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mutter/clutter/clutter-paint-volume.c
Emmanuele Bassi 6a09bf5b52 paint-volume: Add a union method for boxes 
Creating PaintVolume instances is not possible, and it's not recommended
anyway. It is, though, necessary to union paint volumes, especially with
2D boxes, in some cases.

Clutter should provide a simple convenience function that allows
unioning volumes to boxes in a moderately efficient way.

https://bugzilla.gnome.org/show_bug.cgi?id=670021
2012-02-27 11:24:08 +00:00

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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/>.
*
* Authors:
* Robert Bragg <robert@linux.intel.com>
* Emmanuele Bassi <ebassi@linux.intel.com>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include <glib-object.h>
#include <math.h>
#include "clutter-actor-private.h"
#include "clutter-paint-volume-private.h"
#include "clutter-private.h"
#include "clutter-stage-private.h"
G_DEFINE_BOXED_TYPE (ClutterPaintVolume, clutter_paint_volume,
clutter_paint_volume_copy,
clutter_paint_volume_free);
/*<private>
* _clutter_paint_volume_new:
* @actor: a #ClutterActor
*
* Creates a new #ClutterPaintVolume for the given @actor.
*
* Return value: the newly allocated #ClutterPaintVolume. Use
* clutter_paint_volume_free() to free the resources it uses
*
* Since: 1.6
*/
ClutterPaintVolume *
_clutter_paint_volume_new (ClutterActor *actor)
{
ClutterPaintVolume *pv;
g_return_val_if_fail (actor != NULL, NULL);
pv = g_slice_new (ClutterPaintVolume);
pv->actor = actor;
memset (pv->vertices, 0, 8 * sizeof (ClutterVertex));
pv->is_static = FALSE;
pv->is_empty = TRUE;
pv->is_axis_aligned = TRUE;
pv->is_complete = TRUE;
pv->is_2d = TRUE;
return pv;
}
/* Since paint volumes are used so heavily in a typical paint
* traversal of a Clutter scene graph and since paint volumes often
* have a very short life cycle that maps well to stack allocation we
* allow initializing a static ClutterPaintVolume variable to avoid
* hammering the slice allocator.
*
* We were seeing slice allocation take about 1% cumulative CPU time
* for some very simple clutter tests which although it isn't a *lot*
* this is an easy way to basically drop that to 0%.
*
* The PaintVolume will be internally marked as static and
* clutter_paint_volume_free should still be used to "free" static
* volumes. This allows us to potentially store dynamically allocated
* data inside paint volumes in the future since we would be able to
* free it during _paint_volume_free().
*/
void
_clutter_paint_volume_init_static (ClutterPaintVolume *pv,
ClutterActor *actor)
{
pv->actor = actor;
memset (pv->vertices, 0, 8 * sizeof (ClutterVertex));
pv->is_static = TRUE;
pv->is_empty = TRUE;
pv->is_axis_aligned = TRUE;
pv->is_complete = TRUE;
pv->is_2d = TRUE;
}
void
_clutter_paint_volume_copy_static (const ClutterPaintVolume *src_pv,
ClutterPaintVolume *dst_pv)
{
g_return_if_fail (src_pv != NULL && dst_pv != NULL);
memcpy (dst_pv, src_pv, sizeof (ClutterPaintVolume));
dst_pv->is_static = TRUE;
}
/**
* clutter_paint_volume_copy:
* @pv: a #ClutterPaintVolume
*
* Copies @pv into a new #ClutterPaintVolume
*
* Return value: a newly allocated copy of a #ClutterPaintVolume
*
* Since: 1.6
*/
ClutterPaintVolume *
clutter_paint_volume_copy (const ClutterPaintVolume *pv)
{
ClutterPaintVolume *copy;
g_return_val_if_fail (pv != NULL, NULL);
copy = g_slice_dup (ClutterPaintVolume, pv);
copy->is_static = FALSE;
return copy;
}
void
_clutter_paint_volume_set_from_volume (ClutterPaintVolume *pv,
const ClutterPaintVolume *src)
{
gboolean is_static = pv->is_static;
memcpy (pv, src, sizeof (ClutterPaintVolume));
pv->is_static = is_static;
}
/**
* clutter_paint_volume_free:
* @pv: a #ClutterPaintVolume
*
* Frees the resources allocated by @pv
*
* Since: 1.6
*/
void
clutter_paint_volume_free (ClutterPaintVolume *pv)
{
g_return_if_fail (pv != NULL);
if (G_LIKELY (pv->is_static))
return;
g_slice_free (ClutterPaintVolume, pv);
}
/**
* clutter_paint_volume_set_origin:
* @pv: a #ClutterPaintVolume
* @origin: a #ClutterVertex
*
* Sets the origin of the paint volume.
*
* The origin is defined as the X, Y and Z coordinates of the top-left
* corner of an actor's paint volume, in actor coordinates.
*
* The default is origin is assumed at: (0, 0, 0)
*
* Since: 1.6
*/
void
clutter_paint_volume_set_origin (ClutterPaintVolume *pv,
const ClutterVertex *origin)
{
static const int key_vertices[4] = { 0, 1, 3, 4 };
float dx, dy, dz;
int i;
g_return_if_fail (pv != NULL);
dx = origin->x - pv->vertices[0].x;
dy = origin->y - pv->vertices[0].y;
dz = origin->z - pv->vertices[0].z;
/* If we change the origin then all the key vertices of the paint
* volume need to be shifted too... */
for (i = 0; i < 4; i++)
{
pv->vertices[key_vertices[i]].x += dx;
pv->vertices[key_vertices[i]].y += dy;
pv->vertices[key_vertices[i]].z += dz;
}
pv->is_complete = FALSE;
}
/**
* clutter_paint_volume_get_origin:
* @pv: a #ClutterPaintVolume
* @vertex: (out): the return location for a #ClutterVertex
*
* Retrieves the origin of the #ClutterPaintVolume.
*
* Since: 1.6
*/
void
clutter_paint_volume_get_origin (const ClutterPaintVolume *pv,
ClutterVertex *vertex)
{
g_return_if_fail (pv != NULL);
g_return_if_fail (vertex != NULL);
*vertex = pv->vertices[0];
}
static void
_clutter_paint_volume_update_is_empty (ClutterPaintVolume *pv)
{
if (pv->vertices[0].x == pv->vertices[1].x &&
pv->vertices[0].y == pv->vertices[3].y &&
pv->vertices[0].z == pv->vertices[4].z)
pv->is_empty = TRUE;
else
pv->is_empty = FALSE;
}
/**
* clutter_paint_volume_set_width:
* @pv: a #ClutterPaintVolume
* @width: the width of the paint volume, in pixels
*
* Sets the width of the paint volume. The width is measured along
* the x axis in the actor coordinates that @pv is associated with.
*
* Since: 1.6
*/
void
clutter_paint_volume_set_width (ClutterPaintVolume *pv,
gfloat width)
{
gfloat right_xpos;
g_return_if_fail (pv != NULL);
g_return_if_fail (width >= 0.0f);
/* If the volume is currently empty then only the origin is
* currently valid */
if (pv->is_empty)
pv->vertices[1] = pv->vertices[3] = pv->vertices[4] = pv->vertices[0];
if (!pv->is_axis_aligned)
_clutter_paint_volume_axis_align (pv);
right_xpos = pv->vertices[0].x + width;
/* Move the right vertices of the paint box relative to the
* origin... */
pv->vertices[1].x = right_xpos;
/* pv->vertices[2].x = right_xpos; NB: updated lazily */
/* pv->vertices[5].x = right_xpos; NB: updated lazily */
/* pv->vertices[6].x = right_xpos; NB: updated lazily */
pv->is_complete = FALSE;
_clutter_paint_volume_update_is_empty (pv);
}
/**
* clutter_paint_volume_get_width:
* @pv: a #ClutterPaintVolume
*
* Retrieves the width 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 x-axis.
*
* <note><para>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 width might
* not simply be 100px if the child actor has a 3D rotation applied to
* it.</para>
* <para>Remember; after 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.</para></note>
*
* <note>There are no accuracy guarantees for the reported width,
* except that it must always be >= to the true width. This is
* because actors may report simple, loose fitting paint-volumes
* for efficiency</note>
* Return value: the width, in units of @pv's local coordinate system.
*
* Since: 1.6
*/
gfloat
clutter_paint_volume_get_width (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 width;
_clutter_paint_volume_copy_static (pv, &tmp);
_clutter_paint_volume_axis_align (&tmp);
width = tmp.vertices[1].x - tmp.vertices[0].x;
clutter_paint_volume_free (&tmp);
return width;
}
else
return pv->vertices[1].x - pv->vertices[0].x;
}
/**
* clutter_paint_volume_set_height:
* @pv: a #ClutterPaintVolume
* @height: the height of the paint volume, in pixels
*
* Sets the height of the paint volume. The height is measured along
* the y axis in the actor coordinates that @pv is associated with.
*
* Since: 1.6
*/
void
clutter_paint_volume_set_height (ClutterPaintVolume *pv,
gfloat height)
{
gfloat height_ypos;
g_return_if_fail (pv != NULL);
g_return_if_fail (height >= 0.0f);
/* If the volume is currently empty then only the origin is
* currently valid */
if (pv->is_empty)
pv->vertices[1] = pv->vertices[3] = pv->vertices[4] = pv->vertices[0];
if (!pv->is_axis_aligned)
_clutter_paint_volume_axis_align (pv);
height_ypos = pv->vertices[0].y + height;
/* Move the bottom vertices of the paint box relative to the
* origin... */
/* pv->vertices[2].y = height_ypos; NB: updated lazily */
pv->vertices[3].y = height_ypos;
/* pv->vertices[6].y = height_ypos; NB: updated lazily */
/* pv->vertices[7].y = height_ypos; NB: updated lazily */
pv->is_complete = FALSE;
_clutter_paint_volume_update_is_empty (pv);
}
/**
* 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.
*
* <note><para>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.</para>
* <para>Remember; after 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.</para></note>
*
* <note>There are no accuracy guarantees for the reported height,
* except that it must always be >= to the true height. This is
* because actors may report simple, loose fitting paint-volumes
* for efficiency</note>
*
* 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;
}
/**
* clutter_paint_volume_set_depth:
* @pv: a #ClutterPaintVolume
* @depth: the depth of the paint volume, in pixels
*
* Sets the depth of the paint volume. The depth is measured along
* the z axis in the actor coordinates that @pv is associated with.
*
* Since: 1.6
*/
void
clutter_paint_volume_set_depth (ClutterPaintVolume *pv,
gfloat depth)
{
gfloat depth_zpos;
g_return_if_fail (pv != NULL);
g_return_if_fail (depth >= 0.0f);
/* If the volume is currently empty then only the origin is
* currently valid */
if (pv->is_empty)
pv->vertices[1] = pv->vertices[3] = pv->vertices[4] = pv->vertices[0];
if (!pv->is_axis_aligned)
_clutter_paint_volume_axis_align (pv);
depth_zpos = pv->vertices[0].z + depth;
/* Move the back vertices of the paint box relative to the
* origin... */
pv->vertices[4].z = depth_zpos;
/* pv->vertices[5].z = depth_zpos; NB: updated lazily */
/* pv->vertices[6].z = depth_zpos; NB: updated lazily */
/* pv->vertices[7].z = depth_zpos; NB: updated lazily */
pv->is_complete = FALSE;
pv->is_2d = depth ? FALSE : TRUE;
_clutter_paint_volume_update_is_empty (pv);
}
/**
* 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.
*
* <note><para>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.</para>
* <para>Remember; after 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.</para></note>
*
* <note>There are no accuracy guarantees for the reported depth,
* except that it must always be >= to the true depth. This is
* because actors may report simple, loose fitting paint-volumes
* for efficiency.</note>
*
* 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_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.
*
* <note>There are no guarantees about how precisely the two volumes
* will be encompassed.</note>
*
* 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;
}
/**
* clutter_paint_volume_union_box:
* @pv: a #ClutterPaintVolume
* @box: a #ClutterActorBox to union to @pv
*
* Unions the 2D region represented by @box to a #ClutterPaintVolume.
*
* This function is similar to clutter_paint_volume_union(), but it is
* specific for 2D regions.
*
* Since: 1.10
*/
void
clutter_paint_volume_union_box (ClutterPaintVolume *pv,
const ClutterActorBox *box)
{
ClutterPaintVolume volume;
ClutterVertex origin;
g_return_if_fail (pv != NULL);
g_return_if_fail (box != NULL);
_clutter_paint_volume_init_static (&volume, pv->actor);
origin.x = box->x1;
origin.y = box->y1;
origin.z = 0.f;
clutter_paint_volume_set_origin (&volume, &origin);
clutter_paint_volume_set_width (&volume, box->x2 - box->x1);
clutter_paint_volume_set_height (&volume, box->y2 - box->y1);
clutter_paint_volume_union (pv, &volume);
clutter_paint_volume_free (&volume);
}
/* The paint_volume setters only update vertices 0, 1, 3 and
* 4 since the others can be drived from them.
*
* This will set pv->completed = TRUE;
*/
void
_clutter_paint_volume_complete (ClutterPaintVolume *pv)
{
float dx_l2r, dy_l2r, dz_l2r;
float dx_t2b, dy_t2b, dz_t2b;
if (pv->is_empty)
return;
if (pv->is_complete)
return;
/* Find the vector that takes us from any vertex on the left face to
* the corresponding vertex on the right face. */
dx_l2r = pv->vertices[1].x - pv->vertices[0].x;
dy_l2r = pv->vertices[1].y - pv->vertices[0].y;
dz_l2r = pv->vertices[1].z - pv->vertices[0].z;
/* Find the vector that takes us from any vertex on the top face to
* the corresponding vertex on the bottom face. */
dx_t2b = pv->vertices[3].x - pv->vertices[0].x;
dy_t2b = pv->vertices[3].y - pv->vertices[0].y;
dz_t2b = pv->vertices[3].z - pv->vertices[0].z;
/* front-bottom-right */
pv->vertices[2].x = pv->vertices[3].x + dx_l2r;
pv->vertices[2].y = pv->vertices[3].y + dy_l2r;
pv->vertices[2].z = pv->vertices[3].z + dz_l2r;
if (G_UNLIKELY (!pv->is_2d))
{
/* back-top-right */
pv->vertices[5].x = pv->vertices[4].x + dx_l2r;
pv->vertices[5].y = pv->vertices[4].y + dy_l2r;
pv->vertices[5].z = pv->vertices[4].z + dz_l2r;
/* back-bottom-right */
pv->vertices[6].x = pv->vertices[5].x + dx_t2b;
pv->vertices[6].y = pv->vertices[5].y + dy_t2b;
pv->vertices[6].z = pv->vertices[5].z + dz_t2b;
/* back-bottom-left */
pv->vertices[7].x = pv->vertices[4].x + dx_t2b;
pv->vertices[7].y = pv->vertices[4].y + dy_t2b;
pv->vertices[7].z = pv->vertices[4].z + dz_t2b;
}
pv->is_complete = TRUE;
}
/*<private>
* _clutter_paint_volume_get_box:
* @pv: a #ClutterPaintVolume
* @box: a pixel aligned #ClutterGeometry
*
* Transforms a 3D paint volume into a 2D bounding box in the
* same coordinate space as the 3D paint volume.
*
* To get an actors "paint box" you should first project
* the paint volume into window coordinates before getting
* the 2D bounding box.
*
* <note>The coordinates of the returned box are not clamped to
* integer pixel values, if you need them to be clamped you can use
* clutter_actor_box_clamp_to_pixel()</note>
*
* Since: 1.6
*/
void
_clutter_paint_volume_get_bounding_box (ClutterPaintVolume *pv,
ClutterActorBox *box)
{
gfloat x_min, y_min, x_max, y_max;
ClutterVertex *vertices;
int count;
gint i;
g_return_if_fail (pv != NULL);
g_return_if_fail (box != NULL);
if (pv->is_empty)
{
box->x1 = box->x2 = pv->vertices[0].x;
box->y1 = box->y2 = pv->vertices[0].y;
return;
}
/* Updates the vertices we calculate lazily
* (See ClutterPaintVolume typedef for more details) */
_clutter_paint_volume_complete (pv);
vertices = pv->vertices;
x_min = x_max = vertices[0].x;
y_min = y_max = vertices[0].y;
/* Most actors are 2D so we only have to look at the front 4
* vertices of the paint volume... */
if (G_LIKELY (pv->is_2d))
count = 4;
else
count = 8;
for (i = 1; i < count; i++)
{
if (vertices[i].x < x_min)
x_min = vertices[i].x;
else if (vertices[i].x > x_max)
x_max = vertices[i].x;
if (vertices[i].y < y_min)
y_min = vertices[i].y;
else if (vertices[i].y > y_max)
y_max = vertices[i].y;
}
box->x1 = x_min;
box->y1 = y_min;
box->x2 = x_max;
box->y2 = y_max;
}
void
_clutter_paint_volume_project (ClutterPaintVolume *pv,
const CoglMatrix *modelview,
const CoglMatrix *projection,
const float *viewport)
{
int transform_count;
if (pv->is_empty)
{
/* Just transform the origin... */
_clutter_util_fully_transform_vertices (modelview,
projection,
viewport,
pv->vertices,
pv->vertices,
1);
return;
}
/* All the vertices must be up to date, since after the projection
* it wont be trivial to derive the other vertices. */
_clutter_paint_volume_complete (pv);
/* Most actors are 2D so we only have to transform the front 4
* vertices of the paint volume... */
if (G_LIKELY (pv->is_2d))
transform_count = 4;
else
transform_count = 8;
_clutter_util_fully_transform_vertices (modelview,
projection,
viewport,
pv->vertices,
pv->vertices,
transform_count);
pv->is_axis_aligned = FALSE;
}
void
_clutter_paint_volume_transform (ClutterPaintVolume *pv,
const CoglMatrix *matrix)
{
int transform_count;
if (pv->is_empty)
{
gfloat w = 1;
/* Just transform the origin */
cogl_matrix_transform_point (matrix,
&pv->vertices[0].x,
&pv->vertices[0].y,
&pv->vertices[0].z,
&w);
return;
}
/* All the vertices must be up to date, since after the transform
* it wont be trivial to derive the other vertices. */
_clutter_paint_volume_complete (pv);
/* Most actors are 2D so we only have to transform the front 4
* vertices of the paint volume... */
if (G_LIKELY (pv->is_2d))
transform_count = 4;
else
transform_count = 8;
cogl_matrix_transform_points (matrix,
3,
sizeof (ClutterVertex),
pv->vertices,
sizeof (ClutterVertex),
pv->vertices,
transform_count);
pv->is_axis_aligned = FALSE;
}
/* Given a paint volume that has been transformed by an arbitrary
* modelview and is no longer axis aligned, this derives a replacement
* that is axis aligned. */
void
_clutter_paint_volume_axis_align (ClutterPaintVolume *pv)
{
int count;
int i;
ClutterVertex origin;
float max_x;
float max_y;
float max_z;
g_return_if_fail (pv != NULL);
if (pv->is_empty)
return;
if (G_LIKELY (pv->is_axis_aligned))
return;
if (G_LIKELY (pv->vertices[0].x == pv->vertices[1].x &&
pv->vertices[0].y == pv->vertices[3].y &&
pv->vertices[0].z == pv->vertices[4].y))
{
pv->is_axis_aligned = TRUE;
return;
}
if (!pv->is_complete)
_clutter_paint_volume_complete (pv);
origin = pv->vertices[0];
max_x = pv->vertices[0].x;
max_y = pv->vertices[0].y;
max_z = pv->vertices[0].z;
count = pv->is_2d ? 4 : 8;
for (i = 1; i < count; i++)
{
if (pv->vertices[i].x < origin.x)
origin.x = pv->vertices[i].x;
else if (pv->vertices[i].x > max_x)
max_x = pv->vertices[i].x;
if (pv->vertices[i].y < origin.y)
origin.y = pv->vertices[i].y;
else if (pv->vertices[i].y > max_y)
max_y = pv->vertices[i].y;
if (pv->vertices[i].z < origin.z)
origin.z = pv->vertices[i].z;
else if (pv->vertices[i].z > max_z)
max_z = pv->vertices[i].z;
}
pv->vertices[0] = origin;
pv->vertices[1].x = max_x;
pv->vertices[1].y = origin.y;
pv->vertices[1].z = origin.z;
pv->vertices[3].x = origin.x;
pv->vertices[3].y = max_y;
pv->vertices[3].z = origin.z;
pv->vertices[4].x = origin.x;
pv->vertices[4].y = origin.y;
pv->vertices[4].z = max_z;
pv->is_complete = FALSE;
pv->is_axis_aligned = TRUE;
if (pv->vertices[4].z == pv->vertices[0].z)
pv->is_2d = TRUE;
else
pv->is_2d = FALSE;
}
/*<private>
* _clutter_actor_set_default_paint_volume:
* @self: a #ClutterActor
* @check_gtype: if not %G_TYPE_INVALID, match the type of @self against
* this type
* @volume: the #ClutterPaintVolume to set
*
* Sets the default paint volume for @self.
*
* This function should be called by #ClutterActor sub-classes that follow
* the default assumption that their paint volume is defined by their
* allocation.
*
* If @check_gtype is not %G_TYPE_INVALID, this function will check the
* type of @self and only compute the paint volume if the type matches;
* this can be used to avoid computing the paint volume for sub-classes
* of an actor class
*
* Return value: %TRUE if the paint volume was set, and %FALSE otherwise
*/
gboolean
_clutter_actor_set_default_paint_volume (ClutterActor *self,
GType check_gtype,
ClutterPaintVolume *volume)
{
ClutterActorBox box;
if (check_gtype != G_TYPE_INVALID)
{
if (G_OBJECT_TYPE (self) != check_gtype)
return FALSE;
}
/* calling clutter_actor_get_allocation_* can potentially be very
* expensive, as it can result in a synchronous full stage relayout
* and redraw
*/
if (!clutter_actor_has_allocation (self))
return FALSE;
clutter_actor_get_allocation_box (self, &box);
/* we only set the width and height, as the paint volume is defined
* to be relative to the actor's modelview, which means that the
* allocation's origin has already been applied
*/
clutter_paint_volume_set_width (volume, box.x2 - box.x1);
clutter_paint_volume_set_height (volume, box.y2 - box.y1);
return TRUE;
}
/**
* clutter_paint_volume_set_from_allocation:
* @pv: a #ClutterPaintVolume
* @actor: a #ClutterActor
*
* Sets the #ClutterPaintVolume from the allocation of @actor.
*
* This function should be used when overriding the
* #ClutterActorClass.get_paint_volume() by #ClutterActor sub-classes
* that do not paint outside their allocation.
*
* A typical example is:
*
* |[
* static gboolean
* my_actor_get_paint_volume (ClutterActor *self,
* ClutterPaintVolume *volume)
* {
* return clutter_paint_volume_set_from_allocation (volume, self);
* }
* ]|
*
* Return value: %TRUE if the paint volume was successfully set, and %FALSE
* otherwise
*
* Since: 1.6
*/
gboolean
clutter_paint_volume_set_from_allocation (ClutterPaintVolume *pv,
ClutterActor *actor)
{
g_return_val_if_fail (pv != NULL, FALSE);
g_return_val_if_fail (CLUTTER_IS_ACTOR (actor), FALSE);
return _clutter_actor_set_default_paint_volume (actor, G_TYPE_INVALID, pv);
}
/* Currently paint volumes are defined relative to a given actor, but
* in some cases it is desireable to be able to change the actor that
* a volume relates too (For instance for ClutterClone actors where we
* need to masquarade the source actors volume as the volume for the
* clone). */
void
_clutter_paint_volume_set_reference_actor (ClutterPaintVolume *pv,
ClutterActor *actor)
{
g_return_if_fail (pv != NULL);
pv->actor = actor;
}
ClutterCullResult
_clutter_paint_volume_cull (ClutterPaintVolume *pv,
const ClutterPlane *planes)
{
int vertex_count;
ClutterVertex *vertices = pv->vertices;
gboolean partial = FALSE;
int i;
int j;
if (pv->is_empty)
return CLUTTER_CULL_RESULT_OUT;
/* We expect the volume to already be transformed into eye coordinates
*/
g_return_val_if_fail (pv->is_complete == TRUE, CLUTTER_CULL_RESULT_IN);
g_return_val_if_fail (pv->actor == NULL, CLUTTER_CULL_RESULT_IN);
/* Most actors are 2D so we only have to transform the front 4
* vertices of the paint volume... */
if (G_LIKELY (pv->is_2d))
vertex_count = 4;
else
vertex_count = 8;
for (i = 0; i < 4; i++)
{
int out = 0;
for (j = 0; j < vertex_count; j++)
{
ClutterVertex p;
float distance;
/* XXX: for perspective projections this can be optimized
* out because all the planes should pass through the origin
* so (0,0,0) is a valid v0. */
p.x = vertices[j].x - planes[i].v0[0];
p.y = vertices[j].y - planes[i].v0[1];
p.z = vertices[j].z - planes[i].v0[2];
distance = (planes[i].n[0] * p.x +
planes[i].n[1] * p.y +
planes[i].n[2] * p.z);
if (distance < 0)
out++;
}
if (out == vertex_count)
return CLUTTER_CULL_RESULT_OUT;
else if (out != 0)
partial = TRUE;
}
if (partial)
return CLUTTER_CULL_RESULT_PARTIAL;
else
return CLUTTER_CULL_RESULT_IN;
}
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);
}
void
_clutter_paint_volume_transform_relative (ClutterPaintVolume *pv,
ClutterActor *relative_to_ancestor)
{
CoglMatrix matrix;
ClutterActor *actor;
actor = pv->actor;
g_return_if_fail (actor != NULL);
_clutter_paint_volume_set_reference_actor (pv, relative_to_ancestor);
cogl_matrix_init_identity (&matrix);
_clutter_actor_apply_relative_transformation_matrix (actor,
relative_to_ancestor,
&matrix);
_clutter_paint_volume_transform (pv, &matrix);
}
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