SPIRV-Cross/reference/opt/shaders-msl/frag/input-attachment-ms.arrayed-subpass.msl21.frag

#include <metal_stdlib>
#include <simd/simd.h>

using namespace metal;

struct main0_out
{
    float4 FragColor [[color(0)]];
};

fragment main0_out main0(texture2d_ms_array<float> uSubpass0 [[texture(0)]], texture2d_ms_array<float> uSubpass1 [[texture(1)]], uint gl_SampleID [[sample_id]], float4 gl_FragCoord [[position]], uint gl_Layer [[render_target_array_index]])
{
    main0_out out = {};
    gl_FragCoord.xy += get_sample_position(gl_SampleID) - 0.5;
    out.FragColor = (uSubpass0.read(uint2(gl_FragCoord.xy), gl_Layer, 1) + uSubpass1.read(uint2(gl_FragCoord.xy), gl_Layer, 2)) + uSubpass0.read(uint2(gl_FragCoord.xy), gl_Layer, gl_SampleID);
    return out;
}
MSL: Support layered input attachments. These need to use arrayed texture types, or Metal will complain when binding the resource. The target layer is addressed relative to the Layer output by the vertex pipeline, or to the ViewIndex if in a multiview pipeline. Unlike with the s/t coordinates, Vulkan does not forbid non-zero layer coordinates here, though this cannot be expressed in Vulkan GLSL. Supporting 3D textures will require additional work. Part of the problem is that Metal does not allow texture views to subset a 3D texture, so we need some way to pass the base depth to the shader. 2020-08-28 00:24:20 +00:00			`#include <metal_stdlib>`
			`#include <simd/simd.h>`

			`using namespace metal;`

			`struct main0_out`
			`{`
			`float4 FragColor [[color(0)]];`
			`};`

			`fragment main0_out main0(texture2d_ms_array<float> uSubpass0 [[texture(0)]], texture2d_ms_array<float> uSubpass1 [[texture(1)]], uint gl_SampleID [[sample_id]], float4 gl_FragCoord [[position]], uint gl_Layer [[render_target_array_index]])`
			`{`
			`main0_out out = {};`
MSL: Adjust FragCoord for sample-rate shading. In Metal, the `[[position]]` input to a fragment shader remains at fragment center, even at sample rate, like OpenGL and Direct3D. In Vulkan, however, when the fragment shader runs at sample rate, the `FragCoord` builtin moves to the sample position in the framebuffer, instead of the fragment center. To account for this difference, adjust the `FragCoord`, if present, by the sample position. The -0.5 offset is because the fragment center is at (0.5, 0.5). Also, add an option to force sample-rate shading in a fragment shader. Since Metal has no explicit control for this, this is done by adding a dummy `[[sample_id]]` which is otherwise unused, if none is already present. This is intended to be used from e.g. MoltenVK when a pipeline's `minSampleShading` value is nonzero. Instead of checking if any `Input` variables have `Sample` interpolation, I've elected to check that the `SampleRateShading` capability is present. Since `SampleId`, `SamplePosition`, and the `Sample` interpolation decoration require this cap, this should be equivalent for any valid SPIR-V module. If this isn't acceptable, let me know. 2020-11-20 21:41:46 +00:00			`gl_FragCoord.xy += get_sample_position(gl_SampleID) - 0.5;`
MSL: Support layered input attachments. These need to use arrayed texture types, or Metal will complain when binding the resource. The target layer is addressed relative to the Layer output by the vertex pipeline, or to the ViewIndex if in a multiview pipeline. Unlike with the s/t coordinates, Vulkan does not forbid non-zero layer coordinates here, though this cannot be expressed in Vulkan GLSL. Supporting 3D textures will require additional work. Part of the problem is that Metal does not allow texture views to subset a 3D texture, so we need some way to pass the base depth to the shader. 2020-08-28 00:24:20 +00:00			`out.FragColor = (uSubpass0.read(uint2(gl_FragCoord.xy), gl_Layer, 1) + uSubpass1.read(uint2(gl_FragCoord.xy), gl_Layer, 2)) + uSubpass0.read(uint2(gl_FragCoord.xy), gl_Layer, gl_SampleID);`
			`return out;`
			`}`