Had trouble deciding who all to quote...... Settled on these. Combined response, GO!
I tried cloning my display to see how it would affect my framerate in StarCraft 2 but the game was forced into a low resolution for some reason and I couldn't change it. Got a whopping 118 fps! haha so that was useless. Don't feel like going through other games to test.
When the 3D scene of the Zelda demo is on both the TV and subscreen, the only way they differ is in their HUDs -- the actual 3D scene is identical. When you nudge the view around, the scene moves the same on both screens. I'm pretty confident the 3D scene itself is simply copied since it's a waste to render the scene all over again if it's exactly the same anyway. I don't mean to suggest that "simply" copying the scene to the subscreen would come free, but it should still be less taxing than rendering twice.
Here are some
examples of subscreen situations from least to most graphically compromising:
- complex 3D scene on subscreen only
- complex 3D scene on subscreen and simple 2D usage on TV
- complex 3D scene on TV only
- complex 3D scene on TV and simple 2D usage on subscreen
Continued, with a 3D scene on both screens
or with the
illusion of a 3D scene on both:
- complex 3D scene on TV, copied and downscaled to subscreen*
- complex 3D scene on TV and subscreen displaying panoramic image with sprites/objects/effects/localized animations overlayed**
- complex 3D scene on TV and panoramic video on subscreen**
- TV and subscreen displaying different views of the same complex 3D scene (rendered twice)
*What the Zelda demo is probably doing before overlaying the different HUDs. Actually, considering the 3D scene on the TV also gets smaller, it's possible the scene is rendered right at the lower resolution so it doesn't even need to be downscaled.
**Two possibilities for the bird demo if it isn't actually being rendered twice.
Orders could vary depending on the game and specific usage, but in most situations... Well, it makes sense to me at this point in time. I'm basically just thinking out loud.