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Re: glScissor and tiling memory on SGX
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05/14/2012 2:00 PM
post93060
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Re: glScissor and tiling memory on SGX
Keep in mind, you should try to cache as many rects/masks in the 8 bit
stencil buffer. Multiple rects can be stored on each plane of the
stencil. Rendering the rects/mask is more expensive then the actual
stencil test. The stencil test is extremely cheap on PVR compared to
other architectures.
-Joel
On 12-05-14 01:17 PM, Chris Keating wrote:
> Deric: Not screen per se. Just GL stack in general.
>
> Thanks Joel. I'll have to play with that some more. I initially was using
> the stencil buffer but actually noticed a performance decrease at the time
> and so I went back to using the scissor.
>
> Chris Keating
> Crank Software Inc.
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> -----Original Message-----
> From: Joel Pilon [mailto:community-noreply@qnx.com]
> Sent: May-14-12 10:10 AM
> To: opengles-graphics@community.qnx.com
> Cc: Chris Keating; Chris Keating
> Subject: Re: glScissor and tiling memory on SGX
>
> Some of our older SGX drivers had issues with non-fullscreen glScissor
> rects. However, glScissor performs badly on the SGX, and we recommend using
> the stencil buffer to clip content.
>
> -Joel
>
> On 12-05-14 09:41 AM, Chris Keating wrote:
>> Are full-screen and partial-screen glScissor calls handled differently?
>>
>> I ran into an issue where a lot of partial-screen glScissor calls where
> being made and the end result was that a lot of stuff ended up missing from
> the end rasterization. Just setting the glScissor params to (0,0,800,478)
> instead of (0,0,800,480) was enough to show this issue.
>>
>> It kind of looks like some 64x64 macro-tiles are flat out getting dropped
> on the final render. Is it possible that the partial-screen glScissor calls
> are handled differently than full-screen ones, and are causing the SGX to
> run out of internal memory for its tiling lists in this case?
>>
>> Have you seen cases where tiles/macro-tiles have been dropped altogether?
>>
>>
>>
>> _______________________________________________
>>
>> OpenGL ES
>> http://community.qnx.com/sf/go/post93044
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>
>
>
>
> _______________________________________________
>
> OpenGL ES
> http://community.qnx.com/sf/go/post93049
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> _______________________________________________
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> OpenGL ES
> http://community.qnx.com/sf/go/post93056
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