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          fflush(stdout);
  83          T0 = t;
  84          Frames = 0;
  85       }
  86    }
  87 }
  88
  89
  90 static void Reshape( int width, int height )
  91 {
  92    glViewport( 0, 0, width, height );
  93    glMatrixMode( GL_PROJECTION );
  94    glLoadIdentity();
  95    glFrustum( -1.0, 1.0, -1.0, 1.0, 10.0, 100.0 );
  96    glMatrixMode( GL_MODELVIEW );
  97    glLoadIdentity();
  98    glTranslatef( 0.0, 0.0, -70.0 );
  99 }
 100
 101
 102 static void SetMode(GLuint m)
 103 {
 104    /* disable everything */
 105    glDisable(GL_LIGHTING);
 106    glDisable(GL_TEXTURE_2D);
 107    glDisable(GL_TEXTURE_GEN_S);
 108    glDisable(GL_TEXTURE_GEN_T);
 109
 110    /* enable what's needed */
 111    if (m==LIT) {
 112       glEnable(GL_LIGHTING);
 113    }
 114    else if (m==TEXTURED) {
 115       glEnable(GL_TEXTURE_2D);
 116    }
 117    else if (m==REFLECT) {
 118       glEnable(GL_TEXTURE_2D);
 119       glEnable(GL_TEXTURE_GEN_S);
 120       glEnable(GL_TEXTURE_GEN_T);
 121    }
 122 }
 123
 124
 125 static void ModeMenu(int entry)
 126 {
 127    if (entry==ANIMATE) {
 128       Animate = !Animate;
 129       if (Animate)
 130          glutIdleFunc(Idle);
 131       else
 132          glutIdleFunc(NULL);
 133    }
 134    else if (entry==POINT_FILTER) {
 135       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 136       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 137    }
 138    else if (entry==LINEAR_FILTER) {
 139       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 140       glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 141    }
 142    else if (entry==QUIT) {
 143       exit(0);
 144    }
 145    else {
 146       SetMode(entry);
 147    }
 148    glutPostRedisplay();
 149 }
 150
 151
 152 static void Key( unsigned char key, int x, int y )
 153 {
 154    (void) x;
 155    (void) y;
 156    switch (key) {
 157       case ' ':
 158       Animate = !Animate;
 159       if (Animate)
 160          glutIdleFunc(Idle);
 161       else
 162          glutIdleFunc(NULL);
 163       break;
 164       case 27:
 165          glutDestroyWindow(Win);
 166          exit(0);
 167          break;
 168    }
 169    glutPostRedisplay();
 170 }
 171
 172
 173 static void SpecialKey( int key, int x, int y )
 174 {
 175    float step = 3.0;
 176    (void) x;
 177    (void) y;
 178
 179    switch (key) {
 180       case GLUT_KEY_UP:
 181          Xrot += step;
 182          break;
 183       case GLUT_KEY_DOWN:
 184          Xrot -= step;
 185          break;
 186       case GLUT_KEY_LEFT:
 187          Yrot += step;
 188          break;
 189       case GLUT_KEY_RIGHT:
 190          Yrot -= step;
 191          break;
 192    }
 193    glutPostRedisplay();
 194 }
 195
 196
 197 static void Init( int argc, char *argv[] )
 198 {
 199    GLUquadricObj *q = gluNewQuadric();
 200    CylinderObj = glGenLists(1);
 201    glNewList(CylinderObj, GL_COMPILE);
 202
 203    glTranslatef(0.0, 0.0, -1.0);
 204
 205    /* cylinder */
 206    gluQuadricNormals(q, GL_SMOOTH);
 207    gluQuadricTexture(q, GL_TRUE);
 208    gluCylinder(q, 0.6, 0.6, 2.0, 24, 1);
 209
 210    /* end cap */
 211    glTranslatef(0.0, 0.0, 2.0);
 212    gluDisk(q, 0.0, 0.6, 24, 1);
 213
 214    /* other end cap */
 215    glTranslatef(0.0, 0.0, -2.0);
 216    gluQuadricOrientation(q, GLU_INSIDE);
 217    gluDisk(q, 0.0, 0.6, 24, 1);
 218
 219    glEndList();
 220    gluDeleteQuadric(q);
 221
 222    /* lighting */
 223    glEnable(GL_LIGHTING);
 224    {
 225       GLfloat gray[4] = {0.2, 0.2, 0.2, 1.0};
 226       GLfloat white[4] = {1.0, 1.0, 1.0, 1.0};
 227       GLfloat teal[4] = { 0.0, 1.0, 0.8, 1.0 };
 228       glMaterialfv(GL_FRONT, GL_DIFFUSE, teal);
 229       glLightfv(GL_LIGHT0, GL_AMBIENT, gray);
 230       glLightfv(GL_LIGHT0, GL_DIFFUSE, white);
 231       glEnable(GL_LIGHT0);
 232    }
 233
 234    /* fitering = nearest, initially */
 235    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 236    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 237
 238    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
 239    glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_FASTEST);
 240
 241    glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
 242    glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
 243
 244    if (!LoadRGBMipmaps(TEXTURE_FILE, GL_RGB)) {
 245       printf("Error: couldn't load texture image\n");
 246       exit(1);
 247    }
 248
 249    glEnable(GL_CULL_FACE);  /* don't need Z testing for convex objects */
 250
 251    SetMode(LIT);
 252
 253    if (argc > 1 && strcmp(argv[1], "-info")==0) {
 254       printf("GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
 255       printf("GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
 256       printf("GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
 257       printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
 258    }
 259 }
 260
 261
 262 int main( int argc, char *argv[] )
 263 {
 264    glutInit( &argc, argv );
 265    glutInitWindowSize( 400, 400 );
 266    glutInitWindowPosition( 0, 0 );
 267
 268    glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
 269
 270    Win = glutCreateWindow(argv[0] );
 271
 272    Init(argc, argv);
 273
 274    glutReshapeFunc( Reshape );
 275    glutKeyboardFunc( Key );
 276    glutSpecialFunc( SpecialKey );
 277    glutDisplayFunc( Display );
 278    glutIdleFunc( Idle );
 279
 280    glutCreateMenu(ModeMenu);
 281    glutAddMenuEntry("Lit", LIT);
 282    glutAddMenuEntry("Textured", TEXTURED);
 283    glutAddMenuEntry("Reflect", REFLECT);
 284    glutAddMenuEntry("Point Filtered", POINT_FILTER);
 285    glutAddMenuEntry("Linear Filtered", LINEAR_FILTER);
 286    glutAddMenuEntry("Toggle Animation", ANIMATE);
 287    glutAddMenuEntry("Quit", QUIT);
 288    glutAttachMenu(GLUT_RIGHT_BUTTON);
 289
 290    glutMainLoop();
 291    return 0;
 292 }