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
Bug was introduced by the render passes. We had to tweak the bloom
shader a bit so we could reuse it. After that tweaking the original
alpha was ignored.
This patch will read and store the correct alpha channel.
This is using the GGX probe as background. This has the drawback of
having the resolution choosed in the indirect lighting setting.
The blurring is not really high-quality.
The pros is that it has a simple implementation and is fast to evaluate.
This patch also fades the background alpha to make overlay engine draw the
default background color in the correct color space. Removing one colorspace
hack.
Reviewed By: jbakker
Differential Revision: https://developer.blender.org/D6895
This patch adds new render passes to EEVEE. These passes include:
* Emission
* Diffuse Light
* Diffuse Color
* Glossy Light
* Glossy Color
* Environment
* Volume Scattering
* Volume Transmission
* Bloom
* Shadow
With these passes it will be possible to use EEVEE effectively for
compositing. During development we kept a close eye on how to get similar
results compared to cycles render passes there are some differences that
are related to how EEVEE works. For EEVEE we combined the passes to
`Diffuse` and `Specular`. There are no transmittance or sss passes anymore.
Cycles will be changed accordingly.
Cycles volume transmittance is added to multiple surface col passes. For
EEVEE we left the volume transmittance as a separate pass.
Known Limitations
* All materials that use alpha blending will not be rendered in the render
passes. Other transparency modes are supported.
* More GPU memory is required to store the render passes. When rendering
a HD image with all render passes enabled at max extra 570MB GPU memory is
required.
Implementation Details
An overview of render passes have been described in
https://wiki.blender.org/wiki/Source/Render/EEVEE/RenderPasses
Future Developments
* In this implementation the materials are re-rendered for Diffuse/Glossy
and Emission passes. We could use multi target rendering to improve the
render speed.
* Other passes can be added later
* Don't render material based passes when only requesting AO or Shadow.
* Add more passes to the system. These could include Cryptomatte, AOV's, Vector,
ObjectID, MaterialID, UV.
Reviewed By: Clément Foucault
Differential Revision: https://developer.blender.org/D6331
