Android開發(fā)之繪制平面上的多邊形功能分析

public class MyRenderer implements Renderer
{
 float[] triangleData = new float []{
   0.1f,0.6f,0.0f,//上頂點(diǎn)
   -0.3f,0.0f,0.0f,//左頂點(diǎn)
   0.3f,0.1f,0.0f//右頂點(diǎn)
 };
 int[] triangleColor = new int []{
   65535,0,0,0,//上頂點(diǎn)紅色
   0,65535,0,0,//左頂點(diǎn)綠色
   0,0,65535,0//右頂點(diǎn)藍(lán)色
 };
 float[] rectData = new float[]{
   0.4f,0.4f,0.0f,//右上頂點(diǎn)
   0.4f,-0.4f,0.0f,//右下頂點(diǎn)
   -0.4f,0.4f,0.0f,//左上頂點(diǎn)
   -0.4f,-0.4f,0.0f//左下頂點(diǎn)
 };
 int[] rectColor = new int []{
   0,65535,0,0,//右上頂點(diǎn)綠色
   0,0,65535,0,//右下頂點(diǎn)藍(lán)色
   65535,0,0,0,//左上頂點(diǎn)紅色
   65535,65535,0,0//左下頂點(diǎn)黃色
 };
 float[] rectData2 = new float[]{
   -0.4f,0.4f,0.0f,//左上頂點(diǎn)
   0.4f,0.4f,0.0f,
   0.4f,-0.4f,0.0f,
   -0.4f,-0.4f,0.0f
rectColorBuffer };
 float[] pentacle = new float[]{
   0.4f,0.4f,0.0f,
   -0.2f,0.3f,0.0f,
   0.5f,0.0f,0f,
   -0.4f,0.0f,0f
   -0.1f,-0.3f,0f
 };
 FloatBuffer triangleDataBuffer;
 IntBuffer triangleColorBuffer;
 FloatBuffer rectDataBuffer;
 FloatBuffer rectDataBuffer2;
 FloatBuffer pentacleBuffer;
 IntBuffer rectDataBuffer;
 public MyRenderer()
 {
  //將頂點(diǎn)位置數(shù)據(jù)數(shù)組包裝成FloatBuffer；
  triangleDataBuffer = FloatBuffer.wrap(triangleData);
  rectDataBuffer =FloatBuffer.wrap(rectData);
  rectDataBuffer2 =FloatBuffer.wrap(rectData2);
  pentacleBuffer = FloatBuffer.wrap(pentacle);
  //將頂點(diǎn)顏色數(shù)據(jù)數(shù)組包裝成IntBuffer；
  triangleColorBuffer=IntBuffer.wrap(triangleColor);
  rectColorBuffer= IntBuffer.wrap(rectColor);
 };
 //關(guān)閉抗抖動(dòng)
  gl.glDisable(GL10.GL_DITHER);
  //設(shè)置系對(duì)透視進(jìn)行修正
  gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
  gl.glClearColor(0, 0, 0, 0);
  //設(shè)置陰影平滑模式
  gl.glShadeModel(GL10.GL_SMOOTH);
  //啟用深度測(cè)試
  gl.glEnable(GL10.GL_DEPTH_TEST);
  //設(shè)置深度測(cè)試的類型
  gl.glDepthFunc(GL10.GL_LEQUAL);
 }
 public void onSurfaceChanged(GL10 gl,int width,int height)
 {
  //設(shè)置3D視窗的大小和位置
  gl.glViewport(0,0,width,height);
  //將當(dāng)前矩陣模式設(shè)為投影矩陣
  gl.glMatrixMode(GL10.GL_PROJECTION);
  //初始化單位矩陣
  gl.glLoadIdentity();
  //計(jì)算透視視窗的寬度、高度比
  float ratio = (float)width/height;
  //調(diào)用此方法設(shè)置透視視窗的空間大小
  gl.glFrustumf(-ratio,ratio,-1,1,1,10);
 }
 public void onDrawFrame(GL10 gl)
 {
  //清除屏幕緩存和深度緩存
  gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);
  //啟用頂點(diǎn)坐標(biāo)數(shù)據(jù)
  gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
  //啟用頂點(diǎn)顏色數(shù)據(jù)
  gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
  //設(shè)置當(dāng)前矩陣堆棧為模型堆棧
  gl.glMatrixMode(GL10.GL_MODELVIEW);
  //繪制第一個(gè)圖形，重置當(dāng)前的模型視圖矩陣
  gl.glLoadIdentity();
  gl.glTranslatef(-0.32f, 0.35f, -1f);
  //設(shè)置頂點(diǎn)的位置數(shù)據(jù)
  gl.glVertexPointer(3, GL10.GL_FLOAT, 0, triangleDataBuffer);
  //設(shè)置頂點(diǎn)的顏色數(shù)據(jù)
  gl.glColorPointer(4, GL10.GL_FIXED, 0, triangleColorBuffer);
  //根據(jù)頂點(diǎn)數(shù)據(jù)繪制平面圖形
  gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
  //繪制第二個(gè)圖形
  gl.glLoadIdentity();
  gl.glTranslatef(0.6f, 0.8f, -1.5f);
  gl.glVertexPointer(3, GL10.GL_FLOAT, 0, rectDataBuffer);
  gl.glColorPointer(4, GL10.GL_FIXED, 0, rectColorBuffer);
  gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,4);
  //繪制第三個(gè)圖形
  gl.glLoadIdentity();
  gl.glTranslatef(-0.4f, -0.5f, -1.5f);
  gl.glVertexPointer(3,GL10.GL_FLOAT, 0, rectDataBuffer2);
  gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,4);
  //
  gl.glLoadIdentity();
  gl.glTranslatef(0.4f, -0.5f, -1.5f);
  //設(shè)置使用純色填充
  gl.glColor4f(1.0f,0.2f,0.2f,0.0f);
  gl.glDisableClientState(GL10.GL_COLOR_ARRAY);
  gl.glVertexPointer(3, GL10.GL_FLOAT, 0,penTacleBuffer);
  gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP,0,5);
  //繪制結(jié)束
  gl.glFinish();
  gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
 }
}

public void Polygon extends Activity
{
 public void onCreate(Bundle savedInstanceState)
 {
  super.onCreate(savedInstanceState);
  //創(chuàng)建一個(gè)GLSurfaceView，用于顯示OpenGL繪制的圖形
  GLSurfaceView glView = new GLSurfaceView(this);
  //創(chuàng)建GLSurfaceView的內(nèi)容繪制器
  MyRenderer myRender = new MyRenderer();
  //為GLSurfaceView設(shè)置繪制器
  glView.setRenderer(myRender);
  setContentView(glView);
 }
}