From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 2 Nov 2016 22:23:08 +0000 (+0200)
Subject: Use indexed string query to get extensions on OpenGL 3.0 and above
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=bdde5adcb78836c4d75196546059ae827cf3af9e;p=libs%2Fgl.git

Use indexed string query to get extensions on OpenGL 3.0 and above
---

diff --git a/source/extension.cpp b/source/extension.cpp
index e233ee00..2183a965 100644
--- a/source/extension.cpp
+++ b/source/extension.cpp
@@ -75,10 +75,22 @@ bool is_supported(const string &ext)
 
 	if(!init_done)
 	{
-		if(const char *gl_ext = reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS)))
+		if(get_gl_api()==OPENGL && get_gl_version()>=Version(3, 0))
 		{
-			vector<string> exts = split(gl_ext);
-			extensions.insert(exts.begin(), exts.end());
+			typedef GLubyte *(APIENTRY *FPtr_glGetStringi)(GLenum, GLuint);
+			FPtr_glGetStringi glGetStringi = reinterpret_cast<FPtr_glGetStringi>(get_proc_address("glGetStringi"));
+			int n_extensions;
+			glGetIntegerv(GL_NUM_EXTENSIONS, &n_extensions);
+			for(int i=0; i<n_extensions; ++i)
+				extensions.insert(reinterpret_cast<const char *>(glGetStringi(GL_EXTENSIONS, i)));
+		}
+		else
+		{
+			if(const char *gl_ext = reinterpret_cast<const char *>(glGetString(GL_EXTENSIONS)))
+			{
+				vector<string> exts = split(gl_ext);
+				extensions.insert(exts.begin(), exts.end());
+			}
 		}
 
 		if(const char *renderer_ptr = reinterpret_cast<const char *>(glGetString(GL_RENDERER)))