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Make backface culling be part of the legacy state

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This adds an internal function to set the backface culling state on a
pipeline. This includes properties to set the culling mode (front,
back or both) and also to set which face is considered the front
(COGL_WINDING_CLOCKWISE or COGL_WINDING_COUNTER_CLOCKWISE). The actual
front face flushed to GL depends on whether we are rendering to an
offscreen buffer or not. This means that when changing between on- and
off- screen framebuffers it now checks whether the last flushed
pipeline has backface culling enabled and forces a reflush of the cull
face state if so.

The backface culling is now set on a pipeline as part of the legacy
state. This is important because some code in Cogl assumes it can
flush a temporary pipeline to revert to a known state, but previously
this wouldn't disable backface culling so things such as flushing the
clip stack could get confused.

Reviewed-by: Robert Bragg <robert@linux.intel.com>
This commit is contained in:
Neil Roberts
2011-09-15 11:25:39 +01:00
committed by Robert Bragg
parent 879ce7301a
commit dbff3a357e
12 changed files with 258 additions and 103 deletions
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90
cogl/cogl-pipeline-state.c
View File

@ -209,6 +209,27 @@ _cogl_pipeline_logic_ops_state_equal (CoglPipeline *authority0,
return logic_ops_state0->color_mask == logic_ops_state1->color_mask;
}
gboolean
_cogl_pipeline_cull_face_state_equal (CoglPipeline *authority0,
CoglPipeline *authority1)
{
CoglPipelineCullFaceState *cull_face_state0
= &authority0->big_state->cull_face_state;
CoglPipelineCullFaceState *cull_face_state1
= &authority1->big_state->cull_face_state;
/* The cull face state is considered equal if two pipelines are both
set to no culling. If the front winding property is ever used for
anything else or the comparison is used not just for drawing then
this would have to change */
if (cull_face_state0->mode == COGL_PIPELINE_CULL_FACE_MODE_NONE)
return cull_face_state1->mode == COGL_PIPELINE_CULL_FACE_MODE_NONE;
return (cull_face_state0->mode == cull_face_state1->mode &&
cull_face_state0->front_winding == cull_face_state1->front_winding);
}
gboolean
_cogl_pipeline_user_shader_equal (CoglPipeline *authority0,
CoglPipeline *authority1)
@ -1155,6 +1176,52 @@ _cogl_pipeline_set_fog_state (CoglPipeline *pipeline,
_cogl_pipeline_fog_state_equal);
}
void
_cogl_pipeline_set_cull_face_state (CoglPipeline *pipeline,
const CoglPipelineCullFaceState *
cull_face_state)
{
CoglPipelineState state = COGL_PIPELINE_STATE_CULL_FACE;
CoglPipeline *authority;
CoglPipelineCullFaceState *current_cull_face_state;
g_return_if_fail (cogl_is_pipeline (pipeline));
authority = _cogl_pipeline_get_authority (pipeline, state);
current_cull_face_state = &authority->big_state->cull_face_state;
if (current_cull_face_state->mode == cull_face_state->mode &&
current_cull_face_state->front_winding == cull_face_state->front_winding)
return;
/* - Flush journal primitives referencing the current state.
* - Make sure the pipeline has no dependants so it may be modified.
* - If the pipeline isn't currently an authority for the state being
* changed, then initialize that state from the current authority.
*/
_cogl_pipeline_pre_change_notify (pipeline, state, NULL, FALSE);
pipeline->big_state->cull_face_state = *cull_face_state;
_cogl_pipeline_update_authority (pipeline, authority, state,
_cogl_pipeline_cull_face_state_equal);
}
CoglPipelineCullFaceMode
_cogl_pipeline_get_cull_face_mode (CoglPipeline *pipeline)
{
CoglPipelineState state = COGL_PIPELINE_STATE_CULL_FACE;
CoglPipeline *authority;
g_return_val_if_fail (cogl_is_pipeline (pipeline),
COGL_PIPELINE_CULL_FACE_MODE_NONE);
authority = _cogl_pipeline_get_authority (pipeline, state);
return authority->big_state->cull_face_state.mode;
}
float
cogl_pipeline_get_point_size (CoglPipeline *pipeline)
{
@ -1365,3 +1432,26 @@ _cogl_pipeline_hash_logic_ops_state (CoglPipeline *authority,
state->hash = _cogl_util_one_at_a_time_hash (state->hash, &logic_ops_state->color_mask,
sizeof (CoglColorMask));
}
void
_cogl_pipeline_hash_cull_face_state (CoglPipeline *authority,
CoglPipelineHashState *state)
{
CoglPipelineCullFaceState *cull_face_state
= &authority->big_state->cull_face_state;
/* The cull face state is considered equal if two pipelines are both
set to no culling. If the front winding property is ever used for
anything else or the hashing is used not just for drawing then
this would have to change */
if (cull_face_state->mode == COGL_PIPELINE_CULL_FACE_MODE_NONE)
state->hash =
_cogl_util_one_at_a_time_hash (state->hash,
&cull_face_state->mode,
sizeof (CoglPipelineCullFaceMode));
else
state->hash =
_cogl_util_one_at_a_time_hash (state->hash,
cull_face_state,
sizeof (CoglPipelineCullFaceState));
}