【Android开发学习15】Android(安卓)OpenGL ES 纹理映射之glDrawArrays

目标: 为四方体的每个面贴上一张图片，并自动旋转。

一、基础知识:

1.初始化:

// 1.允许2D贴图,纹理
gl.glEnable(GL10.GL_TEXTURE_2D);
// 2.创建纹理
gl.glGenTextures(1, textureids, 0);
// 3.绑定要使用的纹理
gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[0]);
// 4.生成纹理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.iBitmap, 0);
// 5.线性滤波
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_LINEAR);
gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_LINEAR);

2.使用:

// 1.清除屏幕和深度缓存
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
// 2.重置当前的模型观察矩阵
gl.glLoadIdentity();
// 3.开启顶点和纹理功能(开启顶点和纹理缓冲)
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
// 4.设置点点和纹理
gl.glVertexPointer(3, GL10.GL_FIXED, 0, vertexBuffer);
gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, texBuffer);
// 5.向z轴里移入6.0f
gl.glTranslatef(0.0f, 0.0f, -5.0f);
// 6.设置3个方向的旋转
gl.glRotatef(xrot, 1.0f, 0.0f, 0.0f);
gl.glRotatef(yrot, 0.0f, 1.0f, 0.0f);
gl.glRotatef(zrot, 0.0f, 0.0f, 1.0f);
// 7.绘制正方体
for (int i = 0; i < 6; i++) {
switch(i)
{
case 0:
// 8.生成纹理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.iBitmap, 0);
break;
}
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, i * 4, 4);
}

// 9.关闭顶点和纹理功能
gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

// 10.调节旋转角度
xrot+=0.5f;
yrot+=0.4f;
zrot+=0.6f;

3.补充说明，相对上一节中，我多添加了一个函数:

public GLRender(Context context) {        this.context = context;        // 初始化        textureids = new int[1];        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);        vbb.order(ByteOrder.nativeOrder());        vertexBuffer = vbb.asIntBuffer();        vertexBuffer.put(vertices);        vertexBuffer.position(0);        ByteBuffer tbb = ByteBuffer.allocateDirect(texCoords.length * 4 * 6);        tbb.order(ByteOrder.nativeOrder());        texBuffer = tbb.asIntBuffer();        //为每一个面贴上纹理        for (int i = 0; i < 6; i++) {            texBuffer.put(texCoords);        }        texBuffer.position(0);    }

主要是对各个面的顶点做一个初始化。

二、实现:

1. 界面编辑：
【res\layout\main.xml】

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    ><TextView      android:layout_width="fill_parent"     android:layout_height="wrap_content"     android:text="@string/hello"    /><Button    android:id="@+id/button1"    android:layout_width="145dp"    android:layout_height="wrap_content"    android:text="演示开始" /></LinearLayout>

2.代码编辑:
【\src\com\yarin\android\Examples\Activity01.java】

package com.yarin.android.Examples_12_05;import java.io.IOException;import java.io.InputStream;import javax.microedition.khronos.opengles.GL10;import android.app.Activity;import android.content.res.Resources;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.opengl.GLSurfaceView;import android.opengl.GLUtils;import android.opengl.GLSurfaceView.Renderer;import android.os.Bundle;import android.view.View;import android.widget.Button;public class Activity01 extends Activity{Renderer render = new GLRender(this);GLSurfaceView glView;Button start;// 演示开始/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);GLImage.load(this.getResources());glView = new GLSurfaceView(this);glView.setRenderer(render);setContentView(R.layout.main);start=(Button)findViewById(R.id.button1);// "演示开始"按钮初始化start.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {// TODO Auto-generated method stubsetContentView(glView);}});//setContentView(glView);}}class GLImage{public static Bitmap iBitmap;public static Bitmap jBitmap;public static Bitmap kBitmap;public static Bitmap lBitmap;public static Bitmap mBitmap;public static Bitmap nBitmap;public static Bitmap close_Bitmap;public static void load(Resources resources){iBitmap = BitmapFactory.decodeResource(resources, R.drawable.img);jBitmap = BitmapFactory.decodeResource(resources, R.drawable.jmg);kBitmap = BitmapFactory.decodeResource(resources, R.drawable.kmg);lBitmap = BitmapFactory.decodeResource(resources, R.drawable.lmg);mBitmap = BitmapFactory.decodeResource(resources, R.drawable.mmg);nBitmap = BitmapFactory.decodeResource(resources, R.drawable.nmg);close_Bitmap = BitmapFactory.decodeResource(resources, R.drawable.close);}}

【\src\com\yarin\android\Examples\GLRender.java】

package com.yarin.android.Examples_12_05;import java.io.IOException;import java.io.InputStream;import java.nio.ByteBuffer;import java.nio.IntBuffer;import java.nio.ByteOrder;  import javax.microedition.khronos.egl.EGLConfig;import javax.microedition.khronos.opengles.GL10;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.opengl.GLUtils;import android.opengl.GLSurfaceView.Renderer;import android.content.Context;public class GLRender implements Renderer{public Context context;    private int[] textureids;    private IntBuffer vertexBuffer;    private IntBuffer texBuffer;    privatefloat xrot, yrot, zrot;    privateint one = 0x10000;// 正方体顶点    private int[] vertices = {            one, one, -one,              -one, one, -one,            one, one, one,                       -one, one, one,            one, -one,one,            -one, -one, one,                       one, -one, -one,            -one, -one, -one,            one, one,one,                       -one, one, one,            one, -one, one,            -one, -one, one,                       one, -one,-one,            -one, -one, -one,            one, one, -one,                       -one, one, -one,            -one, one,one,            -one, one, -one,                       -one, -one, one,            -one, -one, -one,            one, one,-one,                       one, one, one,            one, -one, -one,            one, -one, one        };    //纹理点    private int[] texCoords = {              0, one,                            one, one,            0, 0,            one, 0    };    public GLRender(Context context) {        this.context = context;        // 初始化        textureids = new int[1];        ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);        vbb.order(ByteOrder.nativeOrder());        vertexBuffer = vbb.asIntBuffer();        vertexBuffer.put(vertices);        vertexBuffer.position(0);        ByteBuffer tbb = ByteBuffer.allocateDirect(texCoords.length * 4 * 6);        tbb.order(ByteOrder.nativeOrder());        texBuffer = tbb.asIntBuffer();        //为每一个面贴上纹理        for (int i = 0; i < 6; i++) {            texBuffer.put(texCoords);        }        texBuffer.position(0);    }@Overridepublic void onDrawFrame(GL10 gl){// 1.清除屏幕和深度缓存gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);// 2.重置当前的模型观察矩阵gl.glLoadIdentity();// 3.开启顶点和纹理功能(开启顶点和纹理缓冲)gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);     // 4.设置点点和纹理        gl.glVertexPointer(3, GL10.GL_FIXED, 0, vertexBuffer);        gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, texBuffer);         // 5.向z轴里移入6.0f        gl.glTranslatef(0.0f, 0.0f, -5.0f);        // 6.设置3个方向的旋转        gl.glRotatef(xrot, 1.0f, 0.0f, 0.0f);        gl.glRotatef(yrot, 0.0f, 1.0f, 0.0f);        gl.glRotatef(zrot, 0.0f, 0.0f, 1.0f);        // 7.绘制正方体        for (int i = 0; i < 6; i++) {        switch(i)        {        case 0:            // 8.生成纹理            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.iBitmap, 0);            break;        case 1:            // 生成纹理            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.jBitmap, 0);            break;        case 2:            // 生成纹理            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.kBitmap, 0);            break;        case 3:            // 生成纹理            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.lBitmap, 0);            break;        case 4:            // 生成纹理            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.mBitmap, 0);            break;        case 5:            // 生成纹理            GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.nBitmap, 0);            break;                            }                    gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, i * 4, 4);        }        // 9.关闭顶点和纹理功能    gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);    gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);        // 10.调节旋转角度    xrot+=0.5f;    yrot+=0.4f;     zrot+=0.6f; }@Overridepublic void onSurfaceChanged(GL10 gl, int width, int height){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, 1, 10);// 选择模型观察矩阵gl.glMatrixMode(GL10.GL_MODELVIEW);// 重置模型观察矩阵gl.glLoadIdentity();}@Overridepublic void onSurfaceCreated(GL10 gl, EGLConfig config){        // 告诉系统对透视进行修正           gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);  // 绿色背景gl.glClearColor(0, 1, 0, 0);gl.glEnable(GL10.GL_CULL_FACE);// 启用阴影平滑gl.glShadeModel(GL10.GL_SMOOTH);// 启用深度测试gl.glEnable(GL10.GL_DEPTH_TEST);//启用纹理映射gl.glClearDepthf(1.0f);//深度测试的类型gl.glDepthFunc(GL10.GL_LEQUAL);// 1.允许2D贴图,纹理gl.glEnable(GL10.GL_TEXTURE_2D);// 2.创建纹理gl.glGenTextures(1, textureids, 0);// 3.绑定要使用的纹理gl.glBindTexture(GL10.GL_TEXTURE_2D, textureids[0]);// 4.生成纹理GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.iBitmap, 0);// 5.线性滤波gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MIN_FILTER,GL10.GL_LINEAR);gl.glTexParameterx(GL10.GL_TEXTURE_2D, GL10.GL_TEXTURE_MAG_FILTER,GL10.GL_LINEAR);}}

三、效果:

本文博客源地址:http://blog.csdn.net/ypist

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