146 lines
4.8 KiB
C
146 lines
4.8 KiB
C
/*
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* The sound effects generator
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*
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* This file is part of ANT (Ant is Not a Telephone)
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*
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* Copyright 2002, 2003 Roland Stigge
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*
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* ANT is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* ANT is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with ANT; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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/* regular GNU system includes */
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#include <stdio.h>
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#include <math.h>
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/* own header files */
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#include "globals.h"
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#include "session.h"
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/* all time constants in seconds or Hz */
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#define RING_PERIOD 4
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#define RING_LENGTH 1.3
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#define RING_FREQUENCY 1300
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/* fade in/out reciprocal period: */
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#define RING_FADE_LENGTH 0.003
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#define RING_SHORT_PERIOD 0.044
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#define RING_SHORT_LENGTH (RING_SHORT_PERIOD / 2)
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#define RINGING_FREQUENCY 425
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/*
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* Effect generator
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* input: session: session, used element: audio_LUT_generate
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* effect: the effect
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* index: parameter for effect (e.g. which touchtone)
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* EFFECT_TOUCHTONE: row * 3 + column (each 0-based)
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* seconds: position of sample in seconds
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* returns: generated ulaw sample
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*/
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unsigned char fxgenerate(session_t *session, enum effect_t effect,
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int index, double seconds) {
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unsigned char x; /* generated ulaw sample (return value) */
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double rest; /* monitor the period in seconds modulo 4 */
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double rest2; /* monitor (short) sinus period */
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double factor; /* envelope factor */
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double factor2; /* envelope help factor (short periods) */
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double f1, f2; /* frequencies for touchtones (row, column) */
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switch(effect) {
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case EFFECT_RING: /* somebody's calling */
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case EFFECT_TEST: /* play test sound */
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if (effect == EFFECT_RING) {
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rest = fmod(seconds, RING_PERIOD); /* 4 sec period */
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} else {
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rest = seconds; /* infinite period */
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}
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rest2 = fmod(seconds, RING_SHORT_PERIOD); /* short period */
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if (rest < RING_FADE_LENGTH) { /* fade in */
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factor = -cos(rest * M_PI / RING_FADE_LENGTH) / 2 + 0.5;
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} else if (rest > RING_LENGTH - RING_FADE_LENGTH &&
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rest < RING_LENGTH) { /* fade out */
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factor = -cos((RING_LENGTH - rest) * 2 * M_PI / (RING_FADE_LENGTH * 2))
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/ 2 + 0.5;
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} else if (rest >= RING_LENGTH) { /* pause */
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factor = 0;
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} else { /* (potential) beep */
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factor = 1;
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}
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if (rest2 > RING_SHORT_PERIOD - 0.5 * RING_FADE_LENGTH) {
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/* fade in short period (1/2) */
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factor2 = -sin((RING_SHORT_PERIOD - rest2)
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* 2 * M_PI / (RING_FADE_LENGTH * 2)) / 2 + 0.5;
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} else if (rest2 < 0.5 * RING_FADE_LENGTH) {
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/* fade in short period (2/2) */
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factor2 = sin(rest2 * 2 * M_PI / (RING_FADE_LENGTH * 2)) / 2 + 0.5;
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} else if (rest2 > RING_SHORT_LENGTH - 0.5 * RING_FADE_LENGTH &&
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rest2 < RING_SHORT_LENGTH + 0.5 * RING_FADE_LENGTH) {
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/* fade out short period */
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factor2 = -sin((rest2 - RING_SHORT_LENGTH)
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* 2 * M_PI / (RING_FADE_LENGTH * 2)) / 2 + 0.5;
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} else if (rest2 <= RING_SHORT_LENGTH) { /* just beep */
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factor2 = 1;
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} else {
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factor2 = 0; /* short pause */
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}
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factor = factor * factor2;
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x = session->audio_LUT_generate[
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(int)(sin(seconds * 2 * M_PI * RING_FREQUENCY)
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* factor * 127.5 + 127.5)];
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break;
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case EFFECT_RINGING: /* waiting for the other end to pick up the phone */
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rest = fmod(seconds, 5);
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if (rest >= 2 && rest < 3) {
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x = session->audio_LUT_generate[ /* beep */
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(int)(sin(seconds * 2 * M_PI * RINGING_FREQUENCY) * 127.5 + 127.5)];
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} else {
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x = session->audio_LUT_generate[128]; /* pause */
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}
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break;
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case EFFECT_TOUCHTONE: /* clicked key pad in conversation mode */
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switch (index / 3) { /* row frequency */
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case 0: f1 = 697; break;
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case 1: f1 = 770; break;
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case 2: f1 = 852; break;
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case 3: f1 = 941; break;
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default: f1 = 0;
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}
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switch (index % 3) { /* column frequency */
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case 0: f2 = 1209; break;
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case 1: f2 = 1336; break;
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case 2: f2 = 1477; break;
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case 3: f2 = 1633; break;
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default: f2 = 0;
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}
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x = session->audio_LUT_generate[
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(int)((sin(seconds * 2 * M_PI * f1) + sin(seconds * 2 * M_PI * f2))
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/ 2 * 127.5 * 0.7 + 127.5)];
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break;
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default:
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fprintf(stderr, "fxgenerate: Unknown effect.\n");
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x = 0;
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}
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return x;
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}
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