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Do not modify parameters in place

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When the apply_transform_to_point() and its relative variant
landed in Clutter 0.3, the initial approach was to modify the
passed vertex as an in-out parameter. This was later dropped
in favour of a more consistent out parameter.

Unfortunately, the implementation never changed: both methods
where modifying the passed vertex with the partial results of
the computations.

This commit copies the contents of the "point" ClutterVertex
argument inside a stack variable and, for good measure, constifies
the argument.

Thanks to Thomas Steinacher for catching this in Python.
This commit is contained in:
Emmanuele Bassi 2008-12-10 23:00:48 +00:00
parent dc6545ccd1
commit bc6a107ff6
2 changed files with 38 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
clutter/clutter-actor.c
View File

@ -893,18 +893,23 @@ clutter_actor_transform_point (ClutterActor *actor,
void
clutter_actor_apply_relative_transform_to_point (ClutterActor *self,
ClutterActor *ancestor,
ClutterVertex *point,
const ClutterVertex *point,
ClutterVertex *vertex)
{
ClutterVertex tmp = { 0, };
ClutterFixed v[4];
ClutterFixed w = COGL_FIXED_1;
g_return_if_fail (CLUTTER_IS_ACTOR (self));
g_return_if_fail (ancestor == NULL || CLUTTER_IS_ACTOR (ancestor));
g_return_if_fail (point != NULL);
g_return_if_fail (vertex != NULL);
tmp = *point;
/* First we tranform the point using the OpenGL modelview matrix */
clutter_actor_transform_point_relative (self, ancestor,
&point->x, &point->y, &point->z,
&tmp.x, &tmp.y, &tmp.z,
&w);
cogl_get_viewport (v);
@ -913,9 +918,9 @@ clutter_actor_apply_relative_transform_to_point (ClutterActor *self,
* The w[3] parameter should always be 1.0 here, so we ignore it; otherwise
* we would have to divide the original verts with it.
*/
vertex->x = COGL_FIXED_MUL ((point->x + COGL_FIXED_0_5), v[2]);
vertex->y = COGL_FIXED_MUL ((COGL_FIXED_0_5 - point->y), v[3]);
vertex->z = COGL_FIXED_MUL ((point->z + COGL_FIXED_0_5), v[2]);
vertex->x = COGL_FIXED_MUL ((tmp.x + COGL_FIXED_0_5), v[2]);
vertex->y = COGL_FIXED_MUL ((COGL_FIXED_0_5 - tmp.y), v[3]);
vertex->z = COGL_FIXED_MUL ((tmp.z + COGL_FIXED_0_5), v[2]);
}
/**
@ -932,28 +937,33 @@ clutter_actor_apply_relative_transform_to_point (ClutterActor *self,
**/
void
clutter_actor_apply_transform_to_point (ClutterActor *self,
ClutterVertex *point,
const ClutterVertex *point,
ClutterVertex *vertex)
{
ClutterVertex tmp = { 0, };
ClutterFixed mtx_p[16];
ClutterFixed v[4];
ClutterFixed w = COGL_FIXED_1;
g_return_if_fail (CLUTTER_IS_ACTOR (self));
g_return_if_fail (point != NULL);
g_return_if_fail (vertex != NULL);
tmp = *point;
/* First we tranform the point using the OpenGL modelview matrix */
clutter_actor_transform_point (self, &point->x, &point->y, &point->z, &w);
clutter_actor_transform_point (self, &tmp.x, &tmp.y, &tmp.z, &w);
cogl_get_projection_matrix (mtx_p);
cogl_get_viewport (v);
/* Now, transform it again with the projection matrix */
mtx_transform (mtx_p, &point->x, &point->y, &point->z, &w);
mtx_transform (mtx_p, &tmp.x, &tmp.y, &tmp.z, &w);
/* Finaly translate from OpenGL coords to window coords */
vertex->x = MTX_GL_SCALE_X (point->x, w, v[2], v[0]);
vertex->y = MTX_GL_SCALE_Y (point->y, w, v[3], v[1]);
vertex->z = MTX_GL_SCALE_Z (point->z, w, v[2], v[0]);
vertex->x = MTX_GL_SCALE_X (tmp.x, w, v[2], v[0]);
vertex->y = MTX_GL_SCALE_Y (tmp.y, w, v[3], v[1]);
vertex->z = MTX_GL_SCALE_Z (tmp.z, w, v[2], v[0]);
}
/* Recursively tranform supplied vertices with the tranform for the current

4
clutter/clutter-actor.h
View File

@ -552,11 +552,11 @@ void clutter_actor_get_abs_allocation_vertices (ClutterActor *self,
ClutterVertex verts[4]);
void clutter_actor_apply_transform_to_point (ClutterActor *self,
ClutterVertex *point,
const ClutterVertex *point,
ClutterVertex *vertex);
void clutter_actor_apply_relative_transform_to_point (ClutterActor *self,
ClutterActor *ancestor,
ClutterVertex *point,
const ClutterVertex *point,
ClutterVertex *vertex);
gboolean clutter_actor_get_paint_visibility (ClutterActor *self);