[Mesa-dev] [PATCH] mesa: don't map depth+stencil buffer twice in glReadPixels()

[Brian Paul]

On 11/16/2011 09:54 AM, Vadim Girlin wrote:
> On Wed, 2011-11-16 at 20:41 +0400, Vadim Girlin wrote:
>> On Wed, 2011-11-16 at 07:53 -0700, Brian Paul wrote:
>>> In slow_read_depth_stencil_pixels_separate() we might have separate
>>> depth and stencil buffers or a combined buffer.  In the later case,
>>> don't map the buffer twice.  This function is used when the depth
>>> scale/bias pixel transfer values are not the defaults.
>>>
>>> Fixes http://bugs.freedesktop.org/show_bug.cgi?id=42963
>>> ---
>>>   src/mesa/main/readpix.c |   14 +++++++++++---
>>>   1 files changed, 11 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/src/mesa/main/readpix.c b/src/mesa/main/readpix.c
>>> index 8550618..0b41de6 100644
>>> --- a/src/mesa/main/readpix.c
>>> +++ b/src/mesa/main/readpix.c
>>> @@ -402,10 +402,16 @@ slow_read_depth_stencil_pixels_separate(struct gl_context *ctx,
>>>      GLubyte *depthMap, *stencilMap;
>>>      int depthStride, stencilStride, j;
>>>
>>> +   /* The depth and stencil buffers might be separate, or a single buffer.
>>> +    * If one buffer, only map it once.
>>> +    */
>>>      ctx->Driver.MapRenderbuffer(ctx, depthRb, x, y, width, height,
>>>   			       GL_MAP_READ_BIT,&depthMap,&depthStride);
>>> -   ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
>>> -			       GL_MAP_READ_BIT,&stencilMap,&stencilStride);
>>> +   if (stencilRb != depthRb) {
>>> +      ctx->Driver.MapRenderbuffer(ctx, stencilRb, x, y, width, height,
>>> +                                  GL_MAP_READ_BIT,&stencilMap,
>>> +&stencilStride);
>>> +   }
>>>
>>
>> Probably we want the following here:
>>
>>     else
>>        stencilMap = depthMap;
>>
>>
>
> And I also forgot stencilStride.
>
> Vadim

Thanks for catching that.  I'll post a new patch.

-Brian