src/demos/rain.cxx

   1 /*
   2  * This program is under the GNU GPL.
   3  * Use at your own risk.
   4  *
   5  * written by David Bucciarelli (humanware@plus.it)
   6  *            Humanware s.r.l.
   7  */
   8
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12 #include <math.h>
  13 #include <time.h>
  14 #include "glut_wrap.h"
  15 #ifndef M_PI
  16 #define M_PI 3.14159265
  17 #endif
  18
  19 #include "particles.h"
  20 extern "C" {
  21 #include "readtex.h"
  22 }
  23
  24 #ifdef _WIN32
  25 #include <windows.h>
  26 #include <mmsystem.h>
  27 #endif
  28
  29 #ifdef XMESA
  30 #include "GL/xmesa.h"
  31 static int fullscreen=1;
  32 #endif
  33
  34 static int WIDTH=640;
  35 static int HEIGHT=480;
  36 static int NUMPART=7500;
  37
  38 #define FRAME 50
  39
  40 static float fogcolor[4]={1.0,1.0,1.0,1.0};
  41
  42 #define DIMP 40.0
  43 #define DIMTP 32.0
  44
  45 static float q[4][3]={
  46   {-DIMP,0.0,-DIMP},
  47   {DIMP,0.0,-DIMP},
  48   {DIMP,0.0,DIMP},
  49   {-DIMP,0.0,DIMP}
  50 };
  51
  52 static float qt[4][2]={
  53   {-DIMTP,-DIMTP},
  54   {DIMTP,-DIMTP},
  55   {DIMTP,DIMTP},
  56   {-DIMTP,DIMTP}
  57 };
  58
  59 static int win=0;
  60
  61 static int fog=1;
  62 static int help=1;
  63
  64 static GLuint groundid;
  65
  66 static float obs[3]={2.0,1.0,0.0};
  67 static float dir[3];
  68 static float v=0.0;
  69 static float alpha=-90.0;
  70 static float beta=90.0;
  71
  72 static particleSystem *ps;
  73
  74 static float gettime()
  75 {
  76   static clock_t told=0;
  77   clock_t tnew,ris;
  78
  79   tnew=clock();
  80
  81   ris=tnew-told;
  82
  83   told=tnew;
  84
  85   return(ris/(float)CLOCKS_PER_SEC);
  86 }
  87
  88 static float gettimerain()
  89 {
  90   static clock_t told=0;
  91   clock_t tnew,ris;
  92
  93   tnew=clock();
  94
  95   ris=tnew-told;
  96
  97   told=tnew;
  98
  99   return(ris/(float)CLOCKS_PER_SEC);
 100 }
 101
 102 static void calcposobs(void)
 103 {
 104   dir[0]=sin(alpha*M_PI/180.0);
 105   dir[2]=cos(alpha*M_PI/180.0)*sin(beta*M_PI/180.0);
 106   dir[1]=cos(beta*M_PI/180.0);
 107
 108   obs[0]+=v*dir[0];
 109   obs[1]+=v*dir[1];
 110   obs[2]+=v*dir[2];
 111
 112   rainParticle::setRainingArea(obs[0]-7.0f,-0.2f,obs[2]-7.0f,obs[0]+7.0f,8.0f,obs[2]+7.0f);
 113 }
 114
 115 static void printstring(void *font, const char *string)
 116 {
 117   int len,i;
 118
 119   len=(int)strlen(string);
 120   for(i=0;i<len;i++)
 121     glutBitmapCharacter(font,string[i]);
 122 }
 123
 124 static void reshape(int width, int height)
 125 {
 126   WIDTH=width;
 127   HEIGHT=height;
 128   glViewport(0,0,(GLint)width,(GLint)height);
 129   glMatrixMode(GL_PROJECTION);
 130   glLoadIdentity();
 131   gluPerspective(70.0,width/(float)height,0.1,30.0);
 132
 133   glMatrixMode(GL_MODELVIEW);
 134 }
 135
 136 static void printhelp(void)
 137 {
 138   glEnable(GL_BLEND);
 139   glColor4f(0.0,0.0,0.0,0.5);
 140   glRecti(40,40,600,440);
 141   glDisable(GL_BLEND);
 142
 143   glColor3f(1.0,0.0,0.0);
 144   glRasterPos2i(300,420);
 145   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"Help");
 146
 147   glRasterPos2i(60,390);
 148   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"h - Toggle Help");
 149
 150   glRasterPos2i(60,360);
 151   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"f - Toggle Fog");
 152   glRasterPos2i(60,330);
 153   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"Arrow Keys - Rotate");
 154   glRasterPos2i(60,300);
 155   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"a - Increase velocity");
 156   glRasterPos2i(60,270);
 157   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"z - Decrease velocity");
 158   glRasterPos2i(60,240);
 159   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"l - Increase rain length");
 160   glRasterPos2i(60,210);
 161   printstring(GLUT_BITMAP_TIMES_ROMAN_24,"k - Decrease rain length");
 162 }
 163
 164 static void drawrain(void)
 165 {
 166   static int count=0;
 167   static char frbuf[80];
 168   float fr;
 169
 170   glEnable(GL_DEPTH_TEST);
 171
 172   if(fog)
 173     glEnable(GL_FOG);
 174   else
 175     glDisable(GL_FOG);
 176
 177   glDepthMask(GL_TRUE);
 178   glClearColor(1.0,1.0,1.0,1.0);
 179   glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
 180
 181   glPushMatrix();
 182   calcposobs();
 183   gluLookAt(obs[0],obs[1],obs[2],
 184             obs[0]+dir[0],obs[1]+dir[1],obs[2]+dir[2],
 185             0.0,1.0,0.0);
 186
 187   glColor4f(1.0,1.0,1.0,1.0);
 188
 189   glEnable(GL_TEXTURE_2D);
 190
 191   glBindTexture(GL_TEXTURE_2D,groundid);
 192   glBegin(GL_QUADS);
 193   glTexCoord2fv(qt[0]);
 194   glVertex3fv(q[0]);
 195   glTexCoord2fv(qt[1]);
 196   glVertex3fv(q[1]);
 197   glTexCoord2fv(qt[2]);
 198   glVertex3fv(q[2]);
 199   glTexCoord2fv(qt[3]);
 200   glVertex3fv(q[3]);
 201   glEnd();
 202
 203   // Particle System
 204
 205   glDisable(GL_TEXTURE_2D);
 206   glShadeModel(GL_SMOOTH);
 207   glEnable(GL_BLEND);
 208
 209   ps->draw();
 210   ps->addTime(gettimerain());
 211
 212   glShadeModel(GL_FLAT);
 213
 214
 215   if((count % FRAME)==0) {
 216     fr=gettime();
 217     sprintf(frbuf,"Frame rate: %f",FRAME/fr);
 218   }
 219
 220   glDisable(GL_TEXTURE_2D);
 221   glDisable(GL_DEPTH_TEST);
 222   glDisable(GL_FOG);
 223
 224   glMatrixMode(GL_PROJECTION);
 225   glLoadIdentity();
 226   glOrtho(-0.5,639.5,-0.5,479.5,-1.0,1.0);
 227   glMatrixMode(GL_MODELVIEW);
 228   glLoadIdentity();
 229
 230   glColor3f(1.0,0.0,0.0);
 231   glRasterPos2i(10,10);
 232   printstring(GLUT_BITMAP_HELVETICA_18,frbuf);
 233   glRasterPos2i(350,470);
 234   printstring(GLUT_BITMAP_HELVETICA_10,"Rain V1.0 Written by David Bucciarelli (humanware@plus.it)");
 235
 236   if(help)
 237     printhelp();
 238
 239   reshape(WIDTH,HEIGHT);
 240   glPopMatrix();
 241
 242   glutSwapBuffers();
 243
 244   count++;
 245 }
 246
 247
 248 static void special(int key, int x, int y)
 249 {
 250   switch (key) {
 251   case GLUT_KEY_LEFT:
 252     alpha+=2.0;
 253     break;
 254   case GLUT_KEY_RIGHT:
 255     alpha-=2.0;
 256     break;
 257   case GLUT_KEY_DOWN:
 258     beta-=2.0;
 259     break;
 260   case GLUT_KEY_UP:
 261     beta+=2.0;
 262     break;
 263   }
 264 }
 265
 266 static void key(unsigned char key, int x, int y)
 267 {
 268   switch (key) {
 269   case 27:
 270     exit(0);
 271     break;
 272
 273   case 'a':
 274     v+=0.01;
 275     break;
 276   case 'z':
 277     v-=0.01;
 278     break;
 279
 280   case 'l':
 281     rainParticle::setLength(rainParticle::getLength()+0.025f);
 282     break;
 283   case 'k':
 284     rainParticle::setLength(rainParticle::getLength()-0.025f);
 285     break;
 286
 287   case 'h':
 288     help=(!help);
 289     break;
 290   case 'f':
 291     fog=(!fog);
 292     break;
 293 #ifdef XMESA
 294   case ' ':
 295     XMesaSetFXmode(fullscreen ? XMESA_FX_FULLSCREEN : XMESA_FX_WINDOW);
 296     fullscreen=(!fullscreen);
 297     break;
 298 #endif
 299   }
 300 }
 301
 302 static void inittextures(void)
 303 {
 304   GLubyte *img;
 305   GLint width,height;
 306   GLenum format;
 307   GLenum gluerr;
 308
 309   glGenTextures(1,&groundid);
 310   glBindTexture(GL_TEXTURE_2D,groundid);
 311
 312   if(!(img=LoadRGBImage(DEMOS_DATA_DIR "s128.rgb",
 313                         &width,&height,&format))){
 314         fprintf(stderr,"Error reading a texture.\n");
 315         exit(-1);
 316   }
 317   glPixelStorei(GL_UNPACK_ALIGNMENT,4);
 318   if((gluerr=(GLenum)gluBuild2DMipmaps(GL_TEXTURE_2D, 3, width, height,GL_RGB,
 319                                GL_UNSIGNED_BYTE, (GLvoid *)(img)))) {
 320     fprintf(stderr,"GLULib%s\n",gluErrorString(gluerr));
 321     exit(-1);
 322   }
 323
 324   glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S,GL_REPEAT);
 325   glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T,GL_REPEAT);
 326
 327   glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR);
 328   glTexParameterf(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
 329
 330   glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_DECAL);
 331 }
 332
 333 static void initparticle(void)
 334 {
 335   ps=new particleSystem;
 336
 337   rainParticle::setRainingArea(-7.0f,-0.2f,-7.0f,7.0f,8.0f,7.0f);
 338
 339   for(int i=0;i<NUMPART;i++) {
 340     rainParticle *p=new rainParticle;
 341     p->randomHeight();
 342
 343     ps->addParticle((particle *)p);
 344   }
 345 }
 346
 347 int main(int ac,char **av)
 348 {
 349   fprintf(stderr,"Rain V1.0\nWritten by David Bucciarelli (humanware@plus.it)\n");
 350
 351   /* Default settings */
 352
 353   WIDTH=640;
 354   HEIGHT=480;
 355
 356   glutInitWindowPosition(0,0);
 357   glutInitWindowSize(WIDTH,HEIGHT);
 358   glutInit(&ac,av);
 359
 360   glutInitDisplayMode(GLUT_RGB|GLUT_DEPTH|GLUT_DOUBLE);
 361
 362   if(!(win=glutCreateWindow("Rain"))) {
 363     fprintf(stderr,"Error opening a window.\n");
 364     exit(-1);
 365   }
 366
 367   reshape(WIDTH,HEIGHT);
 368
 369   inittextures();
 370
 371   glShadeModel(GL_FLAT);
 372   glEnable(GL_DEPTH_TEST);
 373
 374   glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
 375
 376   glEnable(GL_FOG);
 377   glFogi(GL_FOG_MODE,GL_EXP);
 378   glFogfv(GL_FOG_COLOR,fogcolor);
 379   glFogf(GL_FOG_DENSITY,0.1);
 380 #ifdef FX
 381   glHint(GL_FOG_HINT,GL_NICEST);
 382 #endif
 383
 384   initparticle();
 385
 386   glutKeyboardFunc(key);
 387   glutSpecialFunc(special);
 388   glutDisplayFunc(drawrain);
 389   glutIdleFunc(drawrain);
 390   glutReshapeFunc(reshape);
 391   glutMainLoop();
 392
 393   return(0);
 394 }