src/audio/SDL_mixer.c
author Ryan C. Gordon <icculus@icculus.org>
Thu, 31 Aug 2006 21:00:10 +0000
changeset 1994 6abc7e6f9817
parent 1985 8055185ae4ed
child 2013 0615fa58c0be
permissions -rw-r--r--
Added int32 adn float32 support to SDL_LoadWAV_RW().
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2006 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     0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    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, 0x01, 0x02, 0x03,
    51     0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E,
    52     0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
    53     0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24,
    54     0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
    55     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A,
    56     0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45,
    57     0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50,
    58     0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B,
    59     0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66,
    60     0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71,
    61     0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C,
    62     0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
    63     0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92,
    64     0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D,
    65     0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8,
    66     0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3,
    67     0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE,
    68     0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9,
    69     0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4,
    70     0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF,
    71     0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA,
    72     0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5,
    73     0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFE, 0xFE,
    74     0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 0xFE, 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
    86 };
    87 
    88 /* The volume ranges from 0 - 128 */
    89 #define ADJUST_VOLUME(s, v)	(s = (s*v)/SDL_MIX_MAXVOLUME)
    90 #define ADJUST_VOLUME_U8(s, v)	(s = (((s-128)*v)/SDL_MIX_MAXVOLUME)+128)
    91 
    92 void
    93 SDL_MixAudio(Uint8 * dst, const Uint8 * src, Uint32 len, int volume)
    94 {
    95     /* Mix the user-level audio format */
    96     if (current_audio) {
    97         SDL_AudioFormat format;
    98         if (current_audio->convert.needed) {
    99             format = current_audio->convert.src_format;
   100         } else {
   101             format = current_audio->spec.format;
   102         }
   103         SDL_MixAudioFormat(dst, src, format, len, volume);
   104     }
   105 }
   106 
   107 
   108 void
   109 SDL_MixAudioFormat(Uint8 * dst, const Uint8 * src, SDL_AudioFormat format,
   110                    Uint32 len, int volume)
   111 {
   112     if (volume == 0) {
   113         return;
   114     }
   115 
   116     switch (format) {
   117 
   118     case AUDIO_U8:
   119         {
   120 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   121             SDL_MixAudio_m68k_U8((char *) dst, (char *) src,
   122                                  (unsigned long) len, (long) volume,
   123                                  (char *) mix8);
   124 #else
   125             Uint8 src_sample;
   126 
   127             while (len--) {
   128                 src_sample = *src;
   129                 ADJUST_VOLUME_U8(src_sample, volume);
   130                 *dst = mix8[*dst + src_sample];
   131                 ++dst;
   132                 ++src;
   133             }
   134 #endif
   135         }
   136         break;
   137 
   138     case AUDIO_S8:
   139         {
   140 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
   141             if (SDL_HasMMX()) {
   142                 SDL_MixAudio_MMX_S8((char *) dst, (char *) src,
   143                                     (unsigned int) len, (int) volume);
   144             } else
   145 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
   146             if (SDL_HasMMX()) {
   147                 SDL_MixAudio_MMX_S8_VC((char *) dst, (char *) src,
   148                                        (unsigned int) len, (int) volume);
   149             } else
   150 #endif
   151 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   152                 SDL_MixAudio_m68k_S8((char *) dst, (char *) src,
   153                                      (unsigned long) len, (long) volume);
   154 #else
   155             {
   156                 Sint8 *dst8, *src8;
   157                 Sint8 src_sample;
   158                 int dst_sample;
   159                 const int max_audioval = ((1 << (8 - 1)) - 1);
   160                 const int min_audioval = -(1 << (8 - 1));
   161 
   162                 src8 = (Sint8 *) src;
   163                 dst8 = (Sint8 *) dst;
   164                 while (len--) {
   165                     src_sample = *src8;
   166                     ADJUST_VOLUME(src_sample, volume);
   167                     dst_sample = *dst8 + src_sample;
   168                     if (dst_sample > max_audioval) {
   169                         *dst8 = max_audioval;
   170                     } else if (dst_sample < min_audioval) {
   171                         *dst8 = min_audioval;
   172                     } else {
   173                         *dst8 = dst_sample;
   174                     }
   175                     ++dst8;
   176                     ++src8;
   177                 }
   178             }
   179 #endif
   180         }
   181         break;
   182 
   183     case AUDIO_S16LSB:
   184         {
   185 #if defined(__GNUC__) && defined(__i386__) && defined(SDL_ASSEMBLY_ROUTINES)
   186             if (SDL_HasMMX()) {
   187                 SDL_MixAudio_MMX_S16((char *) dst, (char *) src,
   188                                      (unsigned int) len, (int) volume);
   189             } else
   190 #elif ((defined(_MSC_VER) && defined(_M_IX86)) || defined(__WATCOMC__)) && defined(SDL_ASSEMBLY_ROUTINES)
   191             if (SDL_HasMMX()) {
   192                 SDL_MixAudio_MMX_S16_VC((char *) dst, (char *) src,
   193                                         (unsigned int) len, (int) volume);
   194             } else
   195 #endif
   196 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   197                 SDL_MixAudio_m68k_S16LSB((short *) dst, (short *) src,
   198                                          (unsigned long) len, (long) volume);
   199 #else
   200             {
   201                 Sint16 src1, src2;
   202                 int dst_sample;
   203                 const int max_audioval = ((1 << (16 - 1)) - 1);
   204                 const int min_audioval = -(1 << (16 - 1));
   205 
   206                 len /= 2;
   207                 while (len--) {
   208                     src1 = ((src[1]) << 8 | src[0]);
   209                     ADJUST_VOLUME(src1, volume);
   210                     src2 = ((dst[1]) << 8 | dst[0]);
   211                     src += 2;
   212                     dst_sample = src1 + src2;
   213                     if (dst_sample > max_audioval) {
   214                         dst_sample = max_audioval;
   215                     } else 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         {
   230 #if defined(__GNUC__) && defined(__M68000__) && defined(SDL_ASSEMBLY_ROUTINES)
   231             SDL_MixAudio_m68k_S16MSB((short *) dst, (short *) src,
   232                                      (unsigned long) len, (long) volume);
   233 #else
   234             Sint16 src1, src2;
   235             int dst_sample;
   236             const int max_audioval = ((1 << (16 - 1)) - 1);
   237             const int min_audioval = -(1 << (16 - 1));
   238 
   239             len /= 2;
   240             while (len--) {
   241                 src1 = ((src[0]) << 8 | src[1]);
   242                 ADJUST_VOLUME(src1, volume);
   243                 src2 = ((dst[0]) << 8 | dst[1]);
   244                 src += 2;
   245                 dst_sample = src1 + src2;
   246                 if (dst_sample > max_audioval) {
   247                     dst_sample = max_audioval;
   248                 } else if (dst_sample < min_audioval) {
   249                     dst_sample = min_audioval;
   250                 }
   251                 dst[1] = dst_sample & 0xFF;
   252                 dst_sample >>= 8;
   253                 dst[0] = dst_sample & 0xFF;
   254                 dst += 2;
   255             }
   256 #endif
   257         }
   258         break;
   259 
   260     case AUDIO_S32LSB:
   261         {
   262             const Uint32 *src32 = (Uint32 *) src;
   263             Uint32 *dst32 = (Uint32 *) dst;
   264             Sint32 src1, src2;
   265             Sint64 dst_sample;
   266             const Sint64 max_audioval = ((((Sint64) 1) << (32 - 1)) - 1);
   267             const Sint64 min_audioval = -(((Sint64) 1) << (32 - 1));
   268 
   269             len /= 4;
   270             while (len--) {
   271                 src1 = (Sint32) SDL_SwapLE32(*src32);
   272                 src32++;
   273                 ADJUST_VOLUME(src1, volume);
   274                 src2 = (Sint32) SDL_SwapLE32(*dst32);
   275                 dst_sample = src1 + src2;
   276                 if (dst_sample > max_audioval) {
   277                     dst_sample = max_audioval;
   278                 } else if (dst_sample < min_audioval) {
   279                     dst_sample = min_audioval;
   280                 }
   281                 *(dst32++) = SDL_SwapLE32((Uint32) ((Sint32) dst_sample));
   282             }
   283         }
   284         break;
   285 
   286     case AUDIO_S32MSB:
   287         {
   288             const Uint32 *src32 = (Uint32 *) src;
   289             Uint32 *dst32 = (Uint32 *) dst;
   290             Sint32 src1, src2;
   291             Sint64 dst_sample;
   292             const Sint64 max_audioval = ((((Sint64) 1) << (32 - 1)) - 1);
   293             const Sint64 min_audioval = -(((Sint64) 1) << (32 - 1));
   294 
   295             len /= 4;
   296             while (len--) {
   297                 src1 = (Sint32) SDL_SwapBE32(*src32);
   298                 src32++;
   299                 ADJUST_VOLUME(src1, volume);
   300                 src2 = (Sint32) SDL_SwapBE32(*dst32);
   301                 dst_sample = src1 + src2;
   302                 if (dst_sample > max_audioval) {
   303                     dst_sample = max_audioval;
   304                 } else if (dst_sample < min_audioval) {
   305                     dst_sample = min_audioval;
   306                 }
   307                 *(dst32++) = SDL_SwapBE32((Uint32) ((Sint32) dst_sample));
   308             }
   309         }
   310         break;
   311 
   312     case AUDIO_F32LSB:
   313         {
   314             const float fmaxvolume = 1.0f / ((float) SDL_MIX_MAXVOLUME);
   315             const float fvolume = (float) volume;
   316             const float *src32 = (float *) src;
   317             float *dst32 = (float *) dst;
   318             float src1, src2;
   319             double dst_sample;
   320             /* !!! FIXME: are these right? */
   321             const double max_audioval = 3.40282347e+38F;
   322             const double min_audioval = -3.40282347e+38F;
   323 
   324             /* !!! FIXME: this is a little nasty. */
   325             union
   326             {
   327                 float f;
   328                 Uint32 ui32;
   329             } cvt;
   330 
   331             len /= 4;
   332             while (len--) {
   333                 cvt.f = *(src32++);
   334                 cvt.ui32 = SDL_SwapLE32(cvt.ui32);
   335                 src1 = ((cvt.f * fvolume) * fmaxvolume);
   336 
   337                 cvt.f = *dst32;
   338                 cvt.ui32 = SDL_SwapLE32(cvt.ui32);
   339                 src2 = cvt.f;
   340 
   341                 dst_sample = src1 + src2;
   342                 if (dst_sample > max_audioval) {
   343                     dst_sample = max_audioval;
   344                 } else if (dst_sample < min_audioval) {
   345                     dst_sample = min_audioval;
   346                 }
   347                 cvt.f = ((float) dst_sample);
   348                 cvt.ui32 = SDL_SwapLE32(cvt.ui32);
   349                 *(dst32++) = cvt.f;
   350             }
   351         }
   352         break;
   353 
   354     case AUDIO_F32MSB:
   355         {
   356             const float fmaxvolume = 1.0f / ((float) SDL_MIX_MAXVOLUME);
   357             const float fvolume = (float) volume;
   358             const float *src32 = (float *) src;
   359             float *dst32 = (float *) dst;
   360             float src1, src2;
   361             double dst_sample;
   362             /* !!! FIXME: are these right? */
   363             const double max_audioval = 3.40282347e+38F;
   364             const double min_audioval = -3.40282347e+38F;
   365 
   366             /* !!! FIXME: this is a little nasty. */
   367             union
   368             {
   369                 float f;
   370                 Uint32 ui32;
   371             } cvt;
   372 
   373             len /= 4;
   374             while (len--) {
   375                 cvt.f = *(src32++);
   376                 cvt.ui32 = SDL_SwapBE32(cvt.ui32);
   377                 src1 = ((cvt.f * fvolume) * fmaxvolume);
   378 
   379                 cvt.f = *dst32;
   380                 cvt.ui32 = SDL_SwapBE32(cvt.ui32);
   381                 src2 = cvt.f;
   382 
   383                 dst_sample = src1 + src2;
   384                 if (dst_sample > max_audioval) {
   385                     dst_sample = max_audioval;
   386                 } else if (dst_sample < min_audioval) {
   387                     dst_sample = min_audioval;
   388                 }
   389                 cvt.f = ((float) dst_sample);
   390                 cvt.ui32 = SDL_SwapBE32(cvt.ui32);
   391                 *(dst32++) = cvt.f;
   392             }
   393         }
   394         break;
   395 
   396     default:                   /* If this happens... FIXME! */
   397         SDL_SetError("SDL_MixAudio(): unknown audio format");
   398         return;
   399     }
   400 }
   401 
   402 /* vi: set ts=4 sw=4 expandtab: */