/* * Clutter. * * An OpenGL based 'interactive canvas' library. * * Authored By Matthew Allum * Jorn Baayen * Emmanuele Bassi * Tomas Frydrych * * Copyright (C) 2006, 2007 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-alpha * @short_description: A class for calculating an alpha value as a function * of time. * * #ClutterAlpha is a class for calculating an integer value between * 0 and %CLUTTER_ALPHA_MAX_ALPHA as a function of time. You should * provide a #ClutterTimeline and bind it to the #ClutterAlpha object; * you should also provide a function returning the alpha value depending * on the position inside the timeline; this function will be executed * each time a new frame in the #ClutterTimeline is reached. Since the * alpha function is controlled by the timeline instance, you can pause * or stop the #ClutterAlpha from calling the alpha function by controlling * the #ClutterTimeline object. * * #ClutterAlpha is used to "drive" a #ClutterBehaviour instance. * *
* Graphic representation of some alpha functions * *
* * Since: 0.2 */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include "clutter-alpha.h" #include "clutter-main.h" #include "clutter-marshal.h" #include "clutter-private.h" #include "clutter-debug.h" G_DEFINE_TYPE (ClutterAlpha, clutter_alpha, G_TYPE_INITIALLY_UNOWNED); struct _ClutterAlphaPrivate { ClutterTimeline *timeline; guint timeline_new_frame_id; guint32 alpha; ClutterAlphaFunc func; gpointer data; GDestroyNotify destroy; }; enum { PROP_0, PROP_TIMELINE, PROP_ALPHA }; static void timeline_new_frame_cb (ClutterTimeline *timeline, guint current_frame_num, ClutterAlpha *alpha) { ClutterAlphaPrivate *priv = alpha->priv; /* Update alpha value and notify */ if (priv->func) { g_object_ref (alpha); priv->alpha = priv->func (alpha, priv->data); g_object_notify (G_OBJECT (alpha), "alpha"); g_object_unref (alpha); } } static void clutter_alpha_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec) { ClutterAlpha *alpha; ClutterAlphaPrivate *priv; alpha = CLUTTER_ALPHA (object); priv = alpha->priv; switch (prop_id) { case PROP_TIMELINE: clutter_alpha_set_timeline (alpha, g_value_get_object (value)); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static void clutter_alpha_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec) { ClutterAlpha *alpha; ClutterAlphaPrivate *priv; alpha = CLUTTER_ALPHA (object); priv = alpha->priv; switch (prop_id) { case PROP_TIMELINE: g_value_set_object (value, priv->timeline); break; case PROP_ALPHA: g_value_set_uint (value, priv->alpha); break; default: G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec); break; } } static void clutter_alpha_finalize (GObject *object) { ClutterAlphaPrivate *priv = CLUTTER_ALPHA (object)->priv; if (priv->destroy) { priv->destroy (priv->data); priv->destroy = NULL; priv->data = NULL; priv->func = NULL; } G_OBJECT_CLASS (clutter_alpha_parent_class)->finalize (object); } static void clutter_alpha_dispose (GObject *object) { ClutterAlpha *self = CLUTTER_ALPHA(object); clutter_alpha_set_timeline (self, NULL); G_OBJECT_CLASS (clutter_alpha_parent_class)->dispose (object); } static void clutter_alpha_class_init (ClutterAlphaClass *klass) { GObjectClass *object_class = G_OBJECT_CLASS (klass); object_class->set_property = clutter_alpha_set_property; object_class->get_property = clutter_alpha_get_property; object_class->finalize = clutter_alpha_finalize; object_class->dispose = clutter_alpha_dispose; g_type_class_add_private (klass, sizeof (ClutterAlphaPrivate)); /** * ClutterAlpha:timeline: * * A #ClutterTimeline instance used to drive the alpha function. * * Since: 0.2 */ g_object_class_install_property (object_class, PROP_TIMELINE, g_param_spec_object ("timeline", "Timeline", "Timeline", CLUTTER_TYPE_TIMELINE, CLUTTER_PARAM_READWRITE)); /** * ClutterAlpha:alpha: * * The alpha value as computed by the alpha function. * * Since: 0.2 */ g_object_class_install_property (object_class, PROP_ALPHA, g_param_spec_uint ("alpha", "Alpha value", "Alpha value", 0, CLUTTER_ALPHA_MAX_ALPHA, 0, CLUTTER_PARAM_READABLE)); } static void clutter_alpha_init (ClutterAlpha *self) { self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self, CLUTTER_TYPE_ALPHA, ClutterAlphaPrivate); } /** * clutter_alpha_get_alpha: * @alpha: A #ClutterAlpha * * Query the current alpha value. * * Return Value: The current alpha value for the alpha * * Since: 0.2 */ guint32 clutter_alpha_get_alpha (ClutterAlpha *alpha) { g_return_val_if_fail (CLUTTER_IS_ALPHA (alpha), FALSE); return alpha->priv->alpha; } /** * clutter_alpha_set_func: * @alpha: A #ClutterAlpha * @func: A #ClutterAlphaAlphaFunc * @data: user data to be passed to the alpha function, or %NULL * @destroy: notify function used when disposing the alpha function * * Sets the #ClutterAlphaFunc function used to compute * the alpha value at each frame of the #ClutterTimeline * bound to @alpha. * * Since: 0.2 */ void clutter_alpha_set_func (ClutterAlpha *alpha, ClutterAlphaFunc func, gpointer data, GDestroyNotify destroy) { ClutterAlphaPrivate *priv; g_return_if_fail (CLUTTER_IS_ALPHA (alpha)); priv = alpha->priv; if (priv->destroy) { priv->destroy (priv->data); priv->func = NULL; priv->data = NULL; priv->destroy = NULL; } priv->func = func; priv->data = data; priv->destroy = destroy; } /** * clutter_alpha_set_timeline: * @alpha: A #ClutterAlpha * @timeline: A #ClutterTimeline * * Binds @alpha to @timeline. * * Since: 0.2 */ void clutter_alpha_set_timeline (ClutterAlpha *alpha, ClutterTimeline *timeline) { ClutterAlphaPrivate *priv; g_return_if_fail (CLUTTER_IS_ALPHA (alpha)); g_return_if_fail (timeline == NULL || CLUTTER_IS_TIMELINE (timeline)); priv = alpha->priv; if (priv->timeline) { g_signal_handlers_disconnect_by_func (priv->timeline, timeline_new_frame_cb, alpha); g_object_unref (priv->timeline); priv->timeline = NULL; } if (timeline) { priv->timeline = g_object_ref (timeline); g_signal_connect (priv->timeline, "new-frame", G_CALLBACK (timeline_new_frame_cb), alpha); } } /** * clutter_alpha_get_timeline: * @alpha: A #ClutterAlpha * * Gets the #ClutterTimeline bound to @alpha. * * Return value: a #ClutterTimeline instance * * Since: 0.2 */ ClutterTimeline * clutter_alpha_get_timeline (ClutterAlpha *alpha) { g_return_val_if_fail (CLUTTER_IS_ALPHA (alpha), NULL); return alpha->priv->timeline; } /** * clutter_alpha_new: * * Creates a new #ClutterAlpha instance. You must set a function * to compute the alpha value using clutter_alpha_set_func() and * bind a #ClutterTimeline object to the #ClutterAlpha instance * using clutter_alpha_set_timeline(). * * You should use the newly created #ClutterAlpha instance inside * a #ClutterBehaviour object. * * Return value: the newly created empty #ClutterAlpha instance. * * Since: 0.2 */ ClutterAlpha * clutter_alpha_new (void) { return g_object_new (CLUTTER_TYPE_ALPHA, NULL); } /** * clutter_alpha_new_full: * @timeline: #ClutterTimeline timeline * @func: #ClutterAlphaFunc alpha function * @data: data to be passed to the alpha function * @destroy: notify to be called when removing the alpha function * * Creates a new #ClutterAlpha instance and sets the timeline * and alpha function. * * Return Value: the newly created #ClutterAlpha * * Since: 0.2 */ ClutterAlpha * clutter_alpha_new_full (ClutterTimeline *timeline, ClutterAlphaFunc func, gpointer data, GDestroyNotify destroy) { ClutterAlpha *retval; g_return_val_if_fail (CLUTTER_IS_TIMELINE (timeline), NULL); g_return_val_if_fail (func != NULL, NULL); retval = clutter_alpha_new (); clutter_alpha_set_timeline (retval, timeline); clutter_alpha_set_func (retval, func, data, destroy); return retval; } /** * CLUTTER_ALPHA_RAMP_INC: * * Convenience symbol for clutter_ramp_inc_func(). * * Since: 0.2 */ /** * clutter_ramp_inc_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a monotonic increasing ramp. You * can use this function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.2 */ guint32 clutter_ramp_inc_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline *timeline; gint current_frame_num, n_frames; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); return (current_frame_num * CLUTTER_ALPHA_MAX_ALPHA) / n_frames; } /** * CLUTTER_ALPHA_RAMP_DEC: * * Convenience symbol for clutter_ramp_dec_func(). * * Since: 0.2 */ /** * clutter_ramp_dec_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a monotonic decreasing ramp. You * can use this function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.2 */ guint32 clutter_ramp_dec_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline *timeline; gint current_frame_num, n_frames; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); return (n_frames - current_frame_num) * CLUTTER_ALPHA_MAX_ALPHA / n_frames; } /** * CLUTTER_ALPHA_RAMP: * * Convenience symbol for clutter_ramp_func(). * * Since: 0.2 */ /** * clutter_ramp_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a full ramp function (increase for * half the time, decrease for the remaining half). You can use this * function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.2 */ guint32 clutter_ramp_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline *timeline; gint current_frame_num, n_frames; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); if (current_frame_num > (n_frames / 2)) { return (n_frames - current_frame_num) * CLUTTER_ALPHA_MAX_ALPHA / (n_frames / 2); } else { return current_frame_num * CLUTTER_ALPHA_MAX_ALPHA / (n_frames / 2); } } static guint32 sincx1024_func (ClutterAlpha *alpha, ClutterAngle angle, ClutterFixed offset) { ClutterTimeline *timeline; gint current_frame_num, n_frames; ClutterAngle x; unsigned int sine; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = angle * current_frame_num / n_frames; x -= (512 * 512 / angle); sine = ((clutter_sini (x) + offset)/2) * CLUTTER_ALPHA_MAX_ALPHA; sine = sine >> CFX_Q; return sine; } #if 0 /* * The following two functions are left in place for reference * purposes. */ static guint32 sincx_func (ClutterAlpha *alpha, ClutterFixed angle, ClutterFixed offset) { ClutterTimeline *timeline; gint current_frame_num, n_frames; ClutterFixed x, sine; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = angle * current_frame_num / n_frames; x = CLUTTER_FIXED_MUL (x, CFX_PI) - CLUTTER_FIXED_DIV (CFX_PI, angle); sine = (clutter_fixed_sin (x) + offset)/2; CLUTTER_NOTE (ALPHA, "sine: %2f\n", CLUTTER_FIXED_TO_DOUBLE (sine)); return CLUTTER_FIXED_TO_INT (sine * CLUTTER_ALPHA_MAX_ALPHA); } /* NB: angle is not in radians but in muliples of PI, i.e., 2.0 * represents full circle. */ static guint32 sinc_func (ClutterAlpha *alpha, float angle, float offset) { ClutterTimeline *timeline; gint current_frame_num, n_frames; gdouble x, sine; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); /* FIXME: fixed point, and fixed point sine() */ x = (gdouble) (current_frame_num * angle * M_PI) / n_frames ; sine = (sin (x - (M_PI / angle)) + offset) * 0.5f; CLUTTER_NOTE (ALPHA, "sine: %2f\n",sine); return CLUTTER_FLOAT_TO_INT ((sine * (gdouble) CLUTTER_ALPHA_MAX_ALPHA)); } #endif /** * CLUTTER_ALPHA_SINE: * * Convenience symbol for clutter_sine_func(). * * Since: 0.2 */ /** * clutter_sine_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a sine wave. You can use this * function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.2 */ guint32 clutter_sine_func (ClutterAlpha *alpha, gpointer dummy) { #if 0 return sinc_func (alpha, 2.0, 1.0); #else /* 2.0 above represents full circle */ return sincx1024_func (alpha, 1024, CFX_ONE); #endif } /** * CLUTTER_ALPHA_SINE_INC: * * Convenience symbol for clutter_sine_inc_func(). * * Since: 0.2 */ /** * clutter_sine_inc_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a sine wave over interval [0, pi / 2]. * You can use this function as the alpha function for * clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.2 */ guint32 clutter_sine_inc_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline * timeline; gint frame; gint n_frames; ClutterAngle x; ClutterFixed sine; timeline = clutter_alpha_get_timeline (alpha); frame = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = 256 * frame / n_frames; sine = clutter_sini (x) * CLUTTER_ALPHA_MAX_ALPHA; return ((guint32)sine) >> CFX_Q; } /** * CLUTTER_ALPHA_SINE_DEC: * * Convenience symbol for clutter_sine_dec_func(). * * Since: 0.2 */ /** * clutter_sine_dec_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a sine wave over interval [pi / 2, pi]. * You can use this function as the alpha function for * clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.4 */ guint32 clutter_sine_dec_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline * timeline; gint frame; gint n_frames; ClutterAngle x; ClutterFixed sine; timeline = clutter_alpha_get_timeline (alpha); frame = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = 256 * frame / n_frames + 256; sine = clutter_sini (x) * CLUTTER_ALPHA_MAX_ALPHA; return ((guint32)sine) >> CFX_Q; } /** * CLUTTER_ALPHA_SINE_HALF: * * Convenience symbol for clutter_sine_half_func(). * * Since: 0.4 */ /** * clutter_sine_half_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a sine wave over interval [0, pi]. * You can use this function as the alpha function for * clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.4 */ guint32 clutter_sine_half_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline * timeline; gint frame; gint n_frames; ClutterAngle x; ClutterFixed sine; timeline = clutter_alpha_get_timeline (alpha); frame = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = 512 * frame / n_frames; sine = clutter_sini (x) * CLUTTER_ALPHA_MAX_ALPHA; return ((guint32)sine) >> CFX_Q; } /** * CLUTTER_ALPHA_SQUARE: * * Convenience symbol for clutter_square_func(). * * Since: 0.4 */ /** * clutter_square_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a square wave. You can use this * function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value * * Since: 0.4 */ guint32 clutter_square_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline *timeline; gint current_frame_num, n_frames; timeline = clutter_alpha_get_timeline (alpha); current_frame_num = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); return (current_frame_num > (n_frames / 2)) ? CLUTTER_ALPHA_MAX_ALPHA : 0; } /** * CLUTTER_ALPHA_SMOOTHSTEP_INC: * * Convenience symbol for clutter_smoothstep_inc_func(). * * Since: 0.4 */ /** * clutter_smoothstep_inc_func: * @alpha: a #ClutterAlpha * @dummy: unused * * Convenience alpha function for a smoothstep curve. You can use this * function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value * * Since: 0.4 */ guint32 clutter_smoothstep_inc_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline *timeline; gint frame; gint n_frames; guint32 r; guint32 x; /* * The smoothstep function uses f(x) = -2x^3 + 3x^2 where x is from <0,1>, * and precission is critical -- we use 8.24 fixed format for this operation. * The earlier operations involve division, which we cannot do in 8.24 for * numbers in <0,1> we use ClutterFixed. */ timeline = clutter_alpha_get_timeline (alpha); frame = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); /* * Convert x to 8.24 for next step. */ x = CFX_DIV (frame, n_frames) << 8; /* * f(x) = -2x^3 + 3x^2 * * Convert result to ClutterFixed to avoid overflow in next step. */ r = ((x >> 12) * (x >> 12) * 3 - (x >> 15) * (x >> 16) * (x >> 16)) >> 8; return CFX_INT (r * CLUTTER_ALPHA_MAX_ALPHA); } /** * CLUTTER_ALPHA_SMOOTHSTEP_DEC: * * Convenience symbol for clutter_smoothstep_dec_func(). * * Since: 0.4 */ /** * clutter_smoothstep_dec_func: * @alpha: a #ClutterAlpha * @dummy: unused * * Convenience alpha function for a downward smoothstep curve. You can use * this function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value * * Since: 0.4 */ guint32 clutter_smoothstep_dec_func (ClutterAlpha *alpha, gpointer dummy) { return CLUTTER_ALPHA_MAX_ALPHA - clutter_smoothstep_inc_func (alpha, dummy); } /** * CLUTTER_ALPHA_EXP_INC: * * Convenience symbol for clutter_exp_inc_func() * * Since: 0.4 */ /** * clutter_exp_inc_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a 2^x curve. You can use this function as the * alpha function for clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.4 */ guint32 clutter_exp_inc_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline * timeline; gint frame; gint n_frames; ClutterFixed x; ClutterFixed x_alpha_max = 0x100000; guint32 result; /* * Choose x_alpha_max such that * * (2^x_alpha_max) - 1 == CLUTTER_ALPHA_MAX_ALPHA */ #if CLUTTER_ALPHA_MAX_ALPHA != 0xffff #error Adjust x_alpha_max to match CLUTTER_ALPHA_MAX_ALPHA #endif timeline = clutter_alpha_get_timeline (alpha); frame = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = x_alpha_max * frame / n_frames; result = CLAMP (clutter_pow2x (x) - 1, 0, CLUTTER_ALPHA_MAX_ALPHA); return result; } /** * CLUTTER_ALPHA_EXP_DEC: * * Convenience symbold for clutter_exp_dec_func(). * * Since: 0.4 */ /** * clutter_exp_dec_func: * @alpha: a #ClutterAlpha * @dummy: unused argument * * Convenience alpha function for a decreasing 2^x curve. You can use this * function as the alpha function for clutter_alpha_set_func(). * * Return value: an alpha value. * * Since: 0.4 */ guint32 clutter_exp_dec_func (ClutterAlpha *alpha, gpointer dummy) { ClutterTimeline * timeline; gint frame; gint n_frames; ClutterFixed x; ClutterFixed x_alpha_max = 0x100000; guint32 result; /* * Choose x_alpha_max such that * * (2^x_alpha_max) - 1 == CLUTTER_ALPHA_MAX_ALPHA */ #if CLUTTER_ALPHA_MAX_ALPHA != 0xffff #error Adjust x_alpha_max to match CLUTTER_ALPHA_MAX_ALPHA #endif timeline = clutter_alpha_get_timeline (alpha); frame = clutter_timeline_get_current_frame (timeline); n_frames = clutter_timeline_get_n_frames (timeline); x = (x_alpha_max * (n_frames - frame)) / n_frames; result = CLAMP (clutter_pow2x (x) - 1, 0, CLUTTER_ALPHA_MAX_ALPHA); return result; }