OPENGL: Refactor GL extension handling slightly.

5 files changed, 35 insertions, 10 deletions

diff --git a/backends/graphics/opengl/extensions.cpp b/backends/graphics/opengl/extensions.cpp
index 4482ef82b5..c76f8d7ca6 100644
--- a/backends/graphics/opengl/extensions.cpp
+++ b/backends/graphics/opengl/extensions.cpp
@@ -22,25 +22,30 @@
 
 #include "backends/graphics/opengl/extensions.h"
 #include "backends/graphics/opengl/opengl-sys.h"
+#include "backends/graphics/opengl/opengl-graphics.h"
 
 #include "common/tokenizer.h"
 
 namespace OpenGL {
 
-bool g_extNPOTSupported = false;
+void ExtensionsDesc::reset() {
+	NPOTSupported = false;
+}
+
+ExtensionsDesc g_extensions;
 
-void initializeGLExtensions() {
+void OpenGLGraphicsManager::initializeGLExtensions() {
 	const char *extString = (const char *)glGetString(GL_EXTENSIONS);
 
 	// Initialize default state.
-	g_extNPOTSupported = false;
+	g_extensions.reset();
 
 	Common::StringTokenizer tokenizer(extString, " ");
 	while (!tokenizer.empty()) {
 		Common::String token = tokenizer.nextToken();
 
 		if (token == "GL_ARB_texture_non_power_of_two") {
-			g_extNPOTSupported = true;
+			g_extensions.NPOTSupported = true;
 		}
 	}
 }
diff --git a/backends/graphics/opengl/extensions.h b/backends/graphics/opengl/extensions.h
index 87452429e2..5b9eb538d9 100644
--- a/backends/graphics/opengl/extensions.h
+++ b/backends/graphics/opengl/extensions.h
@@ -26,15 +26,28 @@
 namespace OpenGL {
 
 /**
- * Checks for availability of extensions we want to use and initializes them
- * when available.
+ * Description structure of all available extensions.
+ *
+ * This includes information whether extensions we are interested in is
+ * available or not. If extensions we are interested in add additional
+ * functions, we keep function pointers around in here too.
  */
-void initializeGLExtensions();
+struct ExtensionsDesc {
+	/**
+	 * Reset extension state.
+	 *
+	 * This marks all extensions as unavailable.
+	 */
+	void reset();
+
+	/** Whether GL_ARB_texture_non_power_of_two is available or not. */
+	bool NPOTSupported;
+};
 
 /**
- * Whether non power of two textures are supported
+ * Description of all available extensions.
  */
-extern bool g_extNPOTSupported;
+extern ExtensionsDesc g_extensions;
 
 } // End of namespace OpenGL
 
diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index ac6d41d47d..d738f31a37 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -58,6 +58,7 @@ OpenGLGraphicsManager::OpenGLGraphicsManager()
 #endif
     {
 	memset(_gamePalette, 0, sizeof(_gamePalette));
+	g_extensions.reset();
 }
 
 OpenGLGraphicsManager::~OpenGLGraphicsManager() {
diff --git a/backends/graphics/opengl/opengl-graphics.h b/backends/graphics/opengl/opengl-graphics.h
index 9578839383..2a03b878ce 100644
--- a/backends/graphics/opengl/opengl-graphics.h
+++ b/backends/graphics/opengl/opengl-graphics.h
@@ -281,6 +281,12 @@ private:
 	//
 
 	/**
+	 * Checks for availability of extensions we want to use and initializes them
+	 * when available.
+	 */
+	void initializeGLExtensions();
+
+	/**
 	 * Try to determine the internal parameters for a given pixel format.
 	 *
 	 * @return true when the format can be used, false otherwise.
diff --git a/backends/graphics/opengl/texture.cpp b/backends/graphics/opengl/texture.cpp
index 7b0b22d630..36fe5ab744 100644
--- a/backends/graphics/opengl/texture.cpp
+++ b/backends/graphics/opengl/texture.cpp
@@ -105,7 +105,7 @@ void Texture::enableLinearFiltering(bool enable) {
 
 void Texture::allocate(uint width, uint height) {
 	uint texWidth = width, texHeight = height;
-	if (!g_extNPOTSupported) {
+	if (!g_extensions.NPOTSupported) {
 		texWidth  = nextHigher2(texWidth);
 		texHeight = nextHigher2(texHeight);
 	}