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(svn r19332) -Codechange: Simplify sound panning by using float data, and switch to sinusoidal algorithm to maintain output level.

release/1.1
peter1138 2010-03-06 11:08:31 +00:00
parent 1eb52326cf
commit 77fe7e0a74
3 changed files with 18 additions and 15 deletions
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15
src/mixer.cpp
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@ -10,6 +10,7 @@
/** @file mixer.cpp Mixing of sound samples. */ /** @file mixer.cpp Mixing of sound samples. */
#include "stdafx.h" #include "stdafx.h"
#include <math.h>
#include "core/math_func.hpp" #include "core/math_func.hpp"
struct MixerChannel { struct MixerChannel {
@ -185,10 +186,18 @@ void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate, boo
mc->is16bit = is16bit; mc->is16bit = is16bit;
} }
void MxSetChannelVolume(MixerChannel *mc, uint left, uint right) /**
* Set volume and pan parameters for a sound.
* @param mc MixerChannel to set
* @param volume Volume level for sound, range is 0..16384
* @param pan Pan position for sound, range is 0..1
*/
void MxSetChannelVolume(MixerChannel *mc, uint volume, float pan)
{ {
mc->volume_left = left; /* Use sinusoidal pan to maintain overall sound power level regardless
mc->volume_right = right; * of position. */
mc->volume_left = volume * sin((1.0 - pan) * M_PI / 2.0);
mc->volume_right = volume * sin(pan * M_PI / 2.0);
} }

2
src/mixer.h
View File

@ -19,7 +19,7 @@ void MxMixSamples(void *buffer, uint samples);
MixerChannel *MxAllocateChannel(); MixerChannel *MxAllocateChannel();
void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate, bool is16bit); void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, size_t size, uint rate, bool is16bit);
void MxSetChannelVolume(MixerChannel *mc, uint left, uint right); void MxSetChannelVolume(MixerChannel *mc, uint volume, float pan);
void MxActivateChannel(MixerChannel*); void MxActivateChannel(MixerChannel*);
#endif /* MIXER_H */ #endif /* MIXER_H */

16
src/sound.cpp
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@ -24,9 +24,6 @@
static SoundEntry _original_sounds[ORIGINAL_SAMPLE_COUNT]; static SoundEntry _original_sounds[ORIGINAL_SAMPLE_COUNT];
MusicFileSettings msf; MusicFileSettings msf;
/* Number of levels of panning per side */
#define PANNING_LEVELS 16
static void OpenBankFile(const char *filename) static void OpenBankFile(const char *filename)
{ {
memset(_original_sounds, 0, sizeof(_original_sounds)); memset(_original_sounds, 0, sizeof(_original_sounds));
@ -158,7 +155,7 @@ void InitializeSound()
} }
/* Low level sound player */ /* Low level sound player */
static void StartSound(SoundID sound_id, int panning, uint volume) static void StartSound(SoundID sound_id, float pan, uint volume)
{ {
if (volume == 0) return; if (volume == 0) return;
@ -174,12 +171,9 @@ static void StartSound(SoundID sound_id, int panning, uint volume)
if (!SetBankSource(mc, sound)) return; if (!SetBankSource(mc, sound)) return;
/* Apply the sound effect's own volume. */ /* Apply the sound effect's own volume. */
volume = (sound->volume * volume) / 128; volume = sound->volume * volume;
panning = Clamp(panning, -PANNING_LEVELS, PANNING_LEVELS); MxSetChannelVolume(mc, volume, pan);
uint left_vol = (volume * PANNING_LEVELS) - (volume * panning);
uint right_vol = (volume * PANNING_LEVELS) + (volume * panning);
MxSetChannelVolume(mc, left_vol * 128 / PANNING_LEVELS, right_vol * 128 / PANNING_LEVELS);
MxActivateChannel(mc); MxActivateChannel(mc);
} }
@ -244,7 +238,7 @@ static void SndPlayScreenCoordFx(SoundID sound, int left, int right, int top, in
top < vp->virtual_top + vp->virtual_height && bottom > vp->virtual_top) { top < vp->virtual_top + vp->virtual_height && bottom > vp->virtual_top) {
int screen_x = (left + right) / 2 - vp->virtual_left; int screen_x = (left + right) / 2 - vp->virtual_left;
int width = (vp->virtual_width == 0 ? 1 : vp->virtual_width); int width = (vp->virtual_width == 0 ? 1 : vp->virtual_width);
int panning = (screen_x * PANNING_LEVELS * 2) / width - PANNING_LEVELS; float panning = (float)screen_x / width;
StartSound( StartSound(
sound, sound,
@ -278,7 +272,7 @@ void SndPlayVehicleFx(SoundID sound, const Vehicle *v)
void SndPlayFx(SoundID sound) void SndPlayFx(SoundID sound)
{ {
StartSound(sound, 0, msf.effect_vol); StartSound(sound, 0.5, msf.effect_vol);
} }
INSTANTIATE_BASE_MEDIA_METHODS(BaseMedia<SoundsSet>, SoundsSet) INSTANTIATE_BASE_MEDIA_METHODS(BaseMedia<SoundsSet>, SoundsSet)