Solid Staircase Ramps (iOS/Android) Vs. Transparent Staircase Ramps (Xbox 360/PS3)

[PiN WiZ]

Just wanted to know if there was a reason why the staircase ramps on iOS and Android are solid. On the Xbox 360 and PS3 the staircase ramps are transparent, just like on the real table. Is there anyway you can update the iOS/Android table to change the ramps from solid to transparent?

 

[Mike Reitmeyer]

It's for performance reasons. Most platforms the slowdown comes from Overdraw and Fill. When drawing those transparent ramps, you have to draw whats behind them first, then draw the transparency on top. This overdraw requires rendering those pixels more then once which is a big performance hit. The larger the transparent object, the worse it gets. With the ramps being opaque, we can render the ramp, then not render what's behind it, thus reducing the overdraw.

Also transparent objects usually have larger textures (for the alpha channel) and this is also a performance hit (bandwitdth) because you have to pass larger texture data through the GPU.

 

[PiN WiZ]

It's for performance reasons. Most platforms the slowdown comes from Overdraw and Fill. When drawing those transparent ramps, you have to draw whats behind them first, then draw the transparency on top. This overdraw requires rendering those pixels more then once which is a big performance hit. The larger the transparent object, the worse it gets. With the ramps being opaque, we can render the ramp, then not render what's behind it, thus reducing the overdraw.

Also transparent objects usually have larger textures (for the alpha channel) and this is also a performance hit (bandwitdth) because you have to pass larger texture data through the GPU.

So, does this mean that TOTAN is less taxing on the cpu since you were able to include all the transparent ramps on that table?