android OpenGL ES 2.0

一、创建Activity/*为OpenGLES Graphics创建一个Activity,这个Activity与其它类型应用的Activity并无不同，要说不同，也仅仅是放到Activity的layout的View不一样，你需要放入的是一个GLSurfaceView。*/public class OpenGLES20Basic extends Activity {     private GLSurfaceView mGLView;    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        // Create a GLSurfaceView instance and set it as the ContentView for this Activity        /* 为了能在你的Android应用中使用OpenGLES绘画，你必须创建一个view作为容器。而最直接的方式就是从GLSurfaceView和 GLSurfaceView.Renderer分别派生一个类        。GLSurfaceView作为OpenGL绘制所在的容器，而实际的绘图动作都是在GLSurfaceView.Renderer里面发生的。 MyGLSurfaceView 继承自GLSurfaceView，作为承载绘          制内容的容器 */                  mGLView = new MyGLSurfaceView(this);          setContentView(mGLView);     }       @Override protected void onPause() { super.onPause(); // The following call pauses the rendering thread. // If your OpenGL application is memory intensive, // you should consider de-allocating objects that // consume significant memory here. mGLView.onPause(); } @Override protected void onResume() { super.onResume(); // The following call resumes a paused rendering thread. // If you de-allocated graphic objects for onPause() // this is a good place to re-allocate them. mGLView.onResume(); }}二、创建MySurfaceView/* 构键一个GLSurfaceView对象，GLSurfaceView中其实不需要做太多工作，实际的绘制任务都在GLSurfaceView.Renderer中了。所以GLSurfaceView中的代码也非常少，你甚至可以直接使用GLSurfaceView，但是，然而，别这样做。因为可以扩展这个类来响应触摸事件等。*/class MyGLSurfaceView extends GLSurfaceView {    public MyGLSurfaceView(Context context) {        super(context);        // Create an OpenGL ES 2.0 context.        setEGLContextClientVersion(2);        // Set the Renderer for drawing on the GLSurfaceView        setRenderer(new MyGLRenderer());        /*         Render the view only when there is a change in the drawing data，这个设置是可选的操作，在RENDERMODE_WHEN_DIRTY模式下，只在绘制数据发生改变时才绘制view，此设置会阻止绘制GLSurfaceView的帧，直到你调用了requestRender()，这样会非常高效。*/        setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);    }}二、创建MyGLRenderer /* 此类控制向GLSurfaceView的绘制工作。它有三个方法被Android系统调用来计算在GLSurfaceView上画什么以及如何画。onSurfaceCreated()- 仅调用一次，用于设置view的OpenGLES环境。onDrawFrame()- 每次View被重绘时被调用。onSurfaceChanged()- 如果view的几和形状发生变化了就调用，例如当竖屏变为横屏时。*/public class MyGLRenderer implements GLSurfaceView.Renderer {    private Triangle mTriangle;    @Override    public void onSurfaceCreated(GL10 unused, EGLConfig config) {        // Set the background frame color，设置背景颜色        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);        //定义需要绘制的三角形        mTriangle = new Triangle();    }    @Override    public void onDrawFrame(GL10 unused) {        // Draw background color，绘制背景颜色        GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);        // Draw triangle，执行绘制操作        mTriangle.draw();    }    @Override    public void onSurfaceChanged(GL10 unused, int width, int height) {        // Adjust the viewport based on geometry changes,        // such as screen rotation        GLES20.glViewport(0, 0, width, height);    }    /*下载并编译shader代码*/    public static int loadShader(int type, String shaderCode){        // create a vertex shader type (GLES20.GL_VERTEX_SHADER)        // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)        int shader = GLES20.glCreateShader(type);        // add the source code to the shader and compile it        GLES20.glShaderSource(shader, shaderCode);        GLES20.glCompileShader(shader);        return shader;    }}class Triangle {    //顶点着色器    private final String vertexShaderCode =        "attribute vec4 vPosition;" +        "void main() {" +        "  gl_Position = vPosition;" +        "}";    //片段着色器    private final String fragmentShaderCode =        "precision mediump float;" +        "uniform vec4 vColor;" +        "void main() {" +        "  gl_FragColor = vColor;" +        "}";    private final FloatBuffer vertexBuffer;//顶点buffer    private final int mProgram;            //程序对象    private int mPositionHandle;           //顶点数据在buffer中的位置    private int mColorHandle;              //颜色数据在buffer中的位置    // number of coordinates per vertex in this array    static final int COORDS_PER_VERTEX = 3;    static float triangleCoords[] = { // in counterclockwise order:         0.0f,  0.622008459f, 0.0f,   // top        -0.5f, -0.311004243f, 0.0f,   // bottom left         0.5f, -0.311004243f, 0.0f    // bottom right    };    private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;    private final int vertexStride = COORDS_PER_VERTEX * 4; // bytes per vertex    // Set color with red, green, blue and alpha (opacity) values    float color[] = { 0.63671875f, 0.76953125f, 0.22265625f, 1.0f };    public Triangle() {        // initialize vertex byte buffer for shape coordinates        ByteBuffer bb = ByteBuffer.allocateDirect( triangleCoords.length * 4);// (number of coordinate values * 4 bytes per float                                       // use the device hardware's native byte order        bb.order(ByteOrder.nativeOrder());        // create a floating point buffer from the ByteBuffer        vertexBuffer = bb.asFloatBuffer();        // add the coordinates to the FloatBuffer        vertexBuffer.put(triangleCoords);        // set the buffer to read the first coordinate        vertexBuffer.position(0);        // prepare shaders and OpenGL program        int vertexShader = MyGLRenderer.loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);        int fragmentShader = MyGLRenderer.loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);        mProgram = GLES20.glCreateProgram();             // create empty OpenGL Program        GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program        GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program        GLES20.glLinkProgram(mProgram);                  // create OpenGL program executable    }    public void draw() {        // Add program to OpenGL environment        GLES20.glUseProgram(mProgram);        // get handle to vertex shader's vPosition member        mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");//着色器中定义的变量vPosition对应mPositionHandle         // Enable a handle to the triangle vertices        GLES20.glEnableVertexAttribArray(mPositionHandle);        // Prepare the triangle coordinate data        GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX,                                     GLES20.GL_FLOAT, false,                                     vertexStride, vertexBuffer);        // get handle to fragment shader's vColor member        mColorHandle = GLES20.glGetUniformLocation(mProgram, "vColor");//着色器中定义的变量vColor对应mColorHandle         // Set color for drawing the triangle        GLES20.glUniform4fv(mColorHandle, 1, color, 0);        // Draw the triangle        GLES20.glDrawArrays(GLES20.GL_TRIANGLES, 0, vertexCount);        // Disable vertex array        GLES20.glDisableVertexAttribArray(mPositionHandle);    }}也可以参考http://blog.csdn.net/niu_gao/article/details/8533126，一步一步学习OpenGL ES 2.0系列1-6
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