progs/trivial/quad-clip-nearplane.c

   1 /*
   2  * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
   3  *
   4  * Permission to use, copy, modify, distribute, and sell this software and
   5  * its documentation for any purpose is hereby granted without fee, provided
   6  * that (i) the above copyright notices and this permission notice appear in
   7  * all copies of the software and related documentation, and (ii) the name of
   8  * Silicon Graphics may not be used in any advertising or
   9  * publicity relating to the software without the specific, prior written
  10  * permission of Silicon Graphics.
  11  *
  12  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
  13  * ANY KIND,
  14  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  15  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  16  *
  17  * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
  18  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  19  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  20  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  21  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  22  * OF THIS SOFTWARE.
  23  */
  24
  25 #include <stdio.h>
  26 #include <string.h>
  27 #include <stdlib.h>
  28 #include <GL/glut.h>
  29
  30
  31 #define CI_OFFSET_1 16
  32 #define CI_OFFSET_2 32
  33
  34
  35 GLenum doubleBuffer;
  36 float Z = -6;
  37
  38 static void Init(void)
  39 {
  40    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  41    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  42    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  43
  44    fprintf(stderr, "Press z/Z to translate quad\n");
  45
  46    glClearColor(0.0, 0.0, 1.0, 0.0);
  47 }
  48
  49 static void Reshape(int width, int height)
  50 {
  51     glViewport(0, 0, (GLint)width, (GLint)height);
  52
  53     glMatrixMode(GL_PROJECTION);
  54     glLoadIdentity();
  55     glFrustum(-1.0, 1.0, -1.0, 1.0, 5, 100.0);
  56     glMatrixMode(GL_MODELVIEW);
  57 }
  58
  59 static void Key(unsigned char key, int x, int y)
  60 {
  61     switch (key) {
  62     case 'z':
  63        Z += 0.5;
  64        break;
  65     case 'Z':
  66        Z -= 0.5;
  67        break;
  68     case 27:
  69        exit(1);
  70     default:
  71        return;
  72     }
  73     printf("Z = %f\n", Z);
  74     glutPostRedisplay();
  75 }
  76
  77 static void Draw(void)
  78 {
  79    glClear(GL_COLOR_BUFFER_BIT);
  80
  81    glPushMatrix();
  82    glTranslatef(0, -0.5, Z);
  83
  84    glBegin(GL_QUADS);
  85    glColor3f(1,0,0);
  86    glVertex3f( -0.8, 0, -4.0);
  87    glColor3f(1,1,0);
  88    glVertex3f(  0.8, 0, -4.0);
  89    glColor3f(1,0,1);
  90    glVertex3f(  0.8, 0,  4.0);
  91    glColor3f(0,1,1);
  92    glVertex3f( -0.8, 0,  4.0);
  93    glEnd();
  94
  95    glPopMatrix();
  96
  97    glFlush();
  98
  99    if (doubleBuffer) {
 100       glutSwapBuffers();
 101    }
 102 }
 103
 104 static GLenum Args(int argc, char **argv)
 105 {
 106     GLint i;
 107
 108     doubleBuffer = GL_FALSE;
 109
 110     for (i = 1; i < argc; i++) {
 111         if (strcmp(argv[i], "-sb") == 0) {
 112             doubleBuffer = GL_FALSE;
 113         } else if (strcmp(argv[i], "-db") == 0) {
 114             doubleBuffer = GL_TRUE;
 115         } else {
 116             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 117             return GL_FALSE;
 118         }
 119     }
 120     return GL_TRUE;
 121 }
 122
 123 int main(int argc, char **argv)
 124 {
 125     GLenum type;
 126
 127     glutInit(&argc, argv);
 128
 129     if (Args(argc, argv) == GL_FALSE) {
 130         exit(1);
 131     }
 132
 133     glutInitWindowPosition(0, 0);
 134     glutInitWindowSize( 250, 250);
 135
 136     type = GLUT_RGB | GLUT_ALPHA;
 137     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 138     glutInitDisplayMode(type);
 139
 140     if (glutCreateWindow("First Tri") == GL_FALSE) {
 141         exit(1);
 142     }
 143
 144     Init();
 145
 146     glutReshapeFunc(Reshape);
 147     glutKeyboardFunc(Key);
 148     glutDisplayFunc(Draw);
 149     glutMainLoop();
 150     return 0;
 151 }