From 798703e937da6b4bbbc4a33f6670ca6fa61e47c3 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 25 Nov 2013 17:25:22 +0200
Subject: [PATCH] Check and report the use of legacy built-in variables in a
 program

---
 source/program.cpp | 15 +++++++++++++++
 source/program.h   |  3 +++
 2 files changed, 18 insertions(+)

diff --git a/source/program.cpp b/source/program.cpp
index 111cf64b..ffdd3b63 100644
--- a/source/program.cpp
+++ b/source/program.cpp
@@ -94,6 +94,7 @@ void Program::link()
 			(*i)->compile();
 
 	uniforms.clear();
+	legacy_vars = false;
 
 	glLinkProgram(id);
 	int value;
@@ -127,6 +128,20 @@ void Program::link()
 			info.type = type;
 			uniforms_by_index[i] = &info;
 		}
+		else
+			legacy_vars = true;
+	}
+
+	glGetProgramiv(id, GL_ACTIVE_ATTRIBUTES, &count);
+	for(int i=0; i<count; ++i)
+	{
+		char name[128];
+		int len = 0;
+		int size;
+		GLenum type;
+		glGetActiveAttrib(id, i, sizeof(name), &len, &size, &type, name);
+		if(len && !strncmp(name, "gl_", 3))
+			legacy_vars = true;
 	}
 
 	if(ARB_uniform_buffer_object)
diff --git a/source/program.h b/source/program.h
index 8cdfb6de..a7622ecb 100644
--- a/source/program.h
+++ b/source/program.h
@@ -64,6 +64,7 @@ private:
 	UniformBlockMap uniform_blocks;
 	UniformMap uniforms;
 	unsigned uniform_layout_hash;
+	bool legacy_vars;
 
 public:
 	Program();
@@ -96,6 +97,8 @@ public:
 	const UniformInfo &get_uniform_info(const std::string &) const;
 	int get_uniform_location(const std::string &) const;
 
+	bool uses_legacy_variables() const { return legacy_vars; }
+
 	void bind() const;
 	static void unbind();
 };
-- 
2.43.0