progs/demos/texcyl.c

   1
   2 /*
   3  * Textured cylinder demo: lighting, texturing, reflection mapping.
   4  *
   5  * Command line options:
   6  *    -info      print GL implementation information
   7  *
   8  *
   9  * Brian Paul  May 1997  This program is in the public domain.
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <math.h>
  15 #include <string.h>
  16 #include <GL/glut.h>
  17
  18 #include "readtex.h"
  19
  20 #define TEXTURE_FILE "../images/reflect.rgb"
  21
  22 #define LIT 1
  23 #define TEXTURED 2
  24 #define REFLECT 3
  25 #define ANIMATE 10
  26 #define POINT_FILTER 20
  27 #define LINEAR_FILTER 21
  28 #define QUIT 100
  29
  30 static GLint Win = -1;
  31
  32 static GLuint CylinderObj = 0;
  33 static GLboolean Animate = GL_TRUE;
  34
  35 static GLfloat Xrot = 0.0, Yrot = 0.0, Zrot = 0.0;
  36 static GLfloat DXrot = 50.0, DYrot = 125.0;
  37
  38 /* performance info */
  39 static GLint T0 = 0;
  40 static GLint Frames = 0;
  41
  42
  43 static void Idle( void )
  44 {
  45    static double t0 = -1.;
  46    double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
  47    if (t0 < 0.0)
  48       t0 = t;
  49    dt = t - t0;
  50    t0 = t;
  51
  52    if (Animate) {
  53       Xrot += DXrot * dt;
  54       Yrot += DYrot * dt;
  55       glutPostRedisplay();
  56    }
  57 }
  58
  59
  60 static void Display( void )
  61 {
  62    glClear( GL_COLOR_BUFFER_BIT );
  63
  64    glPushMatrix();
  65    glRotatef(Xrot, 1.0, 0.0, 0.0);
  66    glRotatef(Yrot, 0.0, 1.0, 0.0);
  67    glRotatef(Zrot, 0.0, 0.0, 1.0);
  68    glScalef(5.0, 5.0, 5.0);
  69    glCallList(CylinderObj);
  70
  71    glPopMatrix();
  72
  73    glutSwapBuffers();
  74
  75    if (Animate) {
  76       GLint t = glutGet(GLUT_ELAPSED_TIME);
  77       Frames++;
  78       if (t - T0 >= 5000) {
  79          GLfloat seconds = (t - T0) / 1000.0;
  80          GLfloat fps = Frames / seconds;
  81          printf("%d frames in %g seconds = %g FPS\n", Frames, seconds, fps);
  82          T0 = t;
  83          Frames = 0;
  84       }
  85    }
  86 }
  87
  88
  89 static void Reshape( int width, int height )
  90 {
  91    glViewport( 0, 0, width, height );
  92    glMatrixMode( GL_PROJECTION );
  93    glLoadIdentity();
  94    glFrustum( -1.0, 1.0, -1.0, 1.0, 10.0, 100.0 );
  95    glMatrixMode( GL_MODELVIEW );
  96    glLoadIdentity();
  97    glTranslatef( 0.0, 0.0, -70.0 );
  98 }
  99
 100
 101 static void SetMode(GLuint m)
 102 {
 103    /* disable everything */
 104    glDisable(GL_LIGHTING);
 105    glDisable(GL_TEXTURE_2D);
 106    glDisable(GL_TEXTURE_GEN_S);
 107    glDisable(GL_TEXTURE_GEN_T);
 108
 109    /* enable what's needed */
 110    if (m==LIT) {
 111       glEnable(GL_LIGHTING);
 112    }
 113    else if (m==TEXTURED) {
 114       glEnable(GL_TEXTURE_2D);
 115    }
 116    else if (m==REFLECT) {
 117       glEnable(GL_TEXTURE_2D);
 118       glEnable(GL_TEXTURE_GEN_S);
 119       glEnable(GL_TEXTURE_GEN_T);
 120    }
 121 }
 122
 123
 124 static void ModeMenu(int entry)
 125 {
 126    if (entry==ANIMATE) {
 127       Animate = !Animate;
 128       if (Animate)
 129          glutIdleFunc(Idle);
 130       else
 131          glutIdleFunc(NULL);
 132    }
 133    else if (entry==POINT_FILTER) {
 134       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 135       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 136    }
 137    else if (entry==LINEAR_FILTER) {
 138       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 139       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 140    }
 141    else if (entry==QUIT) {
 142       exit(0);
 143    }
 144    else {
 145       SetMode(entry);
 146    }
 147    glutPostRedisplay();
 148 }
 149
 150
 151 static void Key( unsigned char key, int x, int y )
 152 {
 153    (void) x;
 154    (void) y;
 155    switch (key) {
 156       case ' ':
 157       Animate = !Animate;
 158       if (Animate)
 159          glutIdleFunc(Idle);
 160       else
 161          glutIdleFunc(NULL);
 162       break;
 163       case 27:
 164          glutDestroyWindow(Win);
 165          exit(0);
 166          break;
 167    }
 168    glutPostRedisplay();
 169 }
 170
 171
 172 static void SpecialKey( int key, int x, int y )
 173 {
 174    float step = 3.0;
 175    (void) x;
 176    (void) y;
 177
 178    switch (key) {
 179       case GLUT_KEY_UP:
 180          Xrot += step;
 181          break;
 182       case GLUT_KEY_DOWN:
 183          Xrot -= step;
 184          break;
 185       case GLUT_KEY_LEFT:
 186          Yrot += step;
 187          break;
 188       case GLUT_KEY_RIGHT:
 189          Yrot -= step;
 190          break;
 191    }
 192    glutPostRedisplay();
 193 }
 194
 195
 196 static void Init( int argc, char *argv[] )
 197 {
 198    GLUquadricObj *q = gluNewQuadric();
 199    CylinderObj = glGenLists(1);
 200    glNewList(CylinderObj, GL_COMPILE);
 201
 202    glTranslatef(0.0, 0.0, -1.0);
 203
 204    /* cylinder */
 205    gluQuadricNormals(q, GL_SMOOTH);
 206    gluQuadricTexture(q, GL_TRUE);
 207    gluCylinder(q, 0.6, 0.6, 2.0, 24, 1);
 208
 209    /* end cap */
 210    glTranslatef(0.0, 0.0, 2.0);
 211    gluDisk(q, 0.0, 0.6, 24, 1);
 212
 213    /* other end cap */
 214    glTranslatef(0.0, 0.0, -2.0);
 215    gluQuadricOrientation(q, GLU_INSIDE);
 216    gluDisk(q, 0.0, 0.6, 24, 1);
 217
 218    glEndList();
 219    gluDeleteQuadric(q);
 220
 221    /* lighting */
 222    glEnable(GL_LIGHTING);
 223    {
 224       GLfloat gray[4] = {0.2, 0.2, 0.2, 1.0};
 225       GLfloat white[4] = {1.0, 1.0, 1.0, 1.0};
 226       GLfloat teal[4] = { 0.0, 1.0, 0.8, 1.0 };
 227       glMaterialfv(GL_FRONT, GL_DIFFUSE, teal);
 228       glLightfv(GL_LIGHT0, GL_AMBIENT, gray);
 229       glLightfv(GL_LIGHT0, GL_DIFFUSE, white);
 230       glEnable(GL_LIGHT0);
 231    }
 232
 233    /* fitering = nearest, initially */
 234    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 235    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 236
 237    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
 238    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST);
 239
 240    glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
 241    glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
 242
 243    if (!LoadRGBMipmaps(TEXTURE_FILE, GL_RGB)) {
 244       printf("Error: couldn't load texture image\n");
 245       exit(1);
 246    }
 247
 248    glEnable(GL_CULL_FACE);  /* don't need Z testing for convex objects */
 249
 250    SetMode(LIT);
 251
 252    if (argc > 1 && strcmp(argv[1], "-info")==0) {
 253       printf("GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
 254       printf("GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
 255       printf("GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
 256       printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
 257    }
 258 }
 259
 260
 261 int main( int argc, char *argv[] )
 262 {
 263    glutInit( &argc, argv );
 264    glutInitWindowSize( 400, 400 );
 265    glutInitWindowPosition( 0, 0 );
 266
 267    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 268
 269    Win = glutCreateWindow(argv[0] );
 270
 271    Init(argc, argv);
 272
 273    glutReshapeFunc( Reshape );
 274    glutKeyboardFunc( Key );
 275    glutSpecialFunc( SpecialKey );
 276    glutDisplayFunc( Display );
 277    glutIdleFunc( Idle );
 278
 279    glutCreateMenu(ModeMenu);
 280    glutAddMenuEntry("Lit", LIT);
 281    glutAddMenuEntry("Textured", TEXTURED);
 282    glutAddMenuEntry("Reflect", REFLECT);
 283    glutAddMenuEntry("Point Filtered", POINT_FILTER);
 284    glutAddMenuEntry("Linear Filtered", LINEAR_FILTER);
 285    glutAddMenuEntry("Toggle Animation", ANIMATE);
 286    glutAddMenuEntry("Quit", QUIT);
 287    glutAttachMenu(GLUT_RIGHT_BUTTON);
 288
 289    glutMainLoop();
 290    return 0;
 291 }