Merge pull request #262 from KhronosGroup/fix-253

Add sampler buffer support to HLSL.

reference/shaders-hlsl/vert/sampler-buffers.vert

@@ -0,0 +1,27 @@
+Buffer<float4> uFloatSampler : register(t1);
+Buffer<int4> uIntSampler : register(t2);
+Buffer<uint4> uUintSampler : register(t3);
+
+static float4 gl_Position;
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+float4 sample_from_function(Buffer<float4> s0, Buffer<int4> s1, Buffer<uint4> s2)
+{
+    return (s0.Load(20) + asfloat(s1.Load(40))) + asfloat(s2.Load(60));
+}
+
+void vert_main()
+{
+    gl_Position = sample_from_function(uFloatSampler, uIntSampler, uUintSampler);
+}
+
+SPIRV_Cross_Output main()
+{
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}

shaders-hlsl/vert/sampler-buffers.vert

@@ -0,0 +1,17 @@
+#version 450
+
+layout(binding = 1) uniform samplerBuffer uFloatSampler;
+layout(binding = 2) uniform isamplerBuffer uIntSampler;
+layout(binding = 3) uniform usamplerBuffer uUintSampler;
+
+vec4 sample_from_function(samplerBuffer s0, isamplerBuffer s1, usamplerBuffer s2)
+{
+	return texelFetch(s0, 20) +
+		intBitsToFloat(texelFetch(s1, 40)) +
+		uintBitsToFloat(texelFetch(s2, 60));
+}
+
+void main()
+{
+	gl_Position = sample_from_function(uFloatSampler, uIntSampler, uUintSampler);
+}

spirv_hlsl.cpp

@@ -48,6 +48,8 @@ string CompilerHLSL::image_type_hlsl_modern(const SPIRType &type)
 {
 	auto &imagetype = get<SPIRType>(type.image.type);
 	const char *dim = nullptr;
+	uint32_t components = 4;
+
 	switch (type.image.dim)
 	{
 	case Dim1D:
@@ -63,17 +65,23 @@ string CompilerHLSL::image_type_hlsl_modern(const SPIRType &type)
 		dim = "Cube";
 		break;
 	case DimRect:
-		SPIRV_CROSS_THROW("Rectangle texture support is not yet implemented for HLSL"); // TODO
+		SPIRV_CROSS_THROW("Rectangle texture support is not yet implemented for HLSL."); // TODO
 	case DimBuffer:
-		// Buffer/RWBuffer.
+		if (type.image.sampled == 1)
-		SPIRV_CROSS_THROW("Buffer/RWBuffer support is not yet implemented for HLSL"); // TODO
+			return join("Buffer<", type_to_glsl(imagetype), components, ">");
+		else if (type.image.sampled == 2)
+		{
+			SPIRV_CROSS_THROW("RWBuffer is not implemented yet for HLSL.");
+			//return join("RWBuffer<", type_to_glsl(imagetype), components, ">");
+		}
+		else
+			SPIRV_CROSS_THROW("Sampler buffers must be either sampled or unsampled. Cannot deduce in runtime.");
 	case DimSubpassData:
 		// This should be implemented same way as desktop GL. Fetch on a 2D texture based on int2(SV_Position).
 		SPIRV_CROSS_THROW("Subpass data support is not yet implemented for HLSL"); // TODO
 	default:
 		SPIRV_CROSS_THROW("Invalid dimension.");
 	}
-	uint32_t components = 4;
 	const char *arrayed = type.image.arrayed ? "Array" : "";
 	return join("Texture", dim, arrayed, "<", type_to_glsl(imagetype), components, ">");
 }
@@ -1024,7 +1032,7 @@ string CompilerHLSL::to_func_call_arg(uint32_t id)
 		// We don't have to consider combined image samplers here via OpSampledImage because
 		// those variables cannot be passed as arguments to functions.
 		// Only global SampledImage variables may be used as arguments.
-		if (type.basetype == SPIRType::SampledImage)
+		if (type.basetype == SPIRType::SampledImage && type.image.dim != DimBuffer)
 			arg_str += ", " + to_sampler_expression(id);
 	}
 
@@ -1072,13 +1080,12 @@ void CompilerHLSL::emit_function_prototype(SPIRFunction &func, uint64_t return_f
 
 		// Flatten a combined sampler to two separate arguments in modern HLSL.
 		auto &arg_type = get<SPIRType>(arg.type);
-		if (options.shader_model > 30 && arg_type.basetype == SPIRType::SampledImage)
+		if (options.shader_model > 30 && arg_type.basetype == SPIRType::SampledImage && arg_type.image.dim != DimBuffer)
 		{
 			// Manufacture automatic sampler arg for SampledImage texture
 			decl += ", ";
-			if (arg_type.basetype == SPIRType::SampledImage)
+			decl += join(arg_type.image.depth ? "SamplerComparisonState " : "SamplerState ",
-				decl += join(arg_type.image.depth ? "SamplerComparisonState " : "SamplerState ",
+			             to_sampler_expression(arg.id));
-				             to_sampler_expression(arg.id));
 		}
 
 		if (&arg != &func.arguments.back())
@@ -1582,7 +1589,8 @@ void CompilerHLSL::emit_texture_op(const Instruction &i)
 	if (op == OpImageFetch)
 	{
 		auto &coordtype = expression_type(coord);
-		coord_expr = join("int", coordtype.vecsize + 1, "(", coord_expr, ", ", to_expression(lod), ")");
+		if (imgtype.image.dim != DimBuffer)
+			coord_expr = join("int", coordtype.vecsize + 1, "(", coord_expr, ", ", to_expression(lod), ")");
 	}
 
 	if (op != OpImageFetch)
@@ -1728,7 +1736,7 @@ void CompilerHLSL::emit_modern_uniform(const SPIRVariable &var)
 	{
 		statement(image_type_hlsl_modern(type), " ", to_name(var.self), to_resource_binding(var), ";");
 
-		if (type.basetype == SPIRType::SampledImage)
+		if (type.basetype == SPIRType::SampledImage && type.image.dim != DimBuffer)
 		{
 			// For combined image samplers, also emit a combined image sampler.
 			if (type.image.depth)