Android开发培训(08)－－使用openGL ES作图

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<uses-feature android:glEsVersion="0x00020000" android:required="true" />

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<supports-gl-texture android:name="GL_OES_compressed_ETC1_RGB8_texture" />
<supports-gl-texture android:name="GL_OES_compressed_paletted_texture" />

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public class OpenGLES20Activity 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.
mGLView = new MyGLSurfaceView(this);
setContentView(mGLView);
}
}

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class MyGLSurfaceView extends GLSurfaceView {
private final MyGLRenderer mRenderer;
public MyGLSurfaceView(Context context){
super(context);
// Create an OpenGL ES 2.0 context
setEGLContextClientVersion(2);
mRenderer = new MyGLRenderer();
// Set the Renderer for drawing on the GLSurfaceView
setRenderer(mRenderer);
}
}

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// Render the view only when there is a change in the drawing data
setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);

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public class MyGLRenderer implements GLSurfaceView.Renderer {
public void onSurfaceCreated(GL10 unused, EGLConfig config) {
// Set the background frame color
GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
}
public void onDrawFrame(GL10 unused) {
// Redraw background color
GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
}
public void onSurfaceChanged(GL10 unused, int width, int height) {
GLES20.glViewport(0, 0, width, height);
}
}

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package com.example.www.graphictest;
import android.opengl.GLSurfaceView;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
private GLSurfaceView mGLView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create a GLSurfaceView instance and set it as the ContentView for this Activity
mGLView = new MyGLSurfaceView(this);
setContentView(mGLView);
}
}

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package com.example.www.graphictest;
import android.content.Context;
import android.opengl.GLSurfaceView;
/**
* Created by wang on 17-8-26.
*/
class MyGLSurfaceView extends GLSurfaceView {
private final MyGLRenderer mRenderer;
public MyGLSurfaceView(Context context) {
super(context);
// Create a OpenGL ES 3.0 context
setEGLContextClientVersion(3);
mRenderer = new MyGLRenderer();
setRenderer(mRenderer);
// Render the view only when there is a change in the drawing data
setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
}
}

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package com.example.www.graphictest;
import android.opengl.GLES30;
import android.opengl.GLSurfaceView;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.opengles.GL10;
/**
* Created by wang on 17-8-26.
*/
class MyGLRenderer implements GLSurfaceView.Renderer{
@Override
public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {
// Set the background frame color
GLES30.glClearColor(0.0f, 0.4f, 0.3f, 1.0f);
}
@Override
public void onSurfaceChanged(GL10 gl10, int width, int height) {
// Adjust the viewport based on geometry changes, such as screen rotaion
GLES30.glViewport(0, 0, width, height);
}
@Override
public void onDrawFrame(GL10 gl10) {
// Draw background color
GLES30.glClear(GLES30.GL_COLOR_BUFFER_BIT | GLES30.GL_DEPTH_BUFFER_BIT);
}
}

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public class Triangle {
private FloatBuffer vertexBuffer;
// 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
};
// 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(
// (number of coordinate values * 4 bytes per float)
triangleCoords.length * 4);
// 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);
}
}

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public class Square {
private FloatBuffer vertexBuffer;
private ShortBuffer drawListBuffer;
// number of coordinates per vertex in this array
static final int COORDS_PER_VERTEX = 3;
static float squareCoords[] = {
-0.5f,
0.5f, 0.0f,
// top left
-0.5f, -0.5f, 0.0f,
// bottom left
0.5f, -0.5f, 0.0f,
// bottom right
0.5f,
0.5f, 0.0f }; // top right
private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices
public Square() {
// initialize vertex byte buffer for shape coordinates
ByteBuffer bb = ByteBuffer.allocateDirect(
// (# of coordinate values * 4 bytes per float)
squareCoords.length * 4);
bb.order(ByteOrder.nativeOrder());
vertexBuffer = bb.asFloatBuffer();
vertexBuffer.put(squareCoords);
vertexBuffer.position(0);
// initialize byte buffer for the draw list
ByteBuffer dlb = ByteBuffer.allocateDirect(
// (# of coordinate values * 2 bytes per short)
drawOrder.length * 2);
dlb.order(ByteOrder.nativeOrder());
drawListBuffer = dlb.asShortBuffer();
drawListBuffer.put(drawOrder);
drawListBuffer.position(0);
}
}

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public class MyGLRenderer implements GLSurfaceView.Renderer {
...
private Triangle mTriangle;
private Square
mSquare;
public void onSurfaceCreated(GL10 unused, EGLConfig config) {
...
// initialize a triangle
mTriangle = new Triangle();
// initialize a square
mSquare = new Square();
}
...
}

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public class Triangle {
private final String vertexShaderCode =
"attribute vec4 vPosition;" +
"void main() {" +
"
gl_Position = vPosition;" +
"}";
private final String fragmentShaderCode =
"precision mediump float;" +
"uniform vec4 vColor;" +
"void main() {" +
"
gl_FragColor = vColor;" +
"}";
...
}

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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;
}

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private int mPositionHandle;
private int mColorHandle;
private final int vertexCount = triangleCoords.length / COORDS_PER_VERTEX;
private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
public void draw() {
// Add program to OpenGL ES environment
GLES20.glUseProgram(mProgram);
// get handle to vertex shader's vPosition member
mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
// 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");
// 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);
}