- allow OpenGL 3.0 MESA drivers to use vid_glswfb

src/gl/system/gl_interface.cpp

@@ -43,6 +43,7 @@ static TArray<FString>  m_Extensions;
 RenderContext gl;
 
 EXTERN_CVAR(Bool, gl_legacy_mode)
+EXTERN_CVAR(Bool, vid_glswfb)
 
 //==========================================================================
 //
@@ -207,7 +208,8 @@ void gl_LoadExtensions()
 	
 		// The minimum requirement for the modern render path is GL 3.3.
 		// Although some GL 3.1 or 3.2 solutions may theoretically work they are usually too broken or too slow.
-		if (gl_version < 3.3f)
+		// unless, of course, we're simply using this as a software backend...
+		if (gl_version < 3.3f && (!vid_glswfb || gl_version < 3.0f))
 		{
 			gl.legacyMode = true;
 			gl.lightmethod = LM_LEGACY;

src/gl/system/gl_swframebuffer.cpp

@@ -200,12 +200,7 @@ OpenGLSWFrameBuffer::OpenGLSWFrameBuffer(void *hMonitor, int width, int height,
 	bool isGLES = (glversion && strlen(glversion) > 10 && memcmp(glversion, "OpenGL ES ", 10) == 0);
 
 	UCVarValue value;
-	// GL 3.0 is mostly broken on MESA drivers which really are the only relevant case here that doesn't fulfill the requirements based on version number alone.
-#ifdef _WIN32
 	value.Bool = !ogl_IsVersionGEQ(3, 0);
-#else
-	value.Bool = !ogl_IsVersionGEQ(3, 1);
-#endif
 	gl_legacy_mode.ForceSet (value, CVAR_Bool);
 
 	if (!isGLES && ogl_IsVersionGEQ(3, 0) == 0)