This isn't pretty but will do just fine until we can get a better abstraction layer on top of (or better yet, in place of) the current render texture stuff.
We need to retain the original value for enableRandomWrite instead of just overriding it if MSAA is enabled.
Currently, we take different internal paths if MSAA is enabled. In the situations that MSAA is not enabled, but MSAA was originally requested, we want to make sure enableRandomWrite can be set on the non-MSAA RT.
Before this change, if MSAA was supported via the RenderPipelineSettings, but not currently enabled by the FrameSettings, the non-MSAA RT was being created without enableRandomWrite, which lead to the RT not being compatible with the passes expecting a UAV.
For most pieces of RT state, if we need to create a non-MSAA RT, we can just copy over the state bits from the MSAA RT. However, we shouldn't be turning on bindTextureMS on a 1x texture. Unity somehow allows this creation, but then this leads to binding errors in the ShaderLab code.
Thomas
Julien Ignace
Sebastien Lagarde
Robert Srinivasiah
sebastienlagarde