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/* * Copyright (c) 1993-1999, 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 * Unpublished-- rights reserved under the copyright laws of the * United States.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. */ /* * tesswind.c * This program demonstrates the winding rule polygon * tessellation property. Four tessellated objects are drawn, * each with very different contours. When the w key is pressed, * the objects are drawn with a different winding rule. */ #include#include #include #ifndef CALLBACK #define CALLBACK #endif GLdouble currentWinding = GLU_TESS_WINDING_ODD; int currentShape = 0; GLUtesselator *tobj; GLuint list; /* Make four display lists, * each with a different tessellated object. */ void makeNewLists (void) { int i; static GLdouble rects[12][3] = {50.0, 50.0, 0.0, 300.0, 50.0, 0.0, 300.0, 300.0, 0.0, 50.0, 300.0, 0.0, 100.0, 100.0, 0.0, 250.0, 100.0, 0.0, 250.0, 250.0, 0.0, 100.0, 250.0, 0.0, 150.0, 150.0, 0.0, 200.0, 150.0, 0.0, 200.0, 200.0, 0.0, 150.0, 200.0, 0.0}; static GLdouble spiral[16][3] = {400.0, 250.0, 0.0, 400.0, 50.0, 0.0, 50.0, 50.0, 0.0, 50.0, 400.0, 0.0, 350.0, 400.0, 0.0, 350.0, 100.0, 0.0, 100.0, 100.0, 0.0, 100.0, 350.0, 0.0, 300.0, 350.0, 0.0, 300.0, 150.0, 0.0, 150.0, 150.0, 0.0, 150.0, 300.0, 0.0, 250.0, 300.0, 0.0, 250.0, 200.0, 0.0, 200.0, 200.0, 0.0, 200.0, 250.0, 0.0}; static GLdouble quad1[4][3] = {50.0, 150.0, 0.0, 350.0, 150.0, 0.0, 350.0, 200.0, 0.0, 50.0, 200.0, 0.0}; static GLdouble quad2[4][3] = {100.0, 100.0, 0.0, 300.0, 100.0, 0.0, 300.0, 350.0, 0.0, 100.0, 350.0, 0.0}; static GLdouble tri[3][3] = {200.0, 50.0, 0.0, 250.0, 300.0, 0.0, 150.0, 300.0, 0.0}; gluTessProperty(tobj, GLU_TESS_WINDING_RULE, currentWinding); glNewList(list, GL_COMPILE); gluTessBeginPolygon(tobj, NULL); gluTessBeginContour(tobj); for (i = 0; i < 4; i++) gluTessVertex(tobj, rects[i], rects[i]); gluTessEndContour(tobj); gluTessBeginContour(tobj); for (i = 4; i < 8; i++) gluTessVertex(tobj, rects[i], rects[i]); gluTessEndContour(tobj); gluTessBeginContour(tobj); for (i = 8; i < 12; i++) gluTessVertex(tobj, rects[i], rects[i]); gluTessEndContour(tobj); gluTessEndPolygon(tobj); glEndList(); glNewList(list+1, GL_COMPILE); gluTessBeginPolygon(tobj, NULL); gluTessBeginContour(tobj); for (i = 0; i < 4; i++) gluTessVertex(tobj, rects[i], rects[i]); gluTessEndContour(tobj); gluTessBeginContour(tobj); for (i = 7; i >= 4; i--) gluTessVertex(tobj, rects[i], rects[i]); gluTessEndContour(tobj); gluTessBeginContour(tobj); for (i = 11; i >= 8; i--) gluTessVertex(tobj, rects[i], rects[i]); gluTessEndContour(tobj); gluTessEndPolygon(tobj); glEndList(); glNewList(list+2, GL_COMPILE); gluTessBeginPolygon(tobj, NULL); gluTessBeginContour(tobj); for (i = 0; i < 16; i++) gluTessVertex(tobj, spiral[i], spiral[i]); gluTessEndContour(tobj); gluTessEndPolygon(tobj); glEndList(); glNewList(list+3, GL_COMPILE); gluTessBeginPolygon(tobj, NULL); gluTessBeginContour(tobj); for (i = 0; i < 4; i++) gluTessVertex(tobj, quad1[i], quad1[i]); gluTessEndContour(tobj); gluTessBeginContour(tobj); for (i = 0; i < 4; i++) gluTessVertex(tobj, quad2[i], quad2[i]); gluTessEndContour(tobj); gluTessBeginContour(tobj); for (i = 0; i < 3; i++) gluTessVertex(tobj, tri[i], tri[i]); gluTessEndContour(tobj); gluTessEndPolygon(tobj); glEndList(); } void display (void) { glClear(GL_COLOR_BUFFER_BIT); glColor3f(1.0, 1.0, 1.0); glPushMatrix(); glCallList(list); glTranslatef(0.0, 500.0, 0.0); glCallList(list+1); glTranslatef(500.0, -500.0, 0.0); glCallList(list+2); glTranslatef(0.0, 500.0, 0.0); glCallList(list+3); glPopMatrix(); 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(); } /* 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. */ void CALLBACK combineCallback(GLdouble coords[3], GLdouble *data[4], GLfloat weight[4], GLdouble **dataOut ) { GLdouble *vertex; vertex = (GLdouble *) malloc(3 * sizeof(GLdouble)); vertex[0] = coords[0]; vertex[1] = coords[1]; vertex[2] = coords[2]; *dataOut = vertex; } void init(void) { glClearColor(0.0, 0.0, 0.0, 0.0); glShadeModel(GL_FLAT); tobj = gluNewTess(); gluTessCallback(tobj, GLU_TESS_VERTEX, glVertex3dv); gluTessCallback(tobj, GLU_TESS_BEGIN, beginCallback); gluTessCallback(tobj, GLU_TESS_END, endCallback); gluTessCallback(tobj, GLU_TESS_ERROR, errorCallback); gluTessCallback(tobj, GLU_TESS_COMBINE, combineCallback); list = glGenLists(4); makeNewLists(); } void reshape(int w, int h) { glViewport(0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); if (w <= h) gluOrtho2D(0.0, 1000.0, 0.0, 1000.0 * (GLdouble)h/(GLdouble)w); else gluOrtho2D(0.0, 1000.0 * (GLdouble)w/(GLdouble)h, 0.0, 1000.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void keyboard(unsigned char key, int x, int y) { switch (key) { case 'w': case 'W': if (currentWinding == GLU_TESS_WINDING_ODD) currentWinding = GLU_TESS_WINDING_NONZERO; else if (currentWinding == GLU_TESS_WINDING_NONZERO) currentWinding = GLU_TESS_WINDING_POSITIVE; else if (currentWinding == GLU_TESS_WINDING_POSITIVE) currentWinding = GLU_TESS_WINDING_NEGATIVE; else if (currentWinding == GLU_TESS_WINDING_NEGATIVE) currentWinding = GLU_TESS_WINDING_ABS_GEQ_TWO; else if (currentWinding == GLU_TESS_WINDING_ABS_GEQ_TWO) currentWinding = GLU_TESS_WINDING_ODD; makeNewLists(); glutPostRedisplay(); break; case 27: exit(0); break; default: 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; }