progs/trivial/tri-z.c

   1 /*
   2  * Copyright (c) 1993-1997, Silicon Graphics, Inc.
   3  * ALL RIGHTS RESERVED
   4  * Permission to use, copy, modify, and distribute this software for
   5  * any purpose and without fee is hereby granted, provided that the above
   6  * copyright notice appear in all copies and that both the copyright notice
   7  * and this permission notice appear in supporting documentation, and that
   8  * the name of Silicon Graphics, Inc. not be used in advertising
   9  * or publicity pertaining to distribution of the software without specific,
  10  * written prior permission.
  11  *
  12  * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
  13  * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
  14  * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
  15  * FITNESS FOR A PARTICULAR PURPOSE.  IN NO EVENT SHALL SILICON
  16  * GRAPHICS, INC.  BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
  17  * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
  18  * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
  19  * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
  20  * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC.  HAS BEEN
  21  * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
  22  * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
  23  * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
  24  *
  25  * US Government Users Restricted Rights
  26  * Use, duplication, or disclosure by the Government is subject to
  27  * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
  28  * (c)(1)(ii) of the Rights in Technical Data and Computer Software
  29  * clause at DFARS 252.227-7013 and/or in similar or successor
  30  * clauses in the FAR or the DOD or NASA FAR Supplement.
  31  * Unpublished-- rights reserved under the copyright laws of the
  32  * United States.  Contractor/manufacturer is Silicon Graphics,
  33  * Inc., 2011 N.  Shoreline Blvd., Mountain View, CA 94039-7311.
  34  *
  35  * OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
  36  */
  37
  38 #include <GL/glut.h>
  39 #include <stdlib.h>
  40
  41 static int leftFirst = GL_TRUE;
  42
  43 static void init(void)
  44 {
  45    glEnable(GL_DEPTH_TEST);
  46    glClearColor (1.0, 0.0, 0.0, 0.0);
  47 }
  48
  49 static void drawLeftTriangle(void)
  50 {
  51    /* draw yellow triangle on LHS of screen */
  52    glBegin (GL_TRIANGLES);
  53       glColor4f(1.0, 1.0, 0.0, 0.75);
  54       glVertex3f(0.1, 0.9, -1.0);
  55       glVertex3f(0.1, 0.1, -1.0);
  56       glVertex3f(0.8, 0.5,  1.0);
  57    glEnd();
  58 }
  59
  60 static void drawRightTriangle(void)
  61 {
  62    /* draw cyan triangle on RHS of screen */
  63    glBegin (GL_TRIANGLES);
  64       glColor4f(0.0, 1.0, 1.0, 0.75);
  65       glVertex3f(0.9, 0.9, 0.0);
  66       glVertex3f(0.2, 0.5, 0.0);
  67       glVertex3f(0.9, 0.1, 0.0);
  68    glEnd();
  69 }
  70
  71 void display(void)
  72 {
  73    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  74
  75    if (leftFirst) {
  76       drawLeftTriangle();
  77       drawRightTriangle();
  78    }
  79    else {
  80       drawRightTriangle();
  81       drawLeftTriangle();
  82    }
  83
  84    glFlush();
  85 }
  86
  87 void reshape(int w, int h)
  88 {
  89    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
  90    glMatrixMode(GL_PROJECTION);
  91    glLoadIdentity();
  92    if (w <= h)
  93       gluOrtho2D (0.0, 1.0, 0.0, 1.0*(GLfloat)h/(GLfloat)w);
  94    else
  95       gluOrtho2D (0.0, 1.0*(GLfloat)w/(GLfloat)h, 0.0, 1.0);
  96 }
  97
  98 /* ARGSUSED1 */
  99 void keyboard(unsigned char key, int x, int y)
 100 {
 101    switch (key) {
 102       case 't':
 103       case 'T':
 104          leftFirst = !leftFirst;
 105          glutPostRedisplay();
 106          break;
 107       case 27:  /*  Escape key  */
 108          exit(0);
 109          break;
 110       default:
 111          break;
 112    }
 113 }
 114
 115 /*  Main Loop
 116  *  Open window with initial window size, title bar,
 117  *  RGBA display mode, and handle input events.
 118  */
 119 int main(int argc, char** argv)
 120 {
 121    glutInit(&argc, argv);
 122    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
 123    glutInitWindowSize (200, 200);
 124    glutCreateWindow (argv[0]);
 125    init();
 126    glutReshapeFunc (reshape);
 127    glutKeyboardFunc (keyboard);
 128    glutDisplayFunc (display);
 129    glutMainLoop();
 130    return 0;
 131 }