应用变焦效果在cocos2D游戏环境中？

Question

我正在与cocos2D游戏引擎一起制作游戏，并在其加载水平时加载所有sprites，现在因为sprites（障碍物）的某些高于320像素，因此似乎很难检查出它们。因此，为了方便起见，我想要应用ZOOM IN和ZOOM out效果，该效果可以一次最小化整个等级的所有精灵，而在缩小情况下，这些效果将驻留在旧的位置。

我可以做到这一点吗？

如果是，那么如何？

请介绍一下缩放也。

Answer 1

缩放，非常简单，只需设置主游戏图层的缩放属性...但有一些捕获。

缩放图层时，它会移动图层的位置。它不会自动缩放到目前正在查看的中心位置。如果您的游戏中有任何类型的滚动，则需要对此进行说明。

为此，请将图层的anchorPoint设置为ccp(0.0f, 0.0f)，然后计算图层的移动量，并相应地重新定位图层。

- (void) scale:(CGFloat) newScale scaleCenter:(CGPoint) scaleCenter { 
    // scaleCenter is the point to zoom to.. 
    // If you are doing a pinch zoom, this should be the center of your pinch. 

    // Get the original center point. 
    CGPoint oldCenterPoint = ccp(scaleCenter.x * yourLayer.scale, scaleCenter.y * yourLayer.scale); 

    // Set the scale. 
    yourLayer.scale = newScale; 

    // Get the new center point. 
    CGPoint newCenterPoint = ccp(scaleCenter.x * yourLayer.scale, scaleCenter.y * yourLayer.scale); 

    // Then calculate the delta. 
    CGPoint centerPointDelta = ccpSub(oldCenterPoint, newCenterPoint); 

    // Now adjust your layer by the delta. 
    yourLayer.position = ccpAdd(yourLayer.position, centerPointDelta); 
} 

捏缩放比较容易...只是检测touchesMoved，然后调用你的缩放例程。

- (void) ccTouchesMoved:(NSSet*)touches withEvent:(UIEvent*)event { 

    // Examine allTouches instead of just touches. Touches tracks only the touch that is currently moving... 
    // But stationary touches still trigger a multi-touch gesture. 
    NSArray* allTouches = [[event allTouches] allObjects]; 

    if ([allTouches count] == 2) {    
     // Get two of the touches to handle the zoom 
     UITouch* touchOne = [allTouches objectAtIndex:0]; 
     UITouch* touchTwo = [allTouches objectAtIndex:1]; 

     // Get the touches and previous touches. 
     CGPoint touchLocationOne = [touchOne locationInView: [touchOne view]]; 
     CGPoint touchLocationTwo = [touchTwo locationInView: [touchTwo view]]; 

     CGPoint previousLocationOne = [touchOne previousLocationInView: [touchOne view]]; 
     CGPoint previousLocationTwo = [touchTwo previousLocationInView: [touchTwo view]]; 

     // Get the distance for the current and previous touches. 
     CGFloat currentDistance = sqrt(
             pow(touchLocationOne.x - touchLocationTwo.x, 2.0f) + 
             pow(touchLocationOne.y - touchLocationTwo.y, 2.0f)); 

     CGFloat previousDistance = sqrt(
             pow(previousLocationOne.x - previousLocationTwo.x, 2.0f) + 
             pow(previousLocationOne.y - previousLocationTwo.y, 2.0f)); 

     // Get the delta of the distances. 
     CGFloat distanceDelta = currentDistance - previousDistance; 

     // Next, position the camera to the middle of the pinch. 
     // Get the middle position of the pinch. 
     CGPoint pinchCenter = ccpMidpoint(touchLocationOne, touchLocationTwo); 

     // Then, convert the screen position to node space... use your game layer to do this. 
     pinchCenter = [yourLayer convertToNodeSpace:pinchCenter]; 

     // Finally, call the scale method to scale by the distanceDelta, pass in the pinch center as well. 
     // Also, multiply the delta by PINCH_ZOOM_MULTIPLIER to slow down the scale speed.  
     // A PINCH_ZOOM_MULTIPLIER of 0.005f works for me, but experiment to find one that you like. 
     [self scale:yourlayer.scale - (distanceDelta * PINCH_ZOOM_MULTIPLIER) 
      scaleCenter:pinchCenter]; 
    }  
} 

Answer 2

如果所有的精灵都有相同的父亲，你可以缩放他们的父母，他们将与它一起缩放，保持他们相对于父母的坐标。

Answer 3

这个代码规模我的层由2至特定位置

[layer setScale:2]; 
    layer.position=ccp(240/2+40,160*1.5); 
    double dx=(touchLocation.x*2-240); 
    double dy=(touchLocation.y*2-160); 
    layer.position=ccp(inGamePlay.position.x-dx,inGamePlay.position.y-dy); 

Answer 4

我的代码和它比其他的要好：

- (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { 

    NSArray* allTouches = [[event allTouches] allObjects]; 
    CCLayer *gameField = (CCLayer *)[self getChildByTag:TAG_GAMEFIELD]; 
    if (allTouches.count == 2) { 

     UIView *v = [[CCDirector sharedDirector] view]; 
     UITouch *tOne = [allTouches objectAtIndex:0]; 
     UITouch *tTwo = [allTouches objectAtIndex:1]; 
     CGPoint firstTouch = [tOne locationInView:v]; 
     CGPoint secondTouch = [tTwo locationInView:v]; 
     CGPoint oldFirstTouch = [tOne previousLocationInView:v]; 
     CGPoint oldSecondTouch = [tTwo previousLocationInView:v]; 
     float oldPinchDistance = ccpDistance(oldFirstTouch, oldSecondTouch); 
     float newPinchDistance = ccpDistance(firstTouch, secondTouch); 

     float distanceDelta = newPinchDistance - oldPinchDistance; 
     NSLog(@"%f", distanceDelta); 
     CGPoint pinchCenter = ccpMidpoint(firstTouch, secondTouch); 
     pinchCenter = [gameField convertToNodeSpace:pinchCenter]; 

     gameField.scale = gameField.scale - distanceDelta/100; 
     if (gameField.scale < 0) { 

      gameField.scale = 0; 
     } 
    } 
}