On 01/19/2012 09:58 AM, Dee Sharpe wrote:
On 1/18/2012 11:19 AM, Brian Paul wrote:
On 01/18/2012 09:01 AM, Dee Sharpe wrote:
While implementing Clear() for a platform, which buffers in
GLContext need to be cleared out of the list of:
DrawBuffer
ReadBuffer
WinSysDrawBuffer
WinSysReadBuffer
Or do they all need to be cleared?
Clearing effects "draw" buffers, not "read" buffers.
Unless a user-created FBO is bound, ctx->WinSysDrawBuffer ==
ctx->DrawBuffer.
You need to clear the color buffers attached to ctx->DrawBuffer. The
number of buffers to clear is ctx->DrawBuffer->_NumColorDrawBuffers
and the indexes/pointers to the renderbuffers is in
_ColorDrawBufferIndexes[] and _ColorDrawBuffers[].
I may actually get rid of the later (redundant) array and just write
a helper function that returns a pointer to a renderbuffer given a
buffer index.
Thanks for the quick reply. So, if I want to directly access the
renderbuffer that I designated as the front left buffer, then I need
to use _ColorDrawBuffers[BUFFER_FRONT_LEFT], correct?
No. The _ColorDrawBuffers[] array is indexed by an integer between 0
and _NumColorDrawBuffers-1. The contents of the array is updated by
calls to glDrawBuffer() or glDrawBuffersARB().
If you specifically want the front-left buffer you'd use:
ctx->DrawBuffer->Attachment[BUFFER_FRONT_LEFT]->Renderbuffer.
-Brian
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