OpenAL tutorial

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DATE: Nov. 12, 2013, 2:48 a.m.

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  1. //http://www.youtube.com/user/thecplusplusguy
  2. //Playing 3D sound with OpenAL, and loading a wav file manually
  3. #include <iostream>
  4. #include <fstream>
  5. #include <cstring>
  6. #include <AL/al.h>
  7. #include <AL/alc.h>
  8. #include <SDL/SDL.h>
  10. bool isBigEndian()
  11. {
  12. int a=1;
  13. return !((char*)&a)[0];
  14. }
  16. int convertToInt(char* buffer,int len)
  17. {
  18. int a=0;
  19. if(!isBigEndian())
  20. for(int i=0;i<len;i++)
  21. ((char*)&a)[i]=buffer[i];
  22. else
  23. for(int i=0;i<len;i++)
  24. ((char*)&a)[3-i]=buffer[i];
  25. return a;
  26. }
  28. char* loadWAV(const char* fn,int& chan,int& samplerate,int& bps,int& size)
  29. {
  30. char buffer[4];
  31. std::ifstream in(fn,std::ios::binary);
  32. in.read(buffer,4);
  33. if(strncmp(buffer,"RIFF",4)!=0)
  34. {
  35. std::cout << "this is not a valid WAVE file" << std::endl;
  36. return NULL;
  37. }
  38. in.read(buffer,4);
  39. in.read(buffer,4); //WAVE
  40. in.read(buffer,4); //fmt
  41. in.read(buffer,4); //16
  42. in.read(buffer,2); //1
  43. in.read(buffer,2);
  44. chan=convertToInt(buffer,2);
  45. in.read(buffer,4);
  46. samplerate=convertToInt(buffer,4);
  47. in.read(buffer,4);
  48. in.read(buffer,2);
  49. in.read(buffer,2);
  50. bps=convertToInt(buffer,2);
  51. in.read(buffer,4); //data
  52. in.read(buffer,4);
  53. size=convertToInt(buffer,4);
  54. char* data=new char[size];
  55. in.read(data,size);
  56. return data;
  57. }
  59. int main(int argc,char** argv)
  60. {
  61. int channel,sampleRate,bps,size;
  62. char* data=loadWAV("test.wav",channel,sampleRate,bps,size);
  63. ALCdevice* device=alcOpenDevice(NULL);
  64. if(device==NULL)
  65. {
  66. std::cout << "cannot open sound card" << std::endl;
  67. return 0;
  68. }
  69. ALCcontext* context=alcCreateContext(device,NULL);
  70. if(context==NULL)
  71. {
  72. std::cout << "cannot open context" << std::endl;
  73. return 0;
  74. }
  75. alcMakeContextCurrent(context);
  77. unsigned int bufferid,format;
  78. alGenBuffers(1,&bufferid);
  79. if(channel==1)
  80. {
  81. if(bps==8)
  82. {
  83. format=AL_FORMAT_MONO8;
  84. }else{
  85. format=AL_FORMAT_MONO16;
  86. }
  87. }else{
  88. if(bps==8)
  89. {
  90. format=AL_FORMAT_STEREO8;
  91. }else{
  92. format=AL_FORMAT_STEREO16;
  93. }
  94. }
  95. alBufferData(bufferid,format,data,size,sampleRate);
  96. unsigned int sourceid;
  97. alGenSources(1,&sourceid);
  98. alSourcei(sourceid,AL_BUFFER,bufferid);
  99. SDL_Init(SDL_INIT_EVERYTHING);
  100. SDL_Surface* screen=SDL_SetVideoMode(640,480,32,SDL_SWSURFACE);
  101. SDL_Event event;
  102. Uint32 start;
  103. bool running;
  104. bool b[4]={0,0,0,0};
  105. float x=0,z=0;
  106. while(running)
  107. {
  108. start=SDL_GetTicks();
  109. while(SDL_PollEvent(&event))
  110. {
  111. switch(event.type)
  112. {
  113. case SDL_QUIT:
  114. running=false;
  115. break;
  116. case SDL_KEYDOWN:
  117. switch(event.key.keysym.sym)
  118. {
  119. case SDLK_UP:
  120. b[0]=true;
  121. break;
  122. case SDLK_RIGHT:
  123. b[1]=true;
  124. break;
  125. case SDLK_DOWN:
  126. b[2]=true;
  127. break;
  128. case SDLK_LEFT:
  129. b[3]=true;
  130. break;
  131. case SDLK_SPACE:
  132. alSourcePlay(sourceid);
  133. break;
  134. }
  135. break;
  136. case SDL_KEYUP:
  137. switch(event.key.keysym.sym)
  138. {
  139. case SDLK_UP:
  140. b[0]=false;
  141. break;
  142. case SDLK_RIGHT:
  143. b[1]=false;
  144. break;
  145. case SDLK_DOWN:
  146. b[2]=false;
  147. break;
  148. case SDLK_LEFT:
  149. b[3]=false;
  150. break;
  151. }
  152. break;
  153. }
  154. }
  156. if(b[0])
  157. z+=0.3;
  158. if(b[1])
  159. x+=0.3;
  160. if(b[2])
  161. z-=0.3;
  162. if(b[3])
  163. x-=0.3;
  164. alSource3f(sourceid,AL_POSITION,x,0,z);
  165. alSourcei(sourceid,AL_LOOPING,AL_TRUE);
  168. float f[]={1,0,0,0,1,0};
  169. alListenerfv(AL_ORIENTATION,f);
  172. if(1000/30.0>SDL_GetTicks()-start)
  173. SDL_Delay(1000/30.0-(SDL_GetTicks()-start));
  174. }
  176. alDeleteSources(1,&sourceid);
  177. alDeleteBuffers(1,&bufferid);
  179. alcDestroyContext(context);
  180. alcCloseDevice(device);
  181. delete[] data;
  182. return 0;
  183. }
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