/* Copyright (c) Mark J. Kilgard, 1994. */ /* * (c) Copyright 1993, 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 * Unpublished-- rights reserved under the copyright laws of the * United States.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. */ /* stencil.c * This program draws two rotated tori in a window. * A diamond in the center of the window masks out part * of the scene. Within this mask, a different model * (a sphere) is drawn in a different color. */ /* * !!! NOTE !!! * * This demo is poorly written. The stencil buffer should be * redrawn in display(), not in the myReshape() function. * The reason is if the window gets "damaged" then the stencil buffer * contents will be in an undefined state (myReshape is not called when * a window is damaged and needs to be redrawn). If the stencil buffer * contents are undefined, the results of display() are unpredictable. * * -Brian */ #include <stdlib.h> #include <GL/glut.h> #define YELLOWMAT 1 #define BLUEMAT 2 void myinit (void) { GLfloat yellow_diffuse[] = { 0.7, 0.7, 0.0, 1.0 }; GLfloat yellow_specular[] = { 1.0, 1.0, 1.0, 1.0 }; GLfloat blue_diffuse[] = { 0.1, 0.1, 0.7, 1.0 }; GLfloat blue_specular[] = { 0.1, 1.0, 1.0, 1.0 }; GLfloat position_one[] = { 1.0, 1.0, 1.0, 0.0 }; glNewList(YELLOWMAT, GL_COMPILE); glMaterialfv(GL_FRONT, GL_DIFFUSE, yellow_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, yellow_specular); glMaterialf(GL_FRONT, GL_SHININESS, 64.0); glEndList(); glNewList(BLUEMAT, GL_COMPILE); glMaterialfv(GL_FRONT, GL_DIFFUSE, blue_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, blue_specular); glMaterialf(GL_FRONT, GL_SHININESS, 45.0); glEndList(); glLightfv(GL_LIGHT0, GL_POSITION, position_one); glEnable(GL_LIGHT0); glEnable(GL_LIGHTING); glDepthFunc(GL_LESS); glEnable(GL_DEPTH_TEST); glClearStencil(0x0); glEnable(GL_STENCIL_TEST); } /* Draw a sphere in a diamond-shaped section in the * middle of a window with 2 tori. */ void display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glStencilOp (GL_KEEP, GL_KEEP, GL_KEEP); /* draw blue sphere where the stencil is 1 */ glStencilFunc (GL_EQUAL, 0x1, 0x1); glCallList (BLUEMAT); glutSolidSphere (0.5, 15, 15); /* draw the tori where the stencil is not 1 */ glStencilFunc (GL_NOTEQUAL, 0x1, 0x1); glPushMatrix(); glRotatef (45.0, 0.0, 0.0, 1.0); glRotatef (45.0, 0.0, 1.0, 0.0); glCallList (YELLOWMAT); glutSolidTorus (0.275, 0.85, 15, 15); glPushMatrix(); glRotatef (90.0, 1.0, 0.0, 0.0); glutSolidTorus (0.275, 0.85, 15, 15); glPopMatrix(); glPopMatrix(); glFlush(); glutSwapBuffers(); } /* Whenever the window is reshaped, redefine the * coordinate system and redraw the stencil area. */ void myReshape(int w, int h) { glViewport(0, 0, w, h); glClear(GL_STENCIL_BUFFER_BIT); /* create a diamond shaped stencil area */ glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrtho(-3.0, 3.0, -3.0, 3.0, -1.0, 1.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glStencilFunc (GL_ALWAYS, 0x1, 0x1); glStencilOp (GL_REPLACE, GL_REPLACE, GL_REPLACE); glBegin(GL_QUADS); glVertex3f (-1.0, 0.0, 0.0); glVertex3f (0.0, 1.0, 0.0); glVertex3f (1.0, 0.0, 0.0); glVertex3f (0.0, -1.0, 0.0); glEnd(); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluPerspective(45.0, (GLfloat) w/(GLfloat) h, 3.0, 7.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glTranslatef(0.0, 0.0, -5.0); } static void key(unsigned char k, int x, int y) { switch (k) { case 27: /* Escape */ exit(0); break; default: return; } glutPostRedisplay(); } /* 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_DOUBLE | GLUT_RGB | GLUT_DEPTH | GLUT_STENCIL); glutInitWindowSize (400, 400); glutCreateWindow (argv[0]); myinit (); glutReshapeFunc (myReshape); glutDisplayFunc(display); glutKeyboardFunc(key); glutMainLoop(); return 0; /* ANSI C requires main to return int. */ }