clutter/clutter/clutter-paint-volume-private.h

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/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Copyright (C) 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 __CLUTTER_PAINT_VOLUME_PRIVATE_H__
#define __CLUTTER_PAINT_VOLUME_PRIVATE_H__
#include <clutter/clutter-types.h>
#include <clutter/clutter-private.h>
G_BEGIN_DECLS
struct _ClutterPaintVolume
{
/* A paint volume represents a volume in a given actors private
* coordinate system. */
ClutterActor *actor;
/* cuboid for the volume:
*
* 4━━━━━━━┓5
* ┏━━━━━━━━┓╱┃
* ┃0 ┊7 1┃ ┃
* ┃ ┄┄┄┄┄┃┄┃6
* ┃3 2┃
* ┗━━━━━━━━┛
*
* 0: top, left (origin) : always valid
* 1: top, right : always valid
* 2: bottom, right : updated lazily
* 3: bottom, left : always valid
*
* 4: top, left, back : always valid
* 5: top, right, back : updated lazily
* 6: bottom, right, back : updated lazily
* 7: bottom, left, back : updated lazily
*
* Elements 0, 1, 3 and 4 are filled in by the PaintVolume setters
*
* Note: the reason for this ordering is that we can simply ignore
* elements 4, 5, 6 and 7 most of the time for 2D actors when
* calculating the projected paint box.
*/
ClutterVertex vertices[8];
/* As an optimization for internally managed PaintVolumes we allow
* initializing ClutterPaintVolume variables allocated on the stack
* so we can avoid hammering the slice allocator. */
guint is_static:1;
/* A newly initialized PaintVolume is considered empty as it is
* degenerate on all three axis.
*
* We consider this carefully when we union an empty volume with
* another so that the union simply results in a copy of the other
* volume instead of also bounding the origin of the empty volume.
*
* For example this is a convenient property when calculating the
* volume of a container as the union of the volume of its children
* where the initial volume passed to the containers
* ->get_paint_volume method will be empty. */
guint is_empty:1;
/* TRUE when we've updated the values we calculate lazily */
guint is_complete:1;
/* TRUE if vertices 4-7 can be ignored. (Only valid if complete is
* TRUE) */
guint is_2d:1;
/* Set to TRUE initialy but cleared if the paint volume is
* transfomed by a matrix. */
guint is_axis_aligned:1;
/* Note: There is a precedence to the above bitfields that should be
* considered whenever we implement code that manipulates
* PaintVolumes...
*
* Firstly if ->is_empty == TRUE then the values for ->is_complete
* and ->is_2d are undefined, so you should typically check
* ->is_empty as the first priority.
*
* XXX: document other invariables...
*/
};
void _clutter_paint_volume_init_static (ClutterPaintVolume *pv,
ClutterActor *actor);
ClutterPaintVolume *_clutter_paint_volume_new (ClutterActor *actor);
void _clutter_paint_volume_copy_static (const ClutterPaintVolume *src_pv,
ClutterPaintVolume *dst_pv);
void _clutter_paint_volume_set_from_volume (ClutterPaintVolume *pv,
const ClutterPaintVolume *src);
void _clutter_paint_volume_complete (ClutterPaintVolume *pv);
void _clutter_paint_volume_transform (ClutterPaintVolume *pv,
const CoglMatrix *matrix);
void _clutter_paint_volume_project (ClutterPaintVolume *pv,
const CoglMatrix *modelview,
const CoglMatrix *projection,
const float *viewport);
void _clutter_paint_volume_get_bounding_box (ClutterPaintVolume *pv,
ClutterActorBox *box);
void _clutter_paint_volume_axis_align (ClutterPaintVolume *pv);
void _clutter_paint_volume_set_reference_actor (ClutterPaintVolume *pv,
ClutterActor *actor);
ClutterCullResult _clutter_paint_volume_cull (ClutterPaintVolume *pv,
const ClutterPlane *planes);
void _clutter_paint_volume_get_stage_paint_box (ClutterPaintVolume *pv,
ClutterStage *stage,
ClutterActorBox *box);
void _clutter_paint_volume_transform_relative (ClutterPaintVolume *pv,
ClutterActor *relative_to_ancestor);
G_END_DECLS
#endif /* __CLUTTER_PAINT_VOLUME_PRIVATE_H__ */