131 lines
2.5 KiB
C
131 lines
2.5 KiB
C
/**
|
|
audio: this file implements the audio system.
|
|
*/
|
|
|
|
#ifndef _LCR_AUDIO
|
|
#define _LCR_AUDIO
|
|
|
|
#define LCR_SOUND_NONE 0
|
|
#define LCR_SOUND_CLICK 1
|
|
#define LCR_SOUND_CRASH_SMALL 2
|
|
#define LCR_SOUND_CRASH_BIG 3
|
|
#define LCR_SOUND_ACCELERATOR 4
|
|
|
|
#define LCR_AUDIO_CRASH_LEN 2048
|
|
|
|
|
|
struct
|
|
{
|
|
uint32_t frame;
|
|
uint8_t soundPlayed;
|
|
uint16_t soundPlayedFrame;
|
|
uint32_t noise;
|
|
|
|
uint8_t crashSample;
|
|
|
|
|
|
int engineIntensity;
|
|
int engineOsc;
|
|
int engineInc;
|
|
|
|
|
|
} LCR_audio;
|
|
|
|
|
|
|
|
|
|
void LCR_audioInit(void)
|
|
{
|
|
LCR_LOG0("initializing audio");
|
|
LCR_audio.frame = 0;
|
|
LCR_audio.soundPlayed = LCR_SOUND_NONE;
|
|
LCR_audio.soundPlayedFrame = 0;
|
|
LCR_audio.noise = 0;
|
|
|
|
LCR_audio.crashSample = 0;
|
|
|
|
LCR_audio.engineOsc = 0;
|
|
|
|
LCR_audio.engineInc = 1;
|
|
|
|
LCR_audio.engineIntensity = 0;
|
|
|
|
|
|
}
|
|
|
|
void LCR_audioSetEngineIntensity(uint8_t value)
|
|
{
|
|
LCR_audio.engineIntensity = value;
|
|
}
|
|
|
|
void LCR_audioPlaySound(uint8_t sound)
|
|
{
|
|
LCR_LOG2("playing sound");
|
|
LCR_audio.soundPlayed = sound;
|
|
LCR_audio.soundPlayedFrame = 0;
|
|
}
|
|
|
|
uint8_t _LCR_audioNoise(void)
|
|
{
|
|
LCR_audio.noise = LCR_audio.noise * 32310901 + 37;
|
|
return LCR_audio.noise >> 16;
|
|
}
|
|
|
|
uint8_t LCR_audioGetNextSample(void)
|
|
{
|
|
unsigned char result = 128;
|
|
|
|
switch (LCR_audio.soundPlayed)
|
|
{
|
|
case LCR_SOUND_CRASH_SMALL:
|
|
case LCR_SOUND_CRASH_BIG:
|
|
{
|
|
int limit = (LCR_audio.soundPlayed == LCR_SOUND_CRASH_BIG ? 256 : 128) -
|
|
(LCR_audio.soundPlayedFrame * 256) / LCR_AUDIO_CRASH_LEN;
|
|
|
|
if (LCR_audio.frame % 2 || // lower frequency
|
|
LCR_audio.soundPlayedFrame < LCR_AUDIO_CRASH_LEN / 4)
|
|
LCR_audio.crashSample = _LCR_audioNoise();
|
|
|
|
if (LCR_audio.crashSample > limit)
|
|
LCR_audio.crashSample = (_LCR_audioNoise() % 2) ? 0 : limit;
|
|
|
|
result += LCR_audio.crashSample - limit / 2;
|
|
|
|
if (limit == 0)
|
|
LCR_audio.soundPlayed = LCR_SOUND_NONE;
|
|
|
|
break;
|
|
}
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (LCR_audio.soundPlayed != LCR_SOUND_NONE)
|
|
LCR_audio.soundPlayedFrame++;
|
|
else
|
|
{
|
|
LCR_audio.engineOsc +=
|
|
LCR_audio.engineInc ?
|
|
(((_LCR_audioNoise() % 256) <
|
|
(10 + LCR_audio.engineIntensity))) : -31;
|
|
|
|
if (LCR_audio.engineInc && LCR_audio.engineOsc >
|
|
(90 + (LCR_audio.engineIntensity / 8)))
|
|
LCR_audio.engineInc = 0;
|
|
else if ((!LCR_audio.engineInc) && LCR_audio.engineOsc < 10)
|
|
LCR_audio.engineInc = 1;
|
|
|
|
result +=
|
|
LCR_audio.engineIntensity < 20 ?
|
|
LCR_audio.engineOsc / 2 : LCR_audio.engineOsc;
|
|
}
|
|
|
|
LCR_audio.frame++;
|
|
|
|
return result;
|
|
}
|
|
|
|
#endif // guard
|