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