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Emulate stereo panning for openAL

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This commit is contained in:
NepDisk 2025-11-24 10:37:43 -05:00
parent 5fd3904b3d
commit 5176755b9a
1 changed files with 12 additions and 2 deletions
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14
src/sdl/al_sound.c
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@ -844,7 +844,17 @@ void I_UpdateSoundParams(INT32 handle, UINT8 vol, UINT8 sep, UINT8 pitch)
ALuint source = handle;
TRY(alSourcef, source, AL_GAIN, sfx_volume * (vol / 255.0f));
TRY(alSourcef, source, AL_PITCH, pitch / 128.0f);
(void)sep;
// TODO: Real 3D Audio.
// create a panning effect by moving the source in an arc around the listener
// Based on https://github.com/kcat/openal-soft/issues/194
float leftpan = min((0xff-sep)<<1, 0xff) / 255.0f;
float rightpan = min(sep<<1, 0xff) / 255.0f;
float pan = (acosf(leftpan) + asinf(rightpan)) / ((float)M_PI); // average angle in [0,1]
pan = 2 * pan - 1; // convert to [-1, 1]
pan = pan * 0.5f; // 0.5 = sin(30') for a +/- 30 degree arc
TRY(alSourcei, source, AL_SOURCE_RELATIVE, AL_TRUE);
TRY(alSource3f, source, AL_POSITION, pan, 0, -sqrtf(1.0f - pan*pan));
}
INT32 I_StartSound(sfxenum_t id, UINT8 vol, UINT8 sep, UINT8 pitch, UINT8 priority, INT32 channel)
@ -873,7 +883,7 @@ INT32 I_StartSound(sfxenum_t id, UINT8 vol, UINT8 sep, UINT8 pitch, UINT8 priori
return INVALID_HANDLE;
}
(void)sep; // panning is now handled by real object positioning instead
//(void)sep; // panning is now handled by real object positioning instead
(void)priority; // priority and channel management is handled by SRB2...
(void)channel; // no longer used
return source;