Does ARM GPU automatically detect and fix overdraw in certain situation or does it use direct rendering as mentioned on Romain Guy article below? Care to elaborate more what's the pros and cons using the autofix overdraw and direct rendering in order to reduce jank in animation, scrolling, and overall UI responsiveness on Android? :)
No, it doesn't. The reason is Android's HWUI doesn't use the Z-buffer at all, every draw command has the same Z depth as far as the GPU is concerned, draw ordering is what determines what you see and what you don't. This is because GUIs are typically full of alpha blended geometry (text, images with alpha channels, etc...) and that *must* be drawn back-to-front thereby resulting in the GPU not knowing it could have rejected a pixel until long after it already drew the pixel.
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chrone - Monday, July 7, 2014 - link
Does ARM GPU automatically detect and fix overdraw in certain situation or does it use direct rendering as mentioned on Romain Guy article below? Care to elaborate more what's the pros and cons using the autofix overdraw and direct rendering in order to reduce jank in animation, scrolling, and overall UI responsiveness on Android? :)http://www.curious-creature.org/2012/12/01/android...
kg4icg - Monday, July 7, 2014 - link
ask during the hangout which will start in roughly 15 minutes,chrone - Monday, July 7, 2014 - link
Thanks dude, I will. :)kllrnohj - Tuesday, July 8, 2014 - link
No, it doesn't. The reason is Android's HWUI doesn't use the Z-buffer at all, every draw command has the same Z depth as far as the GPU is concerned, draw ordering is what determines what you see and what you don't. This is because GUIs are typically full of alpha blended geometry (text, images with alpha channels, etc...) and that *must* be drawn back-to-front thereby resulting in the GPU not knowing it could have rejected a pixel until long after it already drew the pixel.Carolynsa - Monday, August 15, 2016 - link
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