OpenGL ES 正交投影与透视投影效果对比的代码实现

package lxy.litsoft;

import android.app.Activity;
import android.os.Bundle;
import android.widget.CompoundButton;
import android.widget.CompoundButton.OnCheckedChangeListener;
import android.widget.LinearLayout;
import android.widget.ToggleButton;

public class MyActivity extends Activity {

private ToggleButton tb01;
private MySurfaceView mSurfaceView;
private LinearLayout ll;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSurfaceView = new MySurfaceView(this);
mSurfaceView.requestFocus();						//获取焦点
mSurfaceView.setFocusableInTouchMode(true);			//设置为可触控
ll = (LinearLayout)findViewById(R.id.main_line);
ll.addView(mSurfaceView);
tb01 = (ToggleButton)findViewById(R.id.ToggleButton01);
tb01.setOnCheckedChangeListener(new MyListener());
}

private class MyListener implements OnCheckedChangeListener{

@Override
public void onCheckedChanged(CompoundButton buttonView,
boolean isChecked) {
// TODO Auto-generated method stub
mSurfaceView.isPerspection = !mSurfaceView.isPerspection;
//正交投影与透视投影之间切换
mSurfaceView.requestRender();					//重新绘制
}

}

@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
mSurfaceView.onPause();					//挂起
}

@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
mSurfaceView.onResume();				//恢复
}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:id="@+id/main_line"
android:layout_width="fill_parent"
android:layout_height="fill_parent">

<ToggleButton
android:textOn="透视投影"
android:textOff="正交投影"
android:checked="false"
android:id="@+id/ToggleButton01"
android:layout_width="fill_parent"
android:layout_height="wrap_content"></ToggleButton>

</LinearLayout>

package lxy.litsoft;

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

import android.content.Context;
import android.opengl.GLSurfaceView;
import android.view.MotionEvent;

public class MySurfaceView extends GLSurfaceView{

private final float TOUCH_SCALE_FACTOR = 180.0f/320;	//角度缩放比例
private SceneRenderer myRender;							//场景渲染器
public boolean isPerspection = false;			//投影方式标志位
private float mPreviousY;								//上一次的触控位置Y坐标
public float xAngle = 0;								//整体绕x轴旋转的角度

public MySurfaceView(Context context) {
super(context);
// TODO Auto-generated constructor stub
myRender = new SceneRenderer();
this.setRenderer(myRender);							//设置渲染器
this.setRenderMode(GLSurfaceView.RENDERMODE_CONTINUOUSLY);//主动渲染
}

@Override
public boolean onTouchEvent(MotionEvent event) {		//触摸事件回调方法
// TODO Auto-generated method stub
float y = event.getY();								//获得当前触控点Y坐标
switch(event.getAction()){							//获取动作
case MotionEvent.ACTION_MOVE:						//判断是否是滑动
float dy = y - mPreviousY;						//计算触控笔y方向位移
xAngle += dy * TOUCH_SCALE_FACTOR;				//设置沿x轴旋转角度
requestRender();								//重新绘制
}
mPreviousY = y;										//作为上次触控y坐标
return true;
}

private class SceneRenderer implements GLSurfaceView.Renderer{

Hexagon[] ha = new Hexagon[]{					//六边形数组
new Hexagon(0),
new Hexagon(-2),
new Hexagon(-4),
new Hexagon(-6),
new Hexagon(-8),
new Hexagon(-10),
new Hexagon(-12),
};
public SceneRenderer(){}					//渲染器构造
@Override
public void onDrawFrame(GL10 gl) {
// TODO Auto-generated method stub
gl.glEnable(GL10.GL_CULL_FACE);			//设置打开背景剪裁
//			gl.glMatrixMode(GL10.GL_MODELVIEW);		//设置当前矩阵为模式矩阵
gl.glMatrixMode(GL10.GL_PROJECTION);	//设置当前矩阵为投影矩阵
gl.glLoadIdentity();					//设置当前矩阵为单位矩阵
float ratio = (float)320/480;			//透视投影的比例
if(isPerspection){
gl.glFrustumf(-ratio, ratio, -1, 1, 1f, 10);	//计算产生透视投影矩阵
}
else{
gl.glOrthof(-ratio, ratio, -1, 1, 1, 10);		//计算产生正交投影矩阵
}
gl.glShadeModel(GL10.GL_SMOOTH);		//设置平滑着色
gl.glClear(GL10.GL_COLOR_BUFFER_BIT|GL10.GL_DEPTH_BUFFER_BIT);//清除缓存
gl.glTranslatef(0, 0f, -1.4f);			//沿z轴向远处推
gl.glRotatef(xAngle, 1, 0, 0);			//绕x轴旋转指定角度
for(Hexagon th:ha){
th.drawSelf(gl);					//循环绘制六边形数组中的每个六边形
}
}

@Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
// TODO Auto-generated method stub
gl.glViewport(0, 0, width, height);		//设置视窗大小和位置
}

@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
// TODO Auto-generated method stub
gl.glDisable(GL10.GL_DITHER);			//关闭抗抖动
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);//设置Hint模式
gl.glClearColor(0, 0, 0, 0);			//背景着黑色
gl.glEnable(GL10.GL_DEPTH_TEST);		//启用深度测试
}
}
}

package lxy.litsoft;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;

import javax.microedition.khronos.opengles.GL10;

public class Hexagon {
private IntBuffer myVertexBuffer;		//顶点坐标数据缓冲
private IntBuffer myColorsBuffer;		//顶点着色数据缓冲
private ByteBuffer myIndexBuffer;		//顶点构建索引数据缓冲
int vCount = 0;							//顶点个数
int iCount = 0;							//索引个数
public Hexagon(int zOffset){
vCount = 7;
final int UNIT_SIZE = 10000;		//缩放比例
int []vertices = new int[]{			//创建顶点数组
0*UNIT_SIZE, 0*UNIT_SIZE, zOffset*UNIT_SIZE,	//每个顶点三个坐标
2*UNIT_SIZE, 3*UNIT_SIZE, zOffset*UNIT_SIZE,
4*UNIT_SIZE, 0*UNIT_SIZE, zOffset*UNIT_SIZE,
2*UNIT_SIZE, -3*UNIT_SIZE, zOffset*UNIT_SIZE,
-2*UNIT_SIZE, -3*UNIT_SIZE, zOffset*UNIT_SIZE,
-4*UNIT_SIZE, 0*UNIT_SIZE, zOffset*UNIT_SIZE,
-2*UNIT_SIZE, 3*UNIT_SIZE, zOffset*UNIT_SIZE,
};
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length*4);//开辟新内存
vbb.order(ByteOrder.nativeOrder());	//设置字节顺序
myVertexBuffer = vbb.asIntBuffer();	//转换成int型缓冲
myVertexBuffer.put(vertices);		//向缓冲中放入数据
myVertexBuffer.position(0);			//缓冲起始位置

final int one = 65535;				//支持65535色色彩通道
int []colors = new int[]{			//创建顶点颜色数据数组
0, 0, one, 0,					//每个顶点色个色彩值RGBA
0, one, 0, 0,
0, one, one, 0,
one, 0, 0, 0,
one, 0, one, 0,
one, one, 0, 0,
one, one, one, 0,
};
ByteBuffer cbb = ByteBuffer.allocateDirect(colors.length*4);//开辟新内存
cbb.order(ByteOrder.nativeOrder());
myColorsBuffer = cbb.asIntBuffer();
myColorsBuffer.put(colors);
myColorsBuffer.position(0);

iCount = 18;
byte []indices = new byte[]{	//创建索引数组
0, 2, 1,
0, 3, 2,
0, 4, 3,
0, 5, 4,
0, 6, 5,
0, 1, 6,
};
//创建三角形构造索引数据缓冲
myIndexBuffer = ByteBuffer.allocateDirect(indices.length);
myIndexBuffer.put(indices);
myIndexBuffer.position(0);
}

public void drawSelf(GL10 gl){		//绘制函数
gl.glEnableClientState(GL10.GL_COLOR_ARRAY);	//启用顶点坐标数组
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);	//启用顶点颜色数组
gl.glVertexPointer(		//为画笔指定顶点坐标数据
3, 				//每个顶点有3个坐标值
GL10.GL_FIXED, 	//顶点坐标值的类型
0, 				//连续顶点坐标数据之间的间隔
myVertexBuffer	//顶点坐标数据
);
gl.glColorPointer(		//为画笔指定顶点着色数据
4, 				//每个颜色有4个颜色值RGBA
GL10.GL_FIXED, 	//顶点坐标值的类型
0, 				//连续顶点坐标数据之间的间隔
myColorsBuffer	//顶点颜色数据
);
gl.glDrawElements(				//索引法绘制图像
GL10.GL_TRIANGLES, 		//绘制模式
iCount, 				//索引数量
GL10.GL_UNSIGNED_BYTE, 	//索引值的类型
myIndexBuffer			//索引值数据
);
}
}