MSL: Support PrimitiveID in fragment and barycentrics.

reference/opt/shaders-msl/frag/barycentric-nv-nopersp.msl22.frag

@@ -0,0 +1,28 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct Vertices
+{
+    float2 uvs[1];
+};
+
+struct main0_out
+{
+    float2 value [[color(0)]];
+};
+
+struct main0_in
+{
+    float3 gl_BaryCoordNoPerspNV [[barycentric_coord, center_no_perspective]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]], const device Vertices& _19 [[buffer(0)]], uint gl_PrimitiveID [[primitive_id]])
+{
+    main0_out out = {};
+    int _23 = 3 * int(gl_PrimitiveID);
+    out.value = ((_19.uvs[_23] * in.gl_BaryCoordNoPerspNV.x) + (_19.uvs[_23 + 1] * in.gl_BaryCoordNoPerspNV.y)) + (_19.uvs[_23 + 2] * in.gl_BaryCoordNoPerspNV.z);
+    return out;
+}
+

reference/opt/shaders-msl/frag/barycentric-nv.msl22.frag

@@ -0,0 +1,28 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct Vertices
+{
+    float2 uvs[1];
+};
+
+struct main0_out
+{
+    float2 value [[color(0)]];
+};
+
+struct main0_in
+{
+    float3 gl_BaryCoordNV [[barycentric_coord, center_perspective]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]], const device Vertices& _19 [[buffer(0)]], uint gl_PrimitiveID [[primitive_id]])
+{
+    main0_out out = {};
+    int _23 = 3 * int(gl_PrimitiveID);
+    out.value = ((_19.uvs[_23] * in.gl_BaryCoordNV.x) + (_19.uvs[_23 + 1] * in.gl_BaryCoordNV.y)) + (_19.uvs[_23 + 2] * in.gl_BaryCoordNV.z);
+    return out;
+}
+

reference/shaders-msl/frag/barycentric-nv-nopersp.msl22.frag

@@ -0,0 +1,31 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct Vertices
+{
+    float2 uvs[1];
+};
+
+struct main0_out
+{
+    float2 value [[color(0)]];
+};
+
+struct main0_in
+{
+    float3 gl_BaryCoordNoPerspNV [[barycentric_coord, center_no_perspective]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]], const device Vertices& _19 [[buffer(0)]], uint gl_PrimitiveID [[primitive_id]])
+{
+    main0_out out = {};
+    int prim = int(gl_PrimitiveID);
+    float2 uv0 = _19.uvs[(3 * prim) + 0];
+    float2 uv1 = _19.uvs[(3 * prim) + 1];
+    float2 uv2 = _19.uvs[(3 * prim) + 2];
+    out.value = ((uv0 * in.gl_BaryCoordNoPerspNV.x) + (uv1 * in.gl_BaryCoordNoPerspNV.y)) + (uv2 * in.gl_BaryCoordNoPerspNV.z);
+    return out;
+}
+

reference/shaders-msl/frag/barycentric-nv.msl22.frag

@@ -0,0 +1,31 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct Vertices
+{
+    float2 uvs[1];
+};
+
+struct main0_out
+{
+    float2 value [[color(0)]];
+};
+
+struct main0_in
+{
+    float3 gl_BaryCoordNV [[barycentric_coord, center_perspective]];
+};
+
+fragment main0_out main0(main0_in in [[stage_in]], const device Vertices& _19 [[buffer(0)]], uint gl_PrimitiveID [[primitive_id]])
+{
+    main0_out out = {};
+    int prim = int(gl_PrimitiveID);
+    float2 uv0 = _19.uvs[(3 * prim) + 0];
+    float2 uv1 = _19.uvs[(3 * prim) + 1];
+    float2 uv2 = _19.uvs[(3 * prim) + 2];
+    out.value = ((uv0 * in.gl_BaryCoordNV.x) + (uv1 * in.gl_BaryCoordNV.y)) + (uv2 * in.gl_BaryCoordNV.z);
+    return out;
+}
+

shaders-msl/frag/barycentric-nv-nopersp.msl22.frag

@@ -0,0 +1,17 @@
+#version 450
+#extension GL_NV_fragment_shader_barycentric : require
+
+layout(location = 0) out vec2 value;
+
+layout(set = 0, binding = 0) readonly buffer Vertices
+{
+	vec2 uvs[];
+};
+      
+void main () {
+	int prim = gl_PrimitiveID;
+	vec2 uv0 = uvs[3 * prim + 0];
+	vec2 uv1 = uvs[3 * prim + 1];
+	vec2 uv2 = uvs[3 * prim + 2];
+    value = gl_BaryCoordNoPerspNV.x * uv0 + gl_BaryCoordNoPerspNV.y * uv1 + gl_BaryCoordNoPerspNV.z * uv2;
+}

shaders-msl/frag/barycentric-nv.msl22.frag

@@ -0,0 +1,17 @@
+#version 450
+#extension GL_NV_fragment_shader_barycentric : require
+
+layout(location = 0) out vec2 value;
+
+layout(set = 0, binding = 0) readonly buffer Vertices
+{
+	vec2 uvs[];
+};
+      
+void main () {
+	int prim = gl_PrimitiveID;
+	vec2 uv0 = uvs[3 * prim + 0];
+	vec2 uv1 = uvs[3 * prim + 1];
+	vec2 uv2 = uvs[3 * prim + 2];
+    value = gl_BaryCoordNV.x * uv0 + gl_BaryCoordNV.y * uv1 + gl_BaryCoordNV.z * uv2;
+}

spirv_msl.cpp

@@ -1942,6 +1942,7 @@ uint32_t CompilerMSL::add_interface_block(StorageClass storage, bool patch)
 	// Accumulate the variables that should appear in the interface struct.
 	SmallVector<SPIRVariable *> vars;
 	bool incl_builtins = storage == StorageClassOutput || is_tessellation_shader();
+	bool has_seen_barycentric = false;
 
 	ir.for_each_typed_id<SPIRVariable>([&](uint32_t var_id, SPIRVariable &var) {
 		if (var.storage != storage)
@@ -1956,6 +1957,7 @@ uint32_t CompilerMSL::add_interface_block(StorageClass storage, bool patch)
 		bool is_interface_block_builtin =
 		    (bi_type == BuiltInPosition || bi_type == BuiltInPointSize || bi_type == BuiltInClipDistance ||
 		     bi_type == BuiltInCullDistance || bi_type == BuiltInLayer || bi_type == BuiltInViewportIndex ||
+		     bi_type == BuiltInBaryCoordNV || bi_type == BuiltInBaryCoordNoPerspNV ||
 		     bi_type == BuiltInFragDepth || bi_type == BuiltInFragStencilRefEXT || bi_type == BuiltInSampleMask) ||
 		    (get_execution_model() == ExecutionModelTessellationEvaluation &&
 		     (bi_type == BuiltInTessLevelOuter || bi_type == BuiltInTessLevelInner));
@@ -1969,7 +1971,17 @@ uint32_t CompilerMSL::add_interface_block(StorageClass storage, bool patch)
 
 		bool filter_patch_decoration = (has_decoration(var_id, DecorationPatch) || is_patch_block(type)) == patch;
 
-		if (is_active && !is_hidden_variable(var, incl_builtins) && type.pointer && filter_patch_decoration &&
+		bool hidden = is_hidden_variable(var, incl_builtins);
+		// Barycentric inputs must be emitted in stage-in, because they can have interpolation arguments.
+		if (is_active && (bi_type == BuiltInBaryCoordNV || bi_type == BuiltInBaryCoordNoPerspNV))
+		{
+			if (has_seen_barycentric)
+				SPIRV_CROSS_THROW("Cannot declare both BaryCoordNV and BaryCoordNoPerspNV in same shader in MSL.");
+			has_seen_barycentric = true;
+			hidden = false;
+		}
+
+		if (is_active && !hidden && type.pointer && filter_patch_decoration &&
 		    (!is_builtin || is_interface_block_builtin))
 		{
 			vars.push_back(&var);
@@ -5557,7 +5569,7 @@ string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t in
 	// Fragment function inputs
 	if (execution.model == ExecutionModelFragment && type.storage == StorageClassInput)
 	{
-		string quals = "";
+		string quals;
 		if (is_builtin)
 		{
 			switch (builtin)
@@ -5568,7 +5580,10 @@ string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t in
 			case BuiltInSampleId:
 			case BuiltInSampleMask:
 			case BuiltInLayer:
+			case BuiltInBaryCoordNV:
+			case BuiltInBaryCoordNoPerspNV:
 				quals = builtin_qualifier(builtin);
+				break;
 
 			default:
 				break;
@@ -5586,6 +5601,19 @@ string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t in
 					quals = string("user(locn") + convert_to_string(locn) + ")";
 			}
 		}
+
+		if (builtin == BuiltInBaryCoordNV || builtin == BuiltInBaryCoordNoPerspNV)
+		{
+			if (has_member_decoration(type.self, index, DecorationFlat) ||
+			    has_member_decoration(type.self, index, DecorationCentroid) ||
+			    has_member_decoration(type.self, index, DecorationSample) ||
+			    has_member_decoration(type.self, index, DecorationNoPerspective))
+			{
+				// NoPerspective is baked into the builtin type.
+				SPIRV_CROSS_THROW("Flat, Centroid, Sample, NoPerspective decorations are not supported for BaryCoord inputs.");
+			}
+		}
+
 		// Don't bother decorating integers with the 'flat' attribute; it's
 		// the default (in fact, the only option). Also don't bother with the
 		// FragCoord builtin; it's always noperspective on Metal.
@@ -5622,6 +5650,7 @@ string CompilerMSL::member_attribute_qualifier(const SPIRType &type, uint32_t in
 				quals += "center_no_perspective";
 			}
 		}
+
 		if (!quals.empty())
 			return " [[" + quals + "]]";
 	}
@@ -5929,13 +5958,14 @@ void CompilerMSL::entry_point_args_builtin(string &ep_args)
 			    bi_type != BuiltInPatchVertices && bi_type != BuiltInTessLevelInner &&
 			    bi_type != BuiltInTessLevelOuter && bi_type != BuiltInPosition && bi_type != BuiltInPointSize &&
 			    bi_type != BuiltInClipDistance && bi_type != BuiltInCullDistance && bi_type != BuiltInSubgroupEqMask &&
+			    bi_type != BuiltInBaryCoordNV && bi_type != BuiltInBaryCoordNoPerspNV &&
 			    bi_type != BuiltInSubgroupGeMask && bi_type != BuiltInSubgroupGtMask &&
 			    bi_type != BuiltInSubgroupLeMask && bi_type != BuiltInSubgroupLtMask)
 			{
 				if (!ep_args.empty())
 					ep_args += ", ";
 
-				ep_args += builtin_type_decl(bi_type) + " " + to_expression(var_id);
+				ep_args += builtin_type_decl(bi_type, var_id) + " " + to_expression(var_id);
 				ep_args += " [[" + builtin_qualifier(bi_type) + "]]";
 			}
 		}
@@ -6504,7 +6534,7 @@ string CompilerMSL::argument_decl(const SPIRFunction::Parameter &arg)
 	if (var.basevariable == stage_in_ptr_var_id || var.basevariable == stage_out_ptr_var_id)
 		decl += type_to_glsl(type, arg.id);
 	else if (builtin)
-		decl += builtin_type_decl(static_cast<BuiltIn>(get_decoration(arg.id, DecorationBuiltIn)));
+		decl += builtin_type_decl(static_cast<BuiltIn>(get_decoration(arg.id, DecorationBuiltIn)), arg.id);
 	else if ((storage == StorageClassUniform || storage == StorageClassStorageBuffer) && is_array(type))
 		decl += join(type_to_glsl(type, arg.id), "*");
 	else
@@ -7541,6 +7571,12 @@ string CompilerMSL::builtin_to_glsl(BuiltIn builtin, StorageClass storage)
 
 		break;
 
+	case BuiltInBaryCoordNV:
+	case BuiltInBaryCoordNoPerspNV:
+		if (storage == StorageClassInput && current_function && (current_function->self == ir.default_entry_point))
+			return stage_in_var_name + "." + CompilerGLSL::builtin_to_glsl(builtin, storage);
+		break;
+
 	case BuiltInTessLevelOuter:
 		if (get_execution_model() == ExecutionModelTessellationEvaluation)
 		{
@@ -7633,6 +7669,12 @@ string CompilerMSL::builtin_qualifier(BuiltIn builtin)
 			return "threadgroup_position_in_grid";
 		case ExecutionModelTessellationEvaluation:
 			return "patch_id";
+		case ExecutionModelFragment:
+			if (msl_options.is_ios())
+				SPIRV_CROSS_THROW("PrimitiveId is not supported in fragment on iOS.");
+			else if (msl_options.is_macos() && !msl_options.supports_msl_version(2, 2))
+				SPIRV_CROSS_THROW("PrimitiveId on macOS requires MSL 2.2.");
+			return "primitive_id";
 		default:
 			SPIRV_CROSS_THROW("PrimitiveId is not supported in this execution model.");
 		}
@@ -7716,13 +7758,29 @@ string CompilerMSL::builtin_qualifier(BuiltIn builtin)
 		// Shouldn't be reached.
 		SPIRV_CROSS_THROW("Subgroup ballot masks are handled specially in MSL.");
 
+	case BuiltInBaryCoordNV:
+		// TODO: AMD barycentrics as well? Seem to have different swizzle and 2 components rather than 3.
+		if (msl_options.is_ios())
+			SPIRV_CROSS_THROW("Barycentrics not supported on iOS.");
+		else if (!msl_options.supports_msl_version(2, 2))
+			SPIRV_CROSS_THROW("Barycentrics are only supported in MSL 2.2 and above on macOS.");
+		return "barycentric_coord, center_perspective";
+
+	case BuiltInBaryCoordNoPerspNV:
+		// TODO: AMD barycentrics as well? Seem to have different swizzle and 2 components rather than 3.
+		if (msl_options.is_ios())
+			SPIRV_CROSS_THROW("Barycentrics not supported on iOS.");
+		else if (!msl_options.supports_msl_version(2, 2))
+			SPIRV_CROSS_THROW("Barycentrics are only supported in MSL 2.2 and above on macOS.");
+		return "barycentric_coord, center_no_perspective";
+
 	default:
 		return "unsupported-built-in";
 	}
 }
 
 // Returns an MSL string type declaration for a SPIR-V builtin
-string CompilerMSL::builtin_type_decl(BuiltIn builtin)
+string CompilerMSL::builtin_type_decl(BuiltIn builtin, uint32_t id)
 {
 	const SPIREntryPoint &execution = get_entry_point();
 	switch (builtin)
@@ -7822,6 +7880,11 @@ string CompilerMSL::builtin_type_decl(BuiltIn builtin)
 	case BuiltInHelperInvocation:
 		return "bool";
 
+	case BuiltInBaryCoordNV:
+	case BuiltInBaryCoordNoPerspNV:
+		// Use the type as declared, can be 1, 2 or 3 components.
+		return type_to_glsl(get_variable_data_type(get<SPIRVariable>(id)));
+
 	default:
 		return "unsupported-built-in-type";
 	}
@@ -8360,6 +8423,7 @@ void CompilerMSL::bitcast_from_builtin_load(uint32_t source_id, std::string &exp
 	case BuiltInLayer:
 	case BuiltInViewportIndex:
 	case BuiltInFragStencilRefEXT:
+	case BuiltInPrimitiveId:
 		expected_type = SPIRType::UInt;
 		break;
 
@@ -8401,6 +8465,7 @@ void CompilerMSL::bitcast_to_builtin_store(uint32_t target_id, std::string &expr
 	case BuiltInLayer:
 	case BuiltInViewportIndex:
 	case BuiltInFragStencilRefEXT:
+	case BuiltInPrimitiveId:
 		expected_type = SPIRType::UInt;
 		break;
 

spirv_msl.hpp

@@ -471,7 +471,7 @@ protected:
 	std::string to_swizzle_expression(uint32_t id);
 	std::string to_buffer_size_expression(uint32_t id);
 	std::string builtin_qualifier(spv::BuiltIn builtin);
-	std::string builtin_type_decl(spv::BuiltIn builtin);
+	std::string builtin_type_decl(spv::BuiltIn builtin, uint32_t id = 0);
 	std::string built_in_func_arg(spv::BuiltIn builtin, bool prefix_comma);
 	std::string member_attribute_qualifier(const SPIRType &type, uint32_t index);
 	std::string argument_decl(const SPIRFunction::Parameter &arg);