Android开发之绘制平面上的多边形功能分析

public class MyRenderer implements Renderer
{
float[] triangleData = new float []{
0.1f,0.6f,0.0f,//上顶点
-0.3f,0.0f,0.0f,//左顶点
0.3f,0.1f,0.0f//右顶点
};
int[] triangleColor = new int []{
65535,0,0,0,//上顶点红色
0,65535,0,0,//左顶点绿色
0,0,65535,0//右顶点蓝色
};
float[] rectData = new float[]{
0.4f,0.4f,0.0f,//右上顶点
0.4f,-0.4f,0.0f,//右下顶点
-0.4f,0.4f,0.0f,//左上顶点
-0.4f,-0.4f,0.0f//左下顶点
};
int[] rectColor = new int []{
0,65535,0,0,//右上顶点绿色
0,0,65535,0,//右下顶点蓝色
65535,0,0,0,//左上顶点红色
65535,65535,0,0//左下顶点黄色
};
float[] rectData2 = new float[]{
-0.4f,0.4f,0.0f,//左上顶点
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()
{
//将顶点位置数据数组包装成FloatBuffer；
triangleDataBuffer = FloatBuffer.wrap(triangleData);
rectDataBuffer =FloatBuffer.wrap(rectData);
rectDataBuffer2 =FloatBuffer.wrap(rectData2);
pentacleBuffer = FloatBuffer.wrap(pentacle);
//将顶点颜色数据数组包装成IntBuffer；
triangleColorBuffer=IntBuffer.wrap(triangleColor);
rectColorBuffer= IntBuffer.wrap(rectColor);
};
//关闭抗抖动
gl.glDisable(GL10.GL_DITHER);
//设置系对透视进行修正
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
gl.glClearColor(0, 0, 0, 0);
//设置阴影平滑模式
gl.glShadeModel(GL10.GL_SMOOTH);
//启用深度测试
gl.glEnable(GL10.GL_DEPTH_TEST);
//设置深度测试的类型
gl.glDepthFunc(GL10.GL_LEQUAL);
}
public void onSurfaceChanged(GL10 gl,int width,int height)
{
//设置3D视窗的大小和位置
gl.glViewport(0,0,width,height);
//将当前矩阵模式设为投影矩阵
gl.glMatrixMode(GL10.GL_PROJECTION);
//初始化单位矩阵
gl.glLoadIdentity();
//计算透视视窗的宽度、高度比
float ratio = (float)width/height;
//调用此方法设置透视视窗的空间大小
gl.glFrustumf(-ratio,ratio,-1,1,1,10);
}
public void onDrawFrame(GL10 gl)
{
//清除屏幕缓存和深度缓存
gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);
//启用顶点坐标数据
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
//启用顶点颜色数据
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);
//设置当前矩阵堆栈为模型堆栈
gl.glMatrixMode(GL10.GL_MODELVIEW);
//绘制第一个图形，重置当前的模型视图矩阵
gl.glLoadIdentity();
gl.glTranslatef(-0.32f, 0.35f, -1f);
//设置顶点的位置数据
gl.glVertexPointer(3, GL10.GL_FLOAT, 0, triangleDataBuffer);
//设置顶点的颜色数据
gl.glColorPointer(4, GL10.GL_FIXED, 0, triangleColorBuffer);
//根据顶点数据绘制平面图形
gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);
//绘制第二个图形
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);
//绘制第三个图形
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);
//设置使用纯色填充
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);
//绘制结束
gl.glFinish();
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
}
}

public void Polygon extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
//创建一个GLSurfaceView，用于显示OpenGL绘制的图形
GLSurfaceView glView = new GLSurfaceView(this);
//创建GLSurfaceView的内容绘制器
MyRenderer myRender = new MyRenderer();
//为GLSurfaceView设置绘制器
glView.setRenderer(myRender);
setContentView(glView);
}
}