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disable viewport scissor workaround for clear

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We have a workaround in Cogl to fix viewport clipping with Mesa Intel
Gen 6 drivers but this was breaking the semantics of
cogl_framebuffer_clear() which should not be affected by viewport
clipping. This makes sure we disable and restore the workaround when
clearing the framebuffer. This fixes Clutter's test-cogl-viewport
conformance test.
This commit is contained in:
Robert Bragg 2013-01-21 15:35:16 +00:00
parent 3a041ef41b
commit 1d31055ddb
1 changed files with 37 additions and 0 deletions
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37
cogl/cogl-framebuffer.c
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@ -244,11 +244,13 @@ cogl_framebuffer_clear4f (CoglFramebuffer *framebuffer,
float blue,
float alpha)
{
CoglContext *ctx = framebuffer->context;
CoglClipStack *clip_stack = _cogl_framebuffer_get_clip_stack (framebuffer);
int scissor_x0;
int scissor_y0;
int scissor_x1;
int scissor_y1;
CoglBool saved_viewport_scissor_workaround;
_cogl_clip_stack_get_bounds (clip_stack,
&scissor_x0, &scissor_y0,
@ -336,6 +338,31 @@ cogl_framebuffer_clear4f (CoglFramebuffer *framebuffer,
_cogl_framebuffer_flush_journal (framebuffer);
/* XXX: ONGOING BUG: Intel viewport scissor
*
* The semantics of cogl_framebuffer_clear() are that it should not
* be affected by the current viewport and so if we are currently
* applying a workaround for viewport scissoring we need to
* temporarily disable the workaround before clearing so any
* special scissoring for the workaround will be removed first.
*
* Note: we only need to disable the workaround if the current
* viewport doesn't match the framebuffer's size since otherwise
* the workaround wont affect clearing anyway.
*/
if (ctx->needs_viewport_scissor_workaround &&
(framebuffer->viewport_x != 0 ||
framebuffer->viewport_y != 0 ||
framebuffer->viewport_width != framebuffer->width ||
framebuffer->viewport_height != framebuffer->height))
{
saved_viewport_scissor_workaround = TRUE;
ctx->needs_viewport_scissor_workaround = FALSE;
ctx->current_draw_buffer_changes |= COGL_FRAMEBUFFER_STATE_CLIP;
}
else
saved_viewport_scissor_workaround = FALSE;
/* NB: _cogl_framebuffer_flush_state may disrupt various state (such
* as the pipeline state) when flushing the clip stack, so should
* always be done first when preparing to draw. */
@ -345,6 +372,16 @@ cogl_framebuffer_clear4f (CoglFramebuffer *framebuffer,
_cogl_framebuffer_clear_without_flush4f (framebuffer, buffers,
red, green, blue, alpha);
/* XXX: ONGOING BUG: Intel viewport scissor
*
* See comment about temporarily disabling this workaround above
*/
if (saved_viewport_scissor_workaround)
{
ctx->needs_viewport_scissor_workaround = TRUE;
ctx->current_draw_buffer_changes |= COGL_FRAMEBUFFER_STATE_CLIP;
}
/* This is a debugging variable used to visually display the quad
* batches from the journal. It is reset here to increase the
* chances of getting the same colours for each frame during an