JOGLで凹んだポリゴンを描画する

JOGLで凹んだポリゴンを描画するには、以下のコードを実行します。

import java.io.*;
import javax.media.opengl.*;
import javax.media.opengl.glu.*;
import com.sun.opengl.util.*;

public class JoglSample59
{
    // 出力画像サイズ
    private static int width = 300;
    private static int height = 300;

    public static void main(String args[])
        throws IOException
    {
        GLDrawableFactory gldf = 
            GLDrawableFactory.getFactory();
        GLCapabilities glc = new GLCapabilities();
        glc.setDoubleBuffered(false);
        GLPbuffer buf = gldf.createGLPbuffer(
           glc, null, width, height, null);

        buf.addGLEventListener(
            new GLEventListener(){
            // 初期化
            public void init(GLAutoDrawable dr)
            {
                GL gl = dr.getGL();
                // 背景色
                gl.glClearColor(
                    (float)0xf0/(float)0xff, 
                    (float)0xf0/(float)0xff, 
                    (float)0xf0/(float)0xff,
                    1f);
            }

            public void display(GLAutoDrawable dr)
            {
                GL gl = dr.getGL();
                GLU glu = new GLU();
                gl.glViewport(0, 0, width, height);

                // 透視投影
                gl.glMatrixMode(GL.GL_PROJECTION);
                gl.glLoadIdentity();
                float ratio = (float)height/(float)width;
                gl.glFrustum(-1.0f, 1.0f, -ratio, ratio,
                    5.0f, 40.0f);

                gl.glMatrixMode(GL.GL_MODELVIEW);
                gl.glLoadIdentity();
                gl.glTranslatef(0.0f, 0.0f, -7.0f);

                gl.glEnable(GL.GL_LIGHTING);
                gl.glEnable(GL.GL_LIGHT0);
                gl.glEnable(gl.GL_COLOR_MATERIAL);
                gl.glEnable(GL.GL_NORMALIZE);
                gl.glEnable(GL.GL_DEPTH_TEST);
                gl.glClear(GL.GL_COLOR_BUFFER_BIT |GL.GL_DEPTH_BUFFER_BIT );

                gl.glPushMatrix();
                // 面の色を設定
                gl.glColor3f(
                    (float)0x77/(float)0xff, 
                    (float)0x99/(float)0xff, 
                    (float)0xff/(float)0xff
                );

                GLUtessellator tess = glu.gluNewTess();

                TessCB tcb = new TessCB(gl, glu);
                glu.gluTessCallback(tess, GLU.GLU_TESS_VERTEX, tcb);
                glu.gluTessCallback(tess, GLU.GLU_TESS_BEGIN, tcb);
                glu.gluTessCallback(tess, GLU.GLU_TESS_END, tcb);
                glu.gluTessCallback(tess, GLU.GLU_TESS_ERROR, tcb);

                double va[][] = {
                    {1.0, -1.0, 0.0,},
                    {1.0, 1.0, 0.0},
                    {-1.0, 1.0, 0.0},
                    {-1.0, -1.0, 0.0},
                    {0.0, -0.5, 0.0}
                };

                glu.gluTessBeginPolygon(tess, null);
                glu.gluTessBeginContour(tess);
                for(int al=0;al<va.length;al++){
                    glu.gluTessVertex(tess, va[al], 0, va[al]);
                }
                glu.gluTessEndContour(tess);
                glu.gluTessEndPolygon(tess);


                gl.glPopMatrix();
            }

            public void reshape(
                GLAutoDrawable dr,
                int x, int y,
                int width, int height){}

            public void displayChanged(
                GLAutoDrawable dr,
                boolean modeChanged,
                boolean deviceChanged){}


            class TessCB extends 
                GLUtessellatorCallbackAdapter 
            {
                private GL gl = null;
                private GLU glu = null;

                public TessCB(GL gla, GLU glua)
                {
                    gl = gla;
                    glu = glua;
                }
                public void begin(int type)
                {
                    gl.glBegin(type);
                }

                public void end()
                {
                    gl.glEnd();
                }

                public void vertex(Object vertexData)
                {
                    if( vertexData instanceof double[] ){
                        gl.glVertex3dv(
                            (double[])vertexData, 0);
                    }
                }

                public void error(int errnum)
                {
                    System.out.println(
                        glu.gluErrorString(errnum));
                    System.exit(0);
                }
            }
            }
        );

        GLContext context =  buf.createContext(null);
        context.makeCurrent();
        buf.display();
        Screenshot.writeToFile(
            new File("sample1217a.png"), width, height, true);
        context.release();
        context.destroy();
    }

}

出力画像(sample1217a.png)


動作環境
JDK6 Upadate13, JOGL 1.1.1