【Android开发学习18】Android OpenGL ES 光照glDrawArrays

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一、基础知识:

1..光照介绍:

①环境光:
来自四面八方，所有场景中的对象都处于环境光的照射中。

②漫射光:
由特定的光源产生，并在场景中的对象表面产生反射。
处于漫射光直接照射下的任何对象表面都变得很亮，而几乎未被照射到的区域就显示得要暗一些。

2.光照使用:
①设定光源参数:

//环境光
private float[] lightAmbient;
private FloatBuffer AmbientBuffer;
//漫射光
private float[] lightDiffuse;
private FloatBuffer diffuseBuffer;
//光源位置
private float[] lightPosition;
private FloatBuffer positionBuffer;

//灯光
lightAmbient = new float[]{0.5f,0.5f,0.5f,1.0f};
lightDiffuse = new float[]{1.0f,1.0f,1.0f,1.0f};
lightPosition = new float[]{0.0f,0.0f,2.0f,1.0f};

//环境光
ByteBuffer ambientbb = ByteBuffer.allocateDirect(lightAmbient.length * 4 * 6);
ambientbb.order(ByteOrder.nativeOrder());
AmbientBuffer = ambientbb.asFloatBuffer();
AmbientBuffer.put(lightAmbient);
AmbientBuffer.position(0);

//漫射光
ByteBuffer diffusebb = ByteBuffer.allocateDirect(lightDiffuse.length * 4 * 6);
diffusebb.order(ByteOrder.nativeOrder());
diffuseBuffer = diffusebb.asFloatBuffer();
diffuseBuffer.put(lightDiffuse);
diffuseBuffer.position(0);

//灯光位置
ByteBuffer positionbb = ByteBuffer.allocateDirect(lightPosition.length * 4 * 6);
positionbb.order(ByteOrder.nativeOrder());
positionBuffer = positionbb.asFloatBuffer();
positionBuffer.put(lightPosition);
positionBuffer.position(0);

②设置光源:
glLightfv (
int light,// 光源的ID
int pname, // 光源的类型
FloatBuffer params// 光源的数组
)
设定的属性，主要由第二个参数决定:
GL_AMBIENT环境光(光源泛光强度的RGBA值)
GL_DIFFUSE漫射光(光源漫反射强度的RGBA值)
GL_SPECULAR高光(光源镜面反射强度的RGBA值)
GL_POSITION位置(光源的位置)
GL_SPOT_DIRECTION方向(聚光灯的方向)
GL_SPOT_CUTOFF光的角度(聚光灯的截止角度)

// 设置环境光
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_AMBIENT, AmbientBuffer);
// 设置漫射光
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_DIFFUSE, diffuseBuffer);
// 设置灯光位置
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_POSITION, positionBuffer);

③启用光源:
//启用一号光源
gl.glEnable(GL10.GL_LIGHT1);

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();
	GLSurfaceView glView;
	Button start;			// 演示开始

	
	/** Called when the activity is first created. */
	@Override
	public 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() {
			
			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				setContentView(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 java.nio.FloatBuffer;

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
{
	/**
	 * 渲染类
	 * author:pis
	 */

	private int one = 0x10000;

	public boolean mFlag ;
	public boolean bLight = true;//是否开启灯光
	
	private int[] vertices;//顶点数组
	private int[] textCood;//纹理数组
	
	float step = 0.3f;
	float xrot,yrot; //旋转
	float xSpeed,ySpeed; //移动速度
	private int[] textures = new int[1];
	
	private IntBuffer vertexBuffer; //顶点缓冲
	private IntBuffer textCoodBuffer; //纹理缓冲
	/**
	 * 设置灯光
	 * @param context
	 */
	//环境光
	private float[] lightAmbient;
	private FloatBuffer AmbientBuffer;
	//漫射光
	private float[] lightDiffuse;
	private FloatBuffer diffuseBuffer;
	//光源位置
	private float[] lightPosition;
	private FloatBuffer positionBuffer;
	
	/**
	 * 初始化缓冲数据
	 */
	private void initBuffer(){
		//顶点
		ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
		vbb.order(ByteOrder.nativeOrder());
		vertexBuffer = vbb.asIntBuffer();
		vertexBuffer.put(vertices);
		vertexBuffer.position(0);
		
		//纹理
		ByteBuffer tbb = ByteBuffer.allocateDirect(textCood.length * 4 * 6);
		tbb.order(ByteOrder.nativeOrder());
		textCoodBuffer = tbb.asIntBuffer();
		for (int i = 0; i < 6; i++) {			
			textCoodBuffer.put(textCood);
		}
		textCoodBuffer.position(0);
		
		//环境光
		ByteBuffer ambientbb = ByteBuffer.allocateDirect(lightAmbient.length * 4 * 6);
		ambientbb.order(ByteOrder.nativeOrder());
		AmbientBuffer = ambientbb.asFloatBuffer();
		AmbientBuffer.put(lightAmbient);
		AmbientBuffer.position(0);
		
		//漫射光
		ByteBuffer diffusebb = ByteBuffer.allocateDirect(lightDiffuse.length * 4 * 6);
		diffusebb.order(ByteOrder.nativeOrder());
		diffuseBuffer = diffusebb.asFloatBuffer();
		diffuseBuffer.put(lightDiffuse);
		diffuseBuffer.position(0);
		
		//灯光位置
		ByteBuffer positionbb = ByteBuffer.allocateDirect(lightPosition.length * 4 * 6);
		positionbb.order(ByteOrder.nativeOrder());
		positionBuffer = positionbb.asFloatBuffer();
		positionBuffer.put(lightPosition);
		positionBuffer.position(0);
		
	}
	/**
	 * 初始化顶点、纹理、灯光数据
	 */
	private void initData(){
		//顶点数组
		vertices = new int[] { -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 };

		//纹理数组,贴图时注意android中坐标与OpengGL 中定义的不同，android，y轴是向下的
		textCood = new int[] { 0, 0, one, 0, 0, one, one, one };
		//灯光
		lightAmbient = new float[]{0.5f,0.5f,0.5f,1.0f};
		lightDiffuse = new float[]{1.0f,1.0f,1.0f,1.0f};
		lightPosition = new float[]{0.0f,0.0f,2.0f,1.0f};

		
	}
	public GLRender() {
		mFlag=true;
		initData();
		initBuffer();
	}

	
	@Override
	public void onDrawFrame(GL10 gl) {
		//清除颜色和深度缓存
		gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
		gl.glLoadIdentity();
		
		//启用灯光
		gl.glEnable(GL10.GL_LIGHTING);
		
		//启用顶点和纹理缓存
		gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
		gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
		//移动和旋转设置
		gl.glTranslatef(0.0f, 0.0f, -6.0f);
		gl.glRotatef(xrot, 1.0f, 0.0f, 0.0f);
		gl.glRotatef(yrot, 0.0f, 1.0f, 0.0f);
		
		//设置顶点和纹理,经常忘记设置，唉！
		gl.glVertexPointer(3, GL10.GL_FIXED, 0, vertexBuffer);
		gl.glTexCoordPointer(2,GL10.GL_FIXED,0,textCoodBuffer);
		
		//绘制六个面，贴图
		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);
		}
		//取消缓存，需我们自己手动
		gl.glDisableClientState(GL10.GL_VERTEX_ARRAY);
		gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
		gl.glLoadIdentity();
		
		if (mFlag) {
			xrot += 0.5f;
			yrot += 0.5f;
		}
		if (!bLight) {
			gl.glDisable(GL10.GL_LIGHT1);
		} else {
			gl.glEnable(GL10.GL_LIGHT1);
		}
	}

	@Override
	public void onSurfaceChanged(GL10 gl, int width, int height) {
		//场景大小
		gl.glViewport(0, 0, width, height);
		float ratio = (float) width / height;
		//投影矩阵
		gl.glMatrixMode(GL10.GL_PROJECTION);
		//重置下
		gl.glLoadIdentity();
		//视图大小设置
		gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
		//观察模型
		gl.glMatrixMode(GL10.GL_MODELVIEW);
		gl.glLoadIdentity();
	}

	@Override
	public void onSurfaceCreated(GL10 gl, EGLConfig config) {
		//透视效果
		gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
		//清屏
		gl.glClearColor(0, 0, 0, 0);
		//启用阴影平滑
		gl.glShadeModel(GL10.GL_SMOOTH);
		//清除深度缓存
		gl.glClearDepthf(one);
		//启用深度缓存
		gl.glEnable(GL10.GL_DEPTH_TEST);
		//深度缓存模式
		gl.glDepthFunc(GL10.GL_LEQUAL);
		
		/**
		 * 设置纹理
		 */
		//启用纹理
		gl.glEnable(GL10.GL_TEXTURE_2D);
		//创建纹理
		gl.glGenTextures(1, textures, 0);
		//绑定纹理
		gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
		//生成纹理
		GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.kBitmap, 0);
		//线性滤波处理
		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);
		/**
		 * 设置灯光
		 */
		
		//设置环境光
		gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_AMBIENT, AmbientBuffer);
		//设置漫射光
		gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_DIFFUSE, diffuseBuffer);
		//设置灯光位置
		gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_POSITION, positionBuffer);
		//启用1号灯光
		gl.glEnable(GL10.GL_LIGHT1);	
		
	}
}

三、效果: