It draws two diagonal lines to form an X; when 'r' is typed in the window, the lines are rotated in opposite directions.
/* * Copyright (c) 1993-1997, Silicon Graphics, Inc. * ALL RIGHTS RESERVED * Permission to use, copy, modify, and distribute this software for * any purpose and without fee is hereby granted, provided that the above * copyright notice appear in all copies and that both the copyright notice * and this permission notice appear in supporting documentation, and that * the name of Silicon Graphics, Inc. not be used in advertising * or publicity pertaining to distribution of the software without specific, * written prior permission. * * THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS" * AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE, * INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR * FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON * GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT, * SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY * KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION, * LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF * THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN * ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON * ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE * POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE. * * US Government Users Restricted Rights * Use, duplication, or disclosure by the Government is subject to * restrictions set forth in FAR 52.227.19(c)(2) or subparagraph * (c)(1)(ii) of the Rights in Technical Data and Computer Software * clause at DFARS 252.227-7013 and/or in similar or successor * clauses in the FAR or the DOD or NASA FAR Supplement. * Unpublished-- rights reserved under the copyright laws of the * United States. Contractor/manufacturer is Silicon Graphics, * Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311. * * OpenGL(R) is a registered trademark of Silicon Graphics, Inc. */ /* * aargb.c */ #include <GL/openglut.h> #include <stdlib.h> #include <stdio.h> static float rotAngle = 0.; /* Initialize antialiasing for RGBA mode, including alpha * blending, hint, and line width. Print out implementation * specific info on line width granularity and width. */ void init(void) { GLfloat values[2]; glGetFloatv (GL_LINE_WIDTH_GRANULARITY, values); printf ("GL_LINE_WIDTH_GRANULARITY value is %3.1f\n", values[0]); glGetFloatv (GL_LINE_WIDTH_RANGE, values); printf ("GL_LINE_WIDTH_RANGE values are %3.1f %3.1f\n", values[0], values[1]); glEnable (GL_LINE_SMOOTH); glEnable (GL_BLEND); glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); glHint (GL_LINE_SMOOTH_HINT, GL_DONT_CARE); glLineWidth (1.5); glClearColor(0.0, 0.0, 0.0, 0.0); } /* Draw 2 diagonal lines to form an X */ void display(void) { glClear(GL_COLOR_BUFFER_BIT); glColor3f (0.0, 1.0, 0.0); glPushMatrix(); glRotatef(-rotAngle, 0.0, 0.0, 0.1); glBegin (GL_LINES); glVertex2f (-0.5, 0.5); glVertex2f (0.5, -0.5); glEnd (); glPopMatrix(); glColor3f (0.0, 0.0, 1.0); glPushMatrix(); glRotatef(rotAngle, 0.0, 0.0, 0.1); glBegin (GL_LINES); glVertex2f (0.5, 0.5); glVertex2f (-0.5, -0.5); glEnd (); glPopMatrix(); glFlush(); } void reshape(int w, int h) { glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); if (w <= h) gluOrtho2D (-1.0, 1.0, -1.0*(GLfloat)h/(GLfloat)w, 1.0*(GLfloat)h/(GLfloat)w); else gluOrtho2D (-1.0*(GLfloat)w/(GLfloat)h, 1.0*(GLfloat)w/(GLfloat)h, -1.0, 1.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } /* ARGSUSED1 */ void keyboard(unsigned char key, int x, int y) { switch (key) { case 'r': case 'R': rotAngle += 20.; if (rotAngle >= 360.) rotAngle = 0.; glutPostRedisplay(); break; case 27: /* Escape Key */ exit(0); break; default: break; } } /* Main Loop * Open window with initial window size, title bar, * RGBA display mode, and handle input events. */ int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB); glutInitWindowSize (200, 200); glutCreateWindow (argv[0]); init(); glutReshapeFunc (reshape); glutKeyboardFunc (keyboard); glutDisplayFunc (display); glutMainLoop(); return 0; }