plugins/libxfade.c

   1 /* gAlan - Graphical Audio Language
   2  * Copyright (C) 1999 Tony Garnock-Jones
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <stdio.h>
  22 #include <stddef.h>
  23
  24 #include <gdk/gdk.h>
  25 #include <gtk/gtk.h>
  26 #include <gmodule.h>
  27
  28 #include "global.h"
  29 #include "generator.h"
  30 #include "comp.h"
  31 #include "control.h"
  32 #include "gencomp.h"
  33
  34 #define GENERATOR_CLASS_NAME    "xfade"
  35 #define GENERATOR_CLASS_PATH    "Levels/Cross-fader"
  36
  37 #define SIG_LEFT                0
  38 #define SIG_RIGHT               1
  39
  40 #define SIG_OUTPUT              0
  41
  42 #define EVT_AMOUNT              0
  43 #define NUM_EVENT_INPUTS        1
  44
  45 #define NUM_EVENT_OUTPUTS       0
  46
  47 typedef struct Data {
  48   gdouble amount;
  49 } Data;
  50
  51 PRIVATE gboolean init_instance(Generator *g) {
  52   Data *data = safe_malloc(sizeof(Data));
  53   g->data = data;
  54
  55   data->amount = 0;
  56
  57   return TRUE;
  58 }
  59
  60 PRIVATE void destroy_instance(Generator *g) {
  61   free(g->data);
  62 }
  63
  64 PRIVATE void unpickle_instance(Generator *g, ObjectStoreItem *item, ObjectStore *db) {
  65   Data *data = safe_malloc(sizeof(Data));
  66   g->data = data;
  67
  68   data->amount = objectstore_item_get_double(item, "xfade_amount", 0);
  69 }
  70
  71 PRIVATE void pickle_instance(Generator *g, ObjectStoreItem *item, ObjectStore *db) {
  72   Data *data = g->data;
  73   objectstore_item_set_double(item, "xfade_amount", data->amount);
  74 }
  75
  76 PRIVATE gboolean output_generator(Generator *g, SAMPLE *buf, int buflen) {
  77   Data *data = g->data;
  78   SAMPLE bufl[MAXIMUM_REALTIME_STEP];
  79   SAMPLE bufr[MAXIMUM_REALTIME_STEP];
  80   gdouble lfact, rfact;
  81   int i;
  82   gboolean resl, resr;
  83
  84   resl = gen_read_realtime_input(g, SIG_LEFT, -1, bufl, buflen);
  85   resr = gen_read_realtime_input(g, SIG_RIGHT, -1, bufr, buflen);
  86
  87   if (!resl && !resr)
  88     return FALSE;
  89
  90   if (!resl)
  91     memset(bufl, 0, sizeof(SAMPLE) * buflen);
  92
  93   if (!resr)
  94     memset(bufr, 0, sizeof(SAMPLE) * buflen);
  95
  96   if (data->amount > 0) {
  97     rfact = 1;
  98     lfact = 1 - data->amount;
  99   } else {
 100     lfact = 1;
 101     rfact = 1 + data->amount;
 102   }
 103
 104   for (i = 0; i < buflen; i++)
 105     buf[i] = bufl[i] * lfact + bufr[i] * rfact;
 106   return TRUE;
 107 }
 108
 109 PRIVATE void evt_amount_handler(Generator *g, AEvent *event) {
 110   ((Data *) g->data)->amount = MAX(-1, MIN(1, event->d.number));
 111 }
 112
 113 PRIVATE InputSignalDescriptor input_sigs[] = {
 114   { "Left", SIG_FLAG_REALTIME },
 115   { "Right", SIG_FLAG_REALTIME },
 116   { NULL, }
 117 };
 118
 119 PRIVATE OutputSignalDescriptor output_sigs[] = {
 120   { "Output", SIG_FLAG_REALTIME, { output_generator, } },
 121   { NULL, }
 122 };
 123
 124 PRIVATE ControlDescriptor controls[] = {
 125   { CONTROL_KIND_KNOB, "fade", -1,1,0.01,0.01, 0,TRUE, 1,EVT_AMOUNT,
 126     NULL,NULL, control_double_updater, (gpointer) offsetof(Data, amount) },
 127   { CONTROL_KIND_NONE, }
 128 };
 129
 130 PRIVATE void setup_class(void) {
 131   GeneratorClass *k = gen_new_generatorclass(GENERATOR_CLASS_NAME, FALSE,
 132                                              NUM_EVENT_INPUTS, NUM_EVENT_OUTPUTS,
 133                                              input_sigs, output_sigs, controls,
 134                                              init_instance, destroy_instance,
 135                                              unpickle_instance, pickle_instance);
 136
 137   gen_configure_event_input(k, EVT_AMOUNT, "Fade", evt_amount_handler);
 138
 139   gencomp_register_generatorclass(k, FALSE, GENERATOR_CLASS_PATH, NULL, NULL);
 140 }
 141
 142 PUBLIC void init_plugin(void) {
 143   setup_class();
 144 }