AndEngine Example(5):SpriteBatchExample

目标：

1. 了解SpriteBatch

2. 理解DynamicSpriteBatch

3. 两者（SpriteBatch , DynamicSpriteBatch）的区别

4. 绘制多个图形

package org.andengine.examples;

import org.andengine.engine.camera.Camera;
import org.andengine.engine.options.EngineOptions;
import org.andengine.engine.options.ScreenOrientation;
import org.andengine.engine.options.resolutionpolicy.RatioResolutionPolicy;
import org.andengine.entity.scene.Scene;
import org.andengine.entity.scene.background.Background;
import org.andengine.entity.sprite.Sprite;
import org.andengine.entity.sprite.batch.DynamicSpriteBatch;
import org.andengine.entity.sprite.batch.SpriteBatch;
import org.andengine.entity.util.FPSLogger;
import org.andengine.opengl.texture.TextureOptions;
import org.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlas;
import org.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlasTextureRegionFactory;
import org.andengine.opengl.texture.region.ITextureRegion;
import org.andengine.ui.activity.SimpleBaseGameActivity;

/**
* (c) 2010 Nicolas Gramlich
* (c) 2011 Zynga
*
* @author Nicolas Gramlich
* @since 14:27:22 - 14.06.2011
*/
public class SpriteBatchExample extends SimpleBaseGameActivity {
// ===========================================================
// Constants
// ===========================================================

private static final int CAMERA_WIDTH = 720;
private static final int CAMERA_HEIGHT = 480;

// ===========================================================
// Fields
// ===========================================================

private BitmapTextureAtlas mBitmapTextureAtlas;
private ITextureRegion mFaceTextureRegion;

// ===========================================================
// Constructors
// ===========================================================

// ===========================================================
// Getter & Setter
// ===========================================================

// ===========================================================
// Methods for/from SuperClass/Interfaces
// ===========================================================

@Override
public EngineOptions onCreateEngineOptions() {
final Camera camera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT);

return new EngineOptions(true, ScreenOrientation.LANDSCAPE_FIXED, new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), camera);
}

@Override
public void onCreateResources() {
BitmapTextureAtlasTextureRegionFactory.setAssetBasePath("gfx/");

this.mBitmapTextureAtlas = new BitmapTextureAtlas(this.getTextureManager(), 32, 32, TextureOptions.BILINEAR);
this.mFaceTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(this.mBitmapTextureAtlas, this, "face_box.png", 0, 0);
this.mBitmapTextureAtlas.load();
}

@Override
public Scene onCreateScene() {
this.mEngine.registerUpdateHandler(new FPSLogger());

final Scene scene = new Scene();
scene.setBackground(new Background(0.09804f, 0.6274f, 0.8784f));

/* Calculate the coordinates for the face, so its centered on the camera. */
final float centerX = (CAMERA_WIDTH - this.mFaceTextureRegion.getWidth()) / 2;
final float centerY = (CAMERA_HEIGHT - this.mFaceTextureRegion.getHeight()) / 2;

final Sprite faceSprite1 = new Sprite(-50, 0, this.mFaceTextureRegion, this.getVertexBufferObjectManager());
final Sprite faceSprite2 = new Sprite(50, 0, this.mFaceTextureRegion, this.getVertexBufferObjectManager());

faceSprite1.setScale(2);
faceSprite2.setRotation(45);

/* Create the face and add it to the scene. */
final SpriteBatch dynamicSpriteBatch = new DynamicSpriteBatch(this.mBitmapTextureAtlas, 2, this.getVertexBufferObjectManager()) {
@Override
public boolean onUpdateSpriteBatch() {
this.draw(faceSprite1);
this.draw(faceSprite2);

return true;
}
};

final SpriteBatch staticSpriteBatch = new SpriteBatch(this.mBitmapTextureAtlas, 2, this.getVertexBufferObjectManager());
staticSpriteBatch.draw(this.mFaceTextureRegion, -50, 0, this.mFaceTextureRegion.getWidth(), this.mFaceTextureRegion.getHeight(), 2, 2, 1, 1, 1, 1);
staticSpriteBatch.draw(this.mFaceTextureRegion, 50, 0, this.mFaceTextureRegion.getWidth(), this.mFaceTextureRegion.getHeight(), 45, 1, 1, 1, 1);
staticSpriteBatch.submit();

dynamicSpriteBatch.setPosition(centerX, centerY - 50);
staticSpriteBatch.setPosition(centerX, centerY + 50);

scene.attachChild(dynamicSpriteBatch);
scene.attachChild(staticSpriteBatch);

return scene;
}

// ===========================================================
// Methods
// ===========================================================

// ===========================================================
// Inner and Anonymous Classes
// ===========================================================
}

仔细看一下，发现两者的差别在这里：

protected abstract boolean onUpdateSpriteBatch();

@Override
protected void begin() {
super.begin();

if(this.onUpdateSpriteBatch()) {
this.submit();
}
}

实际上就是创建了一个子类必须覆盖的方法。

并且可以决定是否已完成绘制，如果返回true，则表示绘制完成，然后就直接提交了。

如果不采用这种方式，那么就需要自己绘制这些对象，然后提交。

SpriteBatch 的draw有多个重载方法

例如：

draw(this.mFaceTextureRegion, -50, 0, this.mFaceTextureRegion.getWidth(), this.mFaceTextureRegion.getHeight(), 2, 2, 1, 1, 1, 1);

draw(this.mFaceTextureRegion, 50, 0, this.mFaceTextureRegion.getWidth(), this.mFaceTextureRegion.getHeight(), 45, 1, 1, 1, 1);

他们两个并不是多一个参数的问题，而是第一个的2,2表示在X，Y轴上放大两倍

而第二个则是表示旋转。