/** * OpenAL cross platform audio library * Copyright (C) 2009 by Chris Robinson. * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 59 Temple Place - Suite 330, * Boston, MA 02111-1307, USA. * Or go to http://www.gnu.org/copyleft/lgpl.html */ #include "config.h" #include #include #include "alMain.h" #include "alFilter.h" #include "alAuxEffectSlot.h" #include "alError.h" #include "alu.h" typedef struct ALmodulatorState { // Must be first in all effects! ALeffectState state; enum { SINUSOID, SAWTOOTH, SQUARE } Waveform; ALuint index; ALuint step; ALfloat Gain[MAXCHANNELS]; FILTER iirFilter; ALfloat history[1]; } ALmodulatorState; #define WAVEFORM_FRACBITS 16 #define WAVEFORM_FRACMASK ((1<history[offset]; ALfloat a = iir->coeff; ALfloat output = input; output = output + (history[0]-output)*a; history[0] = output; return input - output; } #define DECL_TEMPLATE(func) \ static void Process##func(ALmodulatorState *state, const ALeffectslot *Slot, \ ALuint SamplesToDo, const ALfloat *SamplesIn, \ ALfloat (*SamplesOut)[MAXCHANNELS]) \ { \ const ALfloat gain = Slot->Gain; \ const ALuint step = state->step; \ ALuint index = state->index; \ ALfloat samp; \ ALuint i; \ \ for(i = 0;i < SamplesToDo;i++) \ { \ samp = SamplesIn[i]; \ \ index += step; \ index &= WAVEFORM_FRACMASK; \ samp *= func(index); \ \ samp = hpFilter1P(&state->iirFilter, 0, samp); \ \ /* Apply slot gain */ \ samp *= gain; \ \ SamplesOut[i][FRONT_LEFT] += state->Gain[FRONT_LEFT] * samp; \ SamplesOut[i][FRONT_RIGHT] += state->Gain[FRONT_RIGHT] * samp; \ SamplesOut[i][FRONT_CENTER] += state->Gain[FRONT_CENTER] * samp; \ SamplesOut[i][SIDE_LEFT] += state->Gain[SIDE_LEFT] * samp; \ SamplesOut[i][SIDE_RIGHT] += state->Gain[SIDE_RIGHT] * samp; \ SamplesOut[i][BACK_LEFT] += state->Gain[BACK_LEFT] * samp; \ SamplesOut[i][BACK_RIGHT] += state->Gain[BACK_RIGHT] * samp; \ SamplesOut[i][BACK_CENTER] += state->Gain[BACK_CENTER] * samp; \ } \ state->index = index; \ } DECL_TEMPLATE(Sin) DECL_TEMPLATE(Saw) DECL_TEMPLATE(Square) #undef DECL_TEMPLATE static ALvoid ModulatorDestroy(ALeffectState *effect) { ALmodulatorState *state = (ALmodulatorState*)effect; free(state); } static ALboolean ModulatorDeviceUpdate(ALeffectState *effect, ALCdevice *Device) { ALmodulatorState *state = (ALmodulatorState*)effect; ALuint index; for(index = 0;index < MAXCHANNELS;index++) state->Gain[index] = 0.0f; for(index = 0;index < Device->NumChan;index++) { Channel chan = Device->Speaker2Chan[index]; state->Gain[chan] = 1.0f; } return AL_TRUE; } static ALvoid ModulatorUpdate(ALeffectState *effect, ALCcontext *Context, const ALeffect *Effect) { ALmodulatorState *state = (ALmodulatorState*)effect; ALfloat cw, a = 0.0f; if(Effect->Params.Modulator.Waveform == AL_RING_MODULATOR_SINUSOID) state->Waveform = SINUSOID; else if(Effect->Params.Modulator.Waveform == AL_RING_MODULATOR_SAWTOOTH) state->Waveform = SAWTOOTH; else if(Effect->Params.Modulator.Waveform == AL_RING_MODULATOR_SQUARE) state->Waveform = SQUARE; state->step = Effect->Params.Modulator.Frequency*(1<Device->Frequency; if(!state->step) state->step = 1; cw = cos(2.0*M_PI * Effect->Params.Modulator.HighPassCutoff / Context->Device->Frequency); a = (2.0f-cw) - aluSqrt(aluPow(2.0f-cw, 2.0f) - 1.0f); state->iirFilter.coeff = a; } static ALvoid ModulatorProcess(ALeffectState *effect, const ALeffectslot *Slot, ALuint SamplesToDo, const ALfloat *SamplesIn, ALfloat (*SamplesOut)[MAXCHANNELS]) { ALmodulatorState *state = (ALmodulatorState*)effect; switch(state->Waveform) { case SINUSOID: ProcessSin(state, Slot, SamplesToDo, SamplesIn, SamplesOut); break; case SAWTOOTH: ProcessSaw(state, Slot, SamplesToDo, SamplesIn, SamplesOut); break; case SQUARE: ProcessSquare(state, Slot, SamplesToDo, SamplesIn, SamplesOut); break; } } ALeffectState *ModulatorCreate(void) { ALmodulatorState *state; state = malloc(sizeof(*state)); if(!state) return NULL; state->state.Destroy = ModulatorDestroy; state->state.DeviceUpdate = ModulatorDeviceUpdate; state->state.Update = ModulatorUpdate; state->state.Process = ModulatorProcess; state->index = 0.0f; state->step = 1.0f; state->iirFilter.coeff = 0.0f; state->iirFilter.history[0] = 0.0f; return &state->state; }