EPhysics: body collision data

This patch introduces a wrapper(EPhysics_Body_Collision) to hold
the collision data(the contact body and collision position).

This data type is used by EPHYSICS_CALLBACK_BODY_COLLISION callback. The
collision detection test is migrated to the new API as well.


Patch by: Leandro Dorileo <dorileo@profusion.mobi>



SVN revision: 74500

legacy/ephysics/src/bin/test_collision_detection.c

@@ -14,19 +14,20 @@ struct _Collision_Data {
 };
 
 static void
-_collision_cb(void *data, EPhysics_Body *body __UNUSED__, void *event_info __UNUSED__)
+_collision_cb(void *data, EPhysics_Body *body __UNUSED__, void *event_info)
 {
+   EPhysics_Body *contact_body;
    Collision_Data *collision_data = data;
-   Evas_Object *obj;
-   int x;
+   EPhysics_Body_Collision *collision = event_info;
+   int x, y;
 
-   if (event_info != collision_data->sphere2) return;
+   contact_body = ephysics_body_collision_contact_body_get(collision);
+   if (contact_body != collision_data->sphere2) return;
 
+   ephysics_body_collision_position_get(collision, &x, &y);
    INF("Collision Detected");
 
-   obj = ephysics_body_evas_object_get(collision_data->sphere);
-   evas_object_geometry_get(obj, &x, NULL, NULL, NULL);
-   evas_object_move(collision_data->impact, x - 4, FLOOR_Y - 80);
+   evas_object_move(collision_data->impact, x, y);
    elm_object_signal_emit(collision_data->impact, "impact,show",
                           "ephysics_test");
 }

legacy/ephysics/src/lib/EPhysics.h

@@ -922,6 +922,24 @@ EAPI Eina_Bool ephysics_world_bodies_outside_left_autodel_get(const EPhysics_Wor
 
 typedef struct _EPhysics_Body EPhysics_Body; /**< Body handle, represents an object on EPhysics world. Created with @ref ephysics_body_circle_add() or @ref ephysics_body_box_add() and deleted with @ref ephysics_body_del(). */
 
+/**
+ * @typedef EPhysics_Body_Collision
+ *
+ * Body collision wraps collision informations.
+ *
+ * EPhysics_Body_Collision is used on EPHYSICS_CALLBACK_BODY_COLLISION callback
+ * and is mostly interested to hold informations like:
+ * @li contact_body - the body which the collision occurred against;
+ * @li position - points the position where the collision happened;
+ *
+ * @see ephysics_body_collision_position_get()
+ * @see ephysics_body_collision_contact_body_get()
+ * @see EPHYSICS_CALLBACK_BODY_COLLISION and @ref
+ * ephysics_body_event_callback_add() for collision callback.
+ * @ingroup EPhysics_Body
+ */
+typedef struct _EPhysics_Body_Collision EPhysics_Body_Collision;
+
 /**
  * @enum _EPhysics_Callback_Body_Type
  * @typedef EPhysics_Callback_Body_Type
@@ -1504,12 +1522,25 @@ EAPI void ephysics_body_evas_object_update(EPhysics_Body *body);
  *
  * Update callbacks receives evas object set to body as event_info argument.
  *
- * Regarding EPHYSICS_CALLBACK_BODY_COLLISION:
+ * What follows is a list of details about each callback type:
  *
- * Callbacks are called just after the collision has been actually processed
- * by the physics engine.
+ * - #EPHYSICS_CALLBACK_BODY_UPDATE: Called after every physics iteration. @p
+ *   body points to the EPhysics_Body itself and @p event_info points to the
+ *   evas object associated to the body.
  *
- * The other body involved in the collision is passed as event_info argument.
+ * - #EPHYSICS_CALLBACK_BODY_COLLISION: Called just after the collision has
+ *   been actually processed by the physics engine. The body involved in the
+ *   collision is passed as @p body argument. @p event_info is a pointer to
+ *   @ref EPhysics_Body_Collision - note, this structure(@p event_info) is
+ *   discarded/freed right after callback returns.
+ *
+ * - #EPHYSICS_CALLBACK_BODY_DEL: Called when a body deletion has been issued
+ *   and just before the deletion actually happens. @p body points to the body
+ *   being deleted and no @p event_info is provided.
+ *
+ * - #EPHYSICS_CALLBACK_BODY_STOPPED: Called when a body is found to be
+ *   stopped. @p body points to the body of interest and @p event_info is a
+ *   pointer to the evas object associated to it.
  *
  * @param body The physics body.
  * @param type Type of callback to be listened by @p func.
@@ -1564,6 +1595,39 @@ EAPI void *ephysics_body_event_callback_del(EPhysics_Body *body, EPhysics_Callba
  */
 EAPI void *ephysics_body_event_callback_del_full(EPhysics_Body *body, EPhysics_Callback_Body_Type type, EPhysics_Body_Event_Cb func, void *data);
 
+/**
+ * @brief
+ * Get the position(x, y) of a body's collision.
+ *
+ * Given a body collision data, fills @p x and @p y pointers with the position
+ * where the collision occurred.
+ *
+ * @param collision The body collision data of interest.
+ * @param x The x pointer to set the x coordinate to.
+ * @param y The y pointer to set the y coordinate to.
+ *
+ * @see EPHYSICS_CALLBACK_BODY_COLLISION and @ref
+ * ephysics_body_event_callback_add() for collision callback.
+ * @ingroup EPhysics_Body
+ */
+EAPI void ephysics_body_collision_position_get(const EPhysics_Body_Collision *collision, Evas_Coord *x, Evas_Coord *y);
+
+/**
+ * @brief
+ * Get the body's collision contact body.
+ *
+ * Given a body collision data returns the contact body which a collision
+ * occurred against.
+ *
+ * @param collision The body collision of interest.
+ * @return The contact body of @p collision.
+ *
+ * @see EPHYSICS_CALLBACK_BODY_COLLISION and @ref
+ * ephysics_body_event_callback_add() for collision callback.
+ * @ingroup EPhysics_Body
+ */
+EAPI EPhysics_Body *ephysics_body_collision_contact_body_get(const EPhysics_Body_Collision *collision);
+
 /**
  * @brief
  * Set body's coefficient of restitution.

legacy/ephysics/src/lib/ephysics_body.cpp

@@ -32,6 +32,12 @@ struct _EPhysics_Body {
      Eina_Bool active:1;
 };
 
+struct _EPhysics_Body_Collision {
+     EPhysics_Body *contact_body;
+     Evas_Coord x;
+     Evas_Coord y;
+};
+
 void
 ephysics_body_active_set(EPhysics_Body *body, Eina_Bool active)
 {
@@ -237,10 +243,50 @@ ephysics_body_evas_object_update_select(EPhysics_Body *body)
      _ephysics_body_outside_render_area_check(body);
 }
 
+static void
+ephysics_body_collision_set(EPhysics_Body_Collision *collision, EPhysics_Body *contact_body, btVector3 position)
+{
+   double rate;
+   int height;
+   EPhysics_World *world = contact_body->world;
+
+   ephysics_world_render_geometry_get(world, NULL, NULL, NULL, &height);
+   rate = ephysics_world_rate_get(world);
+   collision->contact_body = contact_body;
+   collision->x = position.getX() * rate;
+   collision->y = height - (position.getY() * rate);
+}
+
+EAPI void
+ephysics_body_collision_position_get(const EPhysics_Body_Collision *collision, Evas_Coord *x, Evas_Coord *y)
+{
+   if (!collision)
+     {
+        ERR("Can't get body's collision data, collision is null.");
+        return;
+     }
+
+   if (x) *x = collision->x;
+   if (y) *y = collision->y;
+}
+
+EAPI EPhysics_Body *
+ephysics_body_collision_contact_body_get(const EPhysics_Body_Collision *collision)
+{
+   if (!collision)
+     {
+        ERR("Can't get body's collision contact body, collision is null.");
+        return NULL;
+     }
+
+   return collision->contact_body;
+}
+
 void
-ephysics_body_contact_processed(EPhysics_Body *body, EPhysics_Body *contact_body)
+ephysics_body_contact_processed(EPhysics_Body *body, EPhysics_Body *contact_body, btVector3 position)
 {
    EPhysics_Body_Callback *cb;
+   EPhysics_Body_Collision *collision;
 
    if ((!body) || (!contact_body))
      return;
@@ -248,7 +294,18 @@ ephysics_body_contact_processed(EPhysics_Body *body, EPhysics_Body *contact_body
    EINA_INLIST_FOREACH(body->callbacks, cb)
      {
         if (cb->type == EPHYSICS_CALLBACK_BODY_COLLISION)
-          cb->func(cb->data, body, (void *) contact_body);
+          {
+             collision = (EPhysics_Body_Collision*)malloc(
+                                              sizeof(EPhysics_Body_Collision));
+             if (!collision)
+               {
+                  ERR("Can't allocate collision data structure.");
+                  continue;
+               }
+             ephysics_body_collision_set(collision, contact_body, position);
+             cb->func(cb->data, body, collision);
+             free(collision);
+          }
      }
 }
 

legacy/ephysics/src/lib/ephysics_private.h

@@ -66,7 +66,7 @@ Eina_Bool ephysics_world_bodies_outside_autodel_get(const EPhysics_World *world)
 
 void ephysics_body_evas_object_update_select(EPhysics_Body *body);
 void ephysics_orphan_body_del(EPhysics_Body *body);
-void ephysics_body_contact_processed(EPhysics_Body *body, EPhysics_Body *contact_body);
+void ephysics_body_contact_processed(EPhysics_Body *body, EPhysics_Body *contact_body, btVector3 position);
 btRigidBody *ephysics_body_rigid_body_get(const EPhysics_Body *body);
 void ephysics_body_active_set(EPhysics_Body *body, Eina_Bool active);
 

legacy/ephysics/src/lib/ephysics_world.cpp

@@ -123,8 +123,8 @@ _ephysics_world_contact_processed_cb(btManifoldPoint &cp, void *b0, void *b1)
    body_0 = (EPhysics_Body *) rigid_body_0->getUserPointer();
    body_1 = (EPhysics_Body *) rigid_body_1->getUserPointer();
 
-   ephysics_body_contact_processed(body_0, body_1);
-   ephysics_body_contact_processed(body_1, body_0);
+   ephysics_body_contact_processed(body_0, body_1, cp.getPositionWorldOnA());
+   ephysics_body_contact_processed(body_1, body_0, cp.getPositionWorldOnB());
 
    return EINA_TRUE;
 }