| DarkTemplar said: This is what we usually call a Corner Case. When the viewport is similar it becomes more like running the game at twice the framerate. Notice that everything is still being processed twice. |
I think that the dual rendering (talking about 3D output, not when the gamepad only is outputting a 2D menu or something like that) adds a dangerous factor, fluctuating performance. Let's say that both are showing a viewport of the scene. If the output of both are on a similar region, textures and 3D models will be the same and will be cached. Now, if they are showing different parts of the scene, we will have more textures and more 3D models, so performance will likely decrease. My point is that changing the vieport in one of the outputs will make performance decrease without any change on the scene and that is harder to optimize.
Anyway, the slow part is rasterization and it will be done twice unless the image is the same on both. But the situation above made me think about how it will handle cache here. Basically, if the models, textures, etc are different on both outputs at some degree, wouldn't it just kill caching performance, since it would need more cache on GPU to store all that data?
