The implementation is pretty straightforward.
In Cycles, sampling the shapes is currently done w.r.t. area instead of solid angle.
There is a paper on solid angle sampling for disks [1], but the described algorithm is based on
simply sampling the enclosing square and rejecting samples outside of the disk, which is not exactly
great for Cycles' RNG (we'd need to setup a LCG for the repeated sampling) and for GPU divergence.
Even worse, the algorithm is only defined for disks. For ellipses, the basic idea still works, but a
way to analytically calculate the solid angle is required. This is technically possible [2], but the
calculation is extremely complex and still requires a lookup table for the Heuman Lambda function.
Therefore, I've decided to not implement that for now, we could still look into it later on.
In Eevee, the code uses the existing ltc_evaluate_disk to implement the lighting calculations.
[1]: "Solid Angle Sampling of Disk and Cylinder Lights"
[2]: "Analytical solution for the solid angle subtended at any point by an ellipse via a point source radiation vector potential"
Reviewers: sergey, brecht, fclem
Differential Revision: https://developer.blender.org/D3171
In object mode, the axes are drawn like any other wire objects with
depth test and depth write. Thus enabling MSAA to work but not their xray
behaviour.
In edit armature/pose mode, draw smooth line without depth testing. This
produces wrong draw ordering problem but still gives the desired xray
behaviour. We do it outside of the MSAA pass since the xray behaviour is not
compatible with it. But we are drawing smoothed lines so no need for MSAA.
The lines are 2px thick and improve readability.
For some we may add per object overrides, but for most we plan to keep them
strictly per viewport settings. Display settings from the mesh still need to
be moved here, only collections were done to remove that code.
We now use a more pleasant and efficient way to display enveloppe bones
and their radius.
For this we use a capsule geometry that is displaced (in the vertex shader)
to a signed distance field that represents the bone shape.
The bone distance radius are now drawn in 3D using a "pseudo-fresnel" effect.
This gives a better understanding of what is inside the radius of influence.
When capsules are not needed, we switch to default raytraced points.
The capsules are not distorded by the bone's matrix (same as their actual
influence radius) and are correctly displayed even with complex scaled
parents hierarchy.
This fix the issue with the zfighting we were getting at bones edges.
Moreover, this enables us to render arbitrarly large outline with
varying thickness.
Because:
- Less redundancy.
- Better suffixes.
Also a few modification to GPU_texture_create_* to simplify the API:
- make the format explicit to the texture creation process.
- remove the component count as it's specified in the GPUTextureFormat.
Brecht authored this commit, but he gave me the honours to actually
do it. Here it goes; Blender Internal. Bye bye, you did great!
* Point density, voxel data, ocean, environment map textures were removed,
as these only worked within BI rendering. Note that the ocean modifier
and the Cycles point density shader node continue to work.
* Dynamic paint using material shading was removed, as this only worked
with BI. If we ever wanted to support this again probably it should go
through the baking API.
* GPU shader export through the Python API was removed. This only worked
for the old BI GLSL shaders, which no longer exists. Doing something
similar for Eevee would be significantly more complicated because it
uses a lot of multiplass rendering and logic outside the shader, it's
probably impractical.
* Collada material import / export code is mostly gone, as it only worked
for BI materials. We need to add Cycles / Eevee material support at some
point.
* The mesh noise operator was removed since it only worked with BI
material texture slots. A displacement modifier can be used instead.
* The delete texture paint slot operator was removed since it only worked
for BI material texture slots. Could be added back with node support.
* Not all legacy viewport features are supported in the new viewport, but
their code was removed. If we need to bring anything back we can look at
older git revisions.
* There is some legacy viewport code that I could not remove yet, and some
that I probably missed.
* Shader node execution code was left mostly intact, even though it is not
used anywhere now. We may eventually use this to replace the texture
nodes with Cycles / Eevee shader nodes.
* The Cycles Bake panel now includes settings for baking multires normal
and displacement maps. The underlying code needs to be merged properly,
and we plan to add back support for multires AO baking and add support
to Cycles baking for features like vertex color, displacement, and other
missing baking features.
* This commit removes DNA and the Python API for BI material, lamp, world
and scene settings. This breaks a lot of addons.
* There is more DNA that can be removed or renamed, where Cycles or Eevee
are reusing some old BI properties but the names are not really correct
anymore.
* Texture slots for materials, lamps and world were removed. They remain
for brushes, particles and freestyle linestyles.
* 'BLENDER_RENDER' remains in the COMPAT_ENGINES of UI panels. Cycles and
other renderers use this to find all panels to show, minus a few panels
that they have their own replacement for.
This is by default. We can still enable the thicker outlines for high dpi
screens or personnal preference but it's not used atm. This also improve
the performance removing 1/3 of the outline cost.
This changes quite a few things.
- Outline is now per object.
- No more outline at object intersection (fix hairs problem).
- Simplify the code quite a bit.
We use a R16UI buffer to save one id per object outline. We convert this id
to color when detecting the outline.
Added textureGatherOffsets to the code but could not test on current hardware
so leaving it commented for now.
The way how particle state is to be accessed or used did not change
in Blender 2.8, so the drawing code should follow old design.
This code is somewhat duplicated from drawobject.c, but old draw
code is on the way to be removed anyway.
This fixes issue with disappearing particles when tweaking number
of particles.
This refactor modernise the use of framebuffers.
It also touches a lot of files so breaking down changes we have:
- GPUTexture: Allow textures to be attached to more than one GPUFrameBuffer.
This allows to create and configure more FBO without the need to attach
and detach texture at drawing time.
- GPUFrameBuffer: The wrapper starts to mimic opengl a bit closer. This
allows to configure the framebuffer inside a context other than the one
that will be rendering the framebuffer. We do the actual configuration
when binding the FBO. We also Keep track of config validity and save
drawbuffers state in the FBO. We remove the different bind/unbind
functions. These make little sense now that we have separate contexts.
- DRWFrameBuffer: We replace DRW_framebuffer functions by GPU_framebuffer
ones to avoid another layer of abstraction. We move the DRW convenience
functions to GPUFramebuffer instead and even add new ones. The MACRO
GPU_framebuffer_ensure_config is pretty much all you need to create and
config a GPUFramebuffer.
- DRWTexture: Due to the removal of DRWFrameBuffer, we needed to create
functions to create textures for thoses framebuffers. Pool textures are
now using default texture parameters for the texture type asked.
- DRWManager: Make sure no framebuffer object is bound when doing cache
filling.
- GPUViewport: Add new color_only_fb and depth_only_fb along with FB API
usage update. This let draw engines render to color/depth only target
and without the need to attach/detach textures.
- WM_window: Assert when a framebuffer is bound when changing context.
This balance the fact we are not track ogl context inside GPUFramebuffer.
- Eevee, Clay, Mode engines: Update to new API. This comes with a lot of
code simplification.
This also come with some cleanups in some engine codes.
This module has no use now with the new DrawManager and DrawEngines and it
is using deprecated paths.
Moving gpu_shader_fullscreen_vert.glsl
to draw/modes/shaders/common_fullscreen_vert.glsl
Instead of creating a new instancing shading group without attrib, we now have instancing calls. The benefits is that they can be culled.
They can be used in conjuction with the standard and generate calls but shader must support it (which is generally not the case).
We store a pointer to the actual count so that the number can be tweaked between redraw.
This will makes multi layer rendering more efficient.
A major bottleneck of current implementation is the call to create_bindings() for basically every drawcalls.
This is due to the VAO being tagged dirty when assigning a new shader to the Batch, defeating the purpose of the Batch (reuse it for drawing).
Since managing hundreds of batches in DrawManager and DrawCache seems not fun enough to me, I prefered rewritting the batches itself.
--- Batch changes ---
For this to happen I needed to change the Instancing to be part of the Batch rather than being another batch supplied at drawtime.
The Gwn_VertBuffers are copied from the batch to be instanciated and a new Gwn_VertBuffer is supplied for instancing attribs.
This mean a VAO can be generated and cached for this instancing case.
A Batch can be rendered with instancing, without instancing attribs and without the need for a new VAO using the GWN_batch_draw_range_ex with the force_instance parameter set to true.
--- Draw manager changes ---
The downside with this approach is that we must track the validity of the instanced batch (the original one). For this the only way (I could think of) is to set a callback for when the batch is getting free.
This means a bit of refactor in the DrawManager with the separation of batching and instancing Batches.
--- VAO cache ---
Each VAO is generated for a given ShaderInterface. This means we can keep it alive as long as the shader interface lives.
If a ShaderInterface is discarded, it needs to destroy every VAO associated to it. Otherwise, a new ShaderInterface with the same adress could be generated and reuse the same VAO with incorrect bindings.
The VAO cache itself is using a mix between a static array of VAO and a dynamic array if the is not enough space in the static.
Using this hybrid approach is a bit more performant than the dynamic array alone.
The array will not resize down but empty entries will be filled up again. It's unlikely we get a buffer overflow from this. Resizing could be done on next allocation if needed.
--- Results ---
Using Cached VAOs means that we are not querying each vertex attrib for each vbo for each drawcall, every redraw!
In a CPU limited test scene (10000 cubes in Clay engine) I get a reduction of CPU drawing time from ~20ms to 13ms.
The only area that is not caching VAOs is the instancing from particles (see comment DRW_shgroup_instance_batch).
This removes the need of custom attribs for instancing.
Instancing works fully with dynamic batches & Gwn_VertFormat now.
This is in prevision of the VAO manager patch.
