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mutter/clutter/clutter-paint-volume.c
Emmanuele Bassi 12370bd4f8 docs: Move to markdown 
We're removing docbook tags in favour of the markdown syntax.
2014-03-17 23:07:58 +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.
*
* 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.
*
* 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 width,
* except that it must always be greater than, or equal to, the
* actor's width. This is because actors may report simple, loose
* fitting paint volumes for efficiency.
* 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.
*
* 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;
}
/**
* 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.
*
* 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_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;
}
/**
* 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 #ClutterActorBox
*
* 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.
*
* The coordinates of the returned box are not clamped to
* integer pixel values; if you need them to be rounded to the
* nearest integer pixel values, you can use the
* clutter_actor_box_clamp_to_pixel() function.
*
* 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].z))
{
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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