297 lines
8.6 KiB
C
297 lines
8.6 KiB
C
/**
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* OpenAL cross platform audio library
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* Copyright (C) 2009 by Chris Robinson.
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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* Or go to http://www.gnu.org/copyleft/lgpl.html
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*/
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#include "config.h"
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#include <math.h>
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#include <stdlib.h>
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#include "alMain.h"
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#include "alFilter.h"
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#include "alAuxEffectSlot.h"
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#include "alError.h"
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#include "alu.h"
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typedef struct ALechoState {
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DERIVE_FROM_TYPE(ALeffectState);
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ALfloat *SampleBuffer;
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ALuint BufferLength;
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// The echo is two tap. The delay is the number of samples from before the
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// current offset
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struct {
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ALuint delay;
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} Tap[2];
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ALuint Offset;
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/* The panning gains for the two taps */
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ALfloat Gain[2][MaxChannels];
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ALfloat FeedGain;
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FILTER iirFilter;
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ALfloat history[2];
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} ALechoState;
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static ALvoid ALechoState_Destroy(ALeffectState *effect)
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{
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ALechoState *state = STATIC_UPCAST(ALechoState, ALeffectState, effect);
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free(state->SampleBuffer);
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state->SampleBuffer = NULL;
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free(state);
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}
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static ALboolean ALechoState_DeviceUpdate(ALeffectState *effect, ALCdevice *Device)
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{
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ALechoState *state = STATIC_UPCAST(ALechoState, ALeffectState, effect);
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ALuint maxlen, i;
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// Use the next power of 2 for the buffer length, so the tap offsets can be
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// wrapped using a mask instead of a modulo
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maxlen = fastf2u(AL_ECHO_MAX_DELAY * Device->Frequency) + 1;
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maxlen += fastf2u(AL_ECHO_MAX_LRDELAY * Device->Frequency) + 1;
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maxlen = NextPowerOf2(maxlen);
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if(maxlen != state->BufferLength)
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{
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void *temp;
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temp = realloc(state->SampleBuffer, maxlen * sizeof(ALfloat));
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if(!temp)
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return AL_FALSE;
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state->SampleBuffer = temp;
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state->BufferLength = maxlen;
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}
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for(i = 0;i < state->BufferLength;i++)
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state->SampleBuffer[i] = 0.0f;
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return AL_TRUE;
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}
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static ALvoid ALechoState_Update(ALeffectState *effect, ALCdevice *Device, const ALeffectslot *Slot)
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{
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ALechoState *state = STATIC_UPCAST(ALechoState, ALeffectState, effect);
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ALuint frequency = Device->Frequency;
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ALfloat lrpan, cw, g, gain;
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ALfloat dirGain;
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ALuint i;
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state->Tap[0].delay = fastf2u(Slot->effect.Echo.Delay * frequency) + 1;
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state->Tap[1].delay = fastf2u(Slot->effect.Echo.LRDelay * frequency);
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state->Tap[1].delay += state->Tap[0].delay;
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lrpan = Slot->effect.Echo.Spread;
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state->FeedGain = Slot->effect.Echo.Feedback;
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cw = cosf(F_PI*2.0f * LOWPASSFREQREF / frequency);
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g = 1.0f - Slot->effect.Echo.Damping;
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state->iirFilter.coeff = lpCoeffCalc(g, cw);
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gain = Slot->Gain;
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for(i = 0;i < MaxChannels;i++)
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{
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state->Gain[0][i] = 0.0f;
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state->Gain[1][i] = 0.0f;
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}
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dirGain = fabsf(lrpan);
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/* First tap panning */
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ComputeAngleGains(Device, atan2f(-lrpan, 0.0f), (1.0f-dirGain)*F_PI, gain, state->Gain[0]);
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/* Second tap panning */
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ComputeAngleGains(Device, atan2f(+lrpan, 0.0f), (1.0f-dirGain)*F_PI, gain, state->Gain[1]);
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}
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static ALvoid ALechoState_Process(ALeffectState *effect, ALuint SamplesToDo, const ALfloat *RESTRICT SamplesIn, ALfloat (*RESTRICT SamplesOut)[BUFFERSIZE])
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{
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ALechoState *state = STATIC_UPCAST(ALechoState, ALeffectState, effect);
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const ALuint mask = state->BufferLength-1;
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const ALuint tap1 = state->Tap[0].delay;
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const ALuint tap2 = state->Tap[1].delay;
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ALuint offset = state->Offset;
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ALfloat smp;
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ALuint base;
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ALuint i, k;
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for(base = 0;base < SamplesToDo;)
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{
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ALfloat temps[64][2];
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ALuint td = minu(SamplesToDo-base, 64);
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for(i = 0;i < td;i++)
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{
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/* First tap */
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temps[i][0] = state->SampleBuffer[(offset-tap1) & mask];
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/* Second tap */
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temps[i][1] = state->SampleBuffer[(offset-tap2) & mask];
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// Apply damping and feedback gain to the second tap, and mix in the
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// new sample
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smp = lpFilter2P(&state->iirFilter, 0, temps[i][1]+SamplesIn[i]);
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state->SampleBuffer[offset&mask] = smp * state->FeedGain;
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}
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for(k = 0;k < MaxChannels;k++)
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{
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ALfloat gain = state->Gain[0][k];
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if(gain > 0.00001f)
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{
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for(i = 0;i < td;i++)
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SamplesOut[k][i+base] += temps[i][0] * gain;
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}
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gain = state->Gain[1][k];
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if(gain > 0.00001f)
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{
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for(i = 0;i < td;i++)
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SamplesOut[k][i+base] += temps[i][1] * gain;
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}
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}
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base += td;
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}
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state->Offset = offset;
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}
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DEFINE_ALEFFECTSTATE_VTABLE(ALechoState);
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ALeffectState *EchoCreate(void)
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{
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ALechoState *state;
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state = malloc(sizeof(*state));
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if(!state) return NULL;
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SET_VTABLE2(ALechoState, ALeffectState, state);
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state->BufferLength = 0;
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state->SampleBuffer = NULL;
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state->Tap[0].delay = 0;
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state->Tap[1].delay = 0;
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state->Offset = 0;
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state->iirFilter.coeff = 0.0f;
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state->iirFilter.history[0] = 0.0f;
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state->iirFilter.history[1] = 0.0f;
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return STATIC_CAST(ALeffectState, state);
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}
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void echo_SetParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint val)
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{ (void)effect;(void)param;(void)val; alSetError(context, AL_INVALID_ENUM); }
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void echo_SetParamiv(ALeffect *effect, ALCcontext *context, ALenum param, const ALint *vals)
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{
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echo_SetParami(effect, context, param, vals[0]);
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}
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void echo_SetParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat val)
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{
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switch(param)
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{
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case AL_ECHO_DELAY:
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if(val >= AL_ECHO_MIN_DELAY && val <= AL_ECHO_MAX_DELAY)
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effect->Echo.Delay = val;
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else
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alSetError(context, AL_INVALID_VALUE);
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break;
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case AL_ECHO_LRDELAY:
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if(val >= AL_ECHO_MIN_LRDELAY && val <= AL_ECHO_MAX_LRDELAY)
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effect->Echo.LRDelay = val;
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else
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alSetError(context, AL_INVALID_VALUE);
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break;
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case AL_ECHO_DAMPING:
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if(val >= AL_ECHO_MIN_DAMPING && val <= AL_ECHO_MAX_DAMPING)
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effect->Echo.Damping = val;
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else
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alSetError(context, AL_INVALID_VALUE);
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break;
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case AL_ECHO_FEEDBACK:
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if(val >= AL_ECHO_MIN_FEEDBACK && val <= AL_ECHO_MAX_FEEDBACK)
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effect->Echo.Feedback = val;
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else
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alSetError(context, AL_INVALID_VALUE);
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break;
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case AL_ECHO_SPREAD:
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if(val >= AL_ECHO_MIN_SPREAD && val <= AL_ECHO_MAX_SPREAD)
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effect->Echo.Spread = val;
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else
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alSetError(context, AL_INVALID_VALUE);
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break;
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default:
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alSetError(context, AL_INVALID_ENUM);
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break;
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}
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}
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void echo_SetParamfv(ALeffect *effect, ALCcontext *context, ALenum param, const ALfloat *vals)
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{
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echo_SetParamf(effect, context, param, vals[0]);
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}
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void echo_GetParami(ALeffect *effect, ALCcontext *context, ALenum param, ALint *val)
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{ (void)effect;(void)param;(void)val; alSetError(context, AL_INVALID_ENUM); }
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void echo_GetParamiv(ALeffect *effect, ALCcontext *context, ALenum param, ALint *vals)
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{
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echo_GetParami(effect, context, param, vals);
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}
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void echo_GetParamf(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *val)
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{
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switch(param)
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{
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case AL_ECHO_DELAY:
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*val = effect->Echo.Delay;
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break;
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case AL_ECHO_LRDELAY:
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*val = effect->Echo.LRDelay;
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break;
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case AL_ECHO_DAMPING:
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*val = effect->Echo.Damping;
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break;
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case AL_ECHO_FEEDBACK:
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*val = effect->Echo.Feedback;
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break;
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case AL_ECHO_SPREAD:
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*val = effect->Echo.Spread;
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break;
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default:
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alSetError(context, AL_INVALID_ENUM);
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break;
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}
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}
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void echo_GetParamfv(ALeffect *effect, ALCcontext *context, ALenum param, ALfloat *vals)
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{
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echo_GetParamf(effect, context, param, vals);
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}
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