Do not modify parameters in placegit-import

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.

2 files changed, 38 insertions, 28 deletions

diff --git a/clutter/clutter-actor.c b/clutter/clutter-actor.c
index f6c040b43..424144436 100644
--- a/clutter/clutter-actor.c
+++ b/clutter/clutter-actor.c
@@ -891,20 +891,25 @@ clutter_actor_transform_point (ClutterActor *actor,
  * Since: 0.6
  */
 void
-clutter_actor_apply_relative_transform_to_point (ClutterActor  *self,
-						 ClutterActor  *ancestor,
-						 ClutterVertex *point,
-						 ClutterVertex *vertex)
+clutter_actor_apply_relative_transform_to_point (ClutterActor        *self,
+						 ClutterActor        *ancestor,
+						 const ClutterVertex *point,
+						 ClutterVertex       *vertex)
 {
-  ClutterFixed  v[4];
-  ClutterFixed  w = COGL_FIXED_1;
+  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]);
 }
 
 /**
@@ -931,29 +936,34 @@ clutter_actor_apply_relative_transform_to_point (ClutterActor  *self,
  * Since: 0.4
  **/
 void
-clutter_actor_apply_transform_to_point (ClutterActor  *self,
-					ClutterVertex *point,
-					ClutterVertex *vertex)
+clutter_actor_apply_transform_to_point (ClutterActor        *self,
+                                        const ClutterVertex *point,
+                                        ClutterVertex       *vertex)
 {
-  ClutterFixed  mtx_p[16];
-  ClutterFixed  v[4];
-  ClutterFixed  w = COGL_FIXED_1;
+  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
diff --git a/clutter/clutter-actor.h b/clutter/clutter-actor.h
index 021460b78..e964a9ef0 100644
--- a/clutter/clutter-actor.h
+++ b/clutter/clutter-actor.h
@@ -551,13 +551,13 @@ void     clutter_actor_box_get_from_vertices          (ClutterVertex    vtx[4],
 void clutter_actor_get_abs_allocation_vertices       (ClutterActor  *self,
                                                       ClutterVertex  verts[4]);
 
-void clutter_actor_apply_transform_to_point          (ClutterActor  *self,
-                                                      ClutterVertex *point,
-                                                      ClutterVertex *vertex);
-void clutter_actor_apply_relative_transform_to_point (ClutterActor  *self,
-                                                      ClutterActor  *ancestor,
-                                                      ClutterVertex *point,
-                                                      ClutterVertex *vertex);
+void clutter_actor_apply_transform_to_point          (ClutterActor        *self,
+                                                      const ClutterVertex *point,
+                                                      ClutterVertex       *vertex);
+void clutter_actor_apply_relative_transform_to_point (ClutterActor        *self,
+                                                      ClutterActor        *ancestor,
+                                                      const ClutterVertex *point,
+                                                      ClutterVertex       *vertex);
 
 gboolean clutter_actor_get_paint_visibility           (ClutterActor *self);