在iOS Metal中执行（支持）float纹理写入时出错

Question

当我尝试从内核写入浮点纹理时，我收到错误：

  

/SourceCache/AcceleratorKit/AcceleratorKit-17.7/ToolsLayers/Debug/MTLDebugComputeCommandEncoder.mm:596：断言失败`不可写纹理格式MTLPixelFormatR32Float在索引2处绑定到启用了写访问权限的着色器参数。＆＃39;

然而，当我去检查文档时，该格式是可着色的和可写入功能的（参见底部的表格）：

https://developer.apple.com/library/prerelease/ios/documentation/Metal/Reference/MetalConstants_Ref/index.html#//apple_ref/c/tdef/MTLPixelFormat

部分代码：

// texture creation
MTLTextureDescriptor *floatTextureDescriptor = [MTLTextureDescriptor texture2DDescriptorWithPixelFormat:MTLPixelFormatR32Float width:_width height:_height mipmapped:NO];
_myFloatTexture = [self.device newTextureWithDescriptor:floatTextureDescriptor];

// texture binding
[computeCommandEncoder setTexture:_myFloatTexture atIndex:2];

// texture used in the shader
void kernel myKernel(//...
                     texture2d<float, access::write> myFloats [[ texture(2) ]],
                     uint2 gid [[ thread_position_in_grid ]])

我做错了什么或者这可能是个错误？

Answer 1

仅iOS 9支持它们。