使用OpenAL混音，添加音频特效
1. OpenAL 支持的混音类型
const static int AUDIO_EFFECT_GENERIC = 0;
const static int AUDIO_EFFECT_PADDED_CELL = 1;//软垫室
const static int AUDIO_EFFECT_ROOM = 2;
const static int AUDIO_EFFECT_BATHROOM = 3;
const static int AUDIO_EFFECT_LIVING_ROOM = 4;
const static int AUDIO_EFFECT_STONE_ROOM = 5;
const static int AUDIO_EFFECT_AUDITORIUM = 6;//礼堂
const static int AUDIO_EFFECT_CONCERT_HALL = 7;//音乐厅
const static int AUDIO_EFFECT_CAVE = 8;
const static int AUDIO_EFFECT_ARENA = 9;//竞技场
const static int AUDIO_EFFECT_HANGAR = 10;//机库
const static int AUDIO_EFFECT_CARPETED_HALLWAY = 11;//地毯走廊
const static int AUDIO_EFFECT_HALLWAY = 12;//走廊
const static int AUDIO_EFFECT_STONE_CORRIDOR = 13;//石头走廊
const static int AUDIO_EFFECT_ALLEY = 14;//巷
const static int AUDIO_EFFECT_FOREST = 15;
const static int AUDIO_EFFECT_CITY = 16;
const static int AUDIO_EFFECT_MOUNTAINS = 17;
const static int AUDIO_EFFECT_OUARRY = 18;//?
const static int AUDIO_EFFECT_PLAIN = 19;//?
const static int AUDIO_EFFECT_PARKING_LOT = 20;//停车场
const static int AUDIO_EFFECT_SEWER_PIPE = 21;//水管
const static int AUDIO_EFFECT_UNDER_WATER = 22;
const static int AUDIO_EFFECT_DRUGGED = 23;//嗑药
const static int AUDIO_EFFECT_DIZZY = 24;//眩晕
const static int AUDIO_EFFECT_PSYCHOTIC = 25;//疯狂2. 初始化音频特效
2.1 Create Aux Effect Slot
alGenAuxiliaryEffectSlots(1, &m_effectSlot);
alGenEffects(1, &m_effect);
alGenFilters(1, &m_filter);2.2 Create Effect
alEffecti(m_effect, AL_EFFECT_TYPE, AL_EFFECT_EAXREVERB);
alAuxiliaryEffectSloti(m_effectSlot, AL_EFFECTSLOT_EFFECT, m_effect);
alFilteri(m_filter, AL_FILTER_TYPE, AL_FILTER_LOWPASS);
alFilterf(m_filter, AL_LOWPASS_GAIN, 0.8f);
alFilterf(m_filter, AL_LOWPASS_GAINHF, 0.3f);2.3 Set Effect
bool setEffect(int iEffectType)
{
switch(iEffectType)
{
case AUDIO_EFFECT_NONE:
m_efxEffect = EFX_REVERB_PRESET_GENERIC;
break;
// case AUDIO_EFFECT_SMALLROOM:
case AUDIO_EFFECT_PADDED_CELL:
m_efxEffect = EFX_REVERB_PRESET_SPACESTATION_SMALLROOM;
m_efxEffect = EFX_REVERB_PRESET_PADDEDCELL;
break;
// case AUDIO_EFFECT_MEDIUMROOM:
case AUDIO_EFFECT_ROOM:
m_efxEffect = EFX_REVERB_PRESET_SPACESTATION_MEDIUMROOM;
m_efxEffect = EFX_REVERB_PRESET_ROOM;
break;
// case AUDIO_EFFECT_LARGEGROOM:
case AUDIO_EFFECT_BATHROOM:
m_efxEffect = EFX_REVERB_PRESET_SPACESTATION_LARGEROOM;
m_efxEffect = EFX_REVERB_PRESET_BATHROOM;
break;
// case AUDIO_EFFECT_MEDIUMHALL:
case AUDIO_EFFECT_LIVING_ROOM:
m_efxEffect = EFX_REVERB_PRESET_SPACESTATION_HALL;
m_efxEffect = EFX_REVERB_PRESET_LIVINGROOM;
break;
// case AUDIO_EFFECT_LARGEHALL:
case AUDIO_EFFECT_STONE_ROOM:
m_efxEffect = EFX_REVERB_PRESET_ICEPALACE_HALL;
m_efxEffect = EFX_REVERB_PRESET_STONEROOM;
break;
// case AUDIO_EFFECT_PLATE:
case AUDIO_EFFECT_AUDITORIUM:
m_efxEffect = EFX_REVERB_PRESET_PLAIN;
m_efxEffect = EFX_REVERB_PRESET_AUDITORIUM;
break;
case AUDIO_EFFECT_CONCERT_HALL:
m_efxEffect = EFX_REVERB_PRESET_CONCERTHALL;
break;
case AUDIO_EFFECT_CAVE:
m_efxEffect = EFX_REVERB_PRESET_CAVE;
break;
case AUDIO_EFFECT_ARENA:
m_efxEffect = EFX_REVERB_PRESET_ARENA;
break;
case AUDIO_EFFECT_HANGAR:
m_efxEffect = EFX_REVERB_PRESET_HANGAR;
break;
case AUDIO_EFFECT_CARPETED_HALLWAY:
m_efxEffect = EFX_REVERB_PRESET_CARPETEDHALLWAY;
break;
case AUDIO_EFFECT_HALLWAY:
m_efxEffect = EFX_REVERB_PRESET_HALLWAY;
break;
case AUDIO_EFFECT_STONE_CORRIDOR:
m_efxEffect = EFX_REVERB_PRESET_STONECORRIDOR;
break;
case AUDIO_EFFECT_ALLEY:
m_efxEffect = EFX_REVERB_PRESET_ALLEY;
break;
case AUDIO_EFFECT_FOREST:
m_efxEffect = EFX_REVERB_PRESET_FOREST;
break;
case AUDIO_EFFECT_CITY:
m_efxEffect = EFX_REVERB_PRESET_CITY;
break;
case AUDIO_EFFECT_MOUNTAINS:
m_efxEffect = EFX_REVERB_PRESET_MOUNTAINS;
break;
case AUDIO_EFFECT_OUARRY:
m_efxEffect = EFX_REVERB_PRESET_QUARRY;
break;
case AUDIO_EFFECT_PLAIN:
m_efxEffect = EFX_REVERB_PRESET_PLAIN;
break;
case AUDIO_EFFECT_PARKING_LOT:
m_efxEffect = EFX_REVERB_PRESET_PARKINGLOT;
break;
case AUDIO_EFFECT_SEWER_PIPE:
m_efxEffect = EFX_REVERB_PRESET_SEWERPIPE;
break;
case AUDIO_EFFECT_UNDER_WATER:
m_efxEffect = EFX_REVERB_PRESET_UNDERWATER;
break;
case AUDIO_EFFECT_DRUGGED:
m_efxEffect = EFX_REVERB_PRESET_DRUGGED;
break;
case AUDIO_EFFECT_DIZZY:
m_efxEffect = EFX_REVERB_PRESET_DIZZY;
break;
case AUDIO_EFFECT_PSYCHOTIC:
m_efxEffect = EFX_REVERB_PRESET_PSYCHOTIC;
break;
default:
CHX_LOG_ERROR("Unknown effect type: %d.", iEffectType);
m_efxEffect = EFX_REVERB_PRESET_GENERIC;
break;
}
XLOGI("%f, %f, %f", m_efxEffect.flDensity, m_efxEffect.flDiffusion, m_efxEffect.flGain);
bool res = setEFXEAXReverbProperties(&m_efxEffect, m_effect);
if (!res)
{
XLOGE("Failed to set Reverb Params.");
}
return res;
}setEFXEAXReverbProperties：
bool setEFXEAXReverbProperties(EFXEAXREVERBPROPERTIES *pEfx, ALuint uiEffect)
{
bool bReturn = false;
if (pEfx)
{
// Clear AL Error code
alGetError();
alEffectf(uiEffect, AL_EAXREVERB_DENSITY, pEfx->flDensity);
alEffectf(uiEffect, AL_EAXREVERB_DIFFUSION, pEfx->flDiffusion);
alEffectf(uiEffect, AL_EAXREVERB_GAIN, pEfx->flGain);
alEffectf(uiEffect, AL_EAXREVERB_GAINHF, pEfx->flGainHF);
alEffectf(uiEffect, AL_EAXREVERB_GAINLF, pEfx->flGainLF);
alEffectf(uiEffect, AL_EAXREVERB_DECAY_TIME, pEfx->flDecayTime);
alEffectf(uiEffect, AL_EAXREVERB_DECAY_HFRATIO, pEfx->flDecayHFRatio);
alEffectf(uiEffect, AL_EAXREVERB_DECAY_LFRATIO, pEfx->flDecayLFRatio);
alEffectf(uiEffect, AL_EAXREVERB_REFLECTIONS_GAIN, pEfx->flReflectionsGain);
alEffectf(uiEffect, AL_EAXREVERB_REFLECTIONS_DELAY, pEfx->flReflectionsDelay);
alEffectfv(uiEffect, AL_EAXREVERB_REFLECTIONS_PAN, pEfx->flReflectionsPan);
alEffectf(uiEffect, AL_EAXREVERB_LATE_REVERB_GAIN, pEfx->flLateReverbGain);
alEffectf(uiEffect, AL_EAXREVERB_LATE_REVERB_DELAY, pEfx->flLateReverbDelay);
alEffectfv(uiEffect, AL_EAXREVERB_LATE_REVERB_PAN, pEfx->flLateReverbPan);
alEffectf(uiEffect, AL_EAXREVERB_ECHO_TIME, pEfx->flEchoTime);
alEffectf(uiEffect, AL_EAXREVERB_ECHO_DEPTH, pEfx->flEchoDepth);
alEffectf(uiEffect, AL_EAXREVERB_MODULATION_TIME, pEfx->flModulationTime);
alEffectf(uiEffect, AL_EAXREVERB_MODULATION_DEPTH, pEfx->flModulationDepth);
alEffectf(uiEffect, AL_EAXREVERB_AIR_ABSORPTION_GAINHF, pEfx->flAirAbsorptionGainHF);
alEffectf(uiEffect, AL_EAXREVERB_HFREFERENCE, pEfx->flHFReference);
alEffectf(uiEffect, AL_EAXREVERB_LFREFERENCE, pEfx->flLFReference);
alEffectf(uiEffect, AL_EAXREVERB_ROOM_ROLLOFF_FACTOR, pEfx->flRoomRolloffFactor);
alEffecti(uiEffect, AL_EAXREVERB_DECAY_HFLIMIT, pEfx->iDecayHFLimit);
if (alGetError() == AL_NO_ERROR)
bReturn = true;
}
return bReturn;
}3. 应用音频特效
应用音频特效在初始化OpenAL之前，即必须在播放之前设置音频特效。在播放过程中无法更改OpenAL音频效果。
bool applyEffect(ALuint source)
{
alGetError();
alAuxiliaryEffectSloti(m_effectSlot, AL_EFFECTSLOT_EFFECT, m_effect);
alSource3i(source, AL_AUXILIARY_SEND_FILTER, m_effectSlot, 0, AL_FILTER_NULL);
if (alGetError() == AL_NO_ERROR)
return true;
else
return false;
}