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clutter/actor: Revert transform order

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When doing affine transforms on 2D and 3D spaces, operations are
done relative to the origin. That means that, when applying
rotations and scales, we must:

 * translate (-anchor_x, -anchor_y, -anchor_z)
 * apply the operation
 * translate (anchor_x, anchor_y, anchor_z)

Since OpenGL has its matrices applied in the reverse order, the
usual way to do it is, then:

 * translate (anchor_x, anchor_y, anchor_z)
 * apply the operation
 * translate (-anchor_x, anchor_y, anchor_z)

However, graphene matrices do not follow the GL format, so matrix
operations are done as the first example. Now that we are using
graphene_matrix_t for every matrix operation, the transform order
is wrong.

Apply the transform operations in the opposite order.
This commit is contained in:
Georges Basile Stavracas Neto 2019-03-12 14:38:11 -03:00
parent 1428280054
commit 3004c5423b
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GPG Key ID: 886C17EE170D1385
1 changed files with 54 additions and 76 deletions
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130
clutter/clutter/clutter-actor.c
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@ -36,15 +36,15 @@
* or clutter_actor_set_rotation(). The order in which the transformations are
* applied is decided by Clutter and it is the following:
*
* 1. translation by the origin of the #ClutterActor:allocation property
* 2. translation by the actor's #ClutterActor:z-position property
* 3. translation by the actor's #ClutterActor:pivot-point property
* 4. scaling by the #ClutterActor:scale-x and #ClutterActor:scale-y factors
* 1. negative translation by the actor's #ClutterActor:pivot-point
* 2. negative translation by the #ClutterActor:anchor-x and #ClutterActor:anchor-y point.
* 3. rotation around the #ClutterActor:rotation-angle-z and #ClutterActor:rotation-center-z
* 4. rotation around the #ClutterActor:rotation-angle-y and #ClutterActor:rotation-center-y
* 5. rotation around the #ClutterActor:rotation-angle-x and #ClutterActor:rotation-center-x
* 6. rotation around the #ClutterActor:rotation-angle-y and #ClutterActor:rotation-center-y
* 7. rotation around the #ClutterActor:rotation-angle-z and #ClutterActor:rotation-center-z
* 8. negative translation by the #ClutterActor:anchor-x and #ClutterActor:anchor-y point.
* 9. negative translation by the actor's #ClutterActor:pivot-point
* 6. scaling by the #ClutterActor:scale-x and #ClutterActor:scale-y factors
* 7. translation by the actor's #ClutterActor:pivot-point property
* 8. translation by the actor's #ClutterActor:z-position property
* 9. translation by the origin of the #ClutterActor:allocation property
*
* ## Modifying an actor's geometry ## {#clutter-actor-geometry}
*
@ -1069,8 +1069,6 @@ static ClutterGravity clutter_anchor_coord_get_gravity (const AnchorCoord *coord
static void clutter_anchor_coord_set_gravity (AnchorCoord *coord,
ClutterGravity gravity);
static gboolean clutter_anchor_coord_is_zero (const AnchorCoord *coord);
static void _clutter_actor_get_relative_transformation_matrix (ClutterActor *self,
ClutterActor *ancestor,
CoglMatrix *matrix);
@ -1111,9 +1109,9 @@ static void clutter_actor_pop_in_cloned_branch (ClutterActor *self,
#define TRANSFORM_ABOUT_ANCHOR_COORD(a,m,c,_transform) G_STMT_START { \
gfloat _tx, _ty, _tz; \
clutter_anchor_coord_get_units ((a), (c), &_tx, &_ty, &_tz); \
cogl_matrix_translate ((m), _tx, _ty, _tz); \
cogl_matrix_translate ((m), -_tx, -_ty, -_tz); \
{ _transform; } \
cogl_matrix_translate ((m), -_tx, -_ty, -_tz); } G_STMT_END
cogl_matrix_translate ((m), _tx, _ty, _tz); } G_STMT_END
static GQuark quark_actor_layout_info = 0;
static GQuark quark_actor_transform_info = 0;
@ -3150,6 +3148,7 @@ clutter_actor_real_apply_transform (ClutterActor *self,
CoglMatrix *transform = &priv->transform;
const ClutterTransformInfo *info;
float pivot_x = 0.f, pivot_y = 0.f;
float tx, ty, tz;
/* we already have a cached transformation */
if (priv->transform_valid)
@ -3193,42 +3192,45 @@ clutter_actor_real_apply_transform (ClutterActor *self,
* space, and to the pivot point
*/
cogl_matrix_translate (transform,
priv->allocation.x1 + pivot_x,
priv->allocation.y1 + pivot_y,
info->pivot_z);
cogl_matrix_multiply (transform, transform, &info->transform);
-pivot_x,
-pivot_y,
-info->pivot_z);
cogl_matrix_multiply (transform, &info->transform, transform);
cogl_matrix_translate (transform,
priv->allocation.x1,
priv->allocation.y1,
0.0f);
goto roll_back_pivot;
}
/* basic translation: :allocation's origin and :z-position; instead
* of decomposing the pivot and translation info separate operations,
* we just compose everything into a single translation
*/
cogl_matrix_translate (transform,
priv->allocation.x1 + pivot_x + info->translation.x,
priv->allocation.y1 + pivot_y + info->translation.y,
info->z_position + info->pivot_z + info->translation.z);
/* XXX:2.0 remove anchor point translation */
clutter_anchor_coord_get_units (self, &info->anchor, &tx, &ty, &tz);
tx += pivot_x;
ty += pivot_y;
tz += info->pivot_z;
/* because the rotation involves translations, we must scale
* before applying the rotations (if we apply the scale after
* the rotations, the translations included in the rotation are
* not scaled and so the entire object will move on the screen
* as a result of rotating it).
*
* XXX:2.0 the comment has to be reworded once we remove the
* per-transformation centers; we also may want to apply rotation
* first and scaling after, to match the matrix decomposition
* code we use when interpolating transformations
*/
if (info->scale_x != 1.0 || info->scale_y != 1.0 || info->scale_z != 1.0)
if (tx != 0.f || ty != 0.f || tz != 0.f)
cogl_matrix_translate (transform, -tx, -ty, -tz);
if (info->rx_angle)
{
/* XXX:2.0 remove anchor coord */
TRANSFORM_ABOUT_ANCHOR_COORD (self, transform,
&info->scale_center,
cogl_matrix_scale (transform,
info->scale_x,
info->scale_y,
info->scale_z));
&info->rx_center,
cogl_matrix_rotate (transform,
info->rx_angle,
1.0, 0, 0));
}
if (info->ry_angle)
{
/* XXX:2.0 remove anchor coord */
TRANSFORM_ABOUT_ANCHOR_COORD (self, transform,
&info->ry_center,
cogl_matrix_rotate (transform,
info->ry_angle,
0, 1.0, 0));
}
if (info->rz_angle)
@ -3241,39 +3243,26 @@ clutter_actor_real_apply_transform (ClutterActor *self,
0, 0, 1.0));
}
if (info->ry_angle)
if (info->scale_x != 1.0 || info->scale_y != 1.0 || info->scale_z != 1.0)
{
/* XXX:2.0 remove anchor coord */
TRANSFORM_ABOUT_ANCHOR_COORD (self, transform,
&info->ry_center,
cogl_matrix_rotate (transform,
info->ry_angle,
0, 1.0, 0));
&info->scale_center,
cogl_matrix_scale (transform,
info->scale_x,
info->scale_y,
info->scale_z));
}
if (info->rx_angle)
{
/* XXX:2.0 remove anchor coord */
TRANSFORM_ABOUT_ANCHOR_COORD (self, transform,
&info->rx_center,
cogl_matrix_rotate (transform,
info->rx_angle,
1.0, 0, 0));
}
/* XXX:2.0 remove anchor point translation */
if (!clutter_anchor_coord_is_zero (&info->anchor))
{
gfloat x, y, z;
clutter_anchor_coord_get_units (self, &info->anchor, &x, &y, &z);
cogl_matrix_translate (transform, -x, -y, -z);
}
cogl_matrix_translate (transform,
priv->allocation.x1 + info->translation.x,
priv->allocation.y1 + info->translation.y,
info->z_position + info->translation.z);
roll_back_pivot:
/* roll back the pivot translation */
if (pivot_x != 0.f || pivot_y != 0.f || info->pivot_z != 0.f)
cogl_matrix_translate (transform, -pivot_x, -pivot_y, -info->pivot_z);
cogl_matrix_translate (transform, pivot_x, pivot_y, info->pivot_z);
/* we have a valid modelview */
priv->transform_valid = TRUE;
@ -16167,17 +16156,6 @@ clutter_anchor_coord_set_gravity (AnchorCoord *coord,
coord->is_fractional = TRUE;
}
static gboolean
clutter_anchor_coord_is_zero (const AnchorCoord *coord)
{
if (coord->is_fractional)
return coord->v.fraction.x == 0.0 && coord->v.fraction.y == 0.0;
else
return (coord->v.units.x == 0.0
&& coord->v.units.y == 0.0
&& coord->v.units.z == 0.0);
}
/**
* clutter_actor_get_flags:
* @self: a #ClutterActor