Implement the extension GL_AMD_shader_fragment_mask

Test/spv.shaderFragMaskAMD.frag

@@ -0,0 +1,29 @@
+#version 450 core
+
+#extension GL_AMD_shader_fragment_mask: enable
+
+layout(binding = 0) uniform sampler2DMS       s2DMS;
+layout(binding = 1) uniform isampler2DMSArray is2DMSArray;
+
+layout(binding = 2, input_attachment_index = 0) uniform usubpassInputMS usubpassMS;
+
+layout(location = 0) out vec4 fragColor;
+
+void main()
+{
+    vec4 f4 = vec4(0.0);
+
+    uint fragMask = fragmentMaskFetchAMD(s2DMS, ivec2(2, 3));
+    uint fragIndex = (fragMask & 0xF0) >> 4;
+    f4 += fragmentFetchAMD(s2DMS, ivec2(2, 3), 1);
+
+    fragMask = fragmentMaskFetchAMD(is2DMSArray, ivec3(2, 3, 1));
+    fragIndex = (fragMask & 0xF0) >> 4;
+    f4 += fragmentFetchAMD(is2DMSArray, ivec3(2, 3, 1), fragIndex);
+
+    fragMask = fragmentMaskFetchAMD(usubpassMS);
+    fragIndex = (fragMask & 0xF0) >> 4;
+    f4 += fragmentFetchAMD(usubpassMS, fragIndex);
+
+    fragColor = f4;
+}