From 5a079a2d114f96d4847d1ee305d5b7c16eeec50e Mon Sep 17 00:00:00 2001 From: 3gg <3gg@shellblade.net> Date: Sat, 27 Dec 2025 12:03:39 -0800 Subject: Initial commit --- contrib/SDL-3.2.8/src/audio/SDL_mixer.c | 290 ++++++++++++++++++++++++++++++++ 1 file changed, 290 insertions(+) create mode 100644 contrib/SDL-3.2.8/src/audio/SDL_mixer.c (limited to 'contrib/SDL-3.2.8/src/audio/SDL_mixer.c') diff --git a/contrib/SDL-3.2.8/src/audio/SDL_mixer.c b/contrib/SDL-3.2.8/src/audio/SDL_mixer.c new file mode 100644 index 0000000..047c6fd --- /dev/null +++ b/contrib/SDL-3.2.8/src/audio/SDL_mixer.c @@ -0,0 +1,290 @@ +/* + Simple DirectMedia Layer + Copyright (C) 1997-2025 Sam Lantinga + + 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_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 MIX_MAXVOLUME 128 +#define ADJUST_VOLUME(type, s, v) ((s) = (type)(((s) * (v)) / MIX_MAXVOLUME)) +#define ADJUST_VOLUME_U8(s, v) ((s) = (Uint8)(((((s) - 128) * (v)) / MIX_MAXVOLUME) + 128)) + +// !!! FIXME: This needs some SIMD magic. +// !!! FIXME: Add fast-path for volume = 1 +// !!! FIXME: Use larger scales for 16-bit/32-bit integers + +bool SDL_MixAudio(Uint8 *dst, const Uint8 *src, SDL_AudioFormat format, Uint32 len, float fvolume) +{ + int volume = (int)SDL_roundf(fvolume * MIX_MAXVOLUME); + + if (volume == 0) { + return true; + } + + switch (format) { + + case SDL_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 SDL_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(Sint8, 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 = (Sint8)dst_sample; + ++dst8; + ++src8; + } + } break; + + case SDL_AUDIO_S16LE: + { + 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_Swap16LE(*(Sint16 *)src); + ADJUST_VOLUME(Sint16, src1, volume); + src2 = SDL_Swap16LE(*(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_Swap16LE((Sint16)dst_sample); + dst += 2; + } + } break; + + case SDL_AUDIO_S16BE: + { + 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_Swap16BE(*(Sint16 *)src); + ADJUST_VOLUME(Sint16, src1, volume); + src2 = SDL_Swap16BE(*(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_Swap16BE((Sint16)dst_sample); + dst += 2; + } + } break; + + case SDL_AUDIO_S32LE: + { + 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_Swap32LE(*src32)); + src32++; + ADJUST_VOLUME(Sint64, src1, volume); + src2 = (Sint64)((Sint32)SDL_Swap32LE(*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_Swap32LE((Uint32)((Sint32)dst_sample)); + } + } break; + + case SDL_AUDIO_S32BE: + { + 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_Swap32BE(*src32)); + src32++; + ADJUST_VOLUME(Sint64, src1, volume); + src2 = (Sint64)((Sint32)SDL_Swap32BE(*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_Swap32BE((Uint32)((Sint32)dst_sample)); + } + } break; + + case SDL_AUDIO_F32LE: + { + const float *src32 = (float *)src; + float *dst32 = (float *)dst; + float src1, src2; + float dst_sample; + const float max_audioval = 1.0f; + const float min_audioval = -1.0f; + + len /= 4; + while (len--) { + src1 = SDL_SwapFloatLE(*src32) * fvolume; + src2 = SDL_SwapFloatLE(*dst32); + src32++; + + 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_SwapFloatLE(dst_sample); + } + } break; + + case SDL_AUDIO_F32BE: + { + const float *src32 = (float *)src; + float *dst32 = (float *)dst; + float src1, src2; + float dst_sample; + const float max_audioval = 1.0f; + const float min_audioval = -1.0f; + + len /= 4; + while (len--) { + src1 = SDL_SwapFloatBE(*src32) * fvolume; + src2 = SDL_SwapFloatBE(*dst32); + src32++; + + 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_SwapFloatBE(dst_sample); + } + } break; + + default: // If this happens... FIXME! + return SDL_SetError("SDL_MixAudio(): unknown audio format"); + } + + return true; +} -- cgit v1.2.3