Create a fake window to check for GL extensions.

common/opengl.cpp

@@ -1075,6 +1075,8 @@ bool GL_Initialize(const char* LibraryName)
 	pfnglPopName = (PFNGLPOPNAME)Sys_GLGetProc("glPopName");
 #endif // LC_OPENGL_DYNAMIC
 
+	GL_InitializeExtensions();
+
 	return true;
 }
 
@@ -1084,31 +1086,28 @@ bool GL_Initialize(const char* LibraryName)
 bool GL_SupportsVertexBufferObject = false;
 bool GL_UseVertexBufferObject = false;
 
-static bool GL_ExtensionSupported(const char* extension)
+bool GL_ExtensionSupported(const GLubyte* Extensions, const char* Name)
 {
-	const GLubyte *extensions = NULL;
 	const GLubyte *start;
 	GLubyte *where, *terminator;
 
 	// Extension names should not have spaces.
-	where = (GLubyte*) strchr(extension, ' ');
+	where = (GLubyte*)strchr(Name, ' ');
-	if (where || *extension == '\0')
+	if (where || *Name == '\0')
 		return false;
 
-	extensions = glGetString(GL_EXTENSIONS);
+	if (!Extensions)
-
-	if (!extensions)
 		return false;
 
 	// It takes a bit of care to be fool-proof about parsing the
 	// OpenGL extensions string. Don't be fooled by sub-strings, etc.
-	for (start = extensions; ;)
+	for (start = Extensions; ;)
 	{
-		where = (GLubyte*)strstr((const char*)start, extension);
+		where = (GLubyte*)strstr((const char*)start, Name);
 		if (!where)
 			break;
 
-		terminator = where + strlen(extension);
+		terminator = where + strlen(Name);
 		if (where == start || *(where - 1) == ' ')
 			if (*terminator == ' ' || *terminator == '\0')
 				return true;
@@ -1120,9 +1119,11 @@ static bool GL_ExtensionSupported(const char* extension)
 }
 
 // Extensions can only be initialized if there's a current OpenGL context.
-void GL_InitializeExtensions()
+void GL_InitializeSharedExtensions()
 {
-	if (GL_ExtensionSupported("GL_ARB_vertex_buffer_object"))
+	const GLubyte* Extensions = glGetString(GL_EXTENSIONS);
+
+	if (GL_ExtensionSupported(Extensions, "GL_ARB_vertex_buffer_object"))
 	{
 		glBindBufferARB = (GLBINDBUFFERARBPROC)Sys_GLGetExtension("glBindBufferARB");
 		glDeleteBuffersARB = (GLDELETEBUFFERSARBPROC)Sys_GLGetExtension("glDeleteBuffersARB");

common/opengl.h

@@ -20,6 +20,8 @@
 bool GL_Initialize(const char* libname);
 void GL_Shutdown();
 void GL_InitializeExtensions();
+void GL_InitializeSharedExtensions();
+bool GL_ExtensionSupported(const GLubyte* Extensions, const char* Name);
 
 extern bool GL_SupportsVertexBufferObject;
 extern bool GL_UseVertexBufferObject;

win/glwindow.cpp

@@ -4,6 +4,16 @@
 #include "tools.h"
 #include "resource.h"
 
+typedef const char* (WINAPI * PFNWGLGETEXTENSIONSSTRINGARBPROC) (HDC hdc);
+typedef BOOL (WINAPI * PFNWGLCHOOSEPIXELFORMATARBPROC) (HDC hdc, const int* piAttribIList, const FLOAT *pfAttribFList, UINT nMaxFormats, int *piFormats, UINT *nNumFormats);
+typedef BOOL (WINAPI * PFNWGLGETPIXELFORMATATTRIBFVARBPROC) (HDC hdc, int iPixelFormat, int iLayerPlane, UINT nAttributes, const int* piAttributes, FLOAT *pfValues);
+typedef BOOL (WINAPI * PFNWGLGETPIXELFORMATATTRIBIVARBPROC) (HDC hdc, int iPixelFormat, int iLayerPlane, UINT nAttributes, const int* piAttributes, int *piValues);
+
+PFNWGLGETEXTENSIONSSTRINGARBPROC wglGetExtensionsStringARB = NULL;
+PFNWGLCHOOSEPIXELFORMATARBPROC wglChoosePixelFormatARB = NULL;
+PFNWGLGETPIXELFORMATATTRIBFVARBPROC wglGetPixelFormatAttribfvARB = NULL;
+PFNWGLGETPIXELFORMATATTRIBIVARBPROC wglGetPixelFormatAttribivARB = NULL;
+
 struct GLWindowPrivate
 {
 	HGLRC m_hrc;
@@ -144,6 +154,86 @@ LRESULT CALLBACK GLWindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam
 	return DefWindowProc(hwnd, uMsg, wParam, lParam);
 }
 
+static LRESULT CALLBACK TempWindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+{
+	if (uMsg != WM_CREATE)
+		return DefWindowProc(hWnd, uMsg, wParam, lParam);
+
+	HDC hDC = GetDC(hWnd);
+
+	PIXELFORMATDESCRIPTOR pfd;
+	memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
+
+	pfd.nSize = sizeof(PIXELFORMATDESCRIPTOR);  
+	pfd.nVersion = 1;
+	pfd.dwFlags = PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_DRAW_TO_WINDOW;
+	pfd.iPixelType = PFD_TYPE_RGBA;
+	pfd.cColorBits = 24;
+	pfd.cDepthBits = 24;
+	pfd.iLayerType = PFD_MAIN_PLANE;
+
+	int PixelFormat = ChoosePixelFormat(hDC, &pfd);
+	if (PixelFormat == 0)
+		return 0;
+
+	if (!SetPixelFormat(hDC, PixelFormat, &pfd))
+		return 0;
+
+	HGLRC hGLRC = wglCreateContext(hDC);
+	wglMakeCurrent(hDC, hGLRC);
+
+	const GLubyte* Extensions;
+
+	wglGetExtensionsStringARB = (PFNWGLGETEXTENSIONSSTRINGARBPROC)wglGetProcAddress("wglGetExtensionsStringARB");
+
+	if (wglGetExtensionsStringARB)
+		Extensions = (GLubyte*)wglGetExtensionsStringARB(wglGetCurrentDC());
+	else
+		Extensions = glGetString(GL_EXTENSIONS);
+
+	GL_InitializeSharedExtensions();
+
+	if (GL_ExtensionSupported(Extensions, "WGL_ARB_pixel_format"))
+	{
+		wglChoosePixelFormatARB = (PFNWGLCHOOSEPIXELFORMATARBPROC)wglGetProcAddress("wglChoosePixelFormatARB");
+		wglGetPixelFormatAttribfvARB = (PFNWGLGETPIXELFORMATATTRIBFVARBPROC)wglGetProcAddress("wglGetPixelFormatAttribfvARB");
+		wglGetPixelFormatAttribivARB = (PFNWGLGETPIXELFORMATATTRIBIVARBPROC)wglGetProcAddress("wglGetPixelFormatAttribivARB");
+	}
+
+	wglMakeCurrent(NULL, NULL);
+	wglDeleteContext(hGLRC);
+
+	ReleaseDC(hWnd, hDC);
+
+	return 0;
+}
+
+void GL_InitializeExtensions()
+{
+	HINSTANCE hInstance;
+	WNDCLASS wc;
+
+	hInstance = GetModuleHandle(NULL);
+
+	wc.style         = CS_OWNDC;
+	wc.lpfnWndProc   = TempWindowProc;
+	wc.cbClsExtra    = 0;
+	wc.cbWndExtra    = 0;
+	wc.hInstance     = hInstance;
+	wc.hIcon         = LoadIcon(NULL, IDI_WINLOGO);
+	wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
+	wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
+	wc.lpszMenuName  = NULL;
+	wc.lpszClassName = "LeoCADGLTempWindow";
+
+    RegisterClass(&wc);
+
+	HWND hWnd = CreateWindow(wc.lpszClassName, "LeoCAD Temp Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, NULL, NULL, hInstance, NULL);
+
+	if (hWnd)
+		DestroyWindow(hWnd);
+}
+
 // ============================================================================
 // GLWindow class
 
@@ -296,7 +386,6 @@ void GLWindow::DestroyContext()
 void GLWindow::OnInitialUpdate()
 {
 	MakeCurrent();
-	GL_InitializeExtensions();
 }
 
 bool GLWindow::MakeCurrent()