**What are push constants?**
Push constants is a way to quickly provide a small amount of uniform data to shaders.
It should be much quicker than UBOs but a huge limitation is the size of data - spec
requires 128 bytes to be available for a push constant range.
**What are the challenges with push constants?**
The challenge with push constants is that the limited available size. According to
the Vulkan spec each platform should at least have 128 bytes reserved for push
constants. Current Mesa/AMD drivers supports 256 bytes, but Mesa/Intel is only 128
bytes.
**What is our solution?**
Some shaders of Blender uses more than these boundaries. When more data is needed
push constants will not be used, but the shader will be patched to use an uniform
buffer instead. This mechanism will be part of the Vulkan backend and shader
developers should not see any difference on API level.
**Known limitations**
Current state of the vulkan backend does not track resources that are in the
command queue. This patch includes some test cases that identified this issue as
well. See #104771.
Pull Request #104880
This patch adds initial support for compute shaders to
the vulkan backend. As the development is oriented to the test-
cases we have the implementation is limited to what is used there.
It has been validated that with this patch that the following test
cases are running as expected
- `GPUVulkanTest.gpu_shader_compute_vbo`
- `GPUVulkanTest.gpu_shader_compute_ibo`
- `GPUVulkanTest.gpu_shader_compute_ssbo`
- `GPUVulkanTest.gpu_storage_buffer_create_update_read`
- `GPUVulkanTest.gpu_shader_compute_2d`
This patch includes:
- Allocating VkBuffer on device.
- Uploading data from CPU to VkBuffer.
- Binding VkBuffer as SSBO to a compute shader.
- Execute compute shader and altering VkBuffer.
- Download the VkBuffer to CPU ram.
- Validate that it worked.
- Use device only vertex buffer as SSBO
- Use device only index buffer as SSBO
- Use device only image buffers
GHOST API has been changed as the original design was created before
we even had support for compute shaders in blender. The function
`GHOST_getVulkanBackbuffer` has been separated to retrieve the command
buffer without a backbuffer (`GHOST_getVulkanCommandBuffer`). In order
to do correct command buffer processing we needed access to the queue
owned by GHOST. This is returned as part of the `GHOST_getVulkanHandles`
function.
Open topics (not considered part of this patch)
- Memory barriers & command buffer encoding
- Indirect compute dispatching
- Rest of the test cases
- Data conversions when requested data format is different than on device.
- GPUVulkanTest.gpu_shader_compute_1d is supported on AMD devices.
NVIDIA doesn't seem to support 1d textures.
Pull-request: #104518
Implements virtual shadow mapping for EEVEE-Next primary shadow solution.
This technique aims to deliver really high precision shadowing for many
lights while keeping a relatively low cost.
The technique works by splitting each shadows in tiles that are only
allocated & updated on demand by visible surfaces and volumes.
Local lights use cubemap projection with mipmap level of detail to adapt
the resolution to the receiver distance.
Sun lights use clipmap distribution or cascade distribution (depending on
which is better) for selecting the level of detail with the distance to
the camera.
Current maximum shadow precision for local light is about 1 pixel per 0.01
degrees.
For sun light, the maximum resolution is based on the camera far clip
distance which sets the most coarse clipmap.
## Limitation:
Alpha Blended surfaces might not get correct shadowing in some corner
casses. This is to be fixed in another commit.
While resolution is greatly increase, it is still finite. It is virtually
equivalent to one 8K shadow per shadow cube face and per clipmap level.
There is no filtering present for now.
## Parameters:
Shadow Pool Size: In bytes, amount of GPU memory to dedicate to the
shadow pool (is allocated per viewport).
Shadow Scaling: Scale the shadow resolution. Base resolution should
target subpixel accuracy (within the limitation of the technique).
Related to #93220
Related to #104472
The glsl files + create infos of shaders that are only used
during development where still being compiled into blender.
This isn't needed and shouldn't be included. This change will
only include them when WITH_GTEST and WITH_OPENGL_DRAW_TESTS are
enabled. All other cases those files will be skipped.
This implement most of the functions provided by the BLI math library.
This is part of the effort to unify GLSL and C++ syntax. Ref T103026.
This also adds some infrastructure to make it possible to run GLSL shader unit
test.
Some code already present in other libs is being copied to the new libs.
This patch does not make use of the new libs outside of the tests.
Note that the test is still crashing when using metal.
