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mutter-performance-source/cogl/cogl-clip-state.h
Neil Roberts 30c4678ff4 cogl: Implement retained clip stacks
This adds three new internal API functions which can be used to retain
the clip stack state and restore it later:

 _cogl_get_clip_stack
 _cogl_set_clip_stack
 _cogl_clip_stack_copy

The functions are currently internal and not yet used but we may want
to make them public in future to replace the cogl_clip_stack_save()
and cogl_clip_stack_restore() APIs.

The get function just returns the handle to the clip stack at the top
of the stack of stacks and the set function just replaces it.

The copy function makes a cheap copy of an existing stack by taking a
reference to the top stack entry. This ends up working like a deep
copy because there is no way to modify entries of a stack but it
doesn't actually copy the data.
2010-04-15 14:51:01 +01:00

78 lines
2.1 KiB
C

/*
* Cogl
*
* An object oriented GL/GLES Abstraction/Utility Layer
*
* Copyright (C) 2007,2008,2009,2010 Intel Corporation.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see <http://www.gnu.org/licenses/>.
*
*
*/
#ifndef __COGL_CLIP_STATE_H
#define __COGL_CLIP_STATE_H
typedef struct _CoglClipState CoglClipState;
struct _CoglClipState
{
/* Stack of CoglClipStacks */
GSList *stacks;
gboolean stack_dirty;
gboolean stencil_used;
};
void
_cogl_clip_state_init (CoglClipState *state);
void
_cogl_clip_state_destroy (CoglClipState *state);
void
_cogl_clip_state_dirty (CoglClipState *state);
void
_cogl_clip_state_flush (CoglClipState *clip_state);
/* TODO: we may want to make these two functions public because they
* can be used to implement a better API than cogl_clip_stack_save()
* and cogl_clip_stack_restore().
*/
/*
* _cogl_get_clip_stack:
*
* Gets a handle to the current clip stack. This can be used to later
* return to the same clip stack state with _cogl_set_clip_stack(). A
* reference is not taken on the stack so if you want to keep it you
* should call cogl_handle_ref() or _cogl_clip_stack_copy().
*
* Return value: a handle to the current clip stack.
*/
CoglHandle
_cogl_get_clip_stack (void);
/*
* _cogl_set_clip_stack:
* @handle: a handle to the replacement clip stack
*
* Replaces the current clip stack with @handle.
*
* Return value: a handle to the current clip stack.
*/
void
_cogl_set_clip_stack (CoglHandle handle);
#endif /* __COGL_CLIP_STATE_H */