I am drawing custom things using RHI and shaders of my own. Everything works fine with DX11,OpenGL, GNM on Windows, Linux, OS X, PS4 and Xbox but it doesn’t work on OS X with Metal.
My setup is:
- OS X - El Capitano
- UE4 - 4.12.5
- Xcode - 7.3.1
After further investigation I’ve discovered that FMetalContext::CurrentBoundShaderState is reset after calls to FRHICommandList::Clear.
I tried to explicitly set the shader state (via FRHICommandList::SetBoundShaderState)before every draw, but then I got a another crash inside bindSamplerToTexture which is a function inside inside the METAL Driver.
I also tried to rebind all the samplers and textures ( FGlobalShader::SetShaderSampler / SetShaderTexture), but the result was the same.
The log also shows the following unhelpful message: “Created a hitchy pipeline state for hash”
Any ideas what may be going wrong? Are there any Metal-specific invariants that I am breaking?
Finally, here’s the important part of the call stack that I get on the last crash:
#0 0x0000000157e2b4b6 in SamplerStage::bindSamplerToTexture(unsigned char, unsigned char, bool&, bool&) ()
#1 0x0000000157e2af97 in SamplerStage::writeSamplerState() ()
#2 0x0000000157e2323a in IGRenderStateSamplers::writeIf() ()
#3 0x0000000157e1eb1d in IGAccelRenderCommandEncoder::programPipeline(sPrimitiveData const&) ()
#4 0x0000000157e1f062 in IGAccelRenderCommandEncoder::drawIndexedPrimitives(unsigned long, unsigned int, unsigned long, MTLIGAccelBuffer*, unsigned int, unsigned int, unsigned int, unsigned int) ()
#5 0x0000000157e37eec in -[MTLIGAccelRenderCommandEncoder drawIndexedPrimitives:indexCount:indexType:indexBuffer:indexBufferOffset:instanceCount:baseVertex:baseInstance:] ()
#6 0x0000000159d1b9b9 in FMetalRHICommandContext::RHIDrawIndexedPrimitive(FRHIIndexBuffer*, unsigned int, int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int) at /Volumes/MacintoshHD2/ue-test/UnrealEngine/Engine/Source/Runtime/Apple/MetalRHI/Private/MetalCommands.cpp:567
#7 0x0000000146bf8018 in FRHICommandList::DrawIndexedPrimitive(FRHIIndexBuffer*, unsigned int, int, unsigned int, unsigned int, unsigned int, unsigned int, unsigned int) at /Volumes/MacintoshHD2/ue-test/UnrealEngine/Engine/Source/Runtime/RHI/Public/RHICommandList.h:1598
#8 0x0000000146b49cc7 in FCohRenoirBackend::DrawIndexed(renoir::DrawIndexedCmd const*) at /Users//Documents/Unreal Projects/MyProject3/Plugins/Runtime//CoherentUIGTPlugin/Source/CoherentUIGTPlugin/Private/CohRenoirBackend.cpp:1432