Fix FBO_*() usage when framebuffers are unavailable or undesired.

code/rend2/tr_cmds.c

@@ -498,12 +498,7 @@ void RE_BeginFrame( stereoFrame_t stereoFrame ) {
 				backEnd.colorMask[2] = GL_FALSE;
 				backEnd.colorMask[3] = GL_FALSE;
 				qglClearColor(0.0f, 0.0f, 0.0f, 1.0f);
-				
-				qglDrawBuffer(GL_FRONT);
-				qglClear(GL_COLOR_BUFFER_BIT);
-				qglDrawBuffer(GL_BACK);
-				qglClear(GL_COLOR_BUFFER_BIT);
-				
+								
 				if (glRefConfig.framebufferObject)
 				{
 					// clear all framebuffers
@@ -530,15 +525,17 @@ void RE_BeginFrame( stereoFrame_t stereoFrame ) {
 								break;
 						}
 
-						qglDrawBuffer(GL_FRONT);
 						qglClear(GL_COLOR_BUFFER_BIT);
-						qglDrawBuffer(GL_BACK);
-						qglClear(GL_COLOR_BUFFER_BIT);	
 					}
 
 					FBO_Bind(NULL);
 				}
 
+				qglDrawBuffer(GL_FRONT);
+				qglClear(GL_COLOR_BUFFER_BIT);
+				qglDrawBuffer(GL_BACK);
+				qglClear(GL_COLOR_BUFFER_BIT);
+
 				r_anaglyphMode->modified = qfalse;
 			}