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