examples/alhrtf.c

   1 /*
   2  * OpenAL HRTF Example
   3  *
   4  * Copyright (c) 2015 by Chris Robinson <chris.kcat@gmail.com>
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24
  25 /* This file contains an example for selecting an HRTF. */
  26
  27 #include <assert.h>
  28 #include <inttypes.h>
  29 #include <limits.h>
  30 #include <math.h>
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33 #include <string.h>
  34
  35 #include "sndfile.h"
  36
  37 #include "AL/al.h"
  38 #include "AL/alc.h"
  39 #include "AL/alext.h"
  40
  41 #include "common/alhelpers.h"
  42
  43
  44 #ifndef M_PI
  45 #define M_PI                         (3.14159265358979323846)
  46 #endif
  47
  48 static LPALCGETSTRINGISOFT alcGetStringiSOFT;
  49 static LPALCRESETDEVICESOFT alcResetDeviceSOFT;
  50
  51 /* LoadBuffer loads the named audio file into an OpenAL buffer object, and
  52  * returns the new buffer ID.
  53  */
  54 static ALuint LoadSound(const char *filename)
  55 {
  56     ALenum err, format;
  57     ALuint buffer;
  58     SNDFILE *sndfile;
  59     SF_INFO sfinfo;
  60     short *membuf;
  61     sf_count_t num_frames;
  62     ALsizei num_bytes;
  63
  64     /* Open the audio file and check that it's usable. */
  65     sndfile = sf_open(filename, SFM_READ, &sfinfo);
  66     if(!sndfile)
  67     {
  68         fprintf(stderr, "Could not open audio in %s: %s\n", filename, sf_strerror(sndfile));
  69         return 0;
  70     }
  71     if(sfinfo.frames < 1 || sfinfo.frames > (sf_count_t)(INT_MAX/sizeof(short))/sfinfo.channels)
  72     {
  73         fprintf(stderr, "Bad sample count in %s (%" PRId64 ")\n", filename, sfinfo.frames);
  74         sf_close(sndfile);
  75         return 0;
  76     }
  77
  78     /* Get the sound format, and figure out the OpenAL format */
  79     format = AL_NONE;
  80     if(sfinfo.channels == 1)
  81         format = AL_FORMAT_MONO16;
  82     else if(sfinfo.channels == 2)
  83         format = AL_FORMAT_STEREO16;
  84     else if(sfinfo.channels == 3)
  85     {
  86         if(sf_command(sndfile, SFC_WAVEX_GET_AMBISONIC, NULL, 0) == SF_AMBISONIC_B_FORMAT)
  87             format = AL_FORMAT_BFORMAT2D_16;
  88     }
  89     else if(sfinfo.channels == 4)
  90     {
  91         if(sf_command(sndfile, SFC_WAVEX_GET_AMBISONIC, NULL, 0) == SF_AMBISONIC_B_FORMAT)
  92             format = AL_FORMAT_BFORMAT3D_16;
  93     }
  94     if(!format)
  95     {
  96         fprintf(stderr, "Unsupported channel count: %d\n", sfinfo.channels);
  97         sf_close(sndfile);
  98         return 0;
  99     }
 100
 101     /* Decode the whole audio file to a buffer. */
 102     membuf = malloc((size_t)(sfinfo.frames * sfinfo.channels) * sizeof(short));
 103
 104     num_frames = sf_readf_short(sndfile, membuf, sfinfo.frames);
 105     if(num_frames < 1)
 106     {
 107         free(membuf);
 108         sf_close(sndfile);
 109         fprintf(stderr, "Failed to read samples in %s (%" PRId64 ")\n", filename, num_frames);
 110         return 0;
 111     }
 112     num_bytes = (ALsizei)(num_frames * sfinfo.channels) * (ALsizei)sizeof(short);
 113
 114     /* Buffer the audio data into a new buffer object, then free the data and
 115      * close the file.
 116      */
 117     buffer = 0;
 118     alGenBuffers(1, &buffer);
 119     alBufferData(buffer, format, membuf, num_bytes, sfinfo.samplerate);
 120
 121     free(membuf);
 122     sf_close(sndfile);
 123
 124     /* Check if an error occured, and clean up if so. */
 125     err = alGetError();
 126     if(err != AL_NO_ERROR)
 127     {
 128         fprintf(stderr, "OpenAL Error: %s\n", alGetString(err));
 129         if(buffer && alIsBuffer(buffer))
 130             alDeleteBuffers(1, &buffer);
 131         return 0;
 132     }
 133
 134     return buffer;
 135 }
 136
 137
 138 int main(int argc, char **argv)
 139 {
 140     ALCdevice *device;
 141     ALCcontext *context;
 142     ALboolean has_angle_ext;
 143     ALuint source, buffer;
 144     const char *soundname;
 145     const char *hrtfname;
 146     ALCint hrtf_state;
 147     ALCint num_hrtf;
 148     ALdouble angle;
 149     ALenum state;
 150
 151     /* Print out usage if no arguments were specified */
 152     if(argc < 2)
 153     {
 154         fprintf(stderr, "Usage: %s [-device <name>] [-hrtf <name>] <soundfile>\n", argv[0]);
 155         return 1;
 156     }
 157
 158     /* Initialize OpenAL, and check for HRTF support. */
 159     argv++; argc--;
 160     if(InitAL(&argv, &argc) != 0)
 161         return 1;
 162
 163     context = alcGetCurrentContext();
 164     device = alcGetContextsDevice(context);
 165     if(!alcIsExtensionPresent(device, "ALC_SOFT_HRTF"))
 166     {
 167         fprintf(stderr, "Error: ALC_SOFT_HRTF not supported\n");
 168         CloseAL();
 169         return 1;
 170     }
 171
 172     /* Define a macro to help load the function pointers. */
 173 #define LOAD_PROC(d, T, x)  ((x) = FUNCTION_CAST(T, alcGetProcAddress((d), #x)))
 174     LOAD_PROC(device, LPALCGETSTRINGISOFT, alcGetStringiSOFT);
 175     LOAD_PROC(device, LPALCRESETDEVICESOFT, alcResetDeviceSOFT);
 176 #undef LOAD_PROC
 177
 178     /* Check for the AL_EXT_STEREO_ANGLES extension to be able to also rotate
 179      * stereo sources.
 180      */
 181     has_angle_ext = alIsExtensionPresent("AL_EXT_STEREO_ANGLES");
 182     printf("AL_EXT_STEREO_ANGLES %sfound\n", has_angle_ext?"":"not ");
 183
 184     /* Check for user-preferred HRTF */
 185     if(strcmp(argv[0], "-hrtf") == 0)
 186     {
 187         hrtfname = argv[1];
 188         soundname = argv[2];
 189     }
 190     else
 191     {
 192         hrtfname = NULL;
 193         soundname = argv[0];
 194     }
 195
 196     /* Enumerate available HRTFs, and reset the device using one. */
 197     alcGetIntegerv(device, ALC_NUM_HRTF_SPECIFIERS_SOFT, 1, &num_hrtf);
 198     if(!num_hrtf)
 199         printf("No HRTFs found\n");
 200     else
 201     {
 202         ALCint attr[5];
 203         ALCint index = -1;
 204         ALCint i;
 205
 206         printf("Available HRTFs:\n");
 207         for(i = 0;i < num_hrtf;i++)
 208         {
 209             const ALCchar *name = alcGetStringiSOFT(device, ALC_HRTF_SPECIFIER_SOFT, i);
 210             printf("    %d: %s\n", i, name);
 211
 212             /* Check if this is the HRTF the user requested. */
 213             if(hrtfname && strcmp(name, hrtfname) == 0)
 214                 index = i;
 215         }
 216
 217         i = 0;
 218         attr[i++] = ALC_HRTF_SOFT;
 219         attr[i++] = ALC_TRUE;
 220         if(index == -1)
 221         {
 222             if(hrtfname)
 223                 printf("HRTF \"%s\" not found\n", hrtfname);
 224             printf("Using default HRTF...\n");
 225         }
 226         else
 227         {
 228             printf("Selecting HRTF %d...\n", index);
 229             attr[i++] = ALC_HRTF_ID_SOFT;
 230             attr[i++] = index;
 231         }
 232         attr[i] = 0;
 233
 234         if(!alcResetDeviceSOFT(device, attr))
 235             printf("Failed to reset device: %s\n", alcGetString(device, alcGetError(device)));
 236     }
 237
 238     /* Check if HRTF is enabled, and show which is being used. */
 239     alcGetIntegerv(device, ALC_HRTF_SOFT, 1, &hrtf_state);
 240     if(!hrtf_state)
 241         printf("HRTF not enabled!\n");
 242     else
 243     {
 244         const ALchar *name = alcGetString(device, ALC_HRTF_SPECIFIER_SOFT);
 245         printf("HRTF enabled, using %s\n", name);
 246     }
 247     fflush(stdout);
 248
 249     /* Load the sound into a buffer. */
 250     buffer = LoadSound(soundname);
 251     if(!buffer)
 252     {
 253         CloseAL();
 254         return 1;
 255     }
 256
 257     /* Create the source to play the sound with. */
 258     source = 0;
 259     alGenSources(1, &source);
 260     alSourcei(source, AL_SOURCE_RELATIVE, AL_TRUE);
 261     alSource3f(source, AL_POSITION, 0.0f, 0.0f, -1.0f);
 262     alSourcei(source, AL_BUFFER, (ALint)buffer);
 263     assert(alGetError()==AL_NO_ERROR && "Failed to setup sound source");
 264
 265     /* Play the sound until it finishes. */
 266     angle = 0.0;
 267     alSourcePlay(source);
 268     do {
 269         al_nssleep(10000000);
 270
 271         alcSuspendContext(context);
 272
 273         /* Rotate the source around the listener by about 1/4 cycle per second,
 274          * and keep it within -pi...+pi.
 275          */
 276         angle += 0.01 * M_PI * 0.5;
 277         if(angle > M_PI)
 278             angle -= M_PI*2.0;
 279
 280         /* This only rotates mono sounds. */
 281         alSource3f(source, AL_POSITION, (ALfloat)sin(angle), 0.0f, -(ALfloat)cos(angle));
 282
 283         if(has_angle_ext)
 284         {
 285             /* This rotates stereo sounds with the AL_EXT_STEREO_ANGLES
 286              * extension. Angles are specified counter-clockwise in radians.
 287              */
 288             ALfloat angles[2] = { (ALfloat)(M_PI/6.0 - angle), (ALfloat)(-M_PI/6.0 - angle) };
 289             alSourcefv(source, AL_STEREO_ANGLES, angles);
 290         }
 291         alcProcessContext(context);
 292
 293         alGetSourcei(source, AL_SOURCE_STATE, &state);
 294     } while(alGetError() == AL_NO_ERROR && state == AL_PLAYING);
 295
 296     /* All done. Delete resources, and close down OpenAL. */
 297     alDeleteSources(1, &source);
 298     alDeleteBuffers(1, &buffer);
 299     CloseAL();
 300
 301     return 0;
 302 }