fix fullscreen on OS X: wtf?

Author: guregu

engi_glfw.go

@@ -83,15 +83,13 @@ func run(title string, width, height int, fullscreen bool) {
 	gl.Viewport(0, 0, width, height)
 
 	window.SetFramebufferSizeCallback(func(window *glfw.Window, w, h int) {
-		log.Println("RESIZE", width, height, "=>", w, h)
 		oldWidth, oldHeight := width, height
 		width, height = window.GetFramebufferSize()
-		log.Println("BUFSIZE", width, height)
-		if oldWidth == 0 && oldHeight == 0 {
-			gl.Viewport(0, 0, w, h)
-		} else {
-			// this fixes Intel drivers on OS X, idk why
+		if runtime.GOOS == "darwin" && oldWidth/2 == w && oldHeight/2 == h {
+			// I have no idea why, but this fixes fullscreen on OS X w/ retina
 			gl.Viewport(0, h, w, h)
+		} else {
+			gl.Viewport(0, 0, w, h)
 		}
 		responder.Resize(w, h)
 	})