mutter/clutter/clutter-behaviour-path.c
Emmanuele Bassi 7d7372af43 [animation] Move the alpha value to floating point
The current Alpha value is an unsigned integer that can be used
implicitly as a fixed point value. This makes writing an alpha
function overshooting below and above the current range basically
impossible without complicating an already complex code, and
creating weird corner cases.

For this reason, the Alpha value should be defined as a floating
point normalized value, spanning a range between 0.0 and 1.0; in
order to allow overshooting, the valid range is extended one unit
below and one unit above, thus making it -1.0 .. 2.0.

This commit updates the various users of the ClutterAlpha API
and the tests cases.

This commit also removes all the current alpha functions exposed
in the public API.
2009-01-20 16:42:49 +00:00

440 lines
12 KiB
C

/*
* Clutter.
*
* An OpenGL based 'interactive canvas' library.
*
* Authored By Matthew Allum <mallum@openedhand.com>
*
* Copyright (C) 2006 OpenedHand
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:clutter-behaviour-path
* @short_description: A behaviour for moving actors along a #ClutterPath
*
* #ClutterBehaviourPath interpolates actors along a defined path.
*
* A path is described by a #ClutterPath object. The path can contain
* straight line parts and bezier curves. If the path contains
* %CLUTTER_PATH_MOVE_TO parts then the actors will jump to those
* coordinates. This can be used make disjoint paths.
*
* When creating a path behaviour in a #ClutterScript, you can specify
* the path property directly as a string. For example:
*
* |[
* {
* "id" : "spline-path",
* "type" : "ClutterBehaviourPath",
* "path" : "M 50 50 L 100 100",
* "alpha" : {
* "timeline" : "main-timeline",
* "function" : "ramp
* }
* }
* ]|
*
* <note>If the alpha function is a periodic function, i.e. it returns to
* 0 after reaching %CLUTTER_ALPHA_MAX_ALPHA, then the actors will walk
* the path back to the starting #ClutterKnot.</note>
*
* #ClutterBehaviourPath is available since Clutter 0.2
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "clutter-actor.h"
#include "clutter-behaviour.h"
#include "clutter-behaviour-path.h"
#include "clutter-bezier.h"
#include "clutter-debug.h"
#include "clutter-enum-types.h"
#include "clutter-main.h"
#include "clutter-marshal.h"
#include "clutter-private.h"
#include "clutter-script-private.h"
#include "clutter-scriptable.h"
#include <math.h>
static void clutter_scriptable_iface_init (ClutterScriptableIface *iface);
G_DEFINE_TYPE_WITH_CODE (ClutterBehaviourPath,
clutter_behaviour_path,
CLUTTER_TYPE_BEHAVIOUR,
G_IMPLEMENT_INTERFACE (CLUTTER_TYPE_SCRIPTABLE,
clutter_scriptable_iface_init));
struct _ClutterBehaviourPathPrivate
{
ClutterPath *path;
guint last_knot_passed;
};
#define CLUTTER_BEHAVIOUR_PATH_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
CLUTTER_TYPE_BEHAVIOUR_PATH, \
ClutterBehaviourPathPrivate))
enum
{
KNOT_REACHED,
LAST_SIGNAL
};
static guint path_signals[LAST_SIGNAL] = { 0, };
enum
{
PROP_0,
PROP_PATH
};
static void
actor_apply_knot_foreach (ClutterBehaviour *behaviour,
ClutterActor *actor,
gpointer data)
{
ClutterKnot *knot = data;
CLUTTER_NOTE (BEHAVIOUR, "Setting actor to %ix%i", knot->x, knot->y);
clutter_actor_set_position (actor, knot->x, knot->y);
}
static void
clutter_behaviour_path_alpha_notify (ClutterBehaviour *behave,
gdouble alpha_value)
{
ClutterBehaviourPath *pathb = CLUTTER_BEHAVIOUR_PATH (behave);
ClutterBehaviourPathPrivate *priv = pathb->priv;
ClutterKnot position;
guint knot_num;
if (priv->path)
knot_num = clutter_path_get_position (priv->path, alpha_value, &position);
else
{
memset (&position, 0, sizeof (position));
knot_num = 0;
}
clutter_behaviour_actors_foreach (behave,
actor_apply_knot_foreach,
&position);
if (knot_num != priv->last_knot_passed)
{
g_signal_emit (behave, path_signals[KNOT_REACHED], 0, knot_num);
priv->last_knot_passed = knot_num;
}
}
static void
clutter_behaviour_path_get_property (GObject *gobject,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
ClutterBehaviourPath *pathb = CLUTTER_BEHAVIOUR_PATH (gobject);
switch (prop_id)
{
case PROP_PATH:
g_value_set_object (value, clutter_behaviour_path_get_path (pathb));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_path_set_property (GObject *gobject,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
ClutterBehaviourPath *pathb = CLUTTER_BEHAVIOUR_PATH (gobject);
switch (prop_id)
{
case PROP_PATH:
clutter_behaviour_path_set_path (pathb, g_value_get_object (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (gobject, prop_id, pspec);
break;
}
}
static void
clutter_behaviour_path_dispose (GObject *gobject)
{
ClutterBehaviourPath *pathb = CLUTTER_BEHAVIOUR_PATH (gobject);
clutter_behaviour_path_set_path (pathb, NULL);
G_OBJECT_CLASS (clutter_behaviour_path_parent_class)->dispose (gobject);
}
static void
clutter_behaviour_path_class_init (ClutterBehaviourPathClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
ClutterBehaviourClass *behave_class = CLUTTER_BEHAVIOUR_CLASS (klass);
GParamSpec *pspec;
gobject_class->get_property = clutter_behaviour_path_get_property;
gobject_class->set_property = clutter_behaviour_path_set_property;
gobject_class->dispose = clutter_behaviour_path_dispose;
pspec = g_param_spec_object ("path",
"Path",
"The ClutterPath object representing the path "
"to animate along",
CLUTTER_TYPE_PATH,
CLUTTER_PARAM_READWRITE);
g_object_class_install_property (gobject_class, PROP_PATH, pspec);
/**
* ClutterBehaviourPath::knot-reached:
* @pathb: the object which received the signal
* @knot_num: the index of the #ClutterPathKnot reached
*
* This signal is emitted each time a node defined inside the path
* is reached.
*
* Since: 0.2
*/
path_signals[KNOT_REACHED] =
g_signal_new ("knot-reached",
G_TYPE_FROM_CLASS (gobject_class),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (ClutterBehaviourPathClass, knot_reached),
NULL, NULL,
clutter_marshal_VOID__UINT,
G_TYPE_NONE, 1,
G_TYPE_UINT);
behave_class->alpha_notify = clutter_behaviour_path_alpha_notify;
g_type_class_add_private (klass, sizeof (ClutterBehaviourPathPrivate));
}
static ClutterScriptableIface *parent_scriptable_iface = NULL;
static gboolean
clutter_behaviour_path_parse_custom_node (ClutterScriptable *scriptable,
ClutterScript *script,
GValue *value,
const gchar *name,
JsonNode *node)
{
if (strcmp ("path", name) == 0)
{
ClutterPath *path;
GValue node_value = { 0 };
path = g_object_ref_sink (clutter_path_new ());
json_node_get_value (node, &node_value);
if (!G_VALUE_HOLDS (&node_value, G_TYPE_STRING)
|| !clutter_path_set_description (path,
g_value_get_string (&node_value)))
g_warning ("Invalid path description");
g_value_unset (&node_value);
g_value_init (value, G_TYPE_OBJECT);
g_value_take_object (value, path);
return TRUE;
}
/* chain up */
else if (parent_scriptable_iface->parse_custom_node)
return parent_scriptable_iface->parse_custom_node (scriptable, script,
value, name, node);
else
return FALSE;
}
static void
clutter_scriptable_iface_init (ClutterScriptableIface *iface)
{
parent_scriptable_iface = g_type_interface_peek_parent (iface);
if (!parent_scriptable_iface)
parent_scriptable_iface
= g_type_default_interface_peek (CLUTTER_TYPE_SCRIPTABLE);
iface->parse_custom_node = clutter_behaviour_path_parse_custom_node;
}
static void
clutter_behaviour_path_init (ClutterBehaviourPath *self)
{
ClutterBehaviourPathPrivate *priv;
self->priv = priv = CLUTTER_BEHAVIOUR_PATH_GET_PRIVATE (self);
priv->path = NULL;
priv->last_knot_passed = G_MAXUINT;
}
/**
* clutter_behaviour_path_new:
* @alpha: a #ClutterAlpha, or %NULL
* @path: a #ClutterPath or %NULL for an empty path
*
* Creates a new path behaviour. You can use this behaviour to drive
* actors along the nodes of a path, described by @path.
*
* This will claim the floating reference on the #ClutterPath so you
* do not need to unref if it.
*
* Return value: a #ClutterBehaviour
*
* Since: 0.2
*/
ClutterBehaviour *
clutter_behaviour_path_new (ClutterAlpha *alpha,
ClutterPath *path)
{
return g_object_new (CLUTTER_TYPE_BEHAVIOUR_PATH,
"alpha", alpha,
"path", path,
NULL);
}
/**
* clutter_behaviour_path_new_with_description:
* @alpha: a #ClutterAlpha
* @desc: a string description of the path
*
* Creates a new path behaviour using the path described by @desc. See
* clutter_path_add_string() for a description of the format.
*
* Return value: a #ClutterBehaviour
*
* Since: 1.0
*/
ClutterBehaviour *
clutter_behaviour_path_new_with_description (ClutterAlpha *alpha,
const gchar *desc)
{
return g_object_new (CLUTTER_TYPE_BEHAVIOUR_PATH,
"alpha", alpha,
"path", clutter_path_new_with_description (desc),
NULL);
}
/**
* clutter_behaviour_path_new_with_knots:
* @alpha: a #ClutterAlpha
* @knots: an array of #ClutterKnot<!-- -->s
* @n_knots: number of entries in @knots
*
* Creates a new path behaviour that will make the actors visit all of
* the given knots in order with straight lines in between.
*
* A path will be created where the first knot is used in a
* %CLUTTER_PATH_MOVE_TO and the subsequent knots are used in
* %CLUTTER_PATH_LINE_TO<!-- -->s.
*
* Return value: a #ClutterBehaviour
*
* Since: 1.0
*/
ClutterBehaviour *
clutter_behaviour_path_new_with_knots (ClutterAlpha *alpha,
const ClutterKnot *knots,
guint n_knots)
{
ClutterPath *path = clutter_path_new ();
guint i;
if (n_knots > 0)
{
clutter_path_add_move_to (path, knots[0].x, knots[0].y);
for (i = 1; i < n_knots; i++)
clutter_path_add_line_to (path, knots[i].x, knots[i].y);
}
return g_object_new (CLUTTER_TYPE_BEHAVIOUR_PATH,
"alpha", alpha,
"path", path,
NULL);
}
/**
* clutter_behaviour_path_set_path:
* @pathb: the path behaviour
* @path: the new path to follow
*
* Change the path that the actors will follow. This will take the
* floating reference on the #ClutterPath so you do not need to unref
* it.
*
* Since: 1.0
*/
void
clutter_behaviour_path_set_path (ClutterBehaviourPath *pathb,
ClutterPath *path)
{
ClutterBehaviourPathPrivate *priv;
g_return_if_fail (CLUTTER_IS_BEHAVIOUR_PATH (pathb));
priv = pathb->priv;
if (path)
g_object_ref_sink (path);
if (priv->path)
g_object_unref (priv->path);
priv->path = path;
g_object_notify (G_OBJECT (pathb), "path");
}
/**
* clutter_behaviour_path_get_path:
* @pathb: a #ClutterBehaviourPath instance
*
* Get the current path of the behaviour
*
* Return value: the path
*
* Since: 1.0
*/
ClutterPath *
clutter_behaviour_path_get_path (ClutterBehaviourPath *pathb)
{
g_return_val_if_fail (CLUTTER_IS_BEHAVIOUR_PATH (pathb), NULL);
return pathb->priv->path;
}