diff options
Diffstat (limited to 'progs/redbook/tess.c')
-rw-r--r-- | progs/redbook/tess.c | 241 |
1 files changed, 241 insertions, 0 deletions
diff --git a/progs/redbook/tess.c b/progs/redbook/tess.c new file mode 100644 index 00000000000..238a469aff2 --- /dev/null +++ b/progs/redbook/tess.c @@ -0,0 +1,241 @@ +/* + * 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 + * Unpublished-- rights reserved under the copyright laws of the + * United States.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", (char *) estring); + exit(0); +} + +void CALLBACK endCallback(void) +{ + glEnd(); +} + +void CALLBACK vertexCallback(GLvoid *vertex) +{ + const GLdouble *pointer; + + pointer = (GLdouble *) vertex; + glColor3dv(pointer+3); + glVertex3dv(pointer); +} + +/* 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 |