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
main(int,char **)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) = (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 }
303