/**
* clutter_paint_volume_get_depth:
* @pv: a #ClutterPaintVolume
*
* Retrieves the depth of the volume's, axis aligned, bounding box.
*
* In other words; this takes into account what actor's coordinate
* space @pv belongs too and conceptually fits an axis aligned box
* around the volume. It returns the size of that bounding box as
* measured along the z-axis.
*
* If, for example, clutter_actor_get_transformed_paint_volume()
* is used to transform a 2D child actor that is 100px wide, 100px
* high and 0px deep into container coordinates then the depth might
* not simply be 0px if the child actor has a 3D rotation applied to
* it.
*
* Remember: if clutter_actor_get_transformed_paint_volume() is
* used then the transformed volume will be defined relative to the
* container actor and in container coordinates a 2D child actor
* can have a 3D bounding volume.
*
* There are no accuracy guarantees for the reported depth,
* except that it must always be greater than, or equal to, the actor's
* depth. This is because actors may report simple, loose fitting paint
* volumes for efficiency.
*
* Return value: the depth, in units of @pv's local coordinate system.
*
* Since: 1.6
*/
gfloat
clutter_paint_volume_get_depth (const ClutterPaintVolume *pv)
{
g_return_val_if_fail (pv != NULL, 0.0);
if (pv->is_empty)
return 0;
else if (!pv->is_axis_aligned)
{
ClutterPaintVolume tmp;
float depth;
_clutter_paint_volume_copy_static (pv, &tmp);
_clutter_paint_volume_axis_align (&tmp);
depth = tmp.vertices[4].z - tmp.vertices[0].z;
clutter_paint_volume_free (&tmp);
return depth;
}
else
return pv->vertices[4].z - pv->vertices[0].z;
}
/**
* clutter_paint_volume_get_height:
* @pv: a #ClutterPaintVolume
*
* Retrieves the height of the volume's, axis aligned, bounding box.
*
* In other words; this takes into account what actor's coordinate
* space @pv belongs too and conceptually fits an axis aligned box
* around the volume. It returns the size of that bounding box as
* measured along the y-axis.
*
* If, for example, clutter_actor_get_transformed_paint_volume()
* is used to transform a 2D child actor that is 100px wide, 100px
* high and 0px deep into container coordinates then the height might
* not simply be 100px if the child actor has a 3D rotation applied to
* it.
*
* Remember: if clutter_actor_get_transformed_paint_volume() is
* used then a transformed child volume will be defined relative to the
* ancestor container actor and so a 2D child actor
* can have a 3D bounding volume.
*
* There are no accuracy guarantees for the reported height,
* except that it must always be greater than, or equal to, the actor's
* height. This is because actors may report simple, loose fitting paint
* volumes for efficiency.
*
* Return value: the height, in units of @pv's local coordinate system.
*
* Since: 1.6
*/
gfloat
clutter_paint_volume_get_height (const ClutterPaintVolume *pv)
{
g_return_val_if_fail (pv != NULL, 0.0);
if (pv->is_empty)
return 0;
else if (!pv->is_axis_aligned)
{
ClutterPaintVolume tmp;
float height;
_clutter_paint_volume_copy_static (pv, &tmp);
_clutter_paint_volume_axis_align (&tmp);
height = tmp.vertices[3].y - tmp.vertices[0].y;
clutter_paint_volume_free (&tmp);
return height;
}
else
return pv->vertices[3].y - pv->vertices[0].y;
}
void
_clutter_paint_volume_get_stage_paint_box (ClutterPaintVolume *pv,
ClutterStage *stage,
ClutterActorBox *box)
{
ClutterPaintVolume projected_pv;
CoglMatrix modelview;
CoglMatrix projection;
float viewport[4];
_clutter_paint_volume_copy_static (pv, &projected_pv);
cogl_matrix_init_identity (&modelview);
/* If the paint volume isn't already in eye coordinates... */
if (pv->actor)
_clutter_actor_apply_relative_transformation_matrix (pv->actor, NULL,
&modelview);
_clutter_stage_get_projection_matrix (stage, &projection);
_clutter_stage_get_viewport (stage,
&viewport[0],
&viewport[1],
&viewport[2],
&viewport[3]);
_clutter_paint_volume_project (&projected_pv,
&modelview,
&projection,
viewport);
_clutter_paint_volume_get_bounding_box (&projected_pv, box);
_clutter_actor_box_enlarge_for_effects (box);
clutter_paint_volume_free (&projected_pv);
}
/**
* clutter_paint_volume_union:
* @pv: The first #ClutterPaintVolume and destination for resulting
* union
* @another_pv: A second #ClutterPaintVolume to union with @pv
*
* Updates the geometry of @pv to encompass @pv and @another_pv.
*
* There are no guarantees about how precisely the two volumes
* will be unioned.
*
* Since: 1.6
*/
void
clutter_paint_volume_union (ClutterPaintVolume *pv,
const ClutterPaintVolume *another_pv)
{
ClutterPaintVolume aligned_pv;
g_return_if_fail (pv != NULL);
g_return_if_fail (another_pv != NULL);
/* Both volumes have to belong to the same local coordinate space */
g_return_if_fail (pv->actor == another_pv->actor);
/* NB: we only have to update vertices 0, 1, 3 and 4
* (See the ClutterPaintVolume typedef for more details) */
/* We special case empty volumes because otherwise we'd end up
* calculating a bounding box that would enclose the origin of
* the empty volume which isn't desired.
*/
if (another_pv->is_empty)
return;
if (pv->is_empty)
{
_clutter_paint_volume_set_from_volume (pv, another_pv);
goto done;
}
if (!pv->is_axis_aligned)
_clutter_paint_volume_axis_align (pv);
if (!another_pv->is_axis_aligned)
{
_clutter_paint_volume_copy_static (another_pv, &aligned_pv);
_clutter_paint_volume_axis_align (&aligned_pv);
another_pv = &aligned_pv;
}
/* grow left*/
/* left vertices 0, 3, 4, 7 */
if (another_pv->vertices[0].x < pv->vertices[0].x)
{
int min_x = another_pv->vertices[0].x;
pv->vertices[0].x = min_x;
pv->vertices[3].x = min_x;
pv->vertices[4].x = min_x;
/* pv->vertices[7].x = min_x; */
}
/* grow right */
/* right vertices 1, 2, 5, 6 */
if (another_pv->vertices[1].x > pv->vertices[1].x)
{
int max_x = another_pv->vertices[1].x;
pv->vertices[1].x = max_x;
/* pv->vertices[2].x = max_x; */
/* pv->vertices[5].x = max_x; */
/* pv->vertices[6].x = max_x; */
}
/* grow up */
/* top vertices 0, 1, 4, 5 */
if (another_pv->vertices[0].y < pv->vertices[0].y)
{
int min_y = another_pv->vertices[0].y;
pv->vertices[0].y = min_y;
pv->vertices[1].y = min_y;
pv->vertices[4].y = min_y;
/* pv->vertices[5].y = min_y; */
}
/* grow down */
/* bottom vertices 2, 3, 6, 7 */
if (another_pv->vertices[3].y > pv->vertices[3].y)
{
int may_y = another_pv->vertices[3].y;
/* pv->vertices[2].y = may_y; */
pv->vertices[3].y = may_y;
/* pv->vertices[6].y = may_y; */
/* pv->vertices[7].y = may_y; */
}
/* grow forward */
/* front vertices 0, 1, 2, 3 */
if (another_pv->vertices[0].z < pv->vertices[0].z)
{
int min_z = another_pv->vertices[0].z;
pv->vertices[0].z = min_z;
pv->vertices[1].z = min_z;
/* pv->vertices[2].z = min_z; */
pv->vertices[3].z = min_z;
}
/* grow backward */
/* back vertices 4, 5, 6, 7 */
if (another_pv->vertices[4].z > pv->vertices[4].z)
{
int maz_z = another_pv->vertices[4].z;
pv->vertices[4].z = maz_z;
/* pv->vertices[5].z = maz_z; */
/* pv->vertices[6].z = maz_z; */
/* pv->vertices[7].z = maz_z; */
}
if (pv->vertices[4].z == pv->vertices[0].z)
pv->is_2d = TRUE;
else
pv->is_2d = FALSE;
done:
pv->is_empty = FALSE;
pv->is_complete = FALSE;
}
void
_clutter_paint_volume_get_stage_paint_box (ClutterPaintVolume *pv,
ClutterStage *stage,
ClutterActorBox *box)
{
ClutterPaintVolume projected_pv;
CoglMatrix modelview;
CoglMatrix projection;
float viewport[4];
float width;
float height;
_clutter_paint_volume_copy_static (pv, &projected_pv);
cogl_matrix_init_identity (&modelview);
/* If the paint volume isn't already in eye coordinates... */
if (pv->actor)
_clutter_actor_apply_relative_transformation_matrix (pv->actor, NULL,
&modelview);
_clutter_stage_get_projection_matrix (stage, &projection);
_clutter_stage_get_viewport (stage,
&viewport[0],
&viewport[1],
&viewport[2],
&viewport[3]);
_clutter_paint_volume_project (&projected_pv,
&modelview,
&projection,
viewport);
_clutter_paint_volume_get_bounding_box (&projected_pv, box);
/* The aim here is that for a given rectangle defined with floating point
* coordinates we want to determine a stable quantized size in pixels
* that doesn't vary due to the original box's sub-pixel position.
*
* The reason this is important is because effects will use this
* API to determine the size of offscreen framebuffers and so for
* a fixed-size object that may be animated accross the screen we
* want to make sure that the stage paint-box has an equally stable
* size so that effects aren't made to continuously re-allocate
* a corresponding fbo.
*
* The other thing we consider is that the calculation of this box is
* subject to floating point precision issues that might be slightly
* different to the precision issues involved with actually painting the
* actor, which might result in painting slightly leaking outside the
* user's calculated paint-volume. For this we simply aim to pad out the
* paint-volume by at least half a pixel all the way around.
*/
width = box->x2 - box->x1;
height = box->y2 - box->y1;
width = CLUTTER_NEARBYINT (width);
height = CLUTTER_NEARBYINT (height);
/* XXX: NB the width/height may now be up to 0.5px too small so we
* must also pad by 0.25px all around to account for this. In total we
* must padd by at least 0.75px around all sides. */
/* XXX: The furthest that we can overshoot the bottom right corner by
* here is 1.75px in total if you consider that the 0.75 padding could
* just cross an integer boundary and so ceil will effectively add 1.
*/
box->x2 = ceilf (box->x2 + 0.75);
box->y2 = ceilf (box->y2 + 0.75);
/* Now we redefine the top-left relative to the bottom right based on the
* rounded width/height determined above + a constant so that the overall
* size of the box will be stable and not dependant on the box's
* position.
*
* Adding 3px to the width/height will ensure we cover the maximum of
* 1.75px padding on the bottom/right and still ensure we have > 0.75px
* padding on the top/left.
*/
box->x1 = box->x2 - width - 3;
box->y1 = box->y2 - height - 3;
clutter_paint_volume_free (&projected_pv);
}
