Add GLSL support for SV_InnerCoverage (#1740)

This was a fairly straightforward addition once I found the correct GLSL extension spec to use.

3 files changed, 35 insertions, 0 deletions

diff --git a/source/slang/slang-ir-glsl-legalize.cpp b/source/slang/slang-ir-glsl-legalize.cpp
index ae6521076..052b4fb29 100644
--- a/source/slang/slang-ir-glsl-legalize.cpp
+++ b/source/slang/slang-ir-glsl-legalize.cpp
@@ -324,6 +324,16 @@ GLSLSystemValueInfo* getGLSLSystemValueInfo(
             name = "gl_SampleMask[0]";
         }
     }
+    else if(semanticName == "sv_innercoverage")
+    {
+        // uint in hlsl, bool in glsl
+        // https://www.khronos.org/registry/OpenGL/extensions/NV/NV_conservative_raster_underestimation.txt
+
+        context->requireGLSLExtension(UnownedStringSlice::fromLiteral("GL_NV_conservative_raster_underestimation"));
+
+        name = "gl_FragFullyCoveredNV";
+        requiredType = builder->getBasicType(BaseType::Bool);
+    }
     else if(semanticName == "sv_depth")
     {
         // Float in hlsl & glsl
diff --git a/tests/pipeline/rasterization/conservative-rasterization/inner-coverage.slang b/tests/pipeline/rasterization/conservative-rasterization/inner-coverage.slang
new file mode 100644
index 000000000..fe77095df
--- /dev/null
+++ b/tests/pipeline/rasterization/conservative-rasterization/inner-coverage.slang
@@ -0,0 +1,11 @@
+// inner-coverage.slang
+
+//TEST:CROSS_COMPILE:-target spirv -entry main -stage fragment
+
+[shader("fragment")]
+void main(
+    uint innerCoverage : SV_InnerCoverage,
+    out float4 result : SV_Target)
+{
+    result = innerCoverage;
+}
diff --git a/tests/pipeline/rasterization/conservative-rasterization/inner-coverage.slang.glsl b/tests/pipeline/rasterization/conservative-rasterization/inner-coverage.slang.glsl
new file mode 100644
index 000000000..1454d493f
--- /dev/null
+++ b/tests/pipeline/rasterization/conservative-rasterization/inner-coverage.slang.glsl
@@ -0,0 +1,14 @@
+#version 450
+
+#extension GL_NV_conservative_raster_underestimation : require
+
+layout(location = 0)
+out vec4 _S1;
+
+void main()
+{
+    vec4 _S2;
+    _S2 = vec4(uint(gl_FragFullyCoveredNV));
+    _S1 = _S2;
+    return;
+}