From 6ff7aea73057e4a650d8b0ac659d9bba05ba02e2 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 31 Mar 2021 23:21:47 +0300
Subject: [PATCH] Use type information in converting legacy texture sampling
 functions

---
 source/glsl/finalize.cpp | 78 ++++++++++++++--------------------------
 source/glsl/finalize.h   |  1 -
 2 files changed, 27 insertions(+), 52 deletions(-)

diff --git a/source/glsl/finalize.cpp b/source/glsl/finalize.cpp
index 8a525e37..532e2ffc 100644
--- a/source/glsl/finalize.cpp
+++ b/source/glsl/finalize.cpp
@@ -166,12 +166,7 @@ void LegacyConverter::visit(VariableReference &var)
 	{
 		var.name = "gl_FragColor";
 		var.declaration = 0;
-		r_type = "vec4";
 	}
-	else if(var.declaration)
-		r_type = var.declaration->type;
-	else
-		r_type.clear();
 }
 
 void LegacyConverter::visit(Assignment &assign)
@@ -191,58 +186,39 @@ bool LegacyConverter::supports_unified_sampling_functions() const
 
 void LegacyConverter::visit(FunctionCall &call)
 {
-	if(call.name=="texture")
+	if(call.declaration && call.declaration->source==BUILTIN_SOURCE)
 	{
-		string sampler_type;
-		r_type.clear();
-		NodeArray<Expression>::iterator i = call.arguments.begin();
-		if(i!=call.arguments.end())
+		if(!call.name.compare(0, 7, "texture") && call.arguments.size()>=1)
 		{
-			(*i)->visit(*this);
-			sampler_type = r_type;
-
-			for(; i!=call.arguments.end(); ++i)
-				(*i)->visit(*this);
-		}
-
-		if(!supports_unified_sampling_functions())
-		{
-			if(sampler_type=="sampler1D")
-				call.name = "texture1D";
-			else if(sampler_type=="sampler2D")
-				call.name = "texture2D";
-			else if(sampler_type=="sampler3D")
-				call.name = "texture3D";
-			else if(sampler_type=="samplerCube")
-				call.name = "textureCube";
-			else if(sampler_type=="sampler1DShadow")
-				call.name = "shadow1D";
-			else if(sampler_type=="sampler2DShadow")
-				call.name = "shadow2D";
-			else if(sampler_type=="sampler1DArray")
-			{
-				check_extension(&Features::ext_texture_array);
-				call.name = "texture1DArray";
-			}
-			else if(sampler_type=="sampler2DArray")
+			const ImageTypeDeclaration *arg_image = dynamic_cast<const ImageTypeDeclaration *>(call.arguments.front()->type);
+			if(arg_image && !supports_unified_sampling_functions())
 			{
-				check_extension(&Features::ext_texture_array);
-				call.name = "texture2DArray";
-			}
-			else if(sampler_type=="sampler1DArrayShadow")
-			{
-				check_extension(&Features::ext_texture_array);
-				call.name = "shadow1DArray";
-			}
-			else if(sampler_type=="sampler2DArrayShadow")
-			{
-				check_extension(&Features::ext_texture_array);
-				call.name = "shadow2DArray";
+				string suffix = call.name.substr(7);
+				call.name = (arg_image->shadow ? "shadow" : "texture");
+
+				switch(arg_image->dimensions)
+				{
+				case ImageTypeDeclaration::ONE: call.name += "1D"; break;
+				case ImageTypeDeclaration::TWO: call.name += "2D"; break;
+				case ImageTypeDeclaration::THREE: call.name += "3D"; break;
+				case ImageTypeDeclaration::CUBE: call.name += "Cube"; break;
+				}
+
+				if(arg_image->array)
+				{
+					/* Array textures and the unified sampling function name were
+					both introduced in GLSL 1.30. */
+					if(arg_image->dimensions==ImageTypeDeclaration::ONE || arg_image->dimensions==ImageTypeDeclaration::TWO)
+						check_extension(&Features::ext_texture_array);
+					call.name += "Array";
+				}
+
+				call.name += suffix;
 			}
 		}
 	}
-	else
-		TraversingVisitor::visit(call);
+
+	TraversingVisitor::visit(call);
 }
 
 bool LegacyConverter::supports_interface_layouts() const
diff --git a/source/glsl/finalize.h b/source/glsl/finalize.h
index 21b4e316..e0904b2e 100644
--- a/source/glsl/finalize.h
+++ b/source/glsl/finalize.h
@@ -36,7 +36,6 @@ class LegacyConverter: private TraversingVisitor
 private:
 	Stage *stage;
 	Features features;
-	std::string r_type;
 	VariableDeclaration *frag_out;
 	NodeList<Statement>::iterator uniform_insert_point;
 	std::set<Node *> nodes_to_remove;
-- 
2.43.0