JOGLで市松模様の面を描画する

JOGLで市松模様の面を描画するには、以下のコードを実行します。

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

public class JoglSample27
{
  // 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)0x77/(float)0xff,
                  (float)0x99/(float)0xff,
                  (float)0xff/(float)0xff,
                  1f);
          }

          public void display(GLAutoDrawable dr)
          {
              GL gl = dr.getGL();
              GLUT glut = new GLUT();
              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(-2.0f, -2.0f, -12.0f);

              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.glEnable(GL.GL_CULL_FACE);
              gl.glClear(GL.GL_COLOR_BUFFER_BIT |
                  GL.GL_DEPTH_BUFFER_BIT );

              gl.glPushMatrix();
              // X軸回転
              gl.glRotatef(-70.0f, 1.0f, 0.0f, 0.0f);

               float tw = 0.4f;
               float th = 0.4f;
               int xs = 10;
               int ys = 10;
               for(int ly=0;ly<ys;ly++){
                   for(int lx=0;lx<xs;lx++){
                       if( (lx+ly)%2 == 0 ){
                           gl.glColor3f(
                             (float)0xf0/(float)0xff,
                             (float)0xf0/(float)0xff,
                             (float)0xf0/(float)0xff
                           );
                       } else {
                           gl.glColor3f(
                             (float)0x40/(float)0xff,
                             (float)0x40/(float)0xff,
                             (float)0x40/(float)0xff
                           );
                       }
                       gl.glRectf(lx*tw,ly*th,
                           (lx+1)*tw,(ly+1)*tw);
                   }
               }

               gl.glPopMatrix();
           }

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

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

       GLContext context =  buf.createContext(null);
       context.makeCurrent();
       buf.display();
       Screenshot.writeToFile(
           new File("sample1185a.png"), width, height, true);
       context.release();
       context.destroy();
   }
}

出力画像(sample1185a.png)