progs/trivial/dlist-degenerate.c

   1 /**
   2  * Test display list corner cases.
   3  */
   4
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <math.h>
   9 #include <GL/glut.h>
  10
  11
  12 static int Win;
  13 static GLfloat Xrot = 0, Yrot = 0, Zrot = 0;
  14 static GLboolean Anim = GL_FALSE;
  15 static GLuint List1 = 0, List2 = 0;
  16
  17
  18 static void
  19 Idle(void)
  20 {
  21    Xrot += 3.0;
  22    Yrot += 4.0;
  23    Zrot += 2.0;
  24    glutPostRedisplay();
  25 }
  26
  27
  28 static void
  29 Draw(void)
  30 {
  31    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  32
  33    glPushMatrix();
  34    glRotatef(Xrot, 1, 0, 0);
  35    glRotatef(Yrot, 0, 1, 0);
  36    glRotatef(Zrot, 0, 0, 1);
  37
  38    glCallList(List1);
  39    glCallList(List2);
  40
  41    glPopMatrix();
  42
  43    glutSwapBuffers();
  44 }
  45
  46
  47 static void
  48 Reshape(int width, int height)
  49 {
  50    glViewport(0, 0, width, height);
  51    glMatrixMode(GL_PROJECTION);
  52    glLoadIdentity();
  53    glFrustum(-1.0, 1.0, -1.0, 1.0, 5.0, 25.0);
  54    glMatrixMode(GL_MODELVIEW);
  55    glLoadIdentity();
  56    glTranslatef(0.0, 0.0, -15.0);
  57 }
  58
  59
  60 static void
  61 Key(unsigned char key, int x, int y)
  62 {
  63    const GLfloat step = 3.0;
  64    (void) x;
  65    (void) y;
  66    switch (key) {
  67       case 'a':
  68          Anim = !Anim;
  69          if (Anim)
  70             glutIdleFunc(Idle);
  71          else
  72             glutIdleFunc(NULL);
  73          break;
  74       case 'z':
  75          Zrot -= step;
  76          break;
  77       case 'Z':
  78          Zrot += step;
  79          break;
  80       case 27:
  81          glutDestroyWindow(Win);
  82          exit(0);
  83          break;
  84    }
  85    glutPostRedisplay();
  86 }
  87
  88
  89 static void
  90 SpecialKey(int key, int x, int y)
  91 {
  92    const GLfloat step = 3.0;
  93    (void) x;
  94    (void) y;
  95    switch (key) {
  96       case GLUT_KEY_UP:
  97          Xrot -= step;
  98          break;
  99       case GLUT_KEY_DOWN:
 100          Xrot += step;
 101          break;
 102       case GLUT_KEY_LEFT:
 103          Yrot -= step;
 104          break;
 105       case GLUT_KEY_RIGHT:
 106          Yrot += step;
 107          break;
 108    }
 109    glutPostRedisplay();
 110 }
 111
 112
 113 static void
 114 Init(void)
 115 {
 116    /* List1: start of primitive */
 117    List1 = glGenLists(1);
 118    glNewList(List1, GL_COMPILE);
 119      glBegin(GL_POLYGON);
 120      glVertex2f(-1, -1);
 121      glVertex2f( 1, -1);
 122    glEndList();
 123
 124    /* List2: end of primitive */
 125    List2 = glGenLists(1);
 126    glNewList(List2, GL_COMPILE);
 127      glVertex2f( 1, 1);
 128      glVertex2f(-1, 1);
 129      glEnd();
 130    glEndList();
 131
 132    glEnable(GL_DEPTH_TEST);
 133 }
 134
 135
 136 int
 137 main(int argc, char *argv[])
 138 {
 139    glutInit(&argc, argv);
 140    glutInitWindowPosition(0, 0);
 141    glutInitWindowSize(400, 400);
 142    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
 143    Win = glutCreateWindow(argv[0]);
 144    glutReshapeFunc(Reshape);
 145    glutKeyboardFunc(Key);
 146    glutSpecialFunc(SpecialKey);
 147    glutDisplayFunc(Draw);
 148    if (Anim)
 149       glutIdleFunc(Idle);
 150    Init();
 151    glutMainLoop();
 152    return 0;
 153 }