progs/trivial/lineloop-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    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  40    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  41    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  42
  43     glClearColor(0.0, 0.0, 1.0, 0.0);
  44 }
  45
  46 static void Reshape(int width, int height)
  47 {
  48
  49     glViewport(0, 0, (GLint)width, (GLint)height);
  50
  51     glMatrixMode(GL_PROJECTION);
  52     glLoadIdentity();
  53     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  54     glMatrixMode(GL_MODELVIEW);
  55 }
  56
  57 static void Key(unsigned char key, int x, int y)
  58 {
  59
  60     switch (key) {
  61       case 27:
  62         exit(1);
  63       default:
  64         return;
  65     }
  66
  67     glutPostRedisplay();
  68 }
  69
  70 static void Draw(void)
  71 {
  72    glClear(GL_COLOR_BUFFER_BIT);
  73
  74    glBegin(GL_LINE_LOOP);
  75    glColor3f(0,0,.7);
  76    glVertex3f( 0.9, -0.9, -30.0);
  77    glColor3f(.8,0,0);
  78    glVertex3f( 0.9,  0.9, -30.0);
  79    glColor3f(0,.9,0);
  80    glVertex3f(-1.9,  0.0, -30.0);
  81    glEnd();
  82
  83    glFlush();
  84
  85    if (doubleBuffer) {
  86       glutSwapBuffers();
  87    }
  88 }
  89
  90 static GLenum Args(int argc, char **argv)
  91 {
  92     GLint i;
  93
  94     doubleBuffer = GL_FALSE;
  95
  96     for (i = 1; i < argc; i++) {
  97         if (strcmp(argv[i], "-sb") == 0) {
  98             doubleBuffer = GL_FALSE;
  99         } else if (strcmp(argv[i], "-db") == 0) {
 100             doubleBuffer = GL_TRUE;
 101         } else {
 102             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 103             return GL_FALSE;
 104         }
 105     }
 106     return GL_TRUE;
 107 }
 108
 109 int main(int argc, char **argv)
 110 {
 111     GLenum type;
 112
 113     glutInit(&argc, argv);
 114
 115     if (Args(argc, argv) == GL_FALSE) {
 116         exit(1);
 117     }
 118
 119     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 120
 121     type = GLUT_RGB | GLUT_ALPHA;
 122     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 123     glutInitDisplayMode(type);
 124
 125     if (glutCreateWindow("First Tri") == GL_FALSE) {
 126         exit(1);
 127     }
 128
 129     Init();
 130
 131     glutReshapeFunc(Reshape);
 132     glutKeyboardFunc(Key);
 133     glutDisplayFunc(Draw);
 134     glutMainLoop();
 135         return 0;
 136 }