Sound Effects!

-used code from my "PlaySound" project to add audio output to the game
engine
-when objects collide they make a clacking sound

include/audio.h

@@ -0,0 +1,42 @@
+/*  This file is a part of 2DWorld - The Generic 2D Game Engine
+    Copyright (C) 2014  James Nakano
+    2DWorld is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+    2DWorld 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 General Public License for more details.
+    You should have received a copy of the GNU General Public License
+    along with the rest of 2DWorld.  If not, see <http://www.gnu.org/licenses/>.*/
+
+#ifndef AUDIO_H
+#define AUDIO_H
+#ifdef __APPLE__
+#include <OpenAL/al.h>
+#include <OpenAL/alc.h>
+#else
+#include <AL/al.h>
+#include <AL/alc.h>
+#endif
+#include <cstdint>
+#include <fstream>
+
+namespace audio
+{
+extern ALCdevice *device;
+extern ALCcontext *context;
+extern std::ifstream sound_file;
+extern ALuint source;
+extern ALuint buffer;
+extern char* data;
+bool is_big_endian();
+int16_t to_int16(char* buffer, int length);
+int32_t to_int32(char* buffer, int length);
+void load();
+void play();
+void close();
+};
+
+#endif // AUDIO_H

src/audio.cpp

@@ -0,0 +1,166 @@
+/*  This file is a part of 2DWorld - The Generic 2D Game Engine
+    Copyright (C) 2014  James Nakano
+    2DWorld is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+    2DWorld 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 General Public License for more details.
+    You should have received a copy of the GNU General Public License
+    along with the rest of 2DWorld.  If not, see <http://www.gnu.org/licenses/>.*/
+
+#include "audio.h"
+#include <cstdlib>
+#include <cstdio>
+#include <iostream>
+
+std::ifstream audio::sound_file;
+ALCdevice* audio::device;
+ALCcontext* audio::context;
+ALuint audio::source;
+ALuint audio::buffer;
+char* audio::data;
+
+//this function checks endianness
+bool audio::is_big_endian()
+{
+    int i=1;
+    return !((char*)&i)[0];
+}
+
+//this function retrieves the appropriate value according to endianness
+int16_t audio::to_int16(char* buffer, int length)
+{
+    int16_t i=0;
+    if(!is_big_endian())
+        for(int j=0;j<length;j++)
+            ((char*)&i)[j]=buffer[j];
+    else
+        for(int j=0;j<length;j++)
+            ((char*)&i)[3-j]=buffer[j];
+    return i;
+}
+
+//this function retrieves the appropriate value according to endianness
+int32_t audio::to_int32(char* buffer, int length)
+{
+    int32_t i=0;
+    if(!is_big_endian())
+        for(int j=0;j<length;j++)
+            ((char*)&i)[j]=buffer[j];
+    else
+        for(int j=0;j<length;j++)
+            ((char*)&i)[sizeof(int)-1-j]=buffer[j];
+    return i;
+}
+
+void audio::load()
+{
+    char file_info[4];
+    int16_t format_type, channels, byte_sample, bit_sample;
+    int32_t chunk_size, sample_rate, byte_rate, data_size;
+    //open wave file
+    sound_file.open("./audio/collision.wav",std::ios::binary);
+    if(sound_file.bad())
+        std::cerr<<"error opening sound file\n";
+    sound_file.read(file_info,4);
+    //read file information
+    sound_file.read(file_info,4);//"RIFF" label
+    sound_file.read(file_info,4);//"WAVE" label
+    sound_file.read(file_info,4);//"fmt" label
+    sound_file.read(file_info,4);//chunk size
+    chunk_size=to_int32(file_info,4);
+    sound_file.read(file_info,2);//format type
+    format_type=to_int16(file_info,2);
+    sound_file.read(file_info,2);//channels
+    channels=to_int16(file_info,2);
+    sound_file.read(file_info,4);//sample rate
+    sample_rate=to_int32(file_info,4);
+    sound_file.read(file_info,4);//byte rate
+    byte_rate=to_int32(file_info,4);
+    sound_file.read(file_info,2);//byte sample
+    byte_sample=to_int16(file_info,2);
+    sound_file.read(file_info,2);//bit sample
+    bit_sample=to_int16(file_info,2);
+    sound_file.read(file_info,4);//"data" label
+    sound_file.read(file_info,4);//data size
+    data_size=to_int32(file_info,4);
+    data= new char[data_size];//create a buffer to store sound data
+    sound_file.read(data,data_size);//retrieve sound data
+
+    //initialize OpenAL
+    device = alcOpenDevice(NULL);
+    if(!device)
+        std::cerr<<"no sound device\n";
+    context = alcCreateContext(device, NULL);
+    alcMakeContextCurrent(context);
+    if(!context)
+        std::cerr<<"no sound context\n";
+    ALuint format=0;
+    alGenBuffers(1, &buffer);
+    alGenSources(1, &source);
+    if(alGetError() != AL_NO_ERROR)
+        std::cerr<<"error generating source\n";
+
+    //identify wave format
+    if(bit_sample == 8)
+    {
+        if(channels == 1)
+            format = AL_FORMAT_MONO8;
+        else if(channels == 2)
+            format = AL_FORMAT_STEREO8;
+    }
+    else if(bit_sample == 16)
+    {
+        if(channels == 1)
+            format = AL_FORMAT_MONO16;
+        else if(channels == 2)
+            format = AL_FORMAT_STEREO16;
+    }
+    if(!format)
+        std::cerr<<"wrong bit sample\n";
+
+    alBufferData(buffer, format, data, data_size, sample_rate);
+    if(alGetError() != AL_NO_ERROR)
+        std::cerr<<"error loading buffer\n";
+
+    //sound settings
+    ALfloat source_position[] = {0.0, 0.0, 0.0};
+    ALfloat source_velocity[] = {0.0, 0.0, 0.0};
+    ALfloat listener_position[] = {0.0, 0.0, 0.0};
+    ALfloat listener_velocity[] = {0.0, 0.0, 0.0};
+    ALfloat listener_orientation[] = {0.0, 0.0, -1.0, 0.0, 1.0, 0.0};
+
+    //listener
+    alListenerfv(AL_POSITION, listener_position);
+    alListenerfv(AL_VELOCITY, listener_velocity);
+    alListenerfv(AL_ORIENTATION, listener_orientation);
+
+    //source
+    alSourcei(source, AL_BUFFER, buffer);
+    alSourcef(source, AL_PITCH, 1.0f);
+    alSourcef(source, AL_GAIN, 1.0f);
+    alSourcefv(source, AL_POSITION, source_position);
+    alSourcefv(source, AL_VELOCITY, source_velocity);
+    alSourcei(source, AL_LOOPING, AL_FALSE);
+}
+
+void audio::play()
+{
+    alSourcePlay(source);
+    if(alGetError() != AL_NO_ERROR)
+        std::cerr<<"error playing sound\n";
+}
+
+void audio::close()
+{
+    sound_file.close();
+    delete[] data;
+    alDeleteSources(1, &source);
+    alDeleteBuffers(1, &buffer);
+    alcMakeContextCurrent(NULL);
+    alcDestroyContext(context);
+    alcCloseDevice(device);
+}

src/game.cpp

@@ -15,6 +15,7 @@
 #include "window.h"
 #include "controls.h"
 #include "cursor.h"
+#include "audio.h"
 #include "ui.h"
 #include <stdlib.h>
 #include <iostream>
@@ -367,6 +368,8 @@ void game::collision_detection()
             {
                 a.second->identify_touched(*b.second);
                 a.second->repel(*b.second);
+                if(a.second->collided)
+                    audio::play();
             }
         }
     }
@@ -379,6 +382,8 @@ void game::collision_detection()
                 a.second->identify_touched(*b.second);
                 a.second->repel(*b.second);
                 a.second->calc_momentum(*b.second);
+                if(a.second->collided)
+                    audio::play();
             }
         }
     }
@@ -390,6 +395,8 @@ void game::collision_detection()
             {
                 a.second->identify_touched(*b.second);
                 a.second->repel(*b.second);
+                if(a.second->collided)
+                    audio::play();
             }
         }
     }
@@ -616,6 +623,7 @@ void game::quit()
 {
     save_settings();
     std::clog<<"quitting...\n";
+    audio::close();
     exit(0);
 }
 

src/main.cpp

@@ -18,6 +18,7 @@
 #include "window.h"
 #include "game.h"
 #include "controls.h"
+#include "audio.h"
 #ifdef __APPLE__
 #include <OpenGL/gl.h>
 #include <OpenGL/glu.h>
@@ -34,6 +35,7 @@
 
 int main(int argc, char **argv)
 {
+    audio::load();
     std::clog<<"initializing...\n";
     game::initialize();
     game::load_settings();