/* * 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 * Unpublished-- rights reserved under the copyright laws of the * United States.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. */ /* * tess.c * This program demonstrates polygon tessellation. * Two tesselated objects are drawn. The first is a * rectangle with a triangular hole. The second is a * smooth shaded, self-intersecting star. * * Note the exterior rectangle is drawn with its vertices * in counter-clockwise order, but its interior clockwise. * Note the combineCallback is needed for the self-intersecting * star. Also note that removing the TessProperty for the * star will make the interior unshaded (WINDING_ODD). */ #include <GL/glut.h> #include <stdlib.h> #include <stdio.h> #ifdef GLU_VERSION_1_2 /* Win32 calling conventions. */ #ifndef CALLBACK #define CALLBACK #endif GLuint startList; void display (void) { glClear(GL_COLOR_BUFFER_BIT); glColor3f(1.0, 1.0, 1.0); glCallList(startList); glCallList(startList + 1); glFlush(); } void CALLBACK beginCallback(GLenum which) { glBegin(which); } void CALLBACK errorCallback(GLenum errorCode) { const GLubyte *estring; estring = gluErrorString(errorCode); fprintf(stderr, "Tessellation Error: %s\n", estring); exit(0); } void CALLBACK endCallback(void) { glEnd(); } void CALLBACK vertexCallback(GLvoid *vertex) { const GLdouble *pointer; pointer = (GLdouble *) vertex; glColor3dv(pointer+3); glVertex3dv(vertex); } /* combineCallback is used to create a new vertex when edges * intersect. coordinate location is trivial to calculate, * but weight[4] may be used to average color, normal, or texture * coordinate data. In this program, color is weighted. */ void CALLBACK combineCallback(GLdouble coords[3], GLdouble *vertex_data[4], GLfloat weight[4], GLdouble **dataOut ) { GLdouble *vertex; int i; vertex = (GLdouble *) malloc(6 * sizeof(GLdouble)); vertex[0] = coords[0]; vertex[1] = coords[1]; vertex[2] = coords[2]; for (i = 3; i < 6; i++) vertex[i] = weight[0] * vertex_data[0][i] + weight[1] * vertex_data[1][i] + weight[2] * vertex_data[2][i] + weight[3] * vertex_data[3][i]; *dataOut = vertex; } void init (void) { GLUtesselator *tobj; GLdouble rect[4][3] = {{50.0, 50.0, 0.0}, {200.0, 50.0, 0.0}, {200.0, 200.0, 0.0}, {50.0, 200.0, 0.0}}; GLdouble tri[3][3] = {{75.0, 75.0, 0.0}, {125.0, 175.0, 0.0}, {175.0, 75.0, 0.0}}; GLdouble star[5][6] = {{250.0, 50.0, 0.0, 1.0, 0.0, 1.0}, {325.0, 200.0, 0.0, 1.0, 1.0, 0.0}, {400.0, 50.0, 0.0, 0.0, 1.0, 1.0}, {250.0, 150.0, 0.0, 1.0, 0.0, 0.0}, {400.0, 150.0, 0.0, 0.0, 1.0, 0.0}}; glClearColor(0.0, 0.0, 0.0, 0.0); startList = glGenLists(2); tobj = gluNewTess(); gluTessCallback(tobj, GLU_TESS_VERTEX, (GLvoid (CALLBACK*) ()) &glVertex3dv); gluTessCallback(tobj, GLU_TESS_BEGIN, (GLvoid (CALLBACK*) ()) &beginCallback); gluTessCallback(tobj, GLU_TESS_END, (GLvoid (CALLBACK*) ()) &endCallback); gluTessCallback(tobj, GLU_TESS_ERROR, (GLvoid (CALLBACK*) ()) &errorCallback); /* rectangle with triangular hole inside */ glNewList(startList, GL_COMPILE); glShadeModel(GL_FLAT); gluTessBeginPolygon(tobj, NULL); gluTessBeginContour(tobj); gluTessVertex(tobj, rect[0], rect[0]); gluTessVertex(tobj, rect[1], rect[1]); gluTessVertex(tobj, rect[2], rect[2]); gluTessVertex(tobj, rect[3], rect[3]); gluTessEndContour(tobj); gluTessBeginContour(tobj); gluTessVertex(tobj, tri[0], tri[0]); gluTessVertex(tobj, tri[1], tri[1]); gluTessVertex(tobj, tri[2], tri[2]); gluTessEndContour(tobj); gluTessEndPolygon(tobj); glEndList(); gluTessCallback(tobj, GLU_TESS_VERTEX, (GLvoid (CALLBACK*) ()) &vertexCallback); gluTessCallback(tobj, GLU_TESS_BEGIN, (GLvoid (CALLBACK*) ()) &beginCallback); gluTessCallback(tobj, GLU_TESS_END, (GLvoid (CALLBACK*) ()) &endCallback); gluTessCallback(tobj, GLU_TESS_ERROR, (GLvoid (CALLBACK*) ()) &errorCallback); gluTessCallback(tobj, GLU_TESS_COMBINE, (GLvoid (CALLBACK*) ()) &combineCallback); /* smooth shaded, self-intersecting star */ glNewList(startList + 1, GL_COMPILE); glShadeModel(GL_SMOOTH); gluTessProperty(tobj, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_POSITIVE); gluTessBeginPolygon(tobj, NULL); gluTessBeginContour(tobj); gluTessVertex(tobj, star[0], star[0]); gluTessVertex(tobj, star[1], star[1]); gluTessVertex(tobj, star[2], star[2]); gluTessVertex(tobj, star[3], star[3]); gluTessVertex(tobj, star[4], star[4]); gluTessEndContour(tobj); gluTessEndPolygon(tobj); glEndList(); gluDeleteTess(tobj); } void reshape (int w, int h) { glViewport(0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0, (GLdouble) w, 0.0, (GLdouble) h); } /* ARGSUSED1 */ void keyboard(unsigned char key, int x, int y) { switch (key) { case 27: exit(0); break; } } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); glutInitWindowSize(500, 500); glutCreateWindow(argv[0]); init(); glutDisplayFunc(display); glutReshapeFunc(reshape); glutKeyboardFunc(keyboard); glutMainLoop(); return 0; } #else int main(int argc, char** argv) { fprintf (stderr, "This program demonstrates the new tesselator API in GLU 1.2.\n"); fprintf (stderr, "Your GLU library does not support this new interface, sorry.\n"); return 0; } #endif