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使用SurfaceScrollDetector、PinchZoomDetector进行流畅的滚动和缩放
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Stack Overflow用户
提问于 2013-05-16 00:07:06
回答 1查看 2.6K关注 0票数 3

我正在尝试用SurfaceScrollDetector和PinchZoomDetector实现流畅的TMX地图滚动和缩放。

下面是我的代码:

代码语言:javascript
复制
public class TMXTiledMapExample extends SimpleBaseGameActivity implements IOnSceneTouchListener, IScrollDetectorListener, IPinchZoomDetectorListener {

private static final int CAMERA_WIDTH = 480;
private static final int CAMERA_HEIGHT = 320;

private SmoothCamera camera;

private TMXTiledMap mTMXTiledMap;

private SurfaceScrollDetector mScrollDetector;
private PinchZoomDetector mPinchZoomDetector;
private float mPinchZoomStartedCameraZoomFactor;

@Override
public EngineOptions onCreateEngineOptions() {
    this.camera = new SmoothCamera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT, 400, 400, 10f);
    final CroppedResolutionPolicy canvasSurface = new CroppedResolutionPolicy(CAMERA_WIDTH, CAMERA_HEIGHT);
    EngineOptions engineOptions = new EngineOptions(true, ScreenOrientation.LANDSCAPE_FIXED, canvasSurface, this.camera);

    if (MultiTouch.isSupported(this)) {
        if (MultiTouch.isSupportedDistinct(this)) {
            Toast.makeText(this, "MultiTouch detected --> Both controls will work properly!", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(this, "MultiTouch detected, but your device has problems distinguishing between fingers.\n\nControls are placed at different vertical locations.", Toast.LENGTH_LONG)
                    .show();
        }
    } else {
        Toast.makeText(this, "Sorry your device does NOT support MultiTouch!\n\n(Falling back to SingleTouch.)\n\nControls are placed at different vertical locations.", Toast.LENGTH_LONG).show();
    }

    return engineOptions;
}

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

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

    final Scene scene = new Scene();
    scene.setOnAreaTouchTraversalFrontToBack();

    this.mScrollDetector = new SurfaceScrollDetector(this);
    this.mPinchZoomDetector = new PinchZoomDetector(this);

    scene.setOnSceneTouchListener(this);
    scene.setTouchAreaBindingOnActionDownEnabled(true);

    try {
        final TMXLoader tmxLoader = new TMXLoader(this.getAssets(), this.mEngine.getTextureManager(), TextureOptions.BILINEAR, this.getVertexBufferObjectManager(),
                new ITMXTilePropertiesListener() {
                    @Override
                    public void onTMXTileWithPropertiesCreated(final TMXTiledMap pTMXTiledMap, final TMXLayer pTMXLayer, final TMXTile pTMXTile,
                            final TMXProperties<TMXTileProperty> pTMXTileProperties) {
                    }
                });
        this.mTMXTiledMap = tmxLoader.loadFromAsset("tmx/desert2.tmx");

    } catch (final TMXLoadException e) {
        Debug.e(e);
    }

    final TMXLayer tmxLayer = this.mTMXTiledMap.getTMXLayers().get(0);
    scene.attachChild(tmxLayer);

    this.camera.setBounds(0, 0, tmxLayer.getHeight(), tmxLayer.getWidth());
    this.camera.setBoundsEnabled(true);

    return scene;
}

@Override
public void onScrollStarted(final ScrollDetector pScollDetector, final int pPointerID, final float pDistanceX, final float pDistanceY) {
    final float zoomFactor = this.camera.getZoomFactor();
    this.camera.offsetCenter(-pDistanceX / zoomFactor, -pDistanceY / zoomFactor);
}

@Override
public void onScroll(final ScrollDetector pScollDetector, final int pPointerID, final float pDistanceX, final float pDistanceY) {
    final float zoomFactor = this.camera.getZoomFactor();
    this.camera.offsetCenter(-pDistanceX / zoomFactor, -pDistanceY / zoomFactor);
}

@Override
public void onScrollFinished(final ScrollDetector pScollDetector, final int pPointerID, final float pDistanceX, final float pDistanceY) {
    final float zoomFactor = this.camera.getZoomFactor();
    this.camera.offsetCenter(-pDistanceX / zoomFactor, -pDistanceY / zoomFactor);
}

@Override
public void onPinchZoomStarted(final PinchZoomDetector pPinchZoomDetector, final TouchEvent pTouchEvent) {
    this.mPinchZoomStartedCameraZoomFactor = this.camera.getZoomFactor();
}

@Override
public void onPinchZoom(final PinchZoomDetector pPinchZoomDetector, final TouchEvent pTouchEvent, final float pZoomFactor) {
    this.camera.setZoomFactor(this.mPinchZoomStartedCameraZoomFactor * pZoomFactor);
}

@Override
public void onPinchZoomFinished(final PinchZoomDetector pPinchZoomDetector, final TouchEvent pTouchEvent, final float pZoomFactor) {
    this.camera.setZoomFactor(this.mPinchZoomStartedCameraZoomFactor * pZoomFactor);
}

@Override
public boolean onSceneTouchEvent(final Scene pScene, final TouchEvent pSceneTouchEvent) {
    this.mPinchZoomDetector.onTouchEvent(pSceneTouchEvent);

    if (this.mPinchZoomDetector.isZooming()) {
        this.mScrollDetector.setEnabled(false);
    } else {
        if (pSceneTouchEvent.isActionDown()) {
            this.mScrollDetector.setEnabled(true);
        }
        this.mScrollDetector.onTouchEvent(pSceneTouchEvent);
    }

    return true;
}
}

这段代码中的滚动和缩放不是很流畅。它的问题在哪里?如何创建漂亮的惯性滚动?

还有一个关于缩放的问题。如何使用最小和最大缩放因子来限制它?我应该在IPinchZoomDetectorListener方法中设置一个特殊的条件,还是可以通过给我的camera对象提供一些参数来实现?

另外,最后三个SmoothCamera参数- final float pMaxVelocityX,final float pMaxVelocityY,final float pMaxZoomFactorChange的“正常”值是什么?

EN

回答 1

Stack Overflow用户

回答已采纳

发布于 2013-05-16 01:33:45

我以前做过类似的工作,所以我可以帮助你实现你的目标。

首先,如果你想要放大/缩小功能,那么你必须使用ZoomCamera,在这个功能中,你只需要给出宽度和高度,所有其他的参数都是默认值。

代码语言:javascript
复制
    mZoomCamera = new ZoomCamera(0, 0, Constants.CAMERA_WIDTH,
            Constants.CAMERA_HEIGHT);
    mZoomCamera.setBounds(0f, 0f, Constants.CAMERA_WIDTH,
            Constants.CAMERA_HEIGHT);
    mZoomCamera.setBoundsEnabled(true);

在示例代码中,您可以看到我是如何为相机设置界限的,这样相机就没有机会走出这个范围。我还认为,由于您提供的不适当的速度,您会得到异常行为。

为了设置特定的缩放值,你可以使用以下代码。

代码语言:javascript
复制
private void setCameraZoomFactor(float pZoomFactor) {
    newZoomFactor = mPinchZoomStartedCameraZoomFactor * pZoomFactor;
    if (newZoomFactor < 1f)
        newZoomFactor = 1f;
    if (newZoomFactor > 1.5f)
        newZoomFactor = 1.5f;

    mZoomCamera.setZoomFactor(newZoomFactor);
}

您必须在onPinchZoom方法中调用此方法。

我想现在我已经回答了你所有的问题。

票数 3
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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接:

https://stackoverflow.com/questions/16569964

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