Unlike the Material and Object
Index passes, the objects to isolate are selected in compositing, and mattes
will be anti-aliased.
Cryptomatte was already available in Cycles this patch adds it to the EEVEE
render engine. Original specification can be found at
https://raw.githubusercontent.com/Psyop/Cryptomatte/master/specification/IDmattes_poster.pdf
**Accurate mode**
Following Cycles, there are two accuracy modes. The difference between the two
modes is the number of render samples they take into account to create the
render passes. When accurate mode is off the number of levels is used. When
accuracy mode is active, the number of render samples is used.
**Deviation from standard**
Cryptomatte specification is based on a path trace approach where samples and
coverage are calculated at the same time. In EEVEE a sample is an exact match on
top of a prepared depth buffer. Coverage is at that moment always 1. By sampling
multiple times the number of surface hits decides the actual surface coverage
for a matte per pixel.
**Implementation Overview**
When drawing to the cryptomatte GPU buffer the depth of the fragment is matched
to the active depth buffer. The hashes of each cryptomatte layer is written in
the GPU buffer. The exact layout depends on the active cryptomatte layers. The
GPU buffer is downloaded and integrated into an accumulation buffer (stored in
CPU RAM).
The accumulation buffer stores the hashes + weights for a number of levels,
layers per pixel. When a hash already exists the weight will be increased. When
the hash doesn't exists it will be added to the buffer.
After all the samples have been calculated the accumulation buffer is processed.
During this phase the total pixel weights of each layer is mapped to be in a
range between 0 and 1. The hashes are also sorted (highest weight first).
Blender Kernel now has a `BKE_cryptomatte` header that access to common
functions for cryptomatte. This will in the future be used by the API.
* Alpha blended materials aren't supported. Alpha blended materials support in
render passes needs research how to implement it in a maintainable way for any
render pass.
This is a list of tasks that needs to be done for the same release that this
patch lands on (Blender 2.92)
* T82571 Add render tests.
* T82572 Documentation.
* T82573 Store hashes + Object names in the render result header.
* T82574 Use threading to increase performance in accumulation and post
processing.
* T82575 Merge the cycles and EEVEE settings as they are identical.
* T82576 Add RNA to extract the cryptomatte hashes to use in python scripts.
Reviewed By: Clément Foucault
Maniphest Tasks: T81058
Differential Revision: https://developer.blender.org/D9165
This patch adds support for AOVs in EEVEE. AOV Outputs can be defined in the
render pass tab and used in shader materials. Both Object and World based
shaders are supported. The AOV can be previewed in the viewport using the
renderpass selector in the shading popover.
AOV names that conflict with other AOVs are automatically corrected. AOV
conflicts with render passes get a warning icon. The reason behind this is that
changing render engines/passes can change the conflict, but you might not notice
it. Changing this automatically would also make the materials incorrect, so best
to leave this to the user.
**Implementation**
The patch adds a copies the AOV structures of Cycles into Blender. The goal is
that the Cycles will use Blenders AOV defintions. In the Blender kernel
(`layer.c`) the logic of these structures are implemented.
The GLSL shader of any GPUMaterial can hold multiple outputs (the main output
and the AOV outputs) based on the renderPassUBO the right output is selected.
This selection uses an hash that encodes the AOV structure. The full AOV needed
to be encoded when actually drawing the material pass as the AOV type changes
the behavior of the AOV. This isn't known yet when the GLSL is compiled.
**Future Developments**
* The AOV definitions in the render layer panel isn't shared with Cycles.
Cycles should be migrated to use the same viewlayer aovs. During a previous
attempt this failed as the AOV validation in cycles and in Blender have
implementation differences what made it crash when an aov name was invalid.
This could be fixed by extending the external render engine API.
* Add support to Cycles to render AOVs in the 3d viewport.
* Use a drop down list for selecting AOVs in the AOV Output node.
* Give user feedback when multiple AOV output nodes with the same AOV name
exists in the same shader.
* Fix viewing single channel images in the image editor [T83314]
* Reduce viewport render time by only render needed draw passes. [T83316]
Reviewed By: Brecht van Lommel, Clément Foucault
Differential Revision: https://developer.blender.org/D7010
This patch helps the case of intricate reflections where the
ray does not travel far before intersecting the geometry.
In these cases there could be false negative exclusion of the ray
caused by the backface rejection threshold.
The artifact manifested as lines of different values caused by faillure to
trace the depth buffer correctly.
Adding a ad-hoc value to the step size to mitigate the issue.
This patch fix most self intersection comming from reflection rays.
We regenerate the ray if it goes below the shading normal (should be the
geometric normal but we have no access to it here).
Also add the same precision based bias we use for contact shadows.
This fix T81105 Eevee SSR quality regression in 2.91 alpha
Corrects incorrect usages of the word 'loose' when 'lose' was required.
Differential Revision: https://developer.blender.org/D9243
Reviewed by Campbell Barton
Corrects incorrect usage of contraction for 'it is', when possessive 'its' was required.
Differential Revision: https://developer.blender.org/D9250
Reviewed by Campbell Barton
Regular rendering uses a custom blend mode, but render passes renders to
2 separate textures. This wasn't configured correctly inside the
fragment shaders. This patch adds a switch to configure the fragment
shader with the correct attachments.
Backport to Blender 2.83.
Reviewed By: Clément Foucault
Differential Revision: https://developer.blender.org/D9038
Based on http://jcgt.org/published/0008/01/03/
This is a simple trick that does *not* have a huge performance impact but
does work pretty well. It just modifies the Fresnel term to account for
the multibounce energy loss (coloration).
However this makes the shader variations count double. To avoid this we
use a uniform and pass the multiscatter use flag inside the sign of f90.
This is a bit hacky but avoids many code duplication.
This uses the simplification proposed by McAuley in
A Journey Through Implementing Multiscattering BRDFs and Area Lights
This does not handle area light differently than the IBL case but that's
already an issue in current implementation.
This is related to T68460.
Reviewed By: brecht
Differential Revision: https://developer.blender.org/D8912
This wraps the functionality used to speedup EEVEE volumetrics.
This touches the rendering code of EEVEE as it should fix a mis-usage of
the GL barrier. The barrier changed type and location, removing an
unused barrier.
- add the use of DRWShaderLibrary to EEVEE's glsl codebase to reduce code
complexity and duplication.
- split bsdf_common_lib.glsl into multiple sub library which are now shared
with other engines.
- the surface shader code is now more organised and have its own files.
- change default world to use a material nodetree and make lookdev shader
more clear.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D8306
When the film is set to transparent the environment pass should still be
rendered solid. otherwise it renders black.
Reviewed By: Clément Foucault
Differential Revision: https://developer.blender.org/D8046
This revisit the render pipeline to support time slicing for better motion
blur.
We support accumulation with or without the Post-process motion blur.
If using the post-process, we reuse last step next motion data to avoid
another scene reevaluation.
This also adds support for hair motion blur which is handled in a similar
way as mesh motion blur.
The total number of samples is distributed evenly accross all timesteps to
avoid sampling weighting issues. For this reason, the sample count is
(internally) rounded up to the next multiple of the step count.
Only FX Motion BLur: {F8632258}
FX Motion Blur + 4 time steps: {F8632260}
FX Motion Blur + 32 time steps: {F8632261}
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D8079
This adds object motion blur vectors for EEVEE as well as better noise
reduction for it.
For TAA reprojection we just compute the motion vector on the fly based on
camera motion and depth buffer. This makes possible to store another motion
vector only for the blurring which is not useful for TAA history fetching.
Motion Data is saved per object & per geometry if using deformation blur.
We support deformation motion blur by saving previous VBO and modifying the
actual GPUBatch for the geometry to include theses VBOs.
We store Previous and Next frame motion in the same motion vector buffer
(RG for prev and BA for next). This makes non linear motion blur (like
rotating objects) less prone to outward/inward blur.
We also improve the motion blur post process to expand outside the objects
border. We use a tile base approach and the max size of the blur is set via
a new render setting.
We use a background reconstruction method that needs another setting
(Background Separation).
Sampling is done using a fixed 8 dithered samples per direction. The final
render samples will clear the noise like other stochastic effects.
One caveat is that hair particles are not yet supported. Support will
come in another patch.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D7297
These are the modifications:
-With DRW modification we reduce the number of passes we need to populate.
-Rename passes for consistent naming.
-Reduce complexity in code compilation
-Cleanup how renderpass accumulation passes are setup, using pass instances.
-Make sculpt mode compatible with shadows
-Make hair passes compatible with SSS
-Error shader and lookdev materials now use standalone materials.
-Support default shader (world and material) using a default nodetree internally.
-Change BLEND_CLIP to be emulated by gpu nodetree. Making less shader variations.
-Use BLI_memblock for cache memory allocation.
-Renderpasses are handled by switching a UBO ref bind.
One major hack in this patch is the use of modified pointer as ghash keys.
This rely on the assumption that the keys will never overlap because the
number of options per key will never be bigger than the pointed struct.
The use of one single nodetree to support default material is also a bit hacky
since it won't support concurent usage of this nodetree.
(see EEVEE_shader_default_surface_nodetree)
Another change is that objects with shader errors now appear solid magenta instead
of shaded magenta. This is only because of code reuse purpose but could be changed
if really needed.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D7642
This patch adds support for alpha hash for hair rendering in EEvee. Here's a comparison of with alpha hashing:
{F7588610}
And no alpha hashing:
{F7588615}
Note that this needs "soft shadows" enabled, otherwise shadows will be noisy; here's a render with soft shadows disabled:
{F7588621}
Reviewed By: fclem
Differential Revision: https://developer.blender.org/D5221
* Space: volume density and step size in object or world space
* Step Size: override automatic step size
* Clipping: values below this are ignored for tighter volume bounds
The last two are Cycles only currently.
Ref T73201
Only the volume drawing part is really finished and exposed to the user. Hair
plugs into the existing hair rendering code and is fairly straightforward. The
pointcloud drawing is a hack using overlays rather than Eevee and workbench.
The most tricky part for volume rendering is the case where each volume grid
has a different transform, which requires an additional matrix in the shader
and non-trivial logic in Eevee volume drawing. In the common case were all the
transforms match we don't use the additional per-grid matrix in the shader.
Ref T73201, T68981
Differential Revision: https://developer.blender.org/D6955
We implement cubemap array support for EEVEE's lightcache reflection probes.
This removes stretched texels and bottom hemisphere seams artifacts caused
by the octahedral projection previously used.
This introduce versioning code for the lightcache which will discard any
lightcache version that is not compatible.
Differential Revision: https://developer.blender.org/D7066
Cycles recently fixed this issue, EEVEE needed to be adapted to output
similar results in the light passes.
This patch implements cycles `safe_divide_even_color` function to a GLSL
function that will be used when extracting the light passes.
Reviewed By: fclem
Differential Revision: https://developer.blender.org/D6948
Shadow could penetrate occluded geometry. This patch adds a check to see
if the light is in the right location to light the pixel.
Reviewed By: fclem
Differential Revision: https://developer.blender.org/D6918
