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actor: Clean up the code in ::apply-transform

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Instead of placing the whole body of the function inside an if block,
let's make it clear what each part of the function does. Also, add more
comments.
This commit is contained in:
Emmanuele Bassi 2012-12-16 14:37:42 +00:00
parent 183e7b6176
commit 84b4f2f0a3
1 changed files with 124 additions and 110 deletions
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34
clutter/clutter-actor.c
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@ -2962,13 +2962,14 @@ clutter_actor_real_apply_transform (ClutterActor *self,
ClutterMatrix *matrix)
{
ClutterActorPrivate *priv = self->priv;
if (!priv->transform_valid)
{
CoglMatrix *transform = &priv->transform;
const ClutterTransformInfo *info;
float pivot_x = 0.f, pivot_y = 0.f;
/* we already have a cached transformation */
if (priv->transform_valid)
goto multiply_and_return;
info = _clutter_actor_get_transform_info_or_defaults (self);
/* compute the pivot point given the allocated size */
@ -2988,22 +2989,30 @@ clutter_actor_real_apply_transform (ClutterActor *self,
priv->allocation.x1 + pivot_x + info->translation.x,
priv->allocation.y1 + pivot_y + info->translation.y);
/* we apply the :child-transform from the parent actor, if we have one */
if (priv->parent != NULL)
{
const ClutterTransformInfo *parent_info;
parent_info = _clutter_actor_get_transform_info_or_defaults (priv->parent);
clutter_matrix_init_from_matrix (transform, &(parent_info->child_transform));
}
else
clutter_matrix_init_identity (transform);
/* if we have an overriding transformation, we use that, and get out */
if (info->transform_set)
{
/* we still need to apply the :allocation's origin and :pivot-point
* translations, since :transform is relative to the actor's coordinate
* 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);
goto out;
goto roll_back_pivot;
}
/* basic translation: :allocation's origin and :z-position; instead
@ -3015,14 +3024,18 @@ clutter_actor_real_apply_transform (ClutterActor *self,
priv->allocation.y1 + pivot_y + info->translation.y,
info->z_position + info->pivot_z + info->translation.z);
/*
* because the rotation involves translations, we must scale
/* 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)
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,
@ -3063,7 +3076,7 @@ clutter_actor_real_apply_transform (ClutterActor *self,
1.0, 0, 0));
}
/* XXX:2.0 remove */
/* XXX:2.0 remove anchor point translation */
if (!clutter_anchor_coord_is_zero (&info->anchor))
{
gfloat x, y, z;
@ -3072,14 +3085,15 @@ clutter_actor_real_apply_transform (ClutterActor *self,
cogl_matrix_translate (transform, -x, -y, -z);
}
out:
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);
/* we have a valid modelview */
priv->transform_valid = TRUE;
}
multiply_and_return:
cogl_matrix_multiply (matrix, matrix, &priv->transform);
}