* Adds UAV support for D3D12, Vulkan and reworked support for OpenGL, D3D11
UAV support is now uniform across compute and draw.
To set a UAV you just use bgfx::setImage() and IMAGE2D in the shader, just like in compute.
Due to these changes shaders will have to be recompiled.
The changes include:
- D3D11 requires patching of the UAV slot number (which is now done by modifying the DXBC instead of using a macro)
- If the DXBC binary includes a debug chunk, that is also patched to match the new slot number
- All the other renderers don't need any kind of patching
- There are some shader annotations to better convert the UAV format used in hlsl to spirv
Possibility of further enhancements:
- bgfx::setViewFrameBuffer() only supports binding to a framebuffer or, using BGFX_INVALID_HANDLE, to bind the default backbuffer. This doesn't allow for the case where there is no need to bind to either one of them, for example when using a fragment shader only to read and write to an UAV.
* Bump shader version, because they need to be recompiled.
Because example 42 was using the shaders from example 07 (callback), which have
input vertex attributes position and color, while the mesh from example 42 has
attributes position and normal, this causes problems on Windows when using
AMD gpus (no bunny mesh would appear on the window).
The glsl function findMSB is overriden, causing an error on Windows and Linux
when running on AMD or Intel gpus. Nvidia, for whatever reason, seems to allow
overriding the function.
When compiling shader cs_gdr_stream_compaction.sc on GCN 1.0 gpus
the following error appears:
Compute link error: HW_UNSUPPORTED.
ERROR: Internal compile error, error code: E_SC_NOTSUPPORTED
Shader not supported by HW
These changes avoid the error.