Changeset - r14734:58c3f99dc69c
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master
0 3 0
peter1138 - 14 years ago 2010-03-06 11:08:31
peter1138@openttd.org
(svn r19332) -Codechange: Simplify sound panning by using float data, and switch to sinusoidal algorithm to maintain output level.
3 files changed with 18 insertions and 15 deletions:
0 comments (0 inline, 0 general)
src/mixer.cpp
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@@ -10,6 +10,7 @@
 
/** @file mixer.cpp Mixing of sound samples. */
 

	
 
#include "stdafx.h"
 
#include <math.h>
 
#include "core/math_func.hpp"
 

	
 
struct MixerChannel {
 
@@ -185,10 +186,18 @@ void MxSetChannelRawSrc(MixerChannel *mc
 
	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;
 
	mc->volume_right = right;
 
	/* Use sinusoidal pan to maintain overall sound power level regardless
 
	 * of position. */
 
	mc->volume_left = volume * sin((1.0 - pan) * M_PI / 2.0);
 
	mc->volume_right = volume * sin(pan * M_PI / 2.0);
 
}
 

	
 

	
src/mixer.h
Show inline comments
 
@@ -19,7 +19,7 @@ void MxMixSamples(void *buffer, uint sam
 

	
 
MixerChannel *MxAllocateChannel();
 
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*);
 

	
 
#endif /* MIXER_H */
src/sound.cpp
Show inline comments
 
@@ -24,9 +24,6 @@
 
static SoundEntry _original_sounds[ORIGINAL_SAMPLE_COUNT];
 
MusicFileSettings msf;
 

	
 
/* Number of levels of panning per side */
 
#define PANNING_LEVELS 16
 

	
 
static void OpenBankFile(const char *filename)
 
{
 
	memset(_original_sounds, 0, sizeof(_original_sounds));
 
@@ -158,7 +155,7 @@ void InitializeSound()
 
}
 

	
 
/* 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;
 

	
 
@@ -174,12 +171,9 @@ static void StartSound(SoundID sound_id,
 
	if (!SetBankSource(mc, sound)) return;
 

	
 
	/* Apply the sound effect's own volume. */
 
	volume = (sound->volume * volume) / 128;
 
	volume = sound->volume * volume;
 

	
 
	panning = Clamp(panning, -PANNING_LEVELS, PANNING_LEVELS);
 
	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);
 
	MxSetChannelVolume(mc, volume, pan);
 
	MxActivateChannel(mc);
 
}
 

	
 
@@ -244,7 +238,7 @@ static void SndPlayScreenCoordFx(SoundID
 
				top < vp->virtual_top + vp->virtual_height && bottom > vp->virtual_top) {
 
			int screen_x = (left + right) / 2 - vp->virtual_left;
 
			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(
 
				sound,
 
@@ -278,7 +272,7 @@ void SndPlayVehicleFx(SoundID sound, con
 

	
 
void SndPlayFx(SoundID sound)
 
{
 
	StartSound(sound, 0, msf.effect_vol);
 
	StartSound(sound, 0.5, msf.effect_vol);
 
}
 

	
 
INSTANTIATE_BASE_MEDIA_METHODS(BaseMedia<SoundsSet>, SoundsSet)
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