progs/trivial/line-userclip-clip.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
  37 static void Init(void)
  38 {
  39    static GLdouble plane[4] = { -.5, 0, 1, 0 };
  40
  41    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  42    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  43    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  44
  45    glClearColor(0.0, 0.0, 1.0, 0.0);
  46    glClipPlane(GL_CLIP_PLANE0, plane);
  47    glEnable(GL_CLIP_PLANE0);
  48 }
  49
  50 static void Reshape(int width, int height)
  51 {
  52
  53     glViewport(0, 0, (GLint)width, (GLint)height);
  54
  55     glMatrixMode(GL_PROJECTION);
  56     glLoadIdentity();
  57 /*     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0); */
  58     glMatrixMode(GL_MODELVIEW);
  59 }
  60
  61 static void Key(unsigned char key, int x, int y)
  62 {
  63
  64     switch (key) {
  65       case 27:
  66         exit(1);
  67       default:
  68         return;
  69     }
  70
  71     glutPostRedisplay();
  72 }
  73
  74 static void Draw(void)
  75 {
  76    glClear(GL_COLOR_BUFFER_BIT);
  77
  78    glBegin(GL_LINE_STRIP);
  79    glColor3f(0,0,.7);
  80    glVertex3f( 0.9, -0.9, 0.0);
  81    glColor3f(.8,0,0);
  82    glVertex3f( 0.9,  0.9, 0.0);
  83    glColor3f(0,.9,0);
  84    glVertex3f(-1.9,  0.0, 0.0);
  85    glColor3f(0,0,.7);
  86    glVertex3f( 0.9, -0.9, 0.0);
  87    glEnd();
  88
  89    glFlush();
  90
  91    if (doubleBuffer) {
  92       glutSwapBuffers();
  93    }
  94 }
  95
  96 static GLenum Args(int argc, char **argv)
  97 {
  98     GLint i;
  99
 100     doubleBuffer = GL_FALSE;
 101
 102     for (i = 1; i < argc; i++) {
 103         if (strcmp(argv[i], "-sb") == 0) {
 104             doubleBuffer = GL_FALSE;
 105         } else if (strcmp(argv[i], "-db") == 0) {
 106             doubleBuffer = GL_TRUE;
 107         } else {
 108             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 109             return GL_FALSE;
 110         }
 111     }
 112     return GL_TRUE;
 113 }
 114
 115 int main(int argc, char **argv)
 116 {
 117     GLenum type;
 118
 119     glutInit(&argc, argv);
 120
 121     if (Args(argc, argv) == GL_FALSE) {
 122         exit(1);
 123     }
 124
 125     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 126
 127     type = GLUT_RGB | GLUT_ALPHA;
 128     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 129     glutInitDisplayMode(type);
 130
 131     if (glutCreateWindow("First Tri") == GL_FALSE) {
 132         exit(1);
 133     }
 134
 135     Init();
 136
 137     glutReshapeFunc(Reshape);
 138     glutKeyboardFunc(Key);
 139     glutDisplayFunc(Draw);
 140     glutMainLoop();
 141         return 0;
 142 }