Question

我想在AndEngine中绘制一条线，其效果类似于Fruit Ninja或Veggie Samurai。谁能帮我？并提供示例代码？

Answer 1

也许，我迟到了，但希望这会有所帮助。

    @Override
    public boolean onSceneTouchEvent(Scene pScene, TouchEvent pSceneTouchEvent) {

        final float touchX = pSceneTouchEvent.getX();
        final float touchY = pSceneTouchEvent.getY();

        if (pSceneTouchEvent.isActionDown()) {
            initTrail(touchX, touchY);
            swipeGestureSprite = addSwipeSprite(touchX, touchY);
        } else if (pSceneTouchEvent.isActionMove()) {

            moveTrail(pSceneTouchEvent.getX(), pSceneTouchEvent.getY(), 0);

            if (swipeGestureSprite != null) {
                swipeGestureSprite.setX(touchX);
                swipeGestureSprite.setY(touchY);
            }
        } else if (pSceneTouchEvent.isActionUp()) {

            mScene.detachChild(this.particleSystem);

            if (swipeGestureSprite != null) {
                this.mScene.detachChild(swipeGestureSprite);
                swipeGestureSprite = null;
            }

            return true;
        }

        return false;
    }




    private void initTrail(float mX, float mY) {
        this.particleEmitter = new PointParticleEmitter(mX, mY);
        this.particleSystem = new SpriteParticleSystem(particleEmitter, 1000, 1000, 5000, this.mRibbon, this.getVertexBufferObjectManager());
        particleSystem.addParticleInitializer(new BlendFunctionParticleInitializer<Sprite>(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE));
        particleSystem.addParticleInitializer(new ExpireParticleInitializer<Sprite>(1));
        particleSystem.addParticleModifier(new ScaleParticleModifier<Sprite>(0, 1, 1, 0f));
        particleSystem.addParticleModifier(new AlphaParticleModifier<Sprite>(0, 1, 1, 0));
        this.mScene.attachChild(particleSystem);
    }


private void moveTrail(float trailX, float trailY, int count) {
        if (particleEmitter == null) {
            initTrail(trailX, trailY);
        }

        particleEmitter.setCenter(trailX, trailY);
    }

Answer 2

我认为你必须使用点粒子效果并使用线条绘制算法来创建点之间的线。使用粒子绘制的线代表更多的现实，粒子代表动态的方式，因此您可以摧毁它。你可以问。编辑：对于粒子生成，您可以使用此代码

public void generateParticles(float pX, float pY) {

    pointParticleEmtitter = new PointParticleEmitter(pX, pY);

    particleSystem = new ParticleSystem(pointParticleEmtitter, maxRate,
            minRate, maxParticles, mParticleTextureRegion.deepCopy());

    particleSystem.setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE);
    particleSystem.addParticleInitializer(new ColorInitializer(0.8f, 0.43f,
            0.2f));
    particleSystem.addParticleModifier(new AlphaModifier(1, 0, 0, 0.25f));
    particleSystem.addParticleModifier(new ExpireModifier(0.25f));

    gameObject.getScene().attachChild(particleSystem);

}

对于Line算法，您可以使用此算法

public void drawLine() {
    int x;
    float y, m;

    x = (int) previousX;
    y = (int) previousY;

    m = (currentY - previousY) / (currentX - previousX);

    if (Math.round(previousX) == Math.round(currentX)) {
        if (previousY < currentY) {
            for (y = (int) previousY; y < currentY; ++y)
                pointParticleEmtitter.setCenter(previousX, y);
        } else {
            for (y = (int) previousY; y > currentY; --y)
                pointParticleEmtitter.setCenter(previousX, y);
        }
    } else {
        if (previousX < currentX) {
            for (x = (int) previousX; x < currentX; ++x) {
                y = m * (x - previousX) + previousY;
                pointParticleEmtitter.setCenter(x, y);
            }
        } else if (previousX > currentX) {
            for (x = (int) previousX; x > currentX; --x) {
                y = m * (x - currentX) + currentY;
                pointParticleEmtitter.setCenter(x, y);
            }
        }
    }
}

画线效果触摸像水果忍者或素食武士和引擎

2 个答案: