Mercurial > sdl-ios-xcode
annotate src/audio/SDL_mixer.c @ 261:1c5f68da5fc2
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| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Fri, 04 Jan 2002 20:48:51 +0000 |
| parents | e8157fcb3114 |
| children | f6ffac90895c |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 SDL - Simple DirectMedia Layer | |
| 3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga | |
| 4 | |
| 5 This library is free software; you can redistribute it and/or | |
| 6 modify it under the terms of the GNU Library General Public | |
| 7 License as published by the Free Software Foundation; either | |
| 8 version 2 of the License, or (at your option) any later version. | |
| 9 | |
| 10 This library 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 GNU | |
| 13 Library General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU Library General Public | |
| 16 License along with this library; if not, write to the Free | |
| 17 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 18 | |
| 19 Sam Lantinga | |
|
252
e8157fcb3114
Updated the source with the correct e-mail address
Sam Lantinga <slouken@libsdl.org>
parents:
1
diff
changeset
|
20 slouken@libsdl.org |
| 0 | 21 */ |
| 22 | |
| 23 #ifdef SAVE_RCSID | |
| 24 static char rcsid = | |
| 25 "@(#) $Id$"; | |
| 26 #endif | |
| 27 | |
| 28 /* This provides the default mixing callback for the SDL audio routines */ | |
| 29 | |
| 30 #include <stdio.h> | |
| 31 #include <stdlib.h> | |
| 32 #include <string.h> | |
| 33 | |
| 34 #include "SDL_audio.h" | |
| 35 #include "SDL_mutex.h" | |
| 36 #include "SDL_timer.h" | |
| 37 #include "SDL_sysaudio.h" | |
| 38 | |
| 39 | |
| 40 /* This table is used to add two sound values together and pin | |
| 41 * the value to avoid overflow. (used with permission from ARDI) | |
| 42 * Changed to use 0xFE instead of 0xFF for better sound quality. | |
| 43 */ | |
| 44 static const Uint8 mix8[] = | |
| 45 { | |
| 46 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 47 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 48 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 49 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 50 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 51 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 52 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 53 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 54 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 55 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 56 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, | |
| 57 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, | |
| 58 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, | |
| 59 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, | |
| 60 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, | |
| 61 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, | |
| 62 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, | |
| 63 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, | |
| 64 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, | |
| 65 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, | |
| 66 0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, | |
| 67 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, | |
| 68 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, | |
| 69 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, | |
| 70 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92, | |
| 71 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, | |
| 72 0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, | |
| 73 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3, | |
| 74 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, | |
| 75 0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, | |
| 76 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, | |
| 77 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF, | |
| 78 0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, | |
| 79 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, | |
| 80 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE, | |
| 81 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 82 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 83 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 84 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 85 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 86 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 87 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 88 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 89 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 90 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 91 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, | |
| 92 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE | |
| 93 }; | |
| 94 | |
| 95 /* The volume ranges from 0 - 128 */ | |
| 96 #define ADJUST_VOLUME(s, v) (s = (s*v)/SDL_MIX_MAXVOLUME) | |
| 97 #define ADJUST_VOLUME_U8(s, v) (s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128) | |
| 98 | |
|
1
cf2af46e9e2a
Changes since SDL 1.2.0 release
Sam Lantinga <slouken@lokigames.com>
parents:
0
diff
changeset
|
99 void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume) |
| 0 | 100 { |
| 101 Uint16 format; | |
| 102 | |
| 103 if ( volume == 0 ) { | |
| 104 return; | |
| 105 } | |
| 106 /* Mix the user-level audio format */ | |
| 107 if ( current_audio ) { | |
| 108 if ( current_audio->convert.needed ) { | |
| 109 format = current_audio->convert.src_format; | |
| 110 } else { | |
| 111 format = current_audio->spec.format; | |
| 112 } | |
| 113 } else { | |
| 114 /* HACK HACK HACK */ | |
| 115 format = AUDIO_S16; | |
| 116 } | |
| 117 switch (format) { | |
| 118 | |
| 119 case AUDIO_U8: { | |
| 120 Uint8 src_sample; | |
| 121 | |
| 122 while ( len-- ) { | |
| 123 src_sample = *src; | |
| 124 ADJUST_VOLUME_U8(src_sample, volume); | |
| 125 *dst = mix8[*dst+src_sample]; | |
| 126 ++dst; | |
| 127 ++src; | |
| 128 } | |
| 129 } | |
| 130 break; | |
| 131 | |
| 132 case AUDIO_S8: { | |
| 133 Sint8 *dst8, *src8; | |
| 134 Sint8 src_sample; | |
| 135 int dst_sample; | |
| 136 const int max_audioval = ((1<<(8-1))-1); | |
| 137 const int min_audioval = -(1<<(8-1)); | |
| 138 | |
| 139 src8 = (Sint8 *)src; | |
| 140 dst8 = (Sint8 *)dst; | |
| 141 while ( len-- ) { | |
| 142 src_sample = *src8; | |
| 143 ADJUST_VOLUME(src_sample, volume); | |
| 144 dst_sample = *dst8 + src_sample; | |
| 145 if ( dst_sample > max_audioval ) { | |
| 146 *dst8 = max_audioval; | |
| 147 } else | |
| 148 if ( dst_sample < min_audioval ) { | |
| 149 *dst8 = min_audioval; | |
| 150 } else { | |
| 151 *dst8 = dst_sample; | |
| 152 } | |
| 153 ++dst8; | |
| 154 ++src8; | |
| 155 } | |
| 156 } | |
| 157 break; | |
| 158 | |
| 159 case AUDIO_S16LSB: { | |
| 160 Sint16 src1, src2; | |
| 161 int dst_sample; | |
| 162 const int max_audioval = ((1<<(16-1))-1); | |
| 163 const int min_audioval = -(1<<(16-1)); | |
| 164 | |
| 165 len /= 2; | |
| 166 while ( len-- ) { | |
| 167 src1 = ((src[1])<<8|src[0]); | |
| 168 ADJUST_VOLUME(src1, volume); | |
| 169 src2 = ((dst[1])<<8|dst[0]); | |
| 170 src += 2; | |
| 171 dst_sample = src1+src2; | |
| 172 if ( dst_sample > max_audioval ) { | |
| 173 dst_sample = max_audioval; | |
| 174 } else | |
| 175 if ( dst_sample < min_audioval ) { | |
| 176 dst_sample = min_audioval; | |
| 177 } | |
| 178 dst[0] = dst_sample&0xFF; | |
| 179 dst_sample >>= 8; | |
| 180 dst[1] = dst_sample&0xFF; | |
| 181 dst += 2; | |
| 182 } | |
| 183 } | |
| 184 break; | |
| 185 | |
| 186 case AUDIO_S16MSB: { | |
| 187 Sint16 src1, src2; | |
| 188 int dst_sample; | |
| 189 const int max_audioval = ((1<<(16-1))-1); | |
| 190 const int min_audioval = -(1<<(16-1)); | |
| 191 | |
| 192 len /= 2; | |
| 193 while ( len-- ) { | |
| 194 src1 = ((src[0])<<8|src[1]); | |
| 195 ADJUST_VOLUME(src1, volume); | |
| 196 src2 = ((dst[0])<<8|dst[1]); | |
| 197 src += 2; | |
| 198 dst_sample = src1+src2; | |
| 199 if ( dst_sample > max_audioval ) { | |
| 200 dst_sample = max_audioval; | |
| 201 } else | |
| 202 if ( dst_sample < min_audioval ) { | |
| 203 dst_sample = min_audioval; | |
| 204 } | |
| 205 dst[1] = dst_sample&0xFF; | |
| 206 dst_sample >>= 8; | |
| 207 dst[0] = dst_sample&0xFF; | |
| 208 dst += 2; | |
| 209 } | |
| 210 } | |
| 211 break; | |
| 212 | |
| 213 default: /* If this happens... FIXME! */ | |
| 214 SDL_SetError("SDL_MixAudio(): unknown audio format"); | |
| 215 return; | |
| 216 } | |
| 217 } |