/* Copyright (c) Mark J. Kilgard, 1994. */
/**
* (c) Copyright 1993, 1994, 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* Unpublished-- rights reserved under the copyright laws of the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(TM) is a trademark of Silicon Graphics, Inc.
*/
/*----------------------------------------------------------------------------
*
* ohidden.c : openGL (GLUT) example showing how to use stencils
* to draw outlined polygons.
*
* Author : Yusuf Attarwala
* SGI - Applications
* Date : Jul 93
*
* Update : Mark Kilgard
* Date : Feb 95
*
* note : the main intent of this program is to demo the stencil
* plane functionality, hence the rendering is kept
* simple (wireframe).
*
*---------------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <GL/glut.h>
static int stencilOn = 1;
/* function declarations */
void
drawScene(void), setMatrix(void), animation(void), resize(int w, int h),
keyboard(unsigned char c, int x, int y), menu(int choice), drawWireframe(int face),
drawFilled(int face);
/* global variables */
float ax, ay, az; /* angles for animation */
/* coords of a cube */
static GLfloat cube[8][3] =
{ { 0.0, 0.0, 0.0},
{ 1.0, 0.0, 0.0},
{ 1.0, 0.0, 1.0},
{ 0.0, 0.0, 1.0},
{ 1.0, 1.0, 0.0},
{ 1.0, 1.0, 1.0},
{ 0.0, 1.0, 1.0},
{ 0.0, 1.0, 0.0}};
static int faceIndex[6][4] =
{{0, 1, 2, 3},
{1, 4, 5, 2},
{4, 7, 6, 5},
{7, 0, 3, 6},
{3, 2, 5, 6},
{7, 4, 1, 0}};
int
main(int argc, char **argv)
{
glutInit(&argc, argv);
glutInitWindowSize(400, 400);
glutInitDisplayMode(GLUT_RGB | GLUT_STENCIL | GLUT_DOUBLE | GLUT_DEPTH);
glutCreateWindow("Stenciled hidden surface removal");
ax = 10.0;
ay = -10.0;
az = 0.0;
glutDisplayFunc(drawScene);
glutReshapeFunc(resize);
glutCreateMenu(menu);
glutAddMenuEntry("Motion", 3);
glutAddMenuEntry("Stencil on", 1);
glutAddMenuEntry("Stencil off", 2);
glutAttachMenu(GLUT_RIGHT_BUTTON);
glutKeyboardFunc(keyboard);
glutMainLoop();
return 0; /* ANSI C requires main to return int. */
}
void
drawWireframe(int face)
{
int i;
glBegin(GL_LINE_LOOP);
for (i = 0; i < 4; i++)
glVertex3fv((GLfloat *) cube[faceIndex[face][i]]);
glEnd();
}
void
drawFilled(int face)
{
int i;
glBegin(GL_POLYGON);
for (i = 0; i < 4; i++)
glVertex3fv((GLfloat *) cube[faceIndex[face][i]]);
glEnd();
}
void
drawScene(void)
{
int i;
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glClearColor(0.0, 0.0, 0.0, 0.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotatef(ax, 1.0, 0.0, 0.0);
glRotatef(-ay, 0.0, 1.0, 0.0);
/* all the good stuff follows */
if (stencilOn) {
glEnable(GL_STENCIL_TEST);
glClear(GL_STENCIL_BUFFER_BIT);
glStencilMask(1);
glStencilFunc(GL_ALWAYS, 0, 1);
glStencilOp(GL_INVERT, GL_INVERT, GL_INVERT);
}
glColor3f(1.0, 1.0, 0.0);
for (i = 0; i < 6; i++) {
drawWireframe(i);
if (stencilOn) {
glStencilFunc(GL_EQUAL, 0, 1);
glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
}
glColor3f(0.0, 0.0, 0.0);
drawFilled(i);
glColor3f(1.0, 1.0, 0.0);
if (stencilOn) {
glStencilFunc(GL_ALWAYS, 0, 1);
glStencilOp(GL_INVERT, GL_INVERT, GL_INVERT);
}
glColor3f(1.0, 1.0, 0.0);
drawWireframe(i);
}
glPopMatrix();
if (stencilOn)
glDisable(GL_STENCIL_TEST);
/* end of good stuff */
glutSwapBuffers();
}
void
setMatrix(void)
{
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-2.0, 2.0, -2.0, 2.0, -2.0, 2.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
int count = 0;
void
animation(void)
{
/* animate the cone */
ax += 5.0;
ay -= 2.0;
az += 5.0;
if (ax >= 360)
ax = 0.0;
if (ay <= -360)
ay = 0.0;
if (az >= 360)
az = 0.0;
glutPostRedisplay();
count++;
if (count >= 60)
glutIdleFunc(NULL);
}
void
menu(int choice)
{
switch (choice) {
case 3:
count = 0;
glutIdleFunc(animation);
break;
case 2:
stencilOn = 0;
glutSetWindowTitle("Stencil Disabled");
glutPostRedisplay();
break;
case 1:
stencilOn = 1;
glutSetWindowTitle("Stencil Enabled");
glutPostRedisplay();
break;
}
}
/* ARGSUSED1 */
void
keyboard(unsigned char c, int x, int y)
{
switch (c) {
case 27:
exit(0);
break;
default:
break;
}
}
void
resize(int w, int h)
{
glViewport(0, 0, w, h);
setMatrix();
}