Allow vertex buffer binding when they are used disregarding implicit …

…index

Due to how MoltenVK decides when a buffer can be bound based on
its requirements for the implicit buffer, if the application uses
all bindings, implicit buffer index will be uint max. This lead
to used buffers not being bound.

MoltenVK/MoltenVK/GPUObjects/MVKPipeline.h

@@ -430,6 +430,8 @@ class MVKGraphicsPipeline : public MVKPipeline {
  uint32_t _tessCtlPatchOutputBufferIndex = 0;
  uint32_t _tessCtlLevelBufferIndex = 0;
 
+ static constexpr uint32_t _maxVertexInputBindingBufferCount = 31u; // Taken from Metal Feature Set Table. Highest value out of all present GPUs
+ bool _isVertexInputBindingUsed[_maxVertexInputBindingBufferCount] = { false };
  bool _primitiveRestartEnable = true;
  bool _hasRasterInfo = false;
  bool _needsVertexSwizzleBuffer = false;

MoltenVK/MoltenVK/GPUObjects/MVKPipeline.mm

@@ -1414,6 +1414,7 @@ static MTLVertexFormat mvkAdjustFormatVectorToSize(MTLVertexFormat format, uint3
 
  maxBinding = max(pVKVB->binding, maxBinding);
  uint32_t vbIdx = getMetalBufferIndexForVertexAttributeBinding(pVKVB->binding);
+ _isVertexInputBindingUsed[vbIdx] = true;
  auto vbDesc = inputDesc.layouts[vbIdx];
  if (isVtxStrideStatic && pVKVB->stride == 0) {
  // Stride can't be 0, it will be set later to attributes' maximum offset + size
@@ -1840,7 +1841,7 @@ static MTLVertexFormat mvkAdjustFormatVectorToSize(MTLVertexFormat format, uint3
 }
 
 bool MVKGraphicsPipeline::isValidVertexBufferIndex(MVKShaderStage stage, uint32_t mtlBufferIndex) {
- return mtlBufferIndex < _descriptorBufferCounts.stages[stage] || mtlBufferIndex > getImplicitBufferIndex(stage, 0);
+ return _isVertexInputBindingUsed[mtlBufferIndex] || mtlBufferIndex < _descriptorBufferCounts.stages[stage] || mtlBufferIndex > getImplicitBufferIndex(stage, 0);
 }
 
 // Initializes the vertex attributes in a shader conversion configuration.