Android高级进阶八 Android OpenGL给立方体进行纹理映射

最新版本：Android高级进阶八
Android OpenGL给立方体进行纹理映射

看到了Android高级进阶七
Android OpenGL开发四棱锥和立方体之后，我们是不是增加了使用OpenGL开发图形的兴趣啊，呵呵，希望大家保持热情啊，今天我们接着给已经画好的立方体进行文理处理，效果图如下：



可以看到，我们对正方体做了如下处理：

给正方体增加3轴旋转功能；
给正方体添加纹理；

具体如何实现，我们接着看~~~

//当窗口被创建时我们可以做些初始化工作

@Override

public void onSurfaceCreated(GL10 gl, EGLConfig config) {

// TODO Auto-generated method stub

//设置清除屏幕时所用的颜色，参数依次为红、绿、蓝、Alpha值

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

gl.glEnable(GL10.GL_CULL_FACE);

//启用阴影平滑

gl.glShadeModel(GL10.GL_SMOOTH);

gl.glEnable(GL10.GL_DEPTH_TEST);//启用深度测试

//以下是关于深度缓存的设置，非常重要

gl.glClearDepthf(1.0f);//设置深度缓存

gl.glDepthFunc(GL10.GL_LEQUAL);//所做深度测试的类型

//告诉系统对透视进行修正

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

//允许2D贴图

gl.glEnable(GL10.GL_TEXTURE_2D);

IntBuffer intBuffer = IntBuffer.allocate(1);

//创建纹理

gl.glGenTextures(1, intBuffer);

texture = intBuffer.get();

//设置需要使用的纹理

gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.test);

//生成纹理

GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bmp, 0);

// 线形滤波

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);

}

在onSurfaceChanged方法中，我们需要做一些处理，主要有如下两个方法：

//创建纹理

gl.glGenTextures(1, intBuffer);

这个方法是主要用来创建一个文理，参数1表示数量1，参数intBuffer是文理代号；

gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.test);

//生成纹理

GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bmp, 0);

// 线形滤波

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);

}

接着绑定需要该纹理的target，在onSurfaceChanged方法之后，我们再在onDrawFrame方法中着色和旋转，完全代码如下：

package org.ourunix.android.opengltest;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.nio.IntBuffer;

import javax.microedition.khronos.egl.EGLConfig;

import javax.microedition.khronos.opengles.GL10;

import android.app.Activity;

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;

public class OpenGLTestActivity extends Activity {

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

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

GLSurfaceView glView = new GLSurfaceView(this);

glView.setRenderer(new GLRender());

setContentView(glView);

}

public class GLRender implements Renderer{

private int texture = -1;

private int one = 0x10000;

private int[] quarter = {-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,};

private int[] texCoords = {one,0,0,0,0,one,one,one,

0,0,0,one,one,one,one,0,

one,one,one,0,0,0,0,one,

0,one,one,one,one,0,0,0,

0,0,0,one,one,one,one,0,

one,0,0,0,0,one,one,one,};

private int[] indices = {0,1,3,2,

4,5,7,6,

8,9,11,10,

12,13,15,14,

16,17,19,18,

20,21,23,22};

//准备正方体顶点

private IntBuffer quarterBuffer = BufferUtil.iBuffer(quarter);

//纹理映射数据

private IntBuffer texCoordsBuffer = BufferUtil.iBuffer(texCoords);

// private IntBuffer indicesBuffer = BufferUtil.iBuffer(indices);

ByteBuffer indicesBuffer = ByteBuffer.wrap(new byte[]{

0,1,3,2,

4,5,7,6,

8,9,11,10,

12,13,15,14,

16,17,19,18,

20,21,23,22,

});

private float rotateX; //用于正方体x轴的旋转；

private float rotateY; //用于正方体y轴的旋转；

private float rotateZ; //用于正方体z轴的旋转；

//咳，咳现在开始画图了

@Override

public void onDrawFrame(GL10 gl) {

// TODO Auto-generated method stub

//清楚屏幕和深度缓存

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

//重置当前的观察模型矩阵

gl.glLoadIdentity();

//现将屏幕向里移动，用来画正方体

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

//设置3个方向的旋转

gl.glRotatef(rotateX, 1.0f, 0.0f, 0.0f);

gl.glRotatef(rotateY, 0.0f, 1.0f, 0.0f);

gl.glRotatef(rotateZ, 0.0f, 0.0f, 1.0f);

//通知opnegl将文理名字texture绑定到指定的纹理目标上GL10.GL_TEXTURE_2D

gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);

gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);

//纹理的使用与开启颜色渲染一样，需要开启纹理功能

gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

//设置正方体 各顶点

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

gl.glTexCoordPointer(2, GL10.GL_FIXED, 0, texCoordsBuffer);

//绘制

gl.glDrawElements(GL10.GL_TRIANGLE_STRIP, 24, GL10.GL_UNSIGNED_BYTE, indicesBuffer);

for(int i=0; i<6; i++){

gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, i*4, 4);

}

gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);

gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);

rotateX += 0.5f;

rotateY += 0.6f;

rotateZ += 0.3f;

}

//当窗口改变时，调用，至少在创建窗口时调用一次，这边设置下场景大小

@Override

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

// TODO Auto-generated method stub

//设置OpenGL场景大小

float ratio = (float) width / height;

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

gl.glMatrixMode(GL10.GL_PROJECTION);//设置为投影矩阵模式

gl.glLoadIdentity();//重置

gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);//设置视角

gl.glMatrixMode(GL10.GL_MODELVIEW);

gl.glLoadIdentity();

}

//当窗口被创建时我们可以做些初始化工作

@Override

public void onSurfaceCreated(GL10 gl, EGLConfig config) {

// TODO Auto-generated method stub

//设置清除屏幕时所用的颜色，参数依次为红、绿、蓝、Alpha值

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

gl.glEnable(GL10.GL_CULL_FACE);

//启用阴影平滑

gl.glShadeModel(GL10.GL_SMOOTH);

gl.glEnable(GL10.GL_DEPTH_TEST);//启用深度测试

//以下是关于深度缓存的设置，非常重要

gl.glClearDepthf(1.0f);//设置深度缓存

gl.glDepthFunc(GL10.GL_LEQUAL);//所做深度测试的类型

//告诉系统对透视进行修正

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

//允许2D贴图

gl.glEnable(GL10.GL_TEXTURE_2D);

IntBuffer intBuffer = IntBuffer.allocate(1);

//创建纹理

gl.glGenTextures(1, intBuffer);

texture = intBuffer.get();

//设置需要使用的纹理

gl.glBindTexture(GL10.GL_TEXTURE_2D, texture);

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.test);

//生成纹理

GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, bmp, 0);

// 线形滤波

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);

}

}

public static class BufferUtil {

public static IntBuffer intBuffer;

public static IntBuffer iBuffer(int[] a) {

// 先初始化buffer,数组的长度*4,因为一个float占4个字节

ByteBuffer mbb = ByteBuffer.allocateDirect(a.length * 4);

// 数组排列用nativeOrder

mbb.order(ByteOrder.nativeOrder());

intBuffer = mbb.asIntBuffer();

intBuffer.put(a);

intBuffer.position(0);

return intBuffer;

}

}

}