(Hopefully) fix Editors messing up game viewport for good, fix #300

I worked around the issue for the particle editor, but now it turned out
it can also somehow happen when switching from the Radiant to the Engine
(with F2), so I implemented the "proper" fix of restoring
glConfig.vidWidth/Height, that are overwritten in
RenderSystemLocal::BeginFrame(), in RenderSystemLocal::EndFrame().

neo/renderer/RenderSystem.cpp

@@ -610,13 +610,11 @@ void idRenderSystemLocal::BeginFrame( int windowWidth, int windowHeight ) {
 		windowHeight = tiledViewport[1];
 	}
 
-	// DG: FIXME: WTF?! this is *not* reset in EndFrame() and next time
+	// DG: save the original size, so editors don't mess up the game viewport
-	//     idSessionLocal::UpdateScreen() calls this function to render a proper frame,
+	//     with their tiny (texture-preview etc) viewports.
-	//     passing renderSystem->GetScreenWidth()/Height() WHICH JUST RETURN glConfig.vidWidth/Height
+	origWidth = glConfig.vidWidth;
-	//     will render the whole frame in that resolution (in a corner of the window), unless someone
+	origHeight = glConfig.vidHeight;
-	//     resets glConfig.vid* manually... this is quite fragile, I wonder how many (more) bugs 
+
-	//     (esp. in Editor code) will turn up because of this, but right now I don't dare to change
-	//     the behavior either, in case "fixing" it breaks other things
 	glConfig.vidWidth = windowWidth;
 	glConfig.vidHeight = windowHeight;
 
@@ -730,6 +728,12 @@ void idRenderSystemLocal::EndFrame( int *frontEndMsec, int *backEndMsec ) {
 		}
 	}
 
+	// DG: restore the original size that was set before BeginFrame() overwrote it
+	//     with its function-arguments, so editors don't mess up our viewport.
+	//     (unsure why/how this at least *kinda* worked in original Doom3,
+	//      maybe glConfig.vidWidth/Height was reset if the window gained focus or sth)
+	glConfig.vidWidth = origWidth;
+	glConfig.vidHeight = origHeight;
 }
 
 /*

neo/renderer/RenderSystem_init.cpp

@@ -2143,6 +2143,8 @@ void idRenderSystemLocal::Init( void ) {
 	identitySpace.modelMatrix[0*4+0] = 1.0f;
 	identitySpace.modelMatrix[1*4+1] = 1.0f;
 	identitySpace.modelMatrix[2*4+2] = 1.0f;
+
+	origWidth = origHeight = 0; // DG: for resetting width/height in EndFrame()
 }
 
 /*

neo/renderer/tr_local.h

@@ -796,6 +796,11 @@ public:
 	int						guiRecursionLevel;		// to prevent infinite overruns
 	class idGuiModel *		guiModel;
 	class idGuiModel *		demoGuiModel;
+
+	// DG: remember the original glConfig.vidWidth/Height values that get overwritten in BeginFrame()
+	//     so they can be reset in EndFrame() (Editors tend to mess up the viewport by using BeginFrame())
+	int						origWidth;
+	int						origHeight;
 };
 
 extern backEndState_t		backEnd;

neo/tools/radiant/GLWidget.cpp

@@ -446,18 +446,6 @@ void idGLDrawableMaterial::draw(int x, int y, int w, int h) {
 
 		renderView_t	refdef;
 		
-		// DG: renderSystem->BeginFrame() changes glConfig.vidWidth and vidHeight to w and h
-		//     that is never reset automatically and for some reason glConfig.vidWith/height is even
-		//     used for renderSystem->GetScreenWidth()/Height() so idSessionLocal::UpdateScreen()
-		//     which calls renderSystem->BeginFrame( renderSystem->GetScreenWidth(), renderSystem->GetScreenHeight() );
-		//     won't reset those values to something sane either, causing the game to be rendered in a tiny rectangle
-		//     at the lower left corner of the screen once we're done picking a material here..
-		//     I don't dare to fix this in renderSystem, as other code might rely on this behavior..
-		//     (OTOH I wouldn't be surprised if other callers of renderSystem->BeginFrame() cause the same issue)
-		//     Anyway, my workaround is to remember glConfig.vidWith/Height and set them to the original
-		//     values once we're done rendering here..
-		int oldWidth  = glConfig.vidWidth;
-		int oldHeight = glConfig.vidHeight;
 		// render it
 		renderSystem->BeginFrame(w, h);
 		memset( &refdef, 0, sizeof( refdef ) );
@@ -482,9 +470,6 @@ void idGLDrawableMaterial::draw(int x, int y, int w, int h) {
 
 		qglMatrixMode( GL_MODELVIEW );
 		qglLoadIdentity();
-		// DG: reset glConfig.vidWidth/Height
-		glConfig.vidWidth = oldWidth;
-		glConfig.vidHeight = oldHeight;
 	}
 
 }