From c89b5a1a3ff6467a637b9a0cc2110b4e3a186499 Mon Sep 17 00:00:00 2001
From: Hans-Kristian Arntzen <post@arntzen-software.no>
Date: Tue, 20 Apr 2021 13:58:07 +0200
Subject: [PATCH] GLSL: Support shading rate builtins.

---
 .../frag/shading-rate.vk.nocompat.frag.vk     | 10 ++++++++++
 ...primitive-shading-rate.vk.nocompat.vert.vk |  9 +++++++++
 .../vulkan/frag/shading-rate.vk.nocompat.frag |  9 +++++++++
 .../primitive-shading-rate.vk.nocompat.vert   |  8 ++++++++
 spirv_glsl.cpp                                | 20 +++++++++++++++++++
 5 files changed, 56 insertions(+)
 create mode 100644 reference/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag.vk
 create mode 100644 reference/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert.vk
 create mode 100644 shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag
 create mode 100644 shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert

diff --git a/reference/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag.vk b/reference/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag.vk
new file mode 100644
index 00000000..e5c67115
--- /dev/null
+++ b/reference/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag.vk
@@ -0,0 +1,10 @@
+#version 450
+#extension GL_EXT_fragment_shading_rate : require
+
+layout(location = 0) out uint FragColor;
+
+void main()
+{
+    FragColor = uint(gl_ShadingRateEXT);
+}
+
diff --git a/reference/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert.vk b/reference/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert.vk
new file mode 100644
index 00000000..47367233
--- /dev/null
+++ b/reference/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert.vk
@@ -0,0 +1,9 @@
+#version 450
+#extension GL_EXT_fragment_shading_rate : require
+
+void main()
+{
+    gl_PrimitiveShadingRateEXT = 3;
+    gl_Position = vec4(1.0);
+}
+
diff --git a/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag b/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag
new file mode 100644
index 00000000..8aee6d35
--- /dev/null
+++ b/shaders-no-opt/vulkan/frag/shading-rate.vk.nocompat.frag
@@ -0,0 +1,9 @@
+#version 450
+#extension GL_EXT_fragment_shading_rate : require
+
+layout(location = 0) out uint FragColor;
+
+void main()
+{
+	FragColor = gl_ShadingRateEXT;
+}
diff --git a/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert b/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert
new file mode 100644
index 00000000..95ac8d64
--- /dev/null
+++ b/shaders-no-opt/vulkan/vert/primitive-shading-rate.vk.nocompat.vert
@@ -0,0 +1,8 @@
+#version 450
+#extension GL_EXT_fragment_shading_rate : require
+
+void main()
+{
+	gl_PrimitiveShadingRateEXT = 3;
+	gl_Position = vec4(1.0);
+}
diff --git a/spirv_glsl.cpp b/spirv_glsl.cpp
index 5acbf84a..83df8c84 100644
--- a/spirv_glsl.cpp
+++ b/spirv_glsl.cpp
@@ -8317,6 +8317,22 @@ string CompilerGLSL::builtin_to_glsl(BuiltIn builtin, StorageClass storage)
 			SPIRV_CROSS_THROW("Stencil export not supported in GLES.");
 	}
 
+	case BuiltInPrimitiveShadingRateKHR:
+	{
+		if (!options.vulkan_semantics)
+			SPIRV_CROSS_THROW("Can only use PrimitiveShadingRateKHR in Vulkan GLSL.");
+		require_extension_internal("GL_EXT_fragment_shading_rate");
+		return "gl_PrimitiveShadingRateEXT";
+	}
+
+	case BuiltInShadingRateKHR:
+	{
+		if (!options.vulkan_semantics)
+			SPIRV_CROSS_THROW("Can only use ShadingRateKHR in Vulkan GLSL.");
+		require_extension_internal("GL_EXT_fragment_shading_rate");
+		return "gl_ShadingRateEXT";
+	}
+
 	case BuiltInDeviceIndex:
 		if (!options.vulkan_semantics)
 			SPIRV_CROSS_THROW("Need Vulkan semantics for device group support.");
@@ -15149,6 +15165,8 @@ void CompilerGLSL::cast_from_builtin_load(uint32_t source_id, std::string &expr,
 	case BuiltInFragStencilRefEXT:
 	case BuiltInInstanceCustomIndexNV:
 	case BuiltInSampleMask:
+	case BuiltInPrimitiveShadingRateKHR:
+	case BuiltInShadingRateKHR:
 		expected_type = SPIRType::Int;
 		break;
 
@@ -15193,6 +15211,8 @@ void CompilerGLSL::cast_to_builtin_store(uint32_t target_id, std::string &expr,
 	case BuiltInViewportIndex:
 	case BuiltInFragStencilRefEXT:
 	case BuiltInSampleMask:
+	case BuiltInPrimitiveShadingRateKHR:
+	case BuiltInShadingRateKHR:
 		expected_type = SPIRType::Int;
 		break;