添加视觉下方的手指轻扫，三角形条状像水果忍者Andengine

时间：2012-03-14 09:21:36

标签： andengine swipe gl-triangle-strip

当用户在屏幕上交换手指时，我想显示一个三角形条。我不知道如何使用AndEngine，使用粒子系统或使用精灵或使用Triangle Strip算法......

我没有写过任何代码，因为我很震惊该怎么做。我正在上传图片，请分享您的想法。

triangle strip

更新

  有人在Iphone中做过这个，但遗憾的是我不熟悉语言语法，请帮助我理解这段代码的算法https://github.com/hiepnd/CCBlade

**我想要的效果** fruit ninja effect

  

完成Android项目下载

http://www.andengine.org/forums/resources/complete-runnable-project/1301

我已完成此代码但无法获得所需的效果...... 

    package org.az.algo.examples;

import javax.microedition.khronos.opengles.GL10;

import org.anddev.andengine.engine.Engine;
import org.anddev.andengine.engine.camera.Camera;
import org.anddev.andengine.engine.options.EngineOptions;
import org.anddev.andengine.engine.options.EngineOptions.ScreenOrientation;
import org.anddev.andengine.engine.options.resolutionpolicy.RatioResolutionPolicy;
import org.anddev.andengine.entity.particle.ParticleSystem;
import org.anddev.andengine.entity.particle.emitter.RectangleParticleEmitter;
import org.anddev.andengine.entity.particle.initializer.AlphaInitializer;
import org.anddev.andengine.entity.particle.initializer.ColorInitializer;
import org.anddev.andengine.entity.particle.initializer.GravityInitializer;
import org.anddev.andengine.entity.particle.initializer.RotationInitializer;
import org.anddev.andengine.entity.particle.modifier.AlphaModifier;
import org.anddev.andengine.entity.particle.modifier.ColorModifier;
import org.anddev.andengine.entity.particle.modifier.ExpireModifier;
import org.anddev.andengine.entity.scene.Scene;
import org.anddev.andengine.entity.scene.Scene.IOnSceneTouchListener;
import org.anddev.andengine.entity.sprite.Sprite;
import org.anddev.andengine.entity.util.FPSLogger;
import org.anddev.andengine.input.touch.TouchEvent;
import org.anddev.andengine.opengl.texture.TextureOptions;
import org.anddev.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlas;
import org.anddev.andengine.opengl.texture.atlas.bitmap.BitmapTextureAtlasTextureRegionFactory;
import org.anddev.andengine.opengl.texture.region.TextureRegion;

import android.view.ViewGroup.MarginLayoutParams;
import android.widget.Toast;


public class ParticleSystemSimpleExample extends BaseExample {
    // ===========================================================
    // Constants
    // ===========================================================

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

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

    private Camera mCamera;
    private BitmapTextureAtlas mBitmapTextureAtlas;
    private TextureRegion mParticleTextureRegion;
    private BitmapTextureAtlas mBitmapTextureAtlasStreak;
    private TextureRegion mStreadTextureRegion;

    private Sprite[] mSprite = new Sprite[20];
    private int mIndex = 0;

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

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

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

    @Override
    public Engine onLoadEngine() {
        Toast.makeText(this, "Touch the screen to move the particlesystem.", Toast.LENGTH_LONG).show();
        this.mCamera = new Camera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT);
        return new Engine(new EngineOptions(true, ScreenOrientation.LANDSCAPE, new RatioResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT), this.mCamera));
    }

    @Override
    public void onLoadResources() {
        this.mBitmapTextureAtlas = new BitmapTextureAtlas(32, 32, TextureOptions.BILINEAR_PREMULTIPLYALPHA);
        this.mParticleTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(this.mBitmapTextureAtlas, this, "gfx/particle_point.png", 0, 0);

        this.mBitmapTextureAtlasStreak = new BitmapTextureAtlas(128, 16, TextureOptions.BILINEAR_PREMULTIPLYALPHA);     
        this.mStreadTextureRegion = BitmapTextureAtlasTextureRegionFactory.createFromAsset(this.mBitmapTextureAtlasStreak, this, "gfx/streak1.png", 0, 0);

        this.mEngine.getTextureManager().loadTextures(this.mBitmapTextureAtlas, this.mBitmapTextureAtlasStreak);
    }

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

        final Scene scene = new Scene();

//      final CircleOutlineParticleEmitter particleEmitter = new CircleOutlineParticleEmitter(CAMERA_WIDTH * 0.5f, CAMERA_HEIGHT * 0.5f + 20, 80);
        final RectangleParticleEmitter particleEmitter = new RectangleParticleEmitter(CAMERA_WIDTH * 0.5f, CAMERA_HEIGHT * 0.5f, 5f,5f);

//      final PointParticleEmitter particleEmitter = new PointParticleEmitter(10, 10);      
        final ParticleSystem particleSystem = new ParticleSystem(particleEmitter, 100, 100, 1000, this.mParticleTextureRegion);
        particleSystem.setParticlesSpawnEnabled(false);     

        scene.setOnSceneTouchListener(new IOnSceneTouchListener() {
            @Override
            public boolean onSceneTouchEvent(final Scene pScene, final TouchEvent pSceneTouchEvent) {               

                if(pSceneTouchEvent.getAction() == TouchEvent.ACTION_MOVE){                 

                    particleSystem.setParticlesSpawnEnabled(true);                  
                    particleEmitter.setCenter(pSceneTouchEvent.getX(), pSceneTouchEvent.getY());

                    mSprite[getIndex()].setPosition(pSceneTouchEvent.getX(), pSceneTouchEvent.getY());
                    mSprite[getIndex()].setVisible(true);

                }else if (pSceneTouchEvent.getAction() == TouchEvent.ACTION_UP){

                    particleSystem.setParticlesSpawnEnabled(false);
                    hideAll();

                }else if(pSceneTouchEvent.getAction() == TouchEvent.ACTION_DOWN){

                    particleSystem.reset();

                }

                return true;
            }
        });     

        particleSystem.addParticleInitializer(new ColorInitializer(1, 0, 0));
        particleSystem.addParticleInitializer(new AlphaInitializer(0));
        particleSystem.setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE);
//      particleSystem.addParticleInitializer(new VelocityInitializer(-2, 2, -20, -10));
        particleSystem.addParticleInitializer(new GravityInitializer());

//      particleSystem.addParticleModifier(new ScaleModifier(0.5f, 1.0f, 0, 1.5f));
        particleSystem.addParticleModifier(new ColorModifier(1, 1, 0, 0.5f, 0, 0, 0, 3));
        particleSystem.addParticleModifier(new ColorModifier(1, 1, 0.5f, 1, 0, 1, 4, 6));
        particleSystem.addParticleModifier(new AlphaModifier(0, 1, 0, 0.5f));
        particleSystem.addParticleModifier(new AlphaModifier(1, 0, 2.5f, 3.5f));
        particleSystem.addParticleModifier(new ExpireModifier(6, 6f));

        scene.attachChild(particleSystem);


        for(int i = 0; i < mSprite.length; i++){
            mSprite[i] = new Sprite(-20, 0, mStreadTextureRegion);
            mSprite[i].setVisible(false);
            scene.attachChild(mSprite[i]);
        }





        return scene;
    }

    @Override
    public void onLoadComplete() {

    }


    private int getIndex(){
        if(mIndex >= mSprite.length -1){
            mIndex = 0;
        }
        System.out.println("Index ........ "+mIndex);
        return mIndex++;
    }

    private void hideAll(){
        for(int i = 0; i<mSprite.length; i++){
            mSprite[i].setVisible(false);
            mSprite[i].setPosition(-CAMERA_WIDTH, 0);
        }
    }
    // ===========================================================
    // Methods
    // ===========================================================

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

Image i used whit this code

我在此代码中使用的图片也附有

  

更新

部分效果实现..但快速刷卡问题..所有完整的项目都在这里上传http://www.andengine.org/forums/post31772.html#p31772

partial effect

1 个答案:

答案 0 :(得分：1)

这是LibGDX中的解决方案。它使用GL_TRIANGLE_STRIP。

https://github.com/mattdesl/lwjgl-basics/wiki/LibGDX-Finger-Swipe

最终解决方案使用两个三角形条带和一个自定义texCoord属性，允许我们使用查找纹理来实现虚假（但有效）的抗锯齿。更有效/灵活的抗锯齿将使用着色器和单个三角形条带。使用顶点属性-1.0作为顶部，使用1.0作为滑动的下边缘，使用1.0作为提示。然后在frag着色器中，使用abs（） - 所以0.0表示“中心”，1.0表示“边缘”。

这样的事情：

    color.a *= smoothstep(0.0, 2./thickness, 1.0-abs(vTexCoord.t));
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