The shaders are pretty standard stuff really. Here is the vertex and pixel shaders: struct sVertexInput { packed_float3 m_cPosition; packed_float2 m_cTextureCoords; }; struct sVertexOutput { float4 m_cPosition [[position]]; float2 m_cTextureCoords; }; //============================================================================== // Diffuse vertex shader // // psVertices - input vertices // rsUniforms - uniforms buffer // iVertexID - vertex index // // Returns: sVertexOutput - vertex output //============================================================================== vertex sVertexOutput diffuse_vp_main_vs (const device sVertexInput *psVertices [[buffer (0)]], constant sVPUniforms &rsUniforms [[buffer (1)]], uint iVertexID [[vertex_id]]) { sVertexOutput sVertexOutput; float4 cPosition = float4 (psVertices [iVertexID].m_cPosition, 1.0f); sVertexOutput.m_cPosition = cPosition * rsUniforms.m_cViewProjection; sVertexOutput.m_cTextureCoords = psVertices [iVertexID].m_cTextureCoords; return sVertexOutput; } //============================================================================== // Diffuse fragment shader // // sVertex - output vertex from vertex shader // cDiffuseTexture - diffuse texture // smplDiffuse - diffuse sampler // // Returns: half4 - sampled diffuse texture //============================================================================== fragment half4 diffuse_main_ps (sVertexOutput sVertex [[stage_in]], texture2d float cDiffuseTexture [[texture (0)]], sampler smplDiffuse [[sampler (0)]]) { // sample the diffuse texture half4 cColor = (half4) (cDiffuseTexture.sample (smplDiffuse, sVertex.m_cTextureCoords)); return cColor; }

Also running the EXACT SAME code on a newer iPhone with iOS 13.6.1 runs perfectly with no crashes. I also tried the Metal deffered shading demo from Apple and it exhibits the same crash issue: Could not resolve texture/samplers references But on the newer phone with iOS 13.6.1 the Deffered shading demo runs without a hitch.

Yes the Deferred Lighting demo running on my iPhone 5s with iOS version 10.1.1 will have the same issue and the same error when you create a render pipe line. I keep an old version of iOS on this phone for compatibility issues. I made sure the deployment target in the Deferred Lighting demo was 10. ie. I changed it to run as the minimum deployment target to be 10. I will write a report with Feedback Assistant. But it may be hard to debug this if you don't have an iPhone with an old iOS version. Thanks for helping me!

I did notice that when I downloaded XCode 12 and loaded my project it "recommended" that I update the deployment target to 12. Perhaps it is as you state that the Metal Shader compilers are generating code that the drivers on iOS 10 are not compatible with. I will write the Feedback just the same for completeness. I will try to fix this on my end and if not I guess I will have to upgrade to iOS version on myiPhone5s to 12. Thanks, Juan

OK I finally "solved" this. The issue is that the newly compiled Metal shader library is NOT compatible with the iPhone 5s with iOS version 10.1.1. So calling the method: - (nullable id MTLLibrary)newDefaultLibrary; with the compiled Metal library file will not work. The solution is to run time compile the metal shaders on the target platform with the method: (nullable id MTLLibrary)newLibraryWithSource:(NSString *)source options:(nullable MTLCompileOptions *)options error:(__autoreleasing NSError **)error; With this method I was able to load and run the game. It had negligible impact on the load time of my game.