/* * OpenAL Multi-Zone Reverb Example * * Copyright (c) 2018 by Chris Robinson * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ /* This file contains an example for controlling multiple reverb zones to * smoothly transition between reverb environments. The general concept is to * extend single-reverb by also tracking the closest adjacent environment, and * utilize EAX Reverb's panning vectors to position them relative to the * listener. */ #include #include #include #include "AL/al.h" #include "AL/alc.h" #include "AL/alext.h" #include "AL/efx-presets.h" #include "common/alhelpers.h" #ifndef M_PI #define M_PI 3.14159265358979323846 #endif /* Filter object functions */ static LPALGENFILTERS alGenFilters; static LPALDELETEFILTERS alDeleteFilters; static LPALISFILTER alIsFilter; static LPALFILTERI alFilteri; static LPALFILTERIV alFilteriv; static LPALFILTERF alFilterf; static LPALFILTERFV alFilterfv; static LPALGETFILTERI alGetFilteri; static LPALGETFILTERIV alGetFilteriv; static LPALGETFILTERF alGetFilterf; static LPALGETFILTERFV alGetFilterfv; /* Effect object functions */ static LPALGENEFFECTS alGenEffects; static LPALDELETEEFFECTS alDeleteEffects; static LPALISEFFECT alIsEffect; static LPALEFFECTI alEffecti; static LPALEFFECTIV alEffectiv; static LPALEFFECTF alEffectf; static LPALEFFECTFV alEffectfv; static LPALGETEFFECTI alGetEffecti; static LPALGETEFFECTIV alGetEffectiv; static LPALGETEFFECTF alGetEffectf; static LPALGETEFFECTFV alGetEffectfv; /* Auxiliary Effect Slot object functions */ static LPALGENAUXILIARYEFFECTSLOTS alGenAuxiliaryEffectSlots; static LPALDELETEAUXILIARYEFFECTSLOTS alDeleteAuxiliaryEffectSlots; static LPALISAUXILIARYEFFECTSLOT alIsAuxiliaryEffectSlot; static LPALAUXILIARYEFFECTSLOTI alAuxiliaryEffectSloti; static LPALAUXILIARYEFFECTSLOTIV alAuxiliaryEffectSlotiv; static LPALAUXILIARYEFFECTSLOTF alAuxiliaryEffectSlotf; static LPALAUXILIARYEFFECTSLOTFV alAuxiliaryEffectSlotfv; static LPALGETAUXILIARYEFFECTSLOTI alGetAuxiliaryEffectSloti; static LPALGETAUXILIARYEFFECTSLOTIV alGetAuxiliaryEffectSlotiv; static LPALGETAUXILIARYEFFECTSLOTF alGetAuxiliaryEffectSlotf; static LPALGETAUXILIARYEFFECTSLOTFV alGetAuxiliaryEffectSlotfv; /* LoadEffect loads the given initial reverb properties into the given OpenAL * effect object, and returns non-zero on success. */ static int LoadEffect(ALuint effect, const EFXEAXREVERBPROPERTIES *reverb) { ALenum err; alGetError(); /* Prepare the effect for EAX Reverb (standard reverb doesn't contain * the needed panning vectors). */ alEffecti(effect, AL_EFFECT_TYPE, AL_EFFECT_EAXREVERB); if((err=alGetError()) != AL_NO_ERROR) { fprintf(stderr, "Failed to set EAX Reverb: %s (0x%04x)\n", alGetString(err), err); return 0; } /* Load the reverb properties. */ alEffectf(effect, AL_EAXREVERB_DENSITY, reverb->flDensity); alEffectf(effect, AL_EAXREVERB_DIFFUSION, reverb->flDiffusion); alEffectf(effect, AL_EAXREVERB_GAIN, reverb->flGain); alEffectf(effect, AL_EAXREVERB_GAINHF, reverb->flGainHF); alEffectf(effect, AL_EAXREVERB_GAINLF, reverb->flGainLF); alEffectf(effect, AL_EAXREVERB_DECAY_TIME, reverb->flDecayTime); alEffectf(effect, AL_EAXREVERB_DECAY_HFRATIO, reverb->flDecayHFRatio); alEffectf(effect, AL_EAXREVERB_DECAY_LFRATIO, reverb->flDecayLFRatio); alEffectf(effect, AL_EAXREVERB_REFLECTIONS_GAIN, reverb->flReflectionsGain); alEffectf(effect, AL_EAXREVERB_REFLECTIONS_DELAY, reverb->flReflectionsDelay); alEffectfv(effect, AL_EAXREVERB_REFLECTIONS_PAN, reverb->flReflectionsPan); alEffectf(effect, AL_EAXREVERB_LATE_REVERB_GAIN, reverb->flLateReverbGain); alEffectf(effect, AL_EAXREVERB_LATE_REVERB_DELAY, reverb->flLateReverbDelay); alEffectfv(effect, AL_EAXREVERB_LATE_REVERB_PAN, reverb->flLateReverbPan); alEffectf(effect, AL_EAXREVERB_ECHO_TIME, reverb->flEchoTime); alEffectf(effect, AL_EAXREVERB_ECHO_DEPTH, reverb->flEchoDepth); alEffectf(effect, AL_EAXREVERB_MODULATION_TIME, reverb->flModulationTime); alEffectf(effect, AL_EAXREVERB_MODULATION_DEPTH, reverb->flModulationDepth); alEffectf(effect, AL_EAXREVERB_AIR_ABSORPTION_GAINHF, reverb->flAirAbsorptionGainHF); alEffectf(effect, AL_EAXREVERB_HFREFERENCE, reverb->flHFReference); alEffectf(effect, AL_EAXREVERB_LFREFERENCE, reverb->flLFReference); alEffectf(effect, AL_EAXREVERB_ROOM_ROLLOFF_FACTOR, reverb->flRoomRolloffFactor); alEffecti(effect, AL_EAXREVERB_DECAY_HFLIMIT, reverb->iDecayHFLimit); /* Check if an error occured, and return failure if so. */ if((err=alGetError()) != AL_NO_ERROR) { fprintf(stderr, "Error setting up reverb: %s\n", alGetString(err)); return 0; } return 1; } /* LoadBuffer loads the named audio file into an OpenAL buffer object, and * returns the new buffer ID. */ static ALuint LoadSound(const char *filename) { Sound_Sample *sample; ALenum err, format; ALuint buffer; Uint32 slen; /* Open the audio file */ sample = Sound_NewSampleFromFile(filename, NULL, 65536); if(!sample) { fprintf(stderr, "Could not open audio in %s\n", filename); return 0; } /* Get the sound format, and figure out the OpenAL format */ if(sample->actual.channels == 1) { if(sample->actual.format == AUDIO_U8) format = AL_FORMAT_MONO8; else if(sample->actual.format == AUDIO_S16SYS) format = AL_FORMAT_MONO16; else { fprintf(stderr, "Unsupported sample format: 0x%04x\n", sample->actual.format); Sound_FreeSample(sample); return 0; } } else if(sample->actual.channels == 2) { if(sample->actual.format == AUDIO_U8) format = AL_FORMAT_STEREO8; else if(sample->actual.format == AUDIO_S16SYS) format = AL_FORMAT_STEREO16; else { fprintf(stderr, "Unsupported sample format: 0x%04x\n", sample->actual.format); Sound_FreeSample(sample); return 0; } } else { fprintf(stderr, "Unsupported channel count: %d\n", sample->actual.channels); Sound_FreeSample(sample); return 0; } /* Decode the whole audio stream to a buffer. */ slen = Sound_DecodeAll(sample); if(!sample->buffer || slen == 0) { fprintf(stderr, "Failed to read audio from %s\n", filename); Sound_FreeSample(sample); return 0; } /* Buffer the audio data into a new buffer object, then free the data and * close the file. */ buffer = 0; alGenBuffers(1, &buffer); alBufferData(buffer, format, sample->buffer, slen, sample->actual.rate); Sound_FreeSample(sample); /* Check if an error occured, and clean up if so. */ err = alGetError(); if(err != AL_NO_ERROR) { fprintf(stderr, "OpenAL Error: %s\n", alGetString(err)); if(buffer && alIsBuffer(buffer)) alDeleteBuffers(1, &buffer); return 0; } return buffer; } /* Helper to calculate the dot-product of the two given vectors. */ static ALfloat dot_product(const ALfloat vec0[3], const ALfloat vec1[3]) { return vec0[0]*vec1[0] + vec0[1]*vec1[1] + vec0[2]*vec1[2]; } int main(int argc, char **argv) { static const int MaxTransitions = 8; EFXEAXREVERBPROPERTIES reverb0 = EFX_REVERB_PRESET_CASTLE_LARGEROOM; EFXEAXREVERBPROPERTIES reverb1 = EFX_REVERB_PRESET_CASTLE_LONGPASSAGE; struct timespec basetime; ALCdevice *device = NULL; ALCcontext *context = NULL; ALuint effects[2] = { 0, 0 }; ALuint slots[2] = { 0, 0 }; ALuint direct_filter = 0; ALuint buffer = 0; ALuint source = 0; ALCint num_sends = 0; ALenum state = AL_INITIAL; ALfloat direct_gain = 1.0f; int loops = 0; /* Print out usage if no arguments were specified */ if(argc < 2) { fprintf(stderr, "Usage: %s [-device ] [options] \n\n" "Options:\n" "\t-nodirect\tSilence direct path output (easier to hear reverb)\n\n", argv[0]); return 1; } /* Initialize OpenAL, and check for EFX support with at least 2 auxiliary * sends (if multiple sends are supported, 2 are provided by default; if * you want more, you have to request it through alcCreateContext). */ argv++; argc--; if(InitAL(&argv, &argc) != 0) return 1; while(argc > 0) { if(strcmp(argv[0], "-nodirect") == 0) direct_gain = 0.0f; else break; argv++; argc--; } if(argc < 1) { fprintf(stderr, "No filename spacified.\n"); CloseAL(); return 1; } context = alcGetCurrentContext(); device = alcGetContextsDevice(context); if(!alcIsExtensionPresent(device, "ALC_EXT_EFX")) { fprintf(stderr, "Error: EFX not supported\n"); CloseAL(); return 1; } num_sends = 0; alcGetIntegerv(device, ALC_MAX_AUXILIARY_SENDS, 1, &num_sends); if(alcGetError(device) != ALC_NO_ERROR || num_sends < 2) { fprintf(stderr, "Error: Device does not support multiple sends (got %d, need 2)\n", num_sends); CloseAL(); return 1; } /* Define a macro to help load the function pointers. */ #define LOAD_PROC(x) ((x) = alGetProcAddress(#x)) LOAD_PROC(alGenFilters); LOAD_PROC(alDeleteFilters); LOAD_PROC(alIsFilter); LOAD_PROC(alFilteri); LOAD_PROC(alFilteriv); LOAD_PROC(alFilterf); LOAD_PROC(alFilterfv); LOAD_PROC(alGetFilteri); LOAD_PROC(alGetFilteriv); LOAD_PROC(alGetFilterf); LOAD_PROC(alGetFilterfv); LOAD_PROC(alGenEffects); LOAD_PROC(alDeleteEffects); LOAD_PROC(alIsEffect); LOAD_PROC(alEffecti); LOAD_PROC(alEffectiv); LOAD_PROC(alEffectf); LOAD_PROC(alEffectfv); LOAD_PROC(alGetEffecti); LOAD_PROC(alGetEffectiv); LOAD_PROC(alGetEffectf); LOAD_PROC(alGetEffectfv); LOAD_PROC(alGenAuxiliaryEffectSlots); LOAD_PROC(alDeleteAuxiliaryEffectSlots); LOAD_PROC(alIsAuxiliaryEffectSlot); LOAD_PROC(alAuxiliaryEffectSloti); LOAD_PROC(alAuxiliaryEffectSlotiv); LOAD_PROC(alAuxiliaryEffectSlotf); LOAD_PROC(alAuxiliaryEffectSlotfv); LOAD_PROC(alGetAuxiliaryEffectSloti); LOAD_PROC(alGetAuxiliaryEffectSlotiv); LOAD_PROC(alGetAuxiliaryEffectSlotf); LOAD_PROC(alGetAuxiliaryEffectSlotfv); #undef LOAD_PROC /* Initialize SDL_sound. */ Sound_Init(); /* Load the sound into a buffer. */ buffer = LoadSound(argv[0]); if(!buffer) { CloseAL(); Sound_Quit(); return 1; } /* Generate two effects for two "zones", and load a reverb into each one. * Note that unlike single-zone reverb, where you can store one effect per * preset, for multi-zone reverb you should have one effect per environment * instance, or one per audible zone. This is because we'll be changing the * effects' properties in real-time based on the environment instance * relative to the listener. */ alGenEffects(2, effects); if(!LoadEffect(effects[0], &reverb0) || !LoadEffect(effects[1], &reverb1)) { alDeleteEffects(2, effects); alDeleteBuffers(1, &buffer); Sound_Quit(); CloseAL(); return 1; } /* Create the effect slot objects, one for each "active" effect. */ alGenAuxiliaryEffectSlots(2, slots); /* Tell the effect slots to use the loaded effect objects, with slot 0 for * Zone 0 and slot 1 for Zone 1. Note that this effectively copies the * effect properties. Modifying or deleting the effect object afterward * won't directly affect the effect slot until they're reapplied like this. */ alAuxiliaryEffectSloti(slots[0], AL_EFFECTSLOT_EFFECT, effects[0]); alAuxiliaryEffectSloti(slots[1], AL_EFFECTSLOT_EFFECT, effects[1]); assert(alGetError()==AL_NO_ERROR && "Failed to set effect slot"); /* For the purposes of this example, prepare a filter that optionally * silences the direct path which allows us to hear just the reverberation. * A filter like this is normally used for obstruction, where the path * directly between the listener and source is blocked (the exact * properties depending on the type and thickness of the obstructing * material). */ alGenFilters(1, &direct_filter); alFilteri(direct_filter, AL_FILTER_TYPE, AL_FILTER_LOWPASS); alFilterf(direct_filter, AL_LOWPASS_GAIN, direct_gain); assert(alGetError()==AL_NO_ERROR && "Failed to set direct filter"); /* Create the source to play the sound with. */ source = 0; alGenSources(1, &source); alSourcei(source, AL_LOOPING, AL_TRUE); alSourcei(source, AL_DIRECT_FILTER, direct_filter); alSourcei(source, AL_BUFFER, buffer); /* Connect the source to the effect slots. Here, we connect source send 0 * to Zone 0's slot, and send 1 to Zone 1's slot. Filters can be specified * to occlude the source from each zone by varying amounts; for example, a * source within a particular zone would be unfiltered, while a source that * can only see a zone through a window may be attenuated for that zone. */ alSource3i(source, AL_AUXILIARY_SEND_FILTER, slots[0], 0, AL_FILTER_NULL); alSource3i(source, AL_AUXILIARY_SEND_FILTER, slots[1], 1, AL_FILTER_NULL); assert(alGetError()==AL_NO_ERROR && "Failed to setup sound source"); /* Get the current time as the base for timing in the main loop. */ altimespec_get(&basetime, AL_TIME_UTC); loops = 0; printf("Transition %d of %d...\n", loops+1, MaxTransitions); /* Play the sound for a while. */ alSourcePlay(source); do { /* Individual reverb zones are connected via "portals". Each portal has * a position (center point of the connecting area), a normal (facing * direction), and a radius (approximate size of the connecting area). * For this example it also has movement velocity, although normally it * would be the listener that moves relative to the portal instead of * the portal itself. */ const ALfloat portal_pos[3] = { -10.0f, 0.0f, 0.0f }; const ALfloat portal_norm[3] = { 1.0f, 0.0f, 0.0f }; const ALfloat portal_vel[3] = { 5.0f, 0.0f, 0.0f }; const ALfloat portal_radius = 2.5f; ALfloat other_dir[3], this_dir[3]; ALfloat local_norm[3]; ALfloat local_dir[3]; ALfloat local_radius; ALfloat dist, timediff; struct timespec curtime; /* Start a batch update, to ensure all changes apply simultaneously. */ alcSuspendContext(context); /* Get the current time to track the amount of time that passed. * Convert the difference to seconds. */ altimespec_get(&curtime, AL_TIME_UTC); timediff = (ALfloat)(curtime.tv_sec - basetime.tv_sec); timediff += (ALfloat)(curtime.tv_nsec - basetime.tv_nsec) / 1000000000.0f; /* Avoid negative time deltas, in case of non-monotonic clocks. */ if(timediff < 0.0f) timediff = 0.0f; else while(timediff >= 4.0f) { /* For this example, each transition occurs over 4 seconds. * Decrease the delta and increase the base time to start a new * transition. */ timediff -= 4.0f; basetime.tv_sec += 4; if(++loops < MaxTransitions) printf("Transition %d of %d...\n", loops+1, MaxTransitions); } /* Move the portal according to the amount of time passed. local_dir * represents the listener-relative point to the adjacent zone. */ local_dir[0] = portal_pos[0] + portal_vel[0]*timediff; local_dir[1] = portal_pos[1] + portal_vel[1]*timediff; local_dir[2] = portal_pos[2] + portal_vel[2]*timediff; /* A normal application would also rotate the portal's normal given the * listener orientation, to get the listener-relative normal. * * For this example, the portal is always head-on but every other * transition negates the normal. This effectively simulates a * different portal moving in closer than the last one that faces the * other way, switching the old adjacent zone to a new one. */ local_norm[0] = portal_norm[0] * ((loops&1) ? -1.0f : 1.0f); local_norm[1] = portal_norm[1] * ((loops&1) ? -1.0f : 1.0f); local_norm[2] = portal_norm[2] * ((loops&1) ? -1.0f : 1.0f); /* Calculate the distance from the listener to the portal. */ dist = sqrtf(dot_product(local_dir, local_dir)); if(!(dist > 0.00001f)) { /* We're practically in the center of the portal. Give the panning * vectors a 50/50 split, with Zone 0 covering the half in front of * the normal, and Zone 1 covering the half behind. */ this_dir[0] = local_norm[0] / 2.0f; this_dir[1] = local_norm[1] / 2.0f; this_dir[2] = local_norm[2] / 2.0f; other_dir[0] = local_norm[0] / -2.0f; other_dir[1] = local_norm[1] / -2.0f; other_dir[2] = local_norm[2] / -2.0f; alEffectf(effects[0], AL_EAXREVERB_GAIN, reverb0.flGain); alEffectfv(effects[0], AL_EAXREVERB_REFLECTIONS_PAN, this_dir); alEffectfv(effects[0], AL_EAXREVERB_LATE_REVERB_PAN, this_dir); alEffectf(effects[1], AL_EAXREVERB_GAIN, reverb1.flGain); alEffectfv(effects[1], AL_EAXREVERB_REFLECTIONS_PAN, other_dir); alEffectfv(effects[1], AL_EAXREVERB_LATE_REVERB_PAN, other_dir); } else { const EFXEAXREVERBPROPERTIES *other_reverb; const EFXEAXREVERBPROPERTIES *this_reverb; ALuint other_effect, this_effect; ALfloat spread, attn; /* Normalize the direction to the portal. */ local_dir[0] /= dist; local_dir[1] /= dist; local_dir[2] /= dist; /* Scale the radius according to its local angle. The visibility to * the other zone reduces as the portal becomes perpendicular. */ local_radius = portal_radius * fabsf(dot_product(local_dir, local_norm)); /* Calculate distance attenuation for the other zone, using the * standard inverse distance model with the radius as a reference. */ attn = local_radius / dist; if(attn > 1.0f) attn = 1.0f; /* Calculate the 'spread' of the portal, which is the amount of * coverage the other zone has around the listener. */ spread = atan2f(local_radius, dist) / (ALfloat)M_PI; /* Figure out which zone we're in, given the direction to the * portal and its normal. */ if(dot_product(local_dir, local_norm) <= 0.0f) { /* We're in front of the portal, so we're in Zone 0. */ this_effect = effects[0]; other_effect = effects[1]; this_reverb = &reverb0; other_reverb = &reverb1; } else { /* We're behind the portal, so we're in Zone 1. */ this_effect = effects[1]; other_effect = effects[0]; this_reverb = &reverb1; other_reverb = &reverb0; } /* Scale the other zone's panning vector down as the portal's * spread increases, so that it envelops the listener more. */ other_dir[0] = local_dir[0] * (1.0f-spread); other_dir[1] = local_dir[1] * (1.0f-spread); other_dir[2] = local_dir[2] * (1.0f-spread); /* Pan the current zone to the opposite direction of the portal, * and take the remaining percentage of the portal's spread. */ this_dir[0] = local_dir[0] * -spread; this_dir[1] = local_dir[1] * -spread; this_dir[2] = local_dir[2] * -spread; /* Now set the effects' panning vectors and distance attenuation. */ alEffectf(this_effect, AL_EAXREVERB_GAIN, this_reverb->flGain); alEffectfv(this_effect, AL_EAXREVERB_REFLECTIONS_PAN, this_dir); alEffectfv(this_effect, AL_EAXREVERB_LATE_REVERB_PAN, this_dir); alEffectf(other_effect, AL_EAXREVERB_GAIN, other_reverb->flGain * attn); alEffectfv(other_effect, AL_EAXREVERB_REFLECTIONS_PAN, other_dir); alEffectfv(other_effect, AL_EAXREVERB_LATE_REVERB_PAN, other_dir); } /* Finally, update the effect slots with the updated effect parameters, * and finish the update batch. */ alAuxiliaryEffectSloti(slots[0], AL_EFFECTSLOT_EFFECT, effects[0]); alAuxiliaryEffectSloti(slots[1], AL_EFFECTSLOT_EFFECT, effects[1]); alcProcessContext(context); al_nssleep(10000000); alGetSourcei(source, AL_SOURCE_STATE, &state); } while(alGetError() == AL_NO_ERROR && state == AL_PLAYING && loops < MaxTransitions); /* All done. Delete resources, and close down SDL_sound and OpenAL. */ alDeleteSources(1, &source); alDeleteAuxiliaryEffectSlots(2, slots); alDeleteEffects(2, effects); alDeleteFilters(1, &direct_filter); alDeleteBuffers(1, &buffer); Sound_Quit(); CloseAL(); return 0; }