root/samples/redbook/tess.php

DEFINITIONS

1. display
2. beginCallback
3. errorCallback
4. endCallback
5. vertexCallback
6. combineCallback
7. init
8. reshape

<?php
        /* OpenGL redbook tess */
        
        $startList = 0;

        function display() {
                global $startList;

                glClear(GL_COLOR_BUFFER_BIT);
                glColor3f(1.0, 1.0, 1.0);
                glCallList($startList);
                glCallList($startList + 1);
                glFlush();
        }

        function beginCallback($which) {
                glBegin($which);
        }

        function errorCallback($errorCode) {
                echo "Tessellation Error: " . gluErrorString($errorCode) . "\n";
                exit();
        }

        function endCallback() {
                glEnd();
        }

        function vertexCallback($vertex) {
                glColor3dv(array_slice($vertex, 3));
                glVertex3dv($vertex);
        }

        function combineCallback($coords, $vertex_data, $weight, &$dataOut) {
                $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;
        }

        function init() {
                global $startList;

                $rect = array(
                        array(50.0, 50.0, 0.0),
                        array(200.0, 50.0, 0.0),
                        array(200.0, 200.0, 0.0),
                        array(50.0, 200.0, 0.0)
                );
                $tri = array(
                        array(75.0, 75.0, 0.0),
                        array(125.0, 175.0, 0.0),
                        array(175.0, 75.0, 0.0)
                );
                $star = array(
                        array(250.0, 50.0, 0.0, 1.0, 0.0, 1.0),
                        array(325.0, 200.0, 0.0, 1.0, 1.0, 0.0),
                        array(400.0, 50.0, 0.0, 0.0, 1.0, 1.0),
                        array(250.0, 150.0, 0.0, 1.0, 0.0, 0.0),
                        array(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, 'glVertex3dv');
                gluTessCallback($tobj, GLU_TESS_BEGIN, 'beginCallback');
                gluTessCallback($tobj, GLU_TESS_END, 'endCallback');
                gluTessCallback($tobj, GLU_TESS_ERROR, 'errorCallback');

                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($tobj, GLU_TESS_VERTEX, 'vertexCallback');
                gluTessCallback($tobj, GLU_TESS_BEGIN, 'beginCallback');
                gluTessCallback($tobj, GLU_TESS_END, 'endCallback');
                gluTessCallback($tobj, GLU_TESS_ERROR, 'errorCallback');
                gluTessCallback($tobj, GLU_TESS_COMBINE, 'combineCallback');

                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);
        }

        function reshape($w, $h) {
                glViewport(0, 0, $w, $h);
                glMatrixMode(GL_PROJECTION);
                glLoadIdentity();
                gluOrtho2D(0.0, $w, 0.0, $h);
        }

        glutInit($argv);
        glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
        glutInitWindowSize(500, 500);
        glutCreateWindow($argv[0]);
        init();
        glutDisplayFunc('display');
        glutReshapeFunc('reshape');
        glutMainLoop();