From cb91a6133e1671a4d51a39429ccb35726da9be0d Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 20 Oct 2014 02:33:59 +0300
Subject: [PATCH] The GLSL texture function returns a float for shadow samplers

In contrast with the legacy shadow2D function, which returned vec4.
---
 source/programbuilder.cpp | 36 +++++++++++++++++++++++++++++++++---
 source/programbuilder.h   |  2 +-
 2 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/source/programbuilder.cpp b/source/programbuilder.cpp
index 55d2cf22..3fb9094c 100644
--- a/source/programbuilder.cpp
+++ b/source/programbuilder.cpp
@@ -95,7 +95,7 @@ const ProgramBuilder::VariableDefinition ProgramBuilder::standard_variables[] =
 	{ FRAGMENT, "l_diffuse[i]", "float", "max(dot(n_zzz_normal, n_zzz_light_dir[i]), 0.0)", 0 },
 
 	{ FRAGMENT, "l_shadow", "float", "mix(1.0, shadow_sample, shadow_darkness)", 0 },
-	{ FRAGMENT, "shadow_sample", "float", "shadow2D(shadow, shd_vertex).r", 0 },
+	{ FRAGMENT, "shadow_sample", "float", "shadow2D(shadow, shd_vertex)", 0 },
 
 	{ FRAGMENT, "zzz_reflect_dir", "vec3", "reflect(zzz_incident_dir, n_zzz_normal)", 0 },
 	{ FRAGMENT, "n_zzz_half_vec[i]", "vec3", "normalize(zzz_light_dir[i]-zzz_incident_dir)", 0 },
@@ -241,6 +241,8 @@ ProgramBuilder::ProgramBuilder(const StandardFeatures &f):
 		aliases["texture2D"] = "texture";
 		aliases["shadow2D"] = "texture";
 	}
+	else
+		aliases["shadow2D"] = "shadow2D(...).r";
 }
 
 void ProgramBuilder::set_optimize(bool o)
@@ -650,7 +652,7 @@ vector<string> ProgramBuilder::extract_identifiers(const char *expression)
 	return result;
 }
 
-string ProgramBuilder::replace_identifiers(const char *expression, const map<string, string> &replace_map)
+string ProgramBuilder::replace_identifiers(const char *expression, const map<string, string> &replace_map, bool with_functions)
 {
 	string result;
 	const char *ptr = expression;
@@ -662,7 +664,35 @@ string ProgramBuilder::replace_identifiers(const char *expression, const map<str
 		string identifier(ptr+start, length);
 		map<string, string>::const_iterator i = replace_map.find(identifier);
 		if(i!=replace_map.end())
+		{
+			if(with_functions && ptr[start+length]=='(')
+			{
+				string::size_type lparen = i->second.find('(');
+				string::size_type rparen = i->second.rfind(')');
+				if(lparen!=string::npos && rparen!=string::npos)
+				{
+					unsigned level = 1;
+					unsigned j;
+					for(j=start+length+1; (ptr[j] && level); ++j)
+					{
+						level += (ptr[j]=='(');
+						level -= (ptr[j]==')');
+					}
+
+					if(!level)
+					{
+						string subexpr(ptr+start+length, ptr+j);
+						result += i->second.substr(0, lparen);
+						result += replace_identifiers(subexpr.c_str(), replace_map, with_functions);
+						result += i->second.substr(rparen+1);
+						ptr += j;
+						continue;
+					}
+				}
+			}
+
 			result += i->second;
+		}
 		else
 			result += identifier;
 		ptr += start+length;
@@ -674,7 +704,7 @@ string ProgramBuilder::replace_identifiers(const char *expression, const map<str
 string ProgramBuilder::create_expression(const ShaderVariable &var, const char *loop) const
 {
 	string expr = var.create_expression(loop);
-	return replace_identifiers(expr.c_str(), aliases);
+	return replace_identifiers(expr.c_str(), aliases, true);
 }
 
 
diff --git a/source/programbuilder.h b/source/programbuilder.h
index 9ca9c853..62d8e07a 100644
--- a/source/programbuilder.h
+++ b/source/programbuilder.h
@@ -147,7 +147,7 @@ private:
 	static MatchType name_match(const char *, const char *, const char ** = 0);
 	static bool parse_identifier(const char *, unsigned &, unsigned &);
 	static std::vector<std::string> extract_identifiers(const char *);
-	static std::string replace_identifiers(const char *, const std::map<std::string, std::string> &);
+	static std::string replace_identifiers(const char *, const std::map<std::string, std::string> &, bool = false);
 	std::string create_expression(const ShaderVariable &, const char * = 0) const;
 };
 
-- 
2.43.0