Android应用开发揭秘的第26个程序12_2_openglcolor修改版和高仿版的源码注释

//为三角形和长方形加上颜色

//GfopenelcolorActivity.java

package pak.gfopenglcolor;

import android.app.Activity;

import android.opengl.GLSurfaceView;

import android.opengl.GLSurfaceView.Renderer;

import android.os.Bundle;

public class GfopenelcolorActivity extends Activity

{

Renderer render = new GLRender();

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState)

{

super.onCreate(savedInstanceState);

GLSurfaceView glView = new GLSurfaceView(this);

glView.setRenderer(render);

setContentView(glView);

}

}

//GLRender.java

package pak.gfopenglcolor;

import java.nio.IntBuffer;

import javax.microedition.khronos.egl.EGLConfig;

import javax.microedition.khronos.opengles.GL10;

import android.opengl.GLSurfaceView.Renderer;

public class GLRender implements Renderer

{

int one = 0x10000;

//三角形三个顶点

private IntBuffer triggerBuffer = IntBuffer.wrap(new int[]{

0,one,0, //上顶点

-one,-one,0, //坐下点

one,-one,0,}); //右下点

//正方形的4个顶点

private IntBuffer quaterBuffer = IntBuffer.wrap(new int[]{

one,one,0,

-one,one,0,

one,-one,0,

-one,-one,0});

//三角形的顶点颜色值(r,g,b,a)

private IntBuffer colorBuffer = IntBuffer.wrap(new int[]{

one,0,0,one,

0,one,0,one,

0,0,one,one,

});

@Override

public void onDrawFrame(GL10 gl)

{

// 清除屏幕和深度缓存

gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);

// 重置当前的模型观察矩阵

gl.glLoadIdentity();

// 左移 1.5 单位，并移入屏幕 6.0

gl.glTranslatef(-1.5f, 0.0f, -6.0f);

//设置定点数组

gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

//设置颜色数组

gl.glEnableClientState(GL10.GL_COLOR_ARRAY);

gl.glColorPointer(4, GL10.GL_FIXED, 0, colorBuffer);

// 设置三角形顶点

gl.glVertexPointer(3, GL10.GL_FIXED, 0, triggerBuffer);

//绘制三角形

gl.glDrawArrays(GL10.GL_TRIANGLES, 0, 3);

gl.glDisableClientState(GL10.GL_COLOR_ARRAY);

/* 渲染正方形 */

// 设置当前色为蓝色

gl.glColor4f(0.5f, 0.5f, 1.0f, 1.0f);

// 重置当前的模型观察矩阵

gl.glLoadIdentity();

// 左移 1.5 单位，并移入屏幕 6.0

gl.glTranslatef(1.5f, 0.0f, -6.0f);

//设置和绘制正方形

gl.glVertexPointer(3, GL10.GL_FIXED, 0, quaterBuffer);

gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, 0, 4);

//取消顶点数组

gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

}

@Override

public void onSurfaceChanged(GL10 gl, int width, int height)

{

// TODO Auto-generated method stub

float ratio = (float) width / height;

//设置OpenGL场景的大小

gl.glViewport(0, 0, width, height);

//设置投影矩阵

gl.glMatrixMode(GL10.GL_PROJECTION);

//重置投影矩阵

gl.glLoadIdentity();

// 设置视口的大小

gl.glFrustumf(-ratio, ratio, -1, 1, 1f, 10);

// 选择模型观察矩阵

gl.glMatrixMode(GL10.GL_MODELVIEW);

// 重置模型观察矩阵

gl.glLoadIdentity();

}

@Override

public void onSurfaceCreated(GL10 gl, EGLConfig config)

{

// 启用阴影平滑

gl.glShadeModel(GL10.GL_SMOOTH);

// 黑色背景

gl.glClearColor(0, 0, 0, 0);

// 设置深度缓存

gl.glClearDepthf(1.0f);

// 启用深度测试

gl.glEnable(GL10.GL_DEPTH_TEST);

// 所作深度测试的类型

gl.glDepthFunc(GL10.GL_LEQUAL);

// 告诉系统对透视进行修正

gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);

}

}