- changed minimum required GL version to 1.3. The only 1.4 feature that's required is mipmap generation which on many older cards is available as an extension. The worst thing that can happen with relaxing the version requirement is that on a few ancient graphics cards the mipmapped texture filtering modes produce garbage.

src/gl/system/gl_interface.cpp

@@ -42,6 +42,7 @@
 #include "zstring.h"
 #include "version.h"
 #include "i_system.h"
+#include "v_text.h"
 #include "gl/system/gl_cvars.h"
 
 #if defined (__unix__) || defined (__APPLE__)
@@ -207,10 +208,16 @@ void gl_LoadExtensions()
 
 	const char *version = (const char*)glGetString(GL_VERSION);
 
-	// Don't even start if it's lower than 1.4
-	if (strcmp(version, "1.4") < 0) 
+	// Don't even start if it's lower than 1.3
+	if (strcmp(version, "1.3") < 0) 
 	{
-		I_FatalError("Unsupported OpenGL version.\nAt least GL 1.4 is required to run " GAMENAME ".\n");
+		I_FatalError("Unsupported OpenGL version.\nAt least GL 1.3 is required to run " GAMENAME ".\n");
+	}
+	else if (strcmp(version, "1.4") < 0) 
+	{
+		// The engine will still assume 1.4 but the only 1.4 feature being used is GL_GENERATE_MIPMAP which should be supported as an extension
+		// on most 1.3 cards this is present but let's print a warning that not everything may work as intended.
+		Printf(TEXTCOLOR_RED "The current graphics driver implements a OpenGL version lower than 1.4 and may not support all features " GAMENAME " requires.\n");
 	}
 
 	// This loads any function pointers and flags that require a vaild render context to