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Slightly optimized and fixed float SDL_MixAudioFormat

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Brick 2024-04-09 03:47:26 +01:00 committed by Sam Lantinga
parent 33f28d6143
commit 46cecc42a2
1 changed files with 14 additions and 18 deletions
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32
src/audio/SDL_mixer.c
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@ -231,57 +231,53 @@ int SDL_MixAudioFormat(Uint8 *dst, const Uint8 *src, SDL_AudioFormat format,
case SDL_AUDIO_F32LE: case SDL_AUDIO_F32LE:
{ {
const float fmaxvolume = 1.0f / ((float)SDL_MIX_MAXVOLUME); const float fvolume = volume / ((float)SDL_MIX_MAXVOLUME);
const float fvolume = (float)volume;
const float *src32 = (float *)src; const float *src32 = (float *)src;
float *dst32 = (float *)dst; float *dst32 = (float *)dst;
float src1, src2; float src1, src2;
double dst_sample; float dst_sample;
// !!! FIXME: are these right? const float max_audioval = 1.0f;
const double max_audioval = 3.402823466e+38F; const float min_audioval = -1.0f;
const double min_audioval = -3.402823466e+38F;
len /= 4; len /= 4;
while (len--) { while (len--) {
src1 = ((SDL_SwapFloatLE(*src32) * fvolume) * fmaxvolume); src1 = SDL_SwapFloatLE(*src32) * fvolume;
src2 = SDL_SwapFloatLE(*dst32); src2 = SDL_SwapFloatLE(*dst32);
src32++; src32++;
dst_sample = ((double)src1) + ((double)src2); dst_sample = src1 + src2;
if (dst_sample > max_audioval) { if (dst_sample > max_audioval) {
dst_sample = max_audioval; dst_sample = max_audioval;
} else if (dst_sample < min_audioval) { } else if (dst_sample < min_audioval) {
dst_sample = min_audioval; dst_sample = min_audioval;
} }
*(dst32++) = SDL_SwapFloatLE((float)dst_sample); *(dst32++) = SDL_SwapFloatLE(dst_sample);
} }
} break; } break;
case SDL_AUDIO_F32BE: case SDL_AUDIO_F32BE:
{ {
const float fmaxvolume = 1.0f / ((float)SDL_MIX_MAXVOLUME); const float fvolume = volume / ((float)SDL_MIX_MAXVOLUME);
const float fvolume = (float)volume;
const float *src32 = (float *)src; const float *src32 = (float *)src;
float *dst32 = (float *)dst; float *dst32 = (float *)dst;
float src1, src2; float src1, src2;
double dst_sample; float dst_sample;
// !!! FIXME: are these right? const float max_audioval = 1.0f;
const double max_audioval = 3.402823466e+38F; const float min_audioval = -1.0f;
const double min_audioval = -3.402823466e+38F;
len /= 4; len /= 4;
while (len--) { while (len--) {
src1 = ((SDL_SwapFloatBE(*src32) * fvolume) * fmaxvolume); src1 = SDL_SwapFloatBE(*src32) * fvolume;
src2 = SDL_SwapFloatBE(*dst32); src2 = SDL_SwapFloatBE(*dst32);
src32++; src32++;
dst_sample = ((double)src1) + ((double)src2); dst_sample = src1 + src2;
if (dst_sample > max_audioval) { if (dst_sample > max_audioval) {
dst_sample = max_audioval; dst_sample = max_audioval;
} else if (dst_sample < min_audioval) { } else if (dst_sample < min_audioval) {
dst_sample = min_audioval; dst_sample = min_audioval;
} }
*(dst32++) = SDL_SwapFloatBE((float)dst_sample); *(dst32++) = SDL_SwapFloatBE(dst_sample);
} }
} break; } break;