[GLExtensions] Initial code drop for GLExtensions. This drops GLEW entirely from the codebase. This has been tested on Android and Linux+ATI. Of course untested on Windows and Apple. Also untested with Linux + EGL but should be fine there. There are most likely a couple of extensions I'm missing which would result in null pointer runs but not bad for the initial commit.

Conflicts:
	CMakeLists.txt
	Externals/GLew/glew.vcxproj
	Externals/GLew/glew.vcxproj.filters
	Source/Core/VideoBackends/OGL/CMakeLists.txt
	Source/Core/VideoBackends/OGL/GLFunctions.cpp
	Source/Core/VideoBackends/OGL/GLFunctions.h
	Source/Core/VideoBackends/OGL/GLUtil.h
	Source/Core/VideoBackends/OGL/Render.cpp
	Source/VSProps/Base.props

Source/Core/DolphinWX/GLInterface/AGL.cpp

@@ -26,11 +26,31 @@
 #include "../GLInterface.h"
 #include "AGL.h"
 
+// Copied from
+// https://developer.apple.com/library/mac/documentation/graphicsimaging/conceptual/opengl-macprogguide/opengl_entrypts/opengl_entrypts.html
+void* NSGLGetProcAddress (const char *name)
+{
+	NSSymbol symbol;
+	char *symbolName;
+	symbolName = malloc (strlen (name) + 2); // 1
+	strcpy(symbolName + 1, name); // 2
+	symbolName[0] = '_'; // 3
+	symbol = NULL;
+	if (NSIsSymbolNameDefined (symbolName)) // 4
+		symbol = NSLookupAndBindSymbol (symbolName);
+	free (symbolName); // 5
+	return symbol ? NSAddressOfSymbol (symbol) : NULL; // 6
+}
+
 void cInterfaceAGL::Swap()
 {
 	[GLWin.cocoaCtx flushBuffer];
 }
 
+void* cInterfaceAGL::GetProcAddress(std::string name)
+{
+	return NSGLGetProcAddress(name.c_str());
+}
 // Create rendering window.
 //		Call browser: Core.cpp:EmuThread() > main.cpp:Video_Initialize()
 bool cInterfaceAGL::Create(void *&window_handle)

Source/Core/DolphinWX/GLInterface/AGL.h

@@ -28,6 +28,7 @@ class cInterfaceAGL : public cInterfaceBase
 {
 public:
 	void Swap();
+	void* GetProcAddress(std::string name);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
 	bool ClearCurrent();

Source/Core/DolphinWX/GLInterface/EGL.cpp

@@ -35,6 +35,11 @@ void cInterfaceEGL::SwapInterval(int Interval)
 	eglSwapInterval(GLWin.egl_dpy, Interval);
 }
 
+void* cInterfaceEGL::GetProcAddress(std::string name)
+{
+	return (void*)eglGetProcAddress(name.c_str());
+}
+
 // Create rendering window.
 //		Call browser: Core.cpp:EmuThread() > main.cpp:Video_Initialize()
 bool cInterfaceEGL::Create(void *&window_handle)

Source/Core/DolphinWX/GLInterface/EGL.h

@@ -18,11 +18,7 @@
 #define _INTERFACEEGL_H_
 
 #if USE_GLES
-#ifdef USE_GLES3
-#include <GLES3/gl3.h>
-#else
-#include <GLES2/gl2.h>
-#endif
+#include <GL/gl.h>
 #else
 #include <GL/glxew.h>
 #include <GL/gl.h>
@@ -41,6 +37,7 @@ public:
 	void SwapInterval(int Interval);
 	void Swap();
 	void UpdateFPSDisplay(const char *Text);
+	void* GetProcAddress(std::string name);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
 	void Shutdown();

Source/Core/DolphinWX/GLInterface/GLX.cpp

@@ -22,6 +22,9 @@
 #include "../GLInterface.h"
 #include "GLX.h"
 
+typedef int ( * PFNGLXSWAPINTERVALSGIPROC) (int interval);
+PFNGLXSWAPINTERVALSGIPROC glXSwapIntervalSGI = NULL;
+
 // Show the current FPS
 void cInterfaceGLX::UpdateFPSDisplay(const char *text)
 {
@@ -35,6 +38,10 @@ void cInterfaceGLX::SwapInterval(int Interval)
 	else
 		ERROR_LOG(VIDEO, "No support for SwapInterval (framerate clamped to monitor refresh rate).");
 }
+void* cInterfaceGLX::GetProcAddress(std::string name)
+{
+	return (void*)glXGetProcAddress((const GLubyte*)name.c_str());
+}
 
 void cInterfaceGLX::Swap()
 {
@@ -116,6 +123,7 @@ bool cInterfaceGLX::Create(void *&window_handle)
 		PanicAlert("Unable to create GLX context.");
 		return false;
 	}
+	glXSwapIntervalSGI = (PFNGLXSWAPINTERVALSGIPROC)GLInterface->GetProcAddress("glXSwapIntervalSGI");
 
 	GLWin.x = _tx;
 	GLWin.y = _ty;

Source/Core/DolphinWX/GLInterface/GLX.h

@@ -17,8 +17,8 @@
 #ifndef _INTERFACEGLX_H_
 #define _INTERFACEGLX_H_
 
-#include <GL/glxew.h>
 #include <GL/gl.h>
+#include <GL/glx.h>
 #include <X11/Xlib.h>
 #include <X11/keysym.h>
 
@@ -34,6 +34,7 @@ public:
 	void SwapInterval(int Interval);
 	void Swap();
 	void UpdateFPSDisplay(const char *Text);
+	void* GetProcAddress(std::string name);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
 	bool ClearCurrent();

Source/Core/DolphinWX/GLInterface/InterfaceBase.h

@@ -17,6 +17,7 @@ public:
 	virtual void UpdateFPSDisplay(const char *Text) {}
 	virtual void SetMode(u32 mode) { s_opengl_mode = mode; }
 	virtual u32 GetMode() { return s_opengl_mode; }
+	virtual void* GetProcAddress(std::string name) { return NULL; }
 	virtual bool Create(void *&window_handle) { return true; }
 	virtual bool MakeCurrent() { return true; }
 	virtual bool ClearCurrent() { return true; }

Source/Core/DolphinWX/GLInterface/WGL.cpp

@@ -26,6 +26,11 @@ void cInterfaceWGL::Swap()
 	SwapBuffers(hDC);
 }
 
+void* cInterfaceWGL::GetProcAddress(std::string name)
+{
+	return (void*)wglGetProcAddress((LPCSTR)name.c_str());
+}
+
 // Draw messages on top of the screen
 bool cInterfaceWGL::PeekMessages()
 {

Source/Core/DolphinWX/GLInterface/WGL.h

@@ -19,6 +19,7 @@ public:
 	void SwapInterval(int Interval);
 	void Swap();
 	void UpdateFPSDisplay(const char *Text);
+	void* GetProcAddress(std::string name);
 	bool Create(void *&window_handle);
 	bool MakeCurrent();
 	bool ClearCurrent();