openGL es学习（1.画点与画线）

1.创建一个接口，好处在于直接在activity修改渲染操作，免得换来换去

package com.opengles;

import javax.microedition.khronos.opengles.GL10;

public interface IOpenGLDemo {
    public void DrawScene(GL10 gl);
}

2.创建渲染类OpenGLRenderer

package com.opengles;

import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;

import android.opengl.GLSurfaceView.Renderer;
import android.opengl.GLU;

public class OpenGLRenderer implements Renderer {

    private final IOpenGLDemo openGLDemo;

    public OpenGLRenderer(IOpenGLDemo demo) {
        openGLDemo = demo;
    }

    public void onSurfaceCreated(GL10 gl, EGLConfig config) {
        // Set the background color to black ( rgba ).
        //黑色背景
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.5f);
        // Enable Smooth Shading, default not really needed.
        // 启用阴影平滑（不是必须的）
        gl.glShadeModel(GL10.GL_SMOOTH);
        // Depth buffer setup.
        // 设置深度缓存
        gl.glClearDepthf(1.0f);
        // Enables depth testing.
        // 启用深度测试
        gl.glEnable(GL10.GL_DEPTH_TEST);
        // The type of depth testing to do.
        // 所作深度测试的类型
        gl.glDepthFunc(GL10.GL_LEQUAL);
        // Really nice perspective calculations.
        // 对透视进行修正
        gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_NICEST);

    }

    public void onDrawFrame(GL10 gl) {
        if (openGLDemo != null) {
            openGLDemo.DrawScene(gl);
        }
    }

    public void onSurfaceChanged(GL10 gl, int width, int height) {
        // Sets the current view port to the new size.
        // 设置画面的大小
        gl.glViewport(0, 0, width, height);
        // Select the projection matrix
        // 设置投影矩阵
        gl.glMatrixMode(GL10.GL_PROJECTION);
        // Reset the projection matrix
        // 重置投影矩阵
        gl.glLoadIdentity();
        // Calculate the aspect ratio of the window
        // 设置画面比例
        GLU.gluPerspective(gl, 45.0f, (float) width / (float) height, 0.1f,
                100.0f);
        // Select the modelview matrix
        // 选择模型观察矩阵
        gl.glMatrixMode(GL10.GL_MODELVIEW);
        // Reset the modelview matrix
        // 重置模型观察矩阵
        gl.glLoadIdentity();
    }
}

3.创建activity，实现上面的接口

package com.opengles;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.util.Random;

import javax.microedition.khronos.opengles.GL10;

import android.app.Activity;
import android.opengl.GLSurfaceView;
import android.os.Bundle;
import android.view.Window;
import android.view.WindowManager;

public class Main extends Activity implements IOpenGLDemo {

    private GLSurfaceView mGLSurfaceView;

    // 画点的坐标
    float[] vertexArray = new float[] { 
            -0.8f, -0.4f * 1.732f, 0.0f, 
            0.8f,-0.4f * 1.732f, 0.0f,
            0.0f, 0.4f * 1.732f, 0.0f, };

    // 画线的坐标
    float vertexArray2[] = { 
            -0.8f, -0.4f * 1.732f, 0.0f,
            -0.4f, 0.4f * 1.732f,0.0f, 
            0.0f, -0.4f * 1.732f, 0.0f, 
            0.4f, 0.4f * 1.732f, 0.0f, };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        this.requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);

        mGLSurfaceView = new GLSurfaceView(this);
        mGLSurfaceView.setRenderer(new OpenGLRenderer(this));
        setContentView(mGLSurfaceView);
    }

    //渲染操作就在DrawScene(GL10 gl)这个办法操作
    // 画背景色
    // public void DrawScene(GL10 gl) {
    // gl.glClearColor(0f, 0f, 1.0f, 0.0f);//设置背景颜色
    // // Clears the screen and depth buffer.
    // gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
    // }

    // 画点
//     public void DrawScene(GL10 gl) {
//     gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);//每次画页面把上次的缓存清除掉
//     //System.out.println("这里已经执行");
//     ByteBuffer vbb = ByteBuffer.allocateDirect(vertexArray.length * 4);
//     vbb.order(ByteOrder.nativeOrder());
//     FloatBuffer vertex = vbb.asFloatBuffer();
//     vertex.put(vertexArray);
//     vertex.position(0);
//    
//     gl.glColor4f(1.0f, 0.0f, 0.0f, 1.0f);//点的颜色
//     gl.glPointSize(18f);
//     gl.glLoadIdentity();
//     gl.glTranslatef(0, 0, -4);
//    
//     gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
//    
//     gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertex);//3表示xyz3唯坐标
//     gl.glDrawArrays(GL10.GL_POINTS, 0, 3);
//    
//     gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
//    
//     }

    // 画线
    public void DrawScene(GL10 gl) {
        gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
        ByteBuffer vbb = ByteBuffer.allocateDirect(vertexArray2.length * 4);
        vbb.order(ByteOrder.nativeOrder());
        FloatBuffer vertex = vbb.asFloatBuffer();
        vertex.put(vertexArray);
        vertex.position(0);

        gl.glLoadIdentity();
        gl.glTranslatef(0, 0, -4);

        gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

        gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertex);

        int index = new Random().nextInt(4);
        switch (index) {

        case 1:
            gl.glColor4f(1.0f, 0.0f, 0.0f, 1.0f);
            gl.glDrawArrays(GL10.GL_LINES, 0, 4);
            break;
        case 2:
            gl.glColor4f(0.0f, 1.0f, 0.0f, 1.0f);
            gl.glDrawArrays(GL10.GL_LINE_STRIP, 0, 4);
            break;
        case 3:
            gl.glColor4f(0.0f, 0.0f, 1.0f, 1.0f);
            gl.glDrawArrays(GL10.GL_LINE_LOOP, 0, 4);
            break;
        }

        gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

    }

    @Override
    protected void onResume() {
        // Ideally a game should implement
        // onResume() and onPause()
        // to take appropriate action when the
        // activity looses focus
        super.onResume();
        mGLSurfaceView.onResume();
    }

    @Override
    protected void onPause() {
        // Ideally a game should implement onResume()
        // and onPause()
        // to take appropriate action when the
        // activity looses focus
        super.onPause();
        mGLSurfaceView.onPause();
    }

}

参考于：http://www.apkbus.com/android-20427-1-1.html