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Combined vs individual glClear performance

Hi,

Basically I wanted to know if calling glClear with all buffers bits to clear is faster than clearing them all individually.

So:

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

is faster thabn:

glClear(GL_COLOR_BUFFER_BIT);
glClear(GL_DEPTH_BUFFER_BIT);

Cheers!

Parents
  • It depends on where the clears are. 

    If they are before any glDraw...() calls in the render pass, then they will be combined. On Mali this is a free "start of tile" initialization.

    If they are after any draws then they will not be combined, and will be a "not free" shader-based clear.

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  • It depends on where the clears are. 

    If they are before any glDraw...() calls in the render pass, then they will be combined. On Mali this is a free "start of tile" initialization.

    If they are after any draws then they will not be combined, and will be a "not free" shader-based clear.

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