Merge pull request #521 from KhronosGroup/fix-516

Support dual-source blending on GLSL and MSL.

reference/opt/shaders-msl/frag/dual-source-blending.frag

@@ -0,0 +1,19 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 FragColor0 [[color(0), index(0)]];
+    float4 FragColor1 [[color(0), index(1)]];
+};
+
+fragment main0_out main0()
+{
+    main0_out out = {};
+    out.FragColor0 = float4(1.0);
+    out.FragColor1 = float4(2.0);
+    return out;
+}
+

reference/opt/shaders/desktop-only/frag/dual-source-blending.desktop.frag

@@ -0,0 +1,11 @@
+#version 450
+
+layout(location = 0, index = 0) out vec4 FragColor0;
+layout(location = 0, index = 1) out vec4 FragColor1;
+
+void main()
+{
+    FragColor0 = vec4(1.0);
+    FragColor1 = vec4(2.0);
+}
+

reference/shaders-msl/frag/dual-source-blending.frag

@@ -0,0 +1,19 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 FragColor0 [[color(0), index(0)]];
+    float4 FragColor1 [[color(0), index(1)]];
+};
+
+fragment main0_out main0()
+{
+    main0_out out = {};
+    out.FragColor0 = float4(1.0);
+    out.FragColor1 = float4(2.0);
+    return out;
+}
+

reference/shaders/desktop-only/frag/dual-source-blending.desktop.frag

@@ -0,0 +1,11 @@
+#version 450
+
+layout(location = 0, index = 0) out vec4 FragColor0;
+layout(location = 0, index = 1) out vec4 FragColor1;
+
+void main()
+{
+    FragColor0 = vec4(1.0);
+    FragColor1 = vec4(2.0);
+}
+

shaders-msl/frag/dual-source-blending.frag

@@ -0,0 +1,10 @@
+#version 450
+
+layout(location = 0, index = 0) out vec4 FragColor0;
+layout(location = 0, index = 1) out vec4 FragColor1;
+
+void main()
+{
+	FragColor0 = vec4(1.0);
+	FragColor1 = vec4(2.0);
+}

shaders/desktop-only/frag/dual-source-blending.desktop.frag

@@ -0,0 +1,10 @@
+#version 450
+
+layout(location = 0, index = 0) out vec4 FragColor0;
+layout(location = 0, index = 1) out vec4 FragColor1;
+
+void main()
+{
+	FragColor0 = vec4(1.0);
+	FragColor1 = vec4(2.0);
+}

spirv_common.hpp

@@ -1195,6 +1195,7 @@ struct Meta
 		uint32_t matrix_stride = 0;
 		uint32_t input_attachment = 0;
 		uint32_t spec_id = 0;
+		uint32_t index = 0;
 		bool builtin = false;
 	};
 

spirv_cross.cpp

@@ -1074,6 +1074,10 @@ void Compiler::set_member_decoration(uint32_t id, uint32_t index, Decoration dec
 		dec.matrix_stride = argument;
 		break;
 
+	case DecorationIndex:
+		dec.index = argument;
+		break;
+
 	default:
 		break;
 	}
@@ -1146,6 +1150,8 @@ uint32_t Compiler::get_member_decoration(uint32_t id, uint32_t index, Decoration
 		return dec.offset;
 	case DecorationSpecId:
 		return dec.spec_id;
+	case DecorationIndex:
+		return dec.index;
 	default:
 		return 1;
 	}
@@ -1249,6 +1255,10 @@ void Compiler::set_decoration(uint32_t id, Decoration decoration, uint32_t argum
 		dec.spec_id = argument;
 		break;
 
+	case DecorationIndex:
+		dec.index = argument;
+		break;
+
 	default:
 		break;
 	}
@@ -1320,6 +1330,8 @@ uint32_t Compiler::get_decoration(uint32_t id, Decoration decoration) const
 		return dec.array_stride;
 	case DecorationMatrixStride:
 		return dec.matrix_stride;
+	case DecorationIndex:
+		return dec.index;
 	default:
 		return 1;
 	}

spirv_glsl.cpp

@@ -1209,6 +1209,9 @@ string CompilerGLSL::layout_for_variable(const SPIRVariable &var)
 			attr.push_back(join("location = ", dec.location));
 	}
 
+	if (flags.get(DecorationIndex))
+		attr.push_back(join("index = ", dec.index));
+
 	// set = 0 is the default. Do not emit set = decoration in regular GLSL output, but
 	// we should preserve it in Vulkan GLSL mode.
 	if (var.storage != StorageClassPushConstant)

spirv_msl.cpp

@@ -645,6 +645,12 @@ uint32_t CompilerMSL::add_interface_block(StorageClass storage)
 							mark_location_as_used_by_shader(locn, storage);
 						}
 
+						if (get_decoration_bitset(p_var->self).get(DecorationIndex))
+						{
+							uint32_t index = get_decoration(p_var->self, DecorationIndex);
+							set_member_decoration(ib_type_id, ib_mbr_idx, DecorationIndex, index);
+						}
+
 						// Lower the internal array to flattened output when entry point returns.
 						entry_func.fixup_statements.push_back(
 						    join(ib_var_ref, ".", mbr_name, " = ", to_name(p_var->self), "[", i, "];"));
@@ -674,6 +680,12 @@ uint32_t CompilerMSL::add_interface_block(StorageClass storage)
 						mark_location_as_used_by_shader(locn, storage);
 					}
 
+					if (get_decoration_bitset(p_var->self).get(DecorationIndex))
+					{
+						uint32_t index = get_decoration(p_var->self, DecorationIndex);
+						set_member_decoration(ib_type_id, ib_mbr_idx, DecorationIndex, index);
+					}
+
 					// Mark the member as builtin if needed
 					if (is_builtin)
 					{
@@ -2835,8 +2847,14 @@ string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t in
 			}
 		}
 		uint32_t locn = get_ordered_member_location(type.self, index);
-		if (locn != k_unknown_location)
+		if (locn != k_unknown_location && has_member_decoration(type.self, index, DecorationIndex))
-			return string(" [[color(") + convert_to_string(locn) + ")]]";
+			return join(" [[color(", locn, "), index(", get_member_decoration(type.self, index, DecorationIndex), ")]]");
+		else if (locn != k_unknown_location)
+			return join(" [[color(", locn, ")]]");
+		else if (has_member_decoration(type.self, index, DecorationIndex))
+			return join(" [[index(", get_member_decoration(type.self, index, DecorationIndex), ")]]");
+		else
+			return "";
 	}
 
 	// Compute function inputs