message: Fix post processing issue for Metal
diff: @@ -6,10 +6,10 @@ LAYOUT_LOCATION(0) out vec2 vertex_uv;
  void main() {
  vertex_uv = (position.xy * 0.5 + 0.5) * frameUniforms.resolution.xy;
  -#if defined(TARGET_VULKAN_ENVIRONMENT)
  - // In Vulkan, drawing the top row of pixels occurs when position.y = -1.0, but we're
  - // sampling from a rectangle the sits in the lower-left corner of the texture. Therefore
  - // we need to apply an offset to get the correct texture coordinate.
  +#if defined(TARGET_VULKAN_ENVIRONMENT) || defined(TARGET_METAL_ENVIRONMENT)
  + // In Vulkan and Metal, drawing the top row of pixels occurs when position.y = -1.0 (1.0 for
  + // Metal), but we're sampling from a rectangle the sits in the lower-left corner of the texture.
  + // Therefore we need to apply an offset to get the correct texture coordinate.
  //
  // For example, if the sampled area height is 180 and the texture height is 200,
  // we need to sample the texture in the range [20,200) rather than [0,180).
  