一、基礎知識:
1..光照介紹:
①環境光:
來自四面八方，所有場景中的對象都處於環境光的照射中。
②漫射光:
由特定的光源產生，並在場景中的對象表面產生反射。
處於漫射光直接照射下的任何對象表面都變得很亮，而幾乎未被照射到的區域就顯示得要暗一些。
2.光照使用:
①設定光源參數:
//環境光
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;
//燈光
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};
//環境光
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);
//燈光位置
ByteBuffer positionbb = ByteBuffer.allocateDirect(lightPosition.length * 4 * 6);
positionbb.order(ByteOrder.nativeOrder());
positionBuffer = positionbb.asFloatBuffer();
positionBuffer.put(lightPosition);
positionBuffer.position(0);
②設置光源:
glLightfv (
int light, // 光源的ID
int pname, // 光源的類型
FloatBuffer params // 光源的數組
)
設定的屬性，主要由第二個參數決定:
GL_AMBIENT 環境光(光源泛光強度的RGBA值)
GL_DIFFUSE 漫射光(光源漫反射強度的RGBA值)
GL_SPECULAR 高光(光源鏡面反射強度的RGBA值)
GL_POSITION 位置(光源的位置)
GL_SPOT_DIRECTION 方向(聚光燈的方向)
GL_SPOT_CUTOFF 光的角度(聚光燈的截止角度)
// 設置環境光
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_AMBIENT, AmbientBuffer);
// 設置漫射光
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_DIFFUSE, diffuseBuffer);
// 設置燈光位置
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_POSITION, positionBuffer);
③啟用光源:
//啟用一號光源
gl.glEnable(GL10.GL_LIGHT1);
二、實現:
1. 界面編輯：
【res\layout\main.xml】
[html]
<?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="演示開始" />
</LinearLayout>
2.代碼編輯:
【\src\com\yarin\android\Examples\Activity01.java】
[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; // 演示開始
/** 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); // "演示開始"按鈕初始化
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】
[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
{
/**
* 渲染類
* author:pis
*/
private int one = 0x10000;
public boolean mFlag ;
public boolean bLight = true;//是否開啟燈光
private int[] vertices;//頂點數組
private int[] textCood;//紋理數組
float step = 0.3f;
float xrot,yrot; //旋轉
float xSpeed,ySpeed; //移動速度
private int[] textures = new int[1];
private IntBuffer vertexBuffer; //頂點緩沖
private IntBuffer textCoodBuffer; //紋理緩沖
/**
* 設置燈光
* @param context
*/
//環境光
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;
/**
* 初始化緩沖數據
*/
private void initBuffer(){
//頂點
ByteBuffer vbb = ByteBuffer.allocateDirect(vertices.length * 4);
vbb.order(ByteOrder.nativeOrder());
vertexBuffer = vbb.asIntBuffer();
vertexBuffer.put(vertices);
vertexBuffer.position(0);
//紋理
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);
//環境光
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);
//燈光位置
ByteBuffer positionbb = ByteBuffer.allocateDirect(lightPosition.length * 4 * 6);
positionbb.order(ByteOrder.nativeOrder());
positionBuffer = positionbb.asFloatBuffer();
positionBuffer.put(lightPosition);
positionBuffer.position(0);
}
/**
* 初始化頂點、紋理、燈光數據
*/
private void initData(){
//頂點數組
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 };
//紋理數組,貼圖時註意android中坐標與OpengGL 中定義的不同，android，y軸是向下的
textCood = new int[] { 0, 0, one, 0, 0, one, one, one };
//燈光
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) {
//清除顏色和深度緩存
gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
gl.glLoadIdentity();
//啟用燈光
gl.glEnable(GL10.GL_LIGHTING);
//啟用頂點和紋理緩存
gl.glEnableClientState(GL10.GL_VERTEX_ARRAY);
gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY);
//移動和旋轉設置
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);
//設置頂點和紋理,經常忘記設置，唉！
gl.glVertexPointer(3, GL10.GL_FIXED, 0, vertexBuffer);
gl.glTexCoordPointer(2,GL10.GL_FIXED,0,textCoodBuffer);
//繪制六個面，貼圖
for (int i = 0; i < 6; i++) {
switch(i)
{
case 0:
// 8.生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.iBitmap, 0);
break;
case 1:
// 生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.jBitmap, 0);
break;
case 2:
// 生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.kBitmap, 0);
break;
case 3:
// 生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.lBitmap, 0);
break;
case 4:
// 生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.mBitmap, 0);
break;
case 5:
// 生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.nBitmap, 0);
break;
}
gl.glDrawArrays(GL10.GL_TRIANGLE_STRIP, i * 4, 4);
}
//取消緩存，需我們自己手動
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) {
//場景大小
gl.glViewport(0, 0, width, height);
float ratio = (float) width / height;
//投影矩陣
gl.glMatrixMode(GL10.GL_PROJECTION);
//重置下
gl.glLoadIdentity();
//視圖大小設置
gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
//觀察模型
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
}
@Override
public void onSurfaceCreated(GL10 gl, EGLConfig config) {
//透視效果
gl.glHint(GL10.GL_PERSPECTIVE_CORRECTION_HINT, GL10.GL_FASTEST);
//清屏
gl.glClearColor(0, 0, 0, 0);
//啟用陰影平滑
gl.glShadeModel(GL10.GL_SMOOTH);
//清除深度緩存
gl.glClearDepthf(one);
//啟用深度緩存
gl.glEnable(GL10.GL_DEPTH_TEST);
//深度緩存模式
gl.glDepthFunc(GL10.GL_LEQUAL);
/**
* 設置紋理
*/
//啟用紋理
gl.glEnable(GL10.GL_TEXTURE_2D);
//創建紋理
gl.glGenTextures(1, textures, 0);
//綁定紋理
gl.glBindTexture(GL10.GL_TEXTURE_2D, textures[0]);
//生成紋理
GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, GLImage.kBitmap, 0);
//線性濾波處理
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);
/**
* 設置燈光
*/
//設置環境光
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_AMBIENT, AmbientBuffer);
//設置漫射光
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_DIFFUSE, diffuseBuffer);
//設置燈光位置
gl.glLightfv(GL10.GL_LIGHT1, GL10.GL_POSITION, positionBuffer);
//啟用1號燈光
gl.glEnable(GL10.GL_LIGHT1);
}
}
三、效果:
