/* 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 * Unpublished-- rights reserved under the copyright laws of the * United States.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 #include #include #include 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(); }