| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org> |
| |
| This software is provided 'as-is', without any express or implied |
| warranty. In no event will the authors be held liable for any damages |
| arising from the use of this software. |
| |
| Permission is granted to anyone to use this software for any purpose, |
| including commercial applications, and to alter it and redistribute it |
| freely, subject to the following restrictions: |
| |
| 1. The origin of this software must not be misrepresented; you must not |
| claim that you wrote the original software. If you use this software |
| in a product, an acknowledgment in the product documentation would be |
| appreciated but is not required. |
| 2. Altered source versions must be plainly marked as such, and must not be |
| misrepresented as being the original software. |
| 3. This notice may not be removed or altered from any source distribution. |
| */ |
| #include "../SDL_internal.h" |
| |
| /* This provides the default mixing callback for the SDL audio routines */ |
| |
| #include "SDL_cpuinfo.h" |
| #include "SDL_timer.h" |
| #include "SDL_audio.h" |
| #include "SDL_sysaudio.h" |
| |
| /* This table is used to add two sound values together and pin |
| * the value to avoid overflow. (used with permission from ARDI) |
| */ |
| static const Uint8 mix8[] = { |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x02, 0x03, |
| 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, |
| 0x0F, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, |
| 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, 0x23, 0x24, |
| 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F, |
| 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, |
| 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, |
| 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F, 0x50, |
| 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, |
| 0x5C, 0x5D, 0x5E, 0x5F, 0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, |
| 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F, 0x70, 0x71, |
| 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, |
| 0x7D, 0x7E, 0x7F, 0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, |
| 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F, 0x90, 0x91, 0x92, |
| 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, |
| 0x9E, 0x9F, 0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, |
| 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB0, 0xB1, 0xB2, 0xB3, |
| 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, |
| 0xBF, 0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7, 0xC8, 0xC9, |
| 0xCA, 0xCB, 0xCC, 0xCD, 0xCE, 0xCF, 0xD0, 0xD1, 0xD2, 0xD3, 0xD4, |
| 0xD5, 0xD6, 0xD7, 0xD8, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE, 0xDF, |
| 0xE0, 0xE1, 0xE2, 0xE3, 0xE4, 0xE5, 0xE6, 0xE7, 0xE8, 0xE9, 0xEA, |
| 0xEB, 0xEC, 0xED, 0xEE, 0xEF, 0xF0, 0xF1, 0xF2, 0xF3, 0xF4, 0xF5, |
| 0xF6, 0xF7, 0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, |
| 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF |
| }; |
| |
| /* The volume ranges from 0 - 128 */ |
| #define ADJUST_VOLUME(s, v) (s = (s * v) / SDL_MIX_MAXVOLUME) |
| #define ADJUST_VOLUME_U8(s, v) (s = (((s - 128) * v) / SDL_MIX_MAXVOLUME) + 128) |
| #define ADJUST_VOLUME_U16(s, v) (s = (((s - 32768) * v) / SDL_MIX_MAXVOLUME) + 32768) |
| |
| void SDL_MixAudioFormat(Uint8 *dst, const Uint8 *src, SDL_AudioFormat format, |
| Uint32 len, int volume) |
| { |
| if (volume == 0) { |
| return; |
| } |
| |
| switch (format) { |
| |
| case AUDIO_U8: |
| { |
| Uint8 src_sample; |
| |
| while (len--) { |
| src_sample = *src; |
| ADJUST_VOLUME_U8(src_sample, volume); |
| *dst = mix8[*dst + src_sample]; |
| ++dst; |
| ++src; |
| } |
| } break; |
| |
| case AUDIO_S8: |
| { |
| Sint8 *dst8, *src8; |
| Sint8 src_sample; |
| int dst_sample; |
| const int max_audioval = SDL_MAX_SINT8; |
| const int min_audioval = SDL_MIN_SINT8; |
| |
| src8 = (Sint8 *)src; |
| dst8 = (Sint8 *)dst; |
| while (len--) { |
| src_sample = *src8; |
| ADJUST_VOLUME(src_sample, volume); |
| dst_sample = *dst8 + src_sample; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *dst8 = dst_sample; |
| ++dst8; |
| ++src8; |
| } |
| } break; |
| |
| case AUDIO_S16LSB: |
| { |
| Sint16 src1, src2; |
| int dst_sample; |
| const int max_audioval = SDL_MAX_SINT16; |
| const int min_audioval = SDL_MIN_SINT16; |
| |
| len /= 2; |
| while (len--) { |
| src1 = SDL_SwapLE16(*(Sint16 *)src); |
| ADJUST_VOLUME(src1, volume); |
| src2 = SDL_SwapLE16(*(Sint16 *)dst); |
| src += 2; |
| dst_sample = src1 + src2; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *(Sint16 *)dst = SDL_SwapLE16(dst_sample); |
| dst += 2; |
| } |
| } break; |
| |
| case AUDIO_S16MSB: |
| { |
| Sint16 src1, src2; |
| int dst_sample; |
| const int max_audioval = SDL_MAX_SINT16; |
| const int min_audioval = SDL_MIN_SINT16; |
| |
| len /= 2; |
| while (len--) { |
| src1 = SDL_SwapBE16(*(Sint16 *)src); |
| ADJUST_VOLUME(src1, volume); |
| src2 = SDL_SwapBE16(*(Sint16 *)dst); |
| src += 2; |
| dst_sample = src1 + src2; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *(Sint16 *)dst = SDL_SwapBE16(dst_sample); |
| dst += 2; |
| } |
| } break; |
| |
| case AUDIO_U16LSB: |
| { |
| Uint16 src1, src2; |
| int dst_sample; |
| const int max_audioval = SDL_MAX_SINT16; |
| const int min_audioval = SDL_MIN_SINT16; |
| |
| len /= 2; |
| while (len--) { |
| src1 = SDL_SwapLE16(*(Uint16 *)src); |
| ADJUST_VOLUME_U16(src1, volume); |
| src2 = SDL_SwapLE16(*(Uint16 *)dst); |
| src += 2; |
| dst_sample = src1 + src2 - 32768 * 2; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| dst_sample += 32768; |
| *(Uint16 *)dst = SDL_SwapLE16(dst_sample); |
| dst += 2; |
| } |
| } break; |
| |
| case AUDIO_U16MSB: |
| { |
| Uint16 src1, src2; |
| int dst_sample; |
| const int max_audioval = SDL_MAX_SINT16; |
| const int min_audioval = SDL_MIN_SINT16; |
| |
| len /= 2; |
| while (len--) { |
| src1 = SDL_SwapBE16(*(Uint16 *)src); |
| ADJUST_VOLUME_U16(src1, volume); |
| src2 = SDL_SwapBE16(*(Uint16 *)dst); |
| src += 2; |
| dst_sample = src1 + src2 - 32768 * 2; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| dst_sample += 32768; |
| *(Uint16 *)dst = SDL_SwapBE16(dst_sample); |
| dst += 2; |
| } |
| } break; |
| |
| case AUDIO_S32LSB: |
| { |
| const Uint32 *src32 = (Uint32 *)src; |
| Uint32 *dst32 = (Uint32 *)dst; |
| Sint64 src1, src2; |
| Sint64 dst_sample; |
| const Sint64 max_audioval = SDL_MAX_SINT32; |
| const Sint64 min_audioval = SDL_MIN_SINT32; |
| |
| len /= 4; |
| while (len--) { |
| src1 = (Sint64)((Sint32)SDL_SwapLE32(*src32)); |
| src32++; |
| ADJUST_VOLUME(src1, volume); |
| src2 = (Sint64)((Sint32)SDL_SwapLE32(*dst32)); |
| dst_sample = src1 + src2; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *(dst32++) = SDL_SwapLE32((Uint32)((Sint32)dst_sample)); |
| } |
| } break; |
| |
| case AUDIO_S32MSB: |
| { |
| const Uint32 *src32 = (Uint32 *)src; |
| Uint32 *dst32 = (Uint32 *)dst; |
| Sint64 src1, src2; |
| Sint64 dst_sample; |
| const Sint64 max_audioval = SDL_MAX_SINT32; |
| const Sint64 min_audioval = SDL_MIN_SINT32; |
| |
| len /= 4; |
| while (len--) { |
| src1 = (Sint64)((Sint32)SDL_SwapBE32(*src32)); |
| src32++; |
| ADJUST_VOLUME(src1, volume); |
| src2 = (Sint64)((Sint32)SDL_SwapBE32(*dst32)); |
| dst_sample = src1 + src2; |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *(dst32++) = SDL_SwapBE32((Uint32)((Sint32)dst_sample)); |
| } |
| } break; |
| |
| case AUDIO_F32LSB: |
| { |
| const float fmaxvolume = 1.0f / ((float)SDL_MIX_MAXVOLUME); |
| const float fvolume = (float)volume; |
| const float *src32 = (float *)src; |
| float *dst32 = (float *)dst; |
| float src1, src2; |
| double dst_sample; |
| /* !!! FIXME: are these right? */ |
| const double max_audioval = 3.402823466e+38F; |
| const double min_audioval = -3.402823466e+38F; |
| |
| len /= 4; |
| while (len--) { |
| src1 = ((SDL_SwapFloatLE(*src32) * fvolume) * fmaxvolume); |
| src2 = SDL_SwapFloatLE(*dst32); |
| src32++; |
| |
| dst_sample = ((double)src1) + ((double)src2); |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *(dst32++) = SDL_SwapFloatLE((float)dst_sample); |
| } |
| } break; |
| |
| case AUDIO_F32MSB: |
| { |
| const float fmaxvolume = 1.0f / ((float)SDL_MIX_MAXVOLUME); |
| const float fvolume = (float)volume; |
| const float *src32 = (float *)src; |
| float *dst32 = (float *)dst; |
| float src1, src2; |
| double dst_sample; |
| /* !!! FIXME: are these right? */ |
| const double max_audioval = 3.402823466e+38F; |
| const double min_audioval = -3.402823466e+38F; |
| |
| len /= 4; |
| while (len--) { |
| src1 = ((SDL_SwapFloatBE(*src32) * fvolume) * fmaxvolume); |
| src2 = SDL_SwapFloatBE(*dst32); |
| src32++; |
| |
| dst_sample = ((double)src1) + ((double)src2); |
| if (dst_sample > max_audioval) { |
| dst_sample = max_audioval; |
| } else if (dst_sample < min_audioval) { |
| dst_sample = min_audioval; |
| } |
| *(dst32++) = SDL_SwapFloatBE((float)dst_sample); |
| } |
| } break; |
| |
| default: /* If this happens... FIXME! */ |
| SDL_SetError("SDL_MixAudioFormat(): unknown audio format"); |
| return; |
| } |
| } |
| |
| /* vi: set ts=4 sw=4 expandtab: */ |
