src/audio/SDL_mixer.c

   1 /*
   2     SDL - Simple DirectMedia Layer
   3     Copyright (C) 1997-2009 Sam Lantinga
   4
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Lesser General Public
   7     License as published by the Free Software Foundation; either
   8     version 2.1 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     Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public
  16     License along with this library; if not, write to the Free Software
  17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18
  19     Sam Lantinga
  20     slouken@libsdl.org
  21 */
  22 #include "SDL_config.h"
  23
  24 /* This provides the default mixing callback for the SDL audio routines */
  25
  26 #include "SDL_cpuinfo.h"
  27 #include "SDL_timer.h"
  28 #include "SDL_audio.h"
  29 #include "SDL_sysaudio.h"
  30 #include "SDL_mixer_MMX.h"
  31 #include "SDL_mixer_MMX_VC.h"
  32 #include "SDL_mixer_m68k.h"
  33
  34 /* This table is used to add two sound values together and pin
  35  * the value to avoid overflow.  (used with permission from ARDI)
  36  * Changed to use 0xFE instead of 0xFF for better sound quality.
  37  */
  38 static const Uint8 mix8[] =
  39 {
  40   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  41   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  42   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  43   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  44   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  45   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  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, 0x01, 0x02, 0x03,
  52   0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
  53   0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
  54   0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
  55   0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
  56   0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
  57   0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
  58   0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
  59   0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
  60   0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
  61   0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
  62   0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
  63   0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
  64   0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
  65   0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
  66   0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
  67   0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
  68   0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
  69   0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
  70   0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
  71   0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
  72   0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
  73   0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
  74   0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
  75   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
  76   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
  77   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
  78   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
  79   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE,
  80   0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 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
  87 };
  88
  89 /* The volume ranges from 0 - 128 */
  90 #define ADJUST_VOLUME(s, v)     (s = (s*v)/SDL_MIX_MAXVOLUME)
  91 #define ADJUST_VOLUME_U8(s, v)  (s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)
  92
  93 void SDL_MixAudio (Uint8 *dst, const Uint8 *src, Uint32 len, int volume)
  94 {
  95         Uint16 format;
  96
  97         if ( volume == 0 ) {
  98                 return;
  99         }
 100         /* Mix the user-level audio format */
 101         if ( current_audio ) {
 102                 if ( current_audio->convert.needed ) {
 103                         format = current_audio->convert.src_format;
 104                 } else {
 105                         format = current_audio->spec.format;
 106                 }
 107         } else {
 108                 /* HACK HACK HACK */
 109                 format = AUDIO_S16;
 110         }
 111         switch (format) {
 112
 113                 case AUDIO_U8: {
 114 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 115                         SDL_MixAudio_m68k_U8((char*)dst,(char*)src,(unsigned long)len,(long)volume,(char *)mix8);
 116 #else
 117                         Uint8 src_sample;
 118
 119                         while ( len-- ) {
 120                                 src_sample = *src;
 121                                 ADJUST_VOLUME_U8(src_sample, volume);
 122                                 *dst = mix8[*dst+src_sample];
 123                                 ++dst;
 124                                 ++src;
 125                         }
 126 #endif
 127                 }
 128                 break;
 129
 130                 case AUDIO_S8: {
 131 #if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
 132 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
 133                         if (SDL_HasMMX())
 134                         {
 135                                 SDL_MixAudio_MMX_S8((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 136                         }
 137                         else
 138 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
 139                         if (SDL_HasMMX())
 140                         {
 141                                 SDL_MixAudio_MMX_S8_VC((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 142                         }
 143                         else
 144 #endif
 145 #endif
 146
 147 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 148                         SDL_MixAudio_m68k_S8((char*)dst,(char*)src,(unsigned long)len,(long)volume);
 149 #else
 150                         {
 151                         Sint8 *dst8, *src8;
 152                         Sint8 src_sample;
 153                         int dst_sample;
 154                         const int max_audioval = ((1<<(8-1))-1);
 155                         const int min_audioval = -(1<<(8-1));
 156
 157                         src8 = (Sint8 *)src;
 158                         dst8 = (Sint8 *)dst;
 159                         while ( len-- ) {
 160                                 src_sample = *src8;
 161                                 ADJUST_VOLUME(src_sample, volume);
 162                                 dst_sample = *dst8 + src_sample;
 163                                 if ( dst_sample > max_audioval ) {
 164                                         *dst8 = max_audioval;
 165                                 } else
 166                                 if ( dst_sample < min_audioval ) {
 167                                         *dst8 = min_audioval;
 168                                 } else {
 169                                         *dst8 = dst_sample;
 170                                 }
 171                                 ++dst8;
 172                                 ++src8;
 173                         }
 174                         }
 175 #endif
 176                 }
 177                 break;
 178
 179                 case AUDIO_S16LSB: {
 180 #if defined(SDL_BUGGY_MMX_MIXERS) /* buggy, so we're disabling them. --ryan. */
 181 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
 182                         if (SDL_HasMMX())
 183                         {
 184                                 SDL_MixAudio_MMX_S16((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 185                         }
 186                         else
 187 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
 188                         if (SDL_HasMMX())
 189                         {
 190                                 SDL_MixAudio_MMX_S16_VC((char*)dst,(char*)src,(unsigned int)len,(int)volume);
 191                         }
 192                         else
 193 #endif
 194 #endif
 195
 196 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 197                         SDL_MixAudio_m68k_S16LSB((short*)dst,(short*)src,(unsigned long)len,(long)volume);
 198 #else
 199                         {
 200                         Sint16 src1, src2;
 201                         int dst_sample;
 202                         const int max_audioval = ((1<<(16-1))-1);
 203                         const int min_audioval = -(1<<(16-1));
 204
 205                         len /= 2;
 206                         while ( len-- ) {
 207                                 src1 = ((src[1])<<8|src[0]);
 208                                 ADJUST_VOLUME(src1, volume);
 209                                 src2 = ((dst[1])<<8|dst[0]);
 210                                 src += 2;
 211                                 dst_sample = src1+src2;
 212                                 if ( dst_sample > max_audioval ) {
 213                                         dst_sample = max_audioval;
 214                                 } else
 215                                 if ( dst_sample < min_audioval ) {
 216                                         dst_sample = min_audioval;
 217                                 }
 218                                 dst[0] = dst_sample&0xFF;
 219                                 dst_sample >>= 8;
 220                                 dst[1] = dst_sample&0xFF;
 221                                 dst += 2;
 222                         }
 223                         }
 224 #endif
 225                 }
 226                 break;
 227
 228                 case AUDIO_S16MSB: {
 229 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
 230                         SDL_MixAudio_m68k_S16MSB((short*)dst,(short*)src,(unsigned long)len,(long)volume);
 231 #else
 232                         Sint16 src1, src2;
 233                         int dst_sample;
 234                         const int max_audioval = ((1<<(16-1))-1);
 235                         const int min_audioval = -(1<<(16-1));
 236
 237                         len /= 2;
 238                         while ( len-- ) {
 239                                 src1 = ((src[0])<<8|src[1]);
 240                                 ADJUST_VOLUME(src1, volume);
 241                                 src2 = ((dst[0])<<8|dst[1]);
 242                                 src += 2;
 243                                 dst_sample = src1+src2;
 244                                 if ( dst_sample > max_audioval ) {
 245                                         dst_sample = max_audioval;
 246                                 } else
 247                                 if ( dst_sample < min_audioval ) {
 248                                         dst_sample = min_audioval;
 249                                 }
 250                                 dst[1] = dst_sample&0xFF;
 251                                 dst_sample >>= 8;
 252                                 dst[0] = dst_sample&0xFF;
 253                                 dst += 2;
 254                         }
 255 #endif
 256                 }
 257                 break;
 258
 259                 default: /* If this happens... FIXME! */
 260                         SDL_SetError("SDL_MixAudio(): unknown audio format");
 261                         return;
 262         }
 263 }
 264