progs/trivial/tri-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 static GLenum doubleBuffer;
  32 static GLfloat Xpos = 0, Ypos = 0;
  33
  34
  35 static void Init(void)
  36 {
  37    fprintf(stderr, "GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
  38    fprintf(stderr, "GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
  39    fprintf(stderr, "GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
  40    fflush(stderr);
  41    glClearColor(0.0, 0.0, 1.0, 0.0);
  42 }
  43
  44 static void Reshape(int width, int height)
  45 {
  46     glViewport(0, 0, (GLint)width, (GLint)height);
  47     glMatrixMode(GL_PROJECTION);
  48     glLoadIdentity();
  49     glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
  50     glMatrixMode(GL_MODELVIEW);
  51 }
  52
  53 static void Key(unsigned char key, int x, int y)
  54 {
  55     switch (key) {
  56       case 27:
  57         exit(1);
  58       default:
  59         break;
  60     }
  61     glutPostRedisplay();
  62 }
  63
  64 static void
  65 SpecialKey(int key, int x, int y)
  66 {
  67    const GLfloat step = 0.25;
  68    (void) x;
  69    (void) y;
  70    switch (key) {
  71       case GLUT_KEY_UP:
  72          Ypos += step;
  73          break;
  74       case GLUT_KEY_DOWN:
  75          Ypos -= step;
  76          break;
  77       case GLUT_KEY_LEFT:
  78          Xpos -= step;
  79          break;
  80       case GLUT_KEY_RIGHT:
  81          Xpos += step;
  82          break;
  83    }
  84    glutPostRedisplay();
  85 }
  86
  87 static void Draw(void)
  88 {
  89    glClear(GL_COLOR_BUFFER_BIT);
  90
  91    glPushMatrix();
  92    glTranslatef(Xpos, Ypos, 0);
  93
  94    glBegin(GL_TRIANGLES);
  95    glColor3f(0,0,.7);
  96    glVertex3f( 0.9, -0.9, -30.0);
  97    glColor3f(.8,0,0);
  98    glVertex3f( 0.9,  0.9, -30.0);
  99    glColor3f(0,.9,0);
 100    glVertex3f(-1.9,  0.0, -30.0);
 101    glEnd();
 102
 103    glPopMatrix();
 104
 105    glFlush();
 106
 107    if (doubleBuffer) {
 108       glutSwapBuffers();
 109    }
 110 }
 111
 112 static GLenum Args(int argc, char **argv)
 113 {
 114     GLint i;
 115
 116     doubleBuffer = GL_FALSE;
 117
 118     for (i = 1; i < argc; i++) {
 119         if (strcmp(argv[i], "-sb") == 0) {
 120             doubleBuffer = GL_FALSE;
 121         } else if (strcmp(argv[i], "-db") == 0) {
 122             doubleBuffer = GL_TRUE;
 123         } else {
 124             fprintf(stderr, "%s (Bad option).\n", argv[i]);
 125             return GL_FALSE;
 126         }
 127     }
 128     return GL_TRUE;
 129 }
 130
 131 int main(int argc, char **argv)
 132 {
 133     GLenum type;
 134
 135     glutInit(&argc, argv);
 136
 137     if (Args(argc, argv) == GL_FALSE) {
 138         exit(1);
 139     }
 140
 141     glutInitWindowPosition(0, 0); glutInitWindowSize( 250, 250);
 142
 143     type = GLUT_RGB;
 144     type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
 145     glutInitDisplayMode(type);
 146
 147     if (glutCreateWindow(*argv) == GL_FALSE) {
 148         exit(1);
 149     }
 150
 151     Init();
 152
 153     glutReshapeFunc(Reshape);
 154     glutKeyboardFunc(Key);
 155     glutSpecialFunc(SpecialKey);
 156     glutDisplayFunc(Draw);
 157     glutMainLoop();
 158     return 0;
 159 }