1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/org/hearing.org	Sat Feb 04 03:38:05 2012 -0700
     1.3 @@ -0,0 +1,949 @@
     1.4 +#+title: Simulated Sense of Hearing
     1.5 +#+author: Robert McIntyre
     1.6 +#+email: rlm@mit.edu
     1.7 +#+description: Simulating multiple listeners and the sense of hearing in jMonkeyEngine3
     1.8 +#+keywords: simulated hearing, openal, clojure, jMonkeyEngine3, LWJGL, AI
     1.9 +#+SETUPFILE: ../../aurellem/org/setup.org
    1.10 +#+INCLUDE: ../../aurellem/org/level-0.org
    1.11 +#+BABEL: :exports both :noweb yes :cache no :mkdirp yes
    1.12 +
    1.13 +* Hearing
    1.14 +
    1.15 +I want to be able to place ears in a similar manner to how I place
    1.16 +the eyes.  I want to be able to place ears in a unique spatial
    1.17 +position, and receive as output at every tick the F.F.T. of whatever
    1.18 +signals are happening at that point.
    1.19 +
    1.20 +Hearing is one of the more difficult senses to simulate, because there
    1.21 +is less support for obtaining the actual sound data that is processed
    1.22 +by jMonkeyEngine3.
    1.23 +
    1.24 +jMonkeyEngine's sound system works as follows:
    1.25 +
    1.26 + - jMonkeyEngine uses the =AppSettings= for the particular application
    1.27 +   to determine what sort of =AudioRenderer= should be used.
    1.28 + - although some support is provided for multiple AudioRendering
    1.29 +   backends, jMonkeyEngine at the time of this writing will either
    1.30 +   pick no AudioRenderer at all, or the =LwjglAudioRenderer=
    1.31 + - jMonkeyEngine tries to figure out what sort of system you're
    1.32 +   running and extracts the appropriate native libraries.
    1.33 + - the =LwjglAudioRenderer= uses the [[http://lwjgl.org/][=LWJGL=]] (LightWeight Java Game
    1.34 +   Library) bindings to interface with a C library called [[http://kcat.strangesoft.net/openal.html][=OpenAL=]]
    1.35 + - =OpenAL= calculates the 3D sound localization and feeds a stream of
    1.36 +   sound to any of various sound output devices with which it knows
    1.37 +   how to communicate.
    1.38 +
    1.39 +A consequence of this is that there's no way to access the actual
    1.40 +sound data produced by =OpenAL=.  Even worse, =OpenAL= only supports
    1.41 +one /listener/, which normally isn't a problem for games, but becomes
    1.42 +a problem when trying to make multiple AI creatures that can each hear
    1.43 +the world from a different perspective.
    1.44 +
    1.45 +To make many AI creatures in jMonkeyEngine that can each hear the
    1.46 +world from their own perspective, it is necessary to go all the way
    1.47 +back to =OpenAL= and implement support for simulated hearing there.
    1.48 +
    1.49 +* Extending =OpenAL=
    1.50 +** =OpenAL= Devices
    1.51 +   
    1.52 +=OpenAL= goes to great lengths to support many different systems, all
    1.53 +with different sound capabilities and interfaces.  It accomplishes this
    1.54 +difficult task by providing code for many different sound backends in
    1.55 +pseudo-objects called /Devices/.  There's a device for the Linux Open
    1.56 +Sound System and the Advanced Linux Sound Architecture, there's one
    1.57 +for Direct Sound on Windows, there's even one for Solaris. =OpenAL=
    1.58 +solves the problem of platform independence by providing all these
    1.59 +Devices.
    1.60 +
    1.61 +Wrapper libraries such as LWJGL are free to examine the system on
    1.62 +which they are running and then select an appropriate device for that
    1.63 +system. 
    1.64 +
    1.65 +There are also a few "special" devices that don't interface with any
    1.66 +particular system.  These include the Null Device, which doesn't do
    1.67 +anything, and the Wave Device, which writes whatever sound it receives
    1.68 +to a file, if everything has been set up correctly when configuring
    1.69 +=OpenAL=.
    1.70 +
    1.71 +Actual mixing of the sound data happens in the Devices, and they are
    1.72 +the only point in the sound rendering process where this data is
    1.73 +available. 
    1.74 +
    1.75 +Therefore, in order to support multiple listeners, and get the sound
    1.76 +data in a form that the AIs can use, it is necessary to create a new
    1.77 +Device, which supports this features.
    1.78 +
    1.79 +** The Send Device
    1.80 +Adding a device to OpenAL is rather tricky -- there are five separate
    1.81 +files in the =OpenAL= source tree that must be modified to do so. I've
    1.82 +documented this process [[./add-new-device.org][here]] for anyone who is interested.
    1.83 +
    1.84 +
    1.85 +Onward to that actual Device!
    1.86 +
    1.87 +again, my objectives are:
    1.88 +
    1.89 + - Support Multiple Listeners from jMonkeyEngine3
    1.90 + - Get access to the rendered sound data for further processing from
    1.91 +   clojure.
    1.92 +
    1.93 +** =send.c=
    1.94 +
    1.95 +** Header
    1.96 +#+name: send-header
    1.97 +#+begin_src C
    1.98 +#include "config.h"
    1.99 +#include <stdlib.h>
   1.100 +#include "alMain.h"
   1.101 +#include "AL/al.h"
   1.102 +#include "AL/alc.h"
   1.103 +#include "alSource.h"
   1.104 +#include <jni.h>
   1.105 +
   1.106 +//////////////////// Summary
   1.107 +
   1.108 +struct send_data;
   1.109 +struct context_data;
   1.110 +
   1.111 +static void addContext(ALCdevice *, ALCcontext *);
   1.112 +static void syncContexts(ALCcontext *master, ALCcontext *slave);
   1.113 +static void syncSources(ALsource *master, ALsource *slave, 
   1.114 +			ALCcontext *masterCtx, ALCcontext *slaveCtx);
   1.115 +
   1.116 +static void syncSourcei(ALuint master, ALuint slave,
   1.117 +			ALCcontext *masterCtx, ALCcontext *ctx2, ALenum param);
   1.118 +static void syncSourcef(ALuint master, ALuint slave,
   1.119 +			ALCcontext *masterCtx, ALCcontext *ctx2, ALenum param);
   1.120 +static void syncSource3f(ALuint master, ALuint slave,
   1.121 +			ALCcontext *masterCtx, ALCcontext *ctx2, ALenum param);
   1.122 +
   1.123 +static void swapInContext(ALCdevice *, struct context_data *);
   1.124 +static void saveContext(ALCdevice *, struct context_data *);
   1.125 +static void limitContext(ALCdevice *, ALCcontext *);
   1.126 +static void unLimitContext(ALCdevice *);
   1.127 +
   1.128 +static void init(ALCdevice *);
   1.129 +static void renderData(ALCdevice *, int samples);
   1.130 +
   1.131 +#define UNUSED(x)  (void)(x)
   1.132 +#+end_src
   1.133 +
   1.134 +The main idea behind the Send device is to take advantage of the fact
   1.135 +that LWJGL only manages one /context/ when using OpenAL.  A /context/
   1.136 +is like a container that holds samples and keeps track of where the
   1.137 +listener is.  In order to support multiple listeners, the Send device
   1.138 +identifies the LWJGL context as the master context, and creates any
   1.139 +number of slave contexts to represent additional listeners.  Every
   1.140 +time the device renders sound, it synchronizes every source from the
   1.141 +master LWJGL context to the slave contexts.  Then, it renders each
   1.142 +context separately, using a different listener for each one.  The
   1.143 +rendered sound is made available via JNI to jMonkeyEngine.
   1.144 +
   1.145 +To recap, the process is: 
   1.146 + - Set the LWJGL context as "master" in the =init()= method.
   1.147 + - Create any number of additional contexts via =addContext()=
   1.148 + - At every call to =renderData()= sync the master context with the
   1.149 +   slave contexts with =syncContexts()=
   1.150 + - =syncContexts()= calls =syncSources()= to sync all the sources
   1.151 +   which are in the master context.
   1.152 + - =limitContext()= and =unLimitContext()= make it possible to render
   1.153 +   only one context at a time.
   1.154 +
   1.155 +** Necessary State
   1.156 +#+name: send-state
   1.157 +#+begin_src C
   1.158 +////////////////////  State
   1.159 +
   1.160 +typedef struct context_data {
   1.161 +  ALfloat ClickRemoval[MAXCHANNELS];
   1.162 +  ALfloat PendingClicks[MAXCHANNELS];
   1.163 +  ALvoid *renderBuffer;
   1.164 +  ALCcontext *ctx;
   1.165 +} context_data;
   1.166 +
   1.167 +typedef struct send_data {
   1.168 +  ALuint size;
   1.169 +  context_data **contexts;
   1.170 +  ALuint numContexts;
   1.171 +  ALuint maxContexts;
   1.172 +} send_data;
   1.173 +#+end_src
   1.174 +
   1.175 +Switching between contexts is not the normal operation of a Device,
   1.176 +and one of the problems with doing so is that a Device normally keeps
   1.177 +around a few pieces of state such as the =ClickRemoval= array above
   1.178 +which will become corrupted if the contexts are not done in
   1.179 +parallel. The solution is to create a copy of this normally global
   1.180 +device state for each context, and copy it back and forth into and out
   1.181 +of the actual device state whenever a context is rendered.
   1.182 +
   1.183 +** Synchronization Macros
   1.184 +#+name: sync-macros
   1.185 +#+begin_src C
   1.186 +////////////////////  Context Creation / Synchronization
   1.187 +
   1.188 +#define _MAKE_SYNC(NAME, INIT_EXPR, GET_EXPR, SET_EXPR)	\
   1.189 +  void NAME (ALuint sourceID1, ALuint sourceID2,	\
   1.190 +	     ALCcontext *ctx1, ALCcontext *ctx2,	\
   1.191 +	     ALenum param){				\
   1.192 +    INIT_EXPR;						\
   1.193 +    ALCcontext *current = alcGetCurrentContext();	\
   1.194 +    alcMakeContextCurrent(ctx1);			\
   1.195 +    GET_EXPR;						\
   1.196 +    alcMakeContextCurrent(ctx2);			\
   1.197 +    SET_EXPR;						\
   1.198 +    alcMakeContextCurrent(current);			\
   1.199 +  }
   1.200 +  
   1.201 +#define MAKE_SYNC(NAME, TYPE, GET, SET)			\
   1.202 +  _MAKE_SYNC(NAME,					\
   1.203 +	     TYPE value,				\
   1.204 +             GET(sourceID1, param, &value),		\
   1.205 +             SET(sourceID2, param, value))
   1.206 +  
   1.207 +#define MAKE_SYNC3(NAME, TYPE, GET, SET)				\
   1.208 +  _MAKE_SYNC(NAME,							\
   1.209 +	     TYPE value1; TYPE value2; TYPE value3;,			\
   1.210 +	     GET(sourceID1, param, &value1, &value2, &value3),		\
   1.211 +	     SET(sourceID2, param,  value1,  value2,  value3))
   1.212 +
   1.213 +MAKE_SYNC( syncSourcei,  ALint,   alGetSourcei,  alSourcei);
   1.214 +MAKE_SYNC( syncSourcef,  ALfloat, alGetSourcef,  alSourcef);
   1.215 +MAKE_SYNC3(syncSource3i, ALint,   alGetSource3i, alSource3i);
   1.216 +MAKE_SYNC3(syncSource3f, ALfloat, alGetSource3f, alSource3f);
   1.217 +  
   1.218 +#+end_src
   1.219 +
   1.220 +Setting the state of an =OpenAL= source is done with the =alSourcei=,
   1.221 +=alSourcef=, =alSource3i=, and =alSource3f= functions.  In order to
   1.222 +completely synchronize two sources, it is necessary to use all of
   1.223 +them. These macros help to condense the otherwise repetitive
   1.224 +synchronization code involving these similar low-level =OpenAL= functions.
   1.225 +
   1.226 +** Source Synchronization
   1.227 +#+name: sync-sources
   1.228 +#+begin_src C
   1.229 +void syncSources(ALsource *masterSource, ALsource *slaveSource, 
   1.230 +		 ALCcontext *masterCtx, ALCcontext *slaveCtx){
   1.231 +  ALuint master = masterSource->source;
   1.232 +  ALuint slave = slaveSource->source;
   1.233 +  ALCcontext *current = alcGetCurrentContext();
   1.234 +
   1.235 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_PITCH);
   1.236 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_GAIN);
   1.237 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_MAX_DISTANCE);
   1.238 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_ROLLOFF_FACTOR);
   1.239 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_REFERENCE_DISTANCE);
   1.240 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_MIN_GAIN);
   1.241 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_MAX_GAIN);
   1.242 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_CONE_OUTER_GAIN);
   1.243 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_CONE_INNER_ANGLE);
   1.244 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_CONE_OUTER_ANGLE);
   1.245 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_SEC_OFFSET);
   1.246 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_SAMPLE_OFFSET);
   1.247 +  syncSourcef(master,slave,masterCtx,slaveCtx,AL_BYTE_OFFSET);
   1.248 +    
   1.249 +  syncSource3f(master,slave,masterCtx,slaveCtx,AL_POSITION);
   1.250 +  syncSource3f(master,slave,masterCtx,slaveCtx,AL_VELOCITY);
   1.251 +  syncSource3f(master,slave,masterCtx,slaveCtx,AL_DIRECTION);
   1.252 +  
   1.253 +  syncSourcei(master,slave,masterCtx,slaveCtx,AL_SOURCE_RELATIVE);
   1.254 +  syncSourcei(master,slave,masterCtx,slaveCtx,AL_LOOPING);
   1.255 +
   1.256 +  alcMakeContextCurrent(masterCtx);
   1.257 +  ALint source_type;
   1.258 +  alGetSourcei(master, AL_SOURCE_TYPE, &source_type);
   1.259 +
   1.260 +  // Only static sources are currently synchronized! 
   1.261 +  if (AL_STATIC == source_type){
   1.262 +    ALint master_buffer;
   1.263 +    ALint slave_buffer;
   1.264 +    alGetSourcei(master, AL_BUFFER, &master_buffer);
   1.265 +    alcMakeContextCurrent(slaveCtx);
   1.266 +    alGetSourcei(slave, AL_BUFFER, &slave_buffer);
   1.267 +    if (master_buffer != slave_buffer){
   1.268 +      alSourcei(slave, AL_BUFFER, master_buffer);
   1.269 +    }
   1.270 +  }
   1.271 +  
   1.272 +  // Synchronize the state of the two sources.
   1.273 +  alcMakeContextCurrent(masterCtx);
   1.274 +  ALint masterState;
   1.275 +  ALint slaveState;
   1.276 +
   1.277 +  alGetSourcei(master, AL_SOURCE_STATE, &masterState);
   1.278 +  alcMakeContextCurrent(slaveCtx);
   1.279 +  alGetSourcei(slave, AL_SOURCE_STATE, &slaveState);
   1.280 +
   1.281 +  if (masterState != slaveState){
   1.282 +    switch (masterState){
   1.283 +    case AL_INITIAL : alSourceRewind(slave); break;
   1.284 +    case AL_PLAYING : alSourcePlay(slave);   break;
   1.285 +    case AL_PAUSED  : alSourcePause(slave);  break;
   1.286 +    case AL_STOPPED : alSourceStop(slave);   break;
   1.287 +    }
   1.288 +  }
   1.289 +  // Restore whatever context was previously active.
   1.290 +  alcMakeContextCurrent(current);
   1.291 +}
   1.292 +#+end_src
   1.293 +This function is long because it has to exhaustively go through all the
   1.294 +possible state that a source can have and make sure that it is the
   1.295 +same between the master and slave sources.  I'd like to take this
   1.296 +moment to salute the [[http://connect.creativelabs.com/openal/Documentation/Forms/AllItems.aspx][=OpenAL= Reference Manual]], which provides a very
   1.297 +good description of =OpenAL='s internals.
   1.298 +
   1.299 +** Context Synchronization
   1.300 +#+name: sync-contexts
   1.301 +#+begin_src C
   1.302 +void syncContexts(ALCcontext *master, ALCcontext *slave){
   1.303 +  /* If there aren't sufficient sources in slave to mirror 
   1.304 +     the sources in master, create them. */
   1.305 +  ALCcontext *current = alcGetCurrentContext();
   1.306 +
   1.307 +  UIntMap *masterSourceMap = &(master->SourceMap);
   1.308 +  UIntMap *slaveSourceMap = &(slave->SourceMap);
   1.309 +  ALuint numMasterSources = masterSourceMap->size;
   1.310 +  ALuint numSlaveSources = slaveSourceMap->size;
   1.311 +
   1.312 +  alcMakeContextCurrent(slave);
   1.313 +  if (numSlaveSources < numMasterSources){
   1.314 +    ALuint numMissingSources = numMasterSources - numSlaveSources;
   1.315 +    ALuint newSources[numMissingSources];
   1.316 +    alGenSources(numMissingSources, newSources);
   1.317 +  }
   1.318 +
   1.319 +  /* Now, slave is guaranteed to have at least as many sources
   1.320 +     as master.  Sync each source from master to the corresponding
   1.321 +     source in slave. */
   1.322 +  int i;
   1.323 +  for(i = 0; i < masterSourceMap->size; i++){
   1.324 +    syncSources((ALsource*)masterSourceMap->array[i].value,
   1.325 +		(ALsource*)slaveSourceMap->array[i].value,
   1.326 +		master, slave);
   1.327 +  }
   1.328 +  alcMakeContextCurrent(current);
   1.329 +}
   1.330 +#+end_src
   1.331 +
   1.332 +Most of the hard work in Context Synchronization is done in
   1.333 +=syncSources()=. The only thing that =syncContexts()= has to worry
   1.334 +about is automatically creating new sources whenever a slave context
   1.335 +does not have the same number of sources as the master context.
   1.336 +
   1.337 +** Context Creation
   1.338 +#+name: context-creation
   1.339 +#+begin_src C
   1.340 +static void addContext(ALCdevice *Device, ALCcontext *context){
   1.341 +  send_data *data = (send_data*)Device->ExtraData;
   1.342 +  // expand array if necessary
   1.343 +  if (data->numContexts >= data->maxContexts){
   1.344 +    ALuint newMaxContexts = data->maxContexts*2 + 1;
   1.345 +    data->contexts = realloc(data->contexts, newMaxContexts*sizeof(context_data));
   1.346 +    data->maxContexts = newMaxContexts;
   1.347 +  }
   1.348 +  // create context_data and add it to the main array
   1.349 +  context_data *ctxData;
   1.350 +  ctxData = (context_data*)calloc(1, sizeof(*ctxData));
   1.351 +  ctxData->renderBuffer = 
   1.352 +    malloc(BytesFromDevFmt(Device->FmtType) * 
   1.353 +	   Device->NumChan * Device->UpdateSize);
   1.354 +  ctxData->ctx = context;
   1.355 +
   1.356 +  data->contexts[data->numContexts] = ctxData;
   1.357 +  data->numContexts++;
   1.358 +}
   1.359 +#+end_src
   1.360 +
   1.361 +Here, the slave context is created, and it's data is stored in the
   1.362 +device-wide =ExtraData= structure.  The =renderBuffer= that is created
   1.363 +here is where the rendered sound samples for this slave context will
   1.364 +eventually go.
   1.365 +
   1.366 +** Context Switching
   1.367 +#+name: context-switching
   1.368 +#+begin_src C
   1.369 +////////////////////  Context Switching 
   1.370 +
   1.371 +/* A device brings along with it two pieces of state
   1.372 + * which have to be swapped in and out with each context.
   1.373 + */
   1.374 +static void swapInContext(ALCdevice *Device, context_data *ctxData){
   1.375 +  memcpy(Device->ClickRemoval, ctxData->ClickRemoval, sizeof(ALfloat)*MAXCHANNELS);
   1.376 +  memcpy(Device->PendingClicks, ctxData->PendingClicks, sizeof(ALfloat)*MAXCHANNELS);
   1.377 +}
   1.378 +
   1.379 +static void saveContext(ALCdevice *Device, context_data *ctxData){
   1.380 +  memcpy(ctxData->ClickRemoval, Device->ClickRemoval, sizeof(ALfloat)*MAXCHANNELS);
   1.381 +  memcpy(ctxData->PendingClicks, Device->PendingClicks, sizeof(ALfloat)*MAXCHANNELS);
   1.382 +}  
   1.383 +
   1.384 +static ALCcontext **currentContext;
   1.385 +static ALuint currentNumContext;
   1.386 +
   1.387 +/* By default, all contexts are rendered at once for each call to aluMixData.
   1.388 + * This function uses the internals of the ALCdevice struct to temporally 
   1.389 + * cause aluMixData to only render the chosen context.
   1.390 + */
   1.391 +static void limitContext(ALCdevice *Device, ALCcontext *ctx){
   1.392 +  currentContext  = Device->Contexts;
   1.393 +  currentNumContext  = Device->NumContexts;
   1.394 +  Device->Contexts = &ctx;
   1.395 +  Device->NumContexts = 1;
   1.396 +}
   1.397 +
   1.398 +static void unLimitContext(ALCdevice *Device){
   1.399 +  Device->Contexts = currentContext;
   1.400 +  Device->NumContexts = currentNumContext;
   1.401 +}
   1.402 +#+end_src
   1.403 +
   1.404 +=OpenAL= normally renders all Contexts in parallel, outputting the
   1.405 +whole result to the buffer.  It does this by iterating over the
   1.406 +Device->Contexts array and rendering each context to the buffer in
   1.407 +turn.  By temporally setting Device->NumContexts to 1 and adjusting
   1.408 +the Device's context list to put the desired context-to-be-rendered
   1.409 +into position 0, we can get trick =OpenAL= into rendering each slave
   1.410 +context separate from all the others.
   1.411 +
   1.412 +** Main Device Loop
   1.413 +#+name: main-loop
   1.414 +#+begin_src C
   1.415 +////////////////////   Main Device Loop
   1.416 +
   1.417 +/* Establish the LWJGL context as the master context, which will
   1.418 + * be synchronized to all the slave contexts
   1.419 + */
   1.420 +static void init(ALCdevice *Device){
   1.421 +  ALCcontext *masterContext = alcGetCurrentContext();
   1.422 +  addContext(Device, masterContext);
   1.423 +}
   1.424 +
   1.425 +
   1.426 +static void renderData(ALCdevice *Device, int samples){
   1.427 +  if(!Device->Connected){return;}
   1.428 +  send_data *data = (send_data*)Device->ExtraData;
   1.429 +  ALCcontext *current = alcGetCurrentContext();
   1.430 +
   1.431 +  ALuint i;
   1.432 +  for (i = 1; i < data->numContexts; i++){
   1.433 +    syncContexts(data->contexts[0]->ctx , data->contexts[i]->ctx);
   1.434 +  }
   1.435 +  
   1.436 +  if ((ALuint) samples > Device->UpdateSize){
   1.437 +    printf("exceeding internal buffer size; dropping samples\n");
   1.438 +    printf("requested %d; available %d\n", samples, Device->UpdateSize);
   1.439 +    samples = (int) Device->UpdateSize;
   1.440 +  }
   1.441 +
   1.442 +  for (i = 0; i < data->numContexts; i++){
   1.443 +    context_data *ctxData = data->contexts[i];
   1.444 +    ALCcontext *ctx = ctxData->ctx;
   1.445 +    alcMakeContextCurrent(ctx);
   1.446 +    limitContext(Device, ctx);
   1.447 +    swapInContext(Device, ctxData);
   1.448 +    aluMixData(Device, ctxData->renderBuffer, samples);
   1.449 +    saveContext(Device, ctxData);
   1.450 +    unLimitContext(Device);
   1.451 +  }
   1.452 +  alcMakeContextCurrent(current);
   1.453 +}
   1.454 +#+end_src
   1.455 +
   1.456 +The main loop synchronizes the master LWJGL context with all the slave
   1.457 +contexts, then walks each context, rendering just that context to it's
   1.458 +audio-sample storage buffer.
   1.459 +
   1.460 +** JNI Methods
   1.461 +
   1.462 +At this point, we have the ability to create multiple listeners by
   1.463 +using the master/slave context trick, and the rendered audio data is
   1.464 +waiting patiently in internal buffers, one for each listener.  We need
   1.465 +a way to transport this information to Java, and also a way to drive
   1.466 +this device from Java.  The following JNI interface code is inspired
   1.467 +by the way LWJGL interfaces with =OpenAL=.
   1.468 +
   1.469 +*** step
   1.470 +#+name: jni-step
   1.471 +#+begin_src C
   1.472 +////////////////////   JNI Methods
   1.473 +
   1.474 +#include "com_aurellem_send_AudioSend.h"
   1.475 +
   1.476 +/*
   1.477 + * Class:     com_aurellem_send_AudioSend
   1.478 + * Method:    nstep
   1.479 + * Signature: (JI)V
   1.480 + */
   1.481 +JNIEXPORT void JNICALL Java_com_aurellem_send_AudioSend_nstep
   1.482 +(JNIEnv *env, jclass clazz, jlong device, jint samples){
   1.483 +  UNUSED(env);UNUSED(clazz);UNUSED(device);
   1.484 +  renderData((ALCdevice*)((intptr_t)device), samples);
   1.485 +}
   1.486 +#+end_src
   1.487 +This device, unlike most of the other devices in =OpenAL=, does not
   1.488 +render sound unless asked. This enables the system to slow down or
   1.489 +speed up depending on the needs of the AIs who are using it to
   1.490 +listen.  If the device tried to render samples in real-time, a
   1.491 +complicated AI whose mind takes 100 seconds of computer time to
   1.492 +simulate 1 second of AI-time would miss almost all of the sound in
   1.493 +its environment.
   1.494 +
   1.495 +
   1.496 +*** getSamples
   1.497 +#+name: jni-get-samples
   1.498 +#+begin_src C
   1.499 +/*
   1.500 + * Class:     com_aurellem_send_AudioSend
   1.501 + * Method:    ngetSamples
   1.502 + * Signature: (JLjava/nio/ByteBuffer;III)V
   1.503 + */
   1.504 +JNIEXPORT void JNICALL Java_com_aurellem_send_AudioSend_ngetSamples
   1.505 +(JNIEnv *env, jclass clazz, jlong device, jobject buffer, jint position, 
   1.506 + jint samples, jint n){
   1.507 +  UNUSED(clazz);  
   1.508 +
   1.509 +  ALvoid *buffer_address = 
   1.510 +    ((ALbyte *)(((char*)(*env)->GetDirectBufferAddress(env, buffer)) + position));
   1.511 +  ALCdevice *recorder = (ALCdevice*) ((intptr_t)device);
   1.512 +  send_data *data = (send_data*)recorder->ExtraData;
   1.513 +  if ((ALuint)n > data->numContexts){return;}
   1.514 +  memcpy(buffer_address, data->contexts[n]->renderBuffer, 
   1.515 +	 BytesFromDevFmt(recorder->FmtType) * recorder->NumChan * samples);
   1.516 +}
   1.517 +#+end_src
   1.518 +
   1.519 +This is the transport layer between C and Java that will eventually
   1.520 +allow us to access rendered sound data from clojure.
   1.521 +
   1.522 +*** Listener Management
   1.523 +
   1.524 +=addListener=, =setNthListenerf=, and =setNthListener3f= are
   1.525 +necessary to change the properties of any listener other than the
   1.526 +master one, since only the listener of the current active context is
   1.527 +affected by the normal =OpenAL= listener calls.
   1.528 +#+name: listener-manage
   1.529 +#+begin_src C
   1.530 +/*
   1.531 + * Class:     com_aurellem_send_AudioSend
   1.532 + * Method:    naddListener
   1.533 + * Signature: (J)V
   1.534 + */
   1.535 +JNIEXPORT void JNICALL Java_com_aurellem_send_AudioSend_naddListener
   1.536 +(JNIEnv *env, jclass clazz, jlong device){
   1.537 +  UNUSED(env); UNUSED(clazz);
   1.538 +  //printf("creating new context via naddListener\n");
   1.539 +  ALCdevice *Device = (ALCdevice*) ((intptr_t)device);
   1.540 +  ALCcontext *new = alcCreateContext(Device, NULL);
   1.541 +  addContext(Device, new);
   1.542 +}
   1.543 +
   1.544 +/*
   1.545 + * Class:     com_aurellem_send_AudioSend
   1.546 + * Method:    nsetNthListener3f
   1.547 + * Signature: (IFFFJI)V
   1.548 + */
   1.549 +JNIEXPORT void JNICALL Java_com_aurellem_send_AudioSend_nsetNthListener3f
   1.550 +  (JNIEnv *env, jclass clazz, jint param, 
   1.551 +   jfloat v1, jfloat v2, jfloat v3, jlong device, jint contextNum){
   1.552 +  UNUSED(env);UNUSED(clazz);
   1.553 +
   1.554 +  ALCdevice *Device = (ALCdevice*) ((intptr_t)device);
   1.555 +  send_data *data = (send_data*)Device->ExtraData;
   1.556 +  
   1.557 +  ALCcontext *current = alcGetCurrentContext();
   1.558 +  if ((ALuint)contextNum > data->numContexts){return;}
   1.559 +  alcMakeContextCurrent(data->contexts[contextNum]->ctx);
   1.560 +  alListener3f(param, v1, v2, v3);
   1.561 +  alcMakeContextCurrent(current);
   1.562 +}
   1.563 +
   1.564 +/*
   1.565 + * Class:     com_aurellem_send_AudioSend
   1.566 + * Method:    nsetNthListenerf
   1.567 + * Signature: (IFJI)V
   1.568 + */
   1.569 +JNIEXPORT void JNICALL Java_com_aurellem_send_AudioSend_nsetNthListenerf
   1.570 +(JNIEnv *env, jclass clazz, jint param, jfloat v1, jlong device, 
   1.571 + jint contextNum){
   1.572 +
   1.573 +  UNUSED(env);UNUSED(clazz);
   1.574 +  
   1.575 +  ALCdevice *Device = (ALCdevice*) ((intptr_t)device);
   1.576 +  send_data *data = (send_data*)Device->ExtraData;
   1.577 +  
   1.578 +  ALCcontext *current = alcGetCurrentContext();
   1.579 +  if ((ALuint)contextNum > data->numContexts){return;}
   1.580 +  alcMakeContextCurrent(data->contexts[contextNum]->ctx);
   1.581 +  alListenerf(param, v1);
   1.582 +  alcMakeContextCurrent(current);
   1.583 +}
   1.584 +#+end_src
   1.585 +
   1.586 +*** Initialization
   1.587 +=initDevice= is called from the Java side after LWJGL has created its
   1.588 +context, and before any calls to =addListener=. It establishes the
   1.589 +LWJGL context as the master context.
   1.590 +
   1.591 +=getAudioFormat= is a convenience function that uses JNI to build up a
   1.592 +=javax.sound.sampled.AudioFormat= object from data in the Device. This
   1.593 +way, there is no ambiguity about what the bits created by =step= and
   1.594 +returned by =getSamples= mean.
   1.595 +#+name: jni-init
   1.596 +#+begin_src C
   1.597 +/*
   1.598 + * Class:     com_aurellem_send_AudioSend
   1.599 + * Method:    ninitDevice
   1.600 + * Signature: (J)V
   1.601 + */                     
   1.602 +JNIEXPORT void JNICALL Java_com_aurellem_send_AudioSend_ninitDevice
   1.603 +(JNIEnv *env, jclass clazz, jlong device){
   1.604 +  UNUSED(env);UNUSED(clazz);
   1.605 +  ALCdevice *Device = (ALCdevice*) ((intptr_t)device);
   1.606 +  init(Device);
   1.607 +}
   1.608 +
   1.609 +/*
   1.610 + * Class:     com_aurellem_send_AudioSend
   1.611 + * Method:    ngetAudioFormat
   1.612 + * Signature: (J)Ljavax/sound/sampled/AudioFormat;
   1.613 + */
   1.614 +JNIEXPORT jobject JNICALL Java_com_aurellem_send_AudioSend_ngetAudioFormat
   1.615 +(JNIEnv *env, jclass clazz, jlong device){
   1.616 +  UNUSED(clazz);
   1.617 +  jclass AudioFormatClass = 
   1.618 +    (*env)->FindClass(env, "javax/sound/sampled/AudioFormat");
   1.619 +  jmethodID AudioFormatConstructor = 
   1.620 +    (*env)->GetMethodID(env, AudioFormatClass, "<init>", "(FIIZZ)V");
   1.621 +  
   1.622 +  ALCdevice *Device = (ALCdevice*) ((intptr_t)device);
   1.623 +  int isSigned;
   1.624 +  switch (Device->FmtType)
   1.625 +    {
   1.626 +    case DevFmtUByte: 
   1.627 +    case DevFmtUShort: isSigned = 0; break;  
   1.628 +    default : isSigned = 1;   
   1.629 +    }
   1.630 +  float frequency = Device->Frequency;
   1.631 +  int bitsPerFrame = (8 * BytesFromDevFmt(Device->FmtType));
   1.632 +  int channels = Device->NumChan;
   1.633 +  jobject format = (*env)->
   1.634 +    NewObject(
   1.635 +	      env,AudioFormatClass,AudioFormatConstructor,
   1.636 +	      frequency,
   1.637 +	      bitsPerFrame,
   1.638 +	      channels,
   1.639 +	      isSigned,
   1.640 +	      0);
   1.641 +  return format;
   1.642 +}
   1.643 +#+end_src
   1.644 +
   1.645 +** Boring Device management stuff
   1.646 +This code is more-or-less copied verbatim from the other =OpenAL=
   1.647 +backends. It's the basis for =OpenAL='s primitive object system.
   1.648 +#+name: device-init
   1.649 +#+begin_src C
   1.650 +////////////////////   Device Initialization / Management
   1.651 +
   1.652 +static const ALCchar sendDevice[] = "Multiple Audio Send";
   1.653 +
   1.654 +static ALCboolean send_open_playback(ALCdevice *device, 
   1.655 + const ALCchar *deviceName)
   1.656 +{
   1.657 +  send_data *data;
   1.658 +  // stop any buffering for stdout, so that I can 
   1.659 +  // see the printf statements in my terminal immediately
   1.660 +  setbuf(stdout, NULL);
   1.661 +
   1.662 +  if(!deviceName)
   1.663 +    deviceName = sendDevice;
   1.664 +  else if(strcmp(deviceName, sendDevice) != 0)
   1.665 +    return ALC_FALSE;
   1.666 +  data = (send_data*)calloc(1, sizeof(*data));
   1.667 +  device->szDeviceName = strdup(deviceName);
   1.668 +  device->ExtraData = data;
   1.669 +  return ALC_TRUE;
   1.670 +}
   1.671 +
   1.672 +static void send_close_playback(ALCdevice *device)
   1.673 +{
   1.674 +  send_data *data = (send_data*)device->ExtraData;
   1.675 +  alcMakeContextCurrent(NULL);
   1.676 +  ALuint i;
   1.677 +  // Destroy all slave contexts. LWJGL will take care of 
   1.678 +  // its own context.
   1.679 +  for (i = 1; i < data->numContexts; i++){
   1.680 +    context_data *ctxData = data->contexts[i];
   1.681 +    alcDestroyContext(ctxData->ctx);
   1.682 +    free(ctxData->renderBuffer);
   1.683 +    free(ctxData);
   1.684 +  }
   1.685 +  free(data);
   1.686 +  device->ExtraData = NULL;
   1.687 +}
   1.688 +
   1.689 +static ALCboolean send_reset_playback(ALCdevice *device)
   1.690 +{
   1.691 +  SetDefaultWFXChannelOrder(device);
   1.692 +  return ALC_TRUE;
   1.693 +}
   1.694 +
   1.695 +static void send_stop_playback(ALCdevice *Device){
   1.696 +  UNUSED(Device);
   1.697 +}
   1.698 +
   1.699 +static const BackendFuncs send_funcs = {
   1.700 +  send_open_playback,
   1.701 +  send_close_playback,
   1.702 +  send_reset_playback,
   1.703 +  send_stop_playback,
   1.704 +  NULL,
   1.705 +  NULL,  /* These would be filled with functions to    */
   1.706 +  NULL,  /* handle capturing audio if we we into that  */
   1.707 +  NULL,  /* sort of thing...                           */
   1.708 +  NULL,
   1.709 +  NULL
   1.710 +};
   1.711 +
   1.712 +ALCboolean alc_send_init(BackendFuncs *func_list){
   1.713 +  *func_list = send_funcs;
   1.714 +  return ALC_TRUE;
   1.715 +}
   1.716 +
   1.717 +void alc_send_deinit(void){}
   1.718 +
   1.719 +void alc_send_probe(enum DevProbe type)
   1.720 +{
   1.721 +  switch(type)
   1.722 +    {
   1.723 +    case DEVICE_PROBE:
   1.724 +      AppendDeviceList(sendDevice);
   1.725 +      break;
   1.726 +    case ALL_DEVICE_PROBE:
   1.727 +      AppendAllDeviceList(sendDevice);
   1.728 +      break;
   1.729 +    case CAPTURE_DEVICE_PROBE:
   1.730 +      break;
   1.731 +    }
   1.732 +}
   1.733 +#+end_src
   1.734 +
   1.735 +* The Java interface, =AudioSend=
   1.736 +
   1.737 +The Java interface to the Send Device follows naturally from the JNI
   1.738 +definitions. It is included here for completeness. The only thing here
   1.739 +of note is the =deviceID=. This is available from LWJGL, but to only
   1.740 +way to get it is reflection. Unfortunately, there is no other way to
   1.741 +control the Send device than to obtain a pointer to it.
   1.742 +
   1.743 +#+include: "../java/src/com/aurellem/send/AudioSend.java" src java :exports code
   1.744 +
   1.745 +* Finally, Ears in clojure! 
   1.746 +
   1.747 +Now that the infrastructure is complete (modulo a few patches to
   1.748 +jMonkeyEngine3 to support accessing this modified version of =OpenAL=
   1.749 +that are not worth discussing), the clojure ear abstraction is rather
   1.750 +simple.  Just as there were =SceneProcessors= for vision, there are
   1.751 +now =SoundProcessors= for hearing.
   1.752 +
   1.753 +#+include "../../jmeCapture/src/com/aurellem/capture/audio/SoundProcessor.java" src java 
   1.754 +
   1.755 +
   1.756 +Ears work the same way as vision.
   1.757 +
   1.758 +(hearing creature) will return [init-functions sensor-functions]. The
   1.759 +init functions each take the world and register a SoundProcessor that
   1.760 +does foureier transforms on the incommong sound data, making it
   1.761 +available to each sensor function.
   1.762 +
   1.763 +
   1.764 +#+name: ears
   1.765 +#+begin_src clojure
   1.766 +(ns cortex.hearing
   1.767 +  "Simulate the sense of hearing in jMonkeyEngine3. Enables multiple
   1.768 +  listeners at different positions in the same world. Automatically
   1.769 +  reads ear-nodes from specially prepared blender files and
   1.770 +  instantiates them in the world as actual ears."
   1.771 +  {:author "Robert McIntyre"}
   1.772 +  (:use (cortex world util sense))
   1.773 +  (:use clojure.contrib.def)
   1.774 +  (:import java.nio.ByteBuffer)
   1.775 +  (:import org.tritonus.share.sampled.FloatSampleTools)
   1.776 +  (:import (com.aurellem.capture.audio
   1.777 +            SoundProcessor AudioSendRenderer))
   1.778 +  (:import javax.sound.sampled.AudioFormat)
   1.779 +  (:import (com.jme3.scene Spatial Node))
   1.780 +  (:import com.jme3.audio.Listener)
   1.781 +  (:import com.jme3.app.Application)
   1.782 +  (:import com.jme3.scene.control.AbstractControl))
   1.783 +
   1.784 +(defn sound-processor
   1.785 +  "Deals with converting ByteBuffers into Vectors of floats so that
   1.786 +  the continuation functions can be defined in terms of immutable
   1.787 +  stuff."
   1.788 +  [continuation]
   1.789 +  (proxy [SoundProcessor] []
   1.790 +    (cleanup [])
   1.791 +    (process
   1.792 +      [#^ByteBuffer audioSamples numSamples #^AudioFormat audioFormat]
   1.793 +      (let [bytes  (byte-array numSamples)
   1.794 +            num-floats (/ numSamples  (.getFrameSize audioFormat))
   1.795 +            floats (float-array num-floats)]
   1.796 +        (.get audioSamples bytes 0 numSamples)
   1.797 +        (FloatSampleTools/byte2floatInterleaved
   1.798 +         bytes 0 floats 0 num-floats audioFormat)
   1.799 +        (continuation
   1.800 +         (vec floats))))))
   1.801 +
   1.802 +(defvar 
   1.803 +  ^{:arglists '([creature])}
   1.804 +  ears
   1.805 +  (sense-nodes "ears")
   1.806 +  "Return the children of the creature's \"ears\" node.")
   1.807 +
   1.808 +(defn update-listener-velocity!
   1.809 +  "Update the listener's velocity every update loop."
   1.810 +  [#^Spatial obj #^Listener lis]
   1.811 +  (let [old-position (atom (.getLocation lis))]
   1.812 +    (.addControl
   1.813 +     obj
   1.814 +     (proxy [AbstractControl] []
   1.815 +       (controlUpdate [tpf]
   1.816 +         (let [new-position (.getLocation lis)]
   1.817 +           (.setVelocity
   1.818 +            lis 
   1.819 +            (.mult (.subtract new-position @old-position)
   1.820 +                   (float (/ tpf))))
   1.821 +           (reset! old-position new-position)))
   1.822 +       (controlRender [_ _])))))
   1.823 +
   1.824 +(defn create-listener!  
   1.825 +  "Create a Listener centered on the current position of 'ear 
   1.826 +   which follows the closest physical node in 'creature and 
   1.827 +   sends sound data to 'continuation."
   1.828 +  [#^Application world #^Node creature #^Spatial ear continuation]
   1.829 +  (let [target (closest-node creature ear)
   1.830 +        lis (Listener.)
   1.831 +        audio-renderer (.getAudioRenderer world)
   1.832 +        sp (sound-processor continuation)]
   1.833 +    (.setLocation lis (.getWorldTranslation ear))
   1.834 +    (.setRotation lis (.getWorldRotation ear))
   1.835 +    (bind-sense target lis)
   1.836 +    (update-listener-velocity! target lis)
   1.837 +    (.addListener audio-renderer lis)
   1.838 +    (.registerSoundProcessor audio-renderer lis sp)))
   1.839 +
   1.840 +(defn hearing-fn
   1.841 +  "Returns a functon which returns auditory sensory data when called
   1.842 +   inside a running simulation."
   1.843 +  [#^Node creature #^Spatial ear]
   1.844 +  (let [hearing-data (atom [])
   1.845 +        register-listener!
   1.846 +        (runonce 
   1.847 +         (fn [#^Application world]
   1.848 +           (create-listener!
   1.849 +            world creature ear
   1.850 +            (fn [data]
   1.851 +              (reset! hearing-data (vec data))))))]
   1.852 +    (fn [#^Application world]
   1.853 +      (register-listener! world)
   1.854 +      (let [data @hearing-data
   1.855 +            topology              
   1.856 +            (vec (map #(vector % 0) (range 0 (count data))))
   1.857 +            scaled-data
   1.858 +            (vec
   1.859 +             (map
   1.860 +              #(rem (int (* 255 (/ (+ 1 %) 2)))  256)
   1.861 +              data))]
   1.862 +        [topology scaled-data]))))
   1.863 +    
   1.864 +(defn hearing!
   1.865 +  "Endow the creature in a particular world with the sense of
   1.866 +   hearing. Will return a sequence of functions, one for each ear,
   1.867 +   which when called will return the auditory data from that ear."
   1.868 +  [#^Node creature]
   1.869 +  (for [ear (ears creature)]
   1.870 +    (hearing-fn creature ear)))
   1.871 +
   1.872 +
   1.873 +#+end_src
   1.874 +
   1.875 +* Example
   1.876 +
   1.877 +#+name: test-hearing
   1.878 +#+begin_src clojure :results silent
   1.879 +(ns cortex.test.hearing
   1.880 +  (:use (cortex world util hearing))
   1.881 +  (:import (com.jme3.audio AudioNode Listener))
   1.882 +  (:import com.jme3.scene.Node
   1.883 +	   com.jme3.system.AppSettings))
   1.884 +
   1.885 +(defn setup-fn [world]
   1.886 +  (let [listener (Listener.)]
   1.887 +    (add-ear world listener #(println-repl (nth % 0)))))
   1.888 +  
   1.889 +(defn play-sound [node world value]
   1.890 +  (if (not value)
   1.891 +    (do
   1.892 +      (.playSource (.getAudioRenderer world) node))))
   1.893 +
   1.894 +(defn test-basic-hearing []
   1.895 +   (let [node1 (AudioNode. (asset-manager) "Sounds/pure.wav" false false)]
   1.896 +     (world
   1.897 +      (Node.)
   1.898 +      {"key-space" (partial play-sound node1)}
   1.899 +      setup-fn
   1.900 +      no-op)))
   1.901 +
   1.902 +(defn test-advanced-hearing
   1.903 +  "Testing hearing:
   1.904 +   You should see a blue sphere flying around several
   1.905 +   cubes.  As the sphere approaches each cube, it turns
   1.906 +   green."
   1.907 +  []
   1.908 +  (doto (com.aurellem.capture.examples.Advanced.)
   1.909 +    (.setSettings
   1.910 +     (doto (AppSettings. true)
   1.911 +       (.setAudioRenderer "Send")))
   1.912 +    (.setShowSettings false)
   1.913 +    (.setPauseOnLostFocus false)))
   1.914 +
   1.915 +#+end_src
   1.916 +
   1.917 +This extremely basic program prints out the first sample it encounters
   1.918 +at every time stamp. You can see the rendered sound being printed at
   1.919 +the REPL.
   1.920 +
   1.921 + - As a bonus, this method of capturing audio for AI can also be used
   1.922 +   to capture perfect audio from a jMonkeyEngine application, for use
   1.923 +   in demos and the like.
   1.924 +
   1.925 +
   1.926 +* COMMENT Code Generation
   1.927 +
   1.928 +#+begin_src clojure :tangle ../src/cortex/hearing.clj
   1.929 +<<ears>>
   1.930 +#+end_src
   1.931 +
   1.932 +#+begin_src clojure :tangle ../src/cortex/test/hearing.clj
   1.933 +<<test-hearing>>
   1.934 +#+end_src
   1.935 +
   1.936 +#+begin_src C :tangle ../../audio-send/Alc/backends/send.c
   1.937 +<<send-header>>
   1.938 +<<send-state>>
   1.939 +<<sync-macros>>
   1.940 +<<sync-sources>>
   1.941 +<<sync-contexts>>
   1.942 +<<context-creation>>
   1.943 +<<context-switching>>
   1.944 +<<main-loop>>
   1.945 +<<jni-step>>
   1.946 +<<jni-get-samples>>
   1.947 +<<listener-manage>>
   1.948 +<<jni-init>>
   1.949 +<<device-init>>
   1.950 +#+end_src
   1.951 +
   1.952 +