distortion.c

   1 /*
   2 Calf Box, an open source musical instrument.
   3 Copyright (C) 2010-2011 Krzysztof Foltman
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation, either version 3 of the License, or
   8 (at your option) any later version.
   9
  10 This program is distributed in the hope that it will be useful,
  11 but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 GNU General Public License for more details.
  14
  15 You should have received a copy of the GNU General Public License
  16 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include "config.h"
  20 #include "config-api.h"
  21 #include "dspmath.h"
  22 #include "module.h"
  23 #include <glib.h>
  24 #include <malloc.h>
  25 #include <math.h>
  26 #include <memory.h>
  27 #include <sndfile.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30
  31 #define MODULE_PARAMS distortion_params
  32
  33 struct distortion_params
  34 {
  35     float drive;
  36     float shape;
  37 };
  38
  39 struct distortion_module
  40 {
  41     struct cbox_module module;
  42
  43     struct distortion_params *params, *old_params;
  44 };
  45
  46 gboolean distortion_process_cmd(struct cbox_command_target *ct, struct cbox_command_target *fb, struct cbox_osc_command *cmd, GError **error)
  47 {
  48     struct distortion_module *m = (struct distortion_module *)ct->user_data;
  49
  50     EFFECT_PARAM("/drive", "f", drive, double, dB2gain_simple, -36, 36) else
  51     EFFECT_PARAM("/shape", "f", shape, double, , -1, 2) else
  52     if (!strcmp(cmd->command, "/status") && !strcmp(cmd->arg_types, ""))
  53     {
  54         if (!cbox_check_fb_channel(fb, cmd->command, error))
  55             return FALSE;
  56         return cbox_execute_on(fb, NULL, "/drive", "f", error, gain2dB_simple(m->params->drive))
  57             && cbox_execute_on(fb, NULL, "/shape", "f", error, m->params->shape)
  58             && CBOX_OBJECT_DEFAULT_STATUS(&m->module, fb, error)
  59         ;
  60     }
  61     else
  62         return cbox_object_default_process_cmd(ct, fb, cmd, error);
  63     return TRUE;
  64 }
  65
  66 void distortion_process_event(struct cbox_module *module, const uint8_t *data, uint32_t len)
  67 {
  68     // struct distortion_module *m = module->user_data;
  69 }
  70
  71 void distortion_process_block(struct cbox_module *module, cbox_sample_t **inputs, cbox_sample_t **outputs)
  72 {
  73     struct distortion_module *m = module->user_data;
  74
  75     if (m->params != m->old_params)
  76     {
  77         // update calculated values
  78     }
  79
  80     float drive = m->params->drive;
  81     float shape = m->params->shape;
  82
  83     float a0 = shape;
  84     float a1 = -2 * shape - 0.5;
  85     float a2 = 1.5 + shape;
  86
  87     float post = pow(drive, -0.7);
  88
  89     for (int i = 0; i < CBOX_BLOCK_SIZE; i++)
  90     {
  91         for (int c = 0; c < 2; c++)
  92         {
  93             float val = inputs[c][i];
  94
  95             val *= drive;
  96
  97             if (fabs(val) > 1.0)
  98                 val = (val > 0) ? 1 : -1;
  99             else
 100                 val = a0 * val * val * val * val * val + a1 * val * val * val + a2 * val;
 101
 102             outputs[c][i] = val * post;
 103         }
 104     }
 105 }
 106
 107 MODULE_SIMPLE_DESTROY_FUNCTION(distortion)
 108
 109 MODULE_CREATE_FUNCTION(distortion)
 110 {
 111     static int inited = 0;
 112     if (!inited)
 113     {
 114         inited = 1;
 115     }
 116
 117     struct distortion_module *m = malloc(sizeof(struct distortion_module));
 118     CALL_MODULE_INIT(m, 2, 2, distortion);
 119     m->module.process_event = distortion_process_event;
 120     m->module.process_block = distortion_process_block;
 121     struct distortion_params *p = malloc(sizeof(struct distortion_params));
 122     p->drive = cbox_config_get_gain_db(cfg_section, "drive", 0.f);
 123     p->shape = cbox_config_get_gain_db(cfg_section, "shape", 0.f);
 124     m->params = p;
 125     m->old_params = NULL;
 126
 127     return &m->module;
 128 }
 129
 130
 131 struct cbox_module_keyrange_metadata distortion_keyranges[] = {
 132 };
 133
 134 struct cbox_module_livecontroller_metadata distortion_controllers[] = {
 135 };
 136
 137 DEFINE_MODULE(distortion, 2, 2)
 138