Zoom to a point when using zoomFactor

[edb]

Anybody have any code or ideas on how to zoom in to a specific point when using tk2dCamera.zoomFactor to zoom?

When you change the value of zoomFactor, it zooms in/out on the position of the camera.
I need it zoom in on a specific point (for doing a pinch zoom on mobile devices).

Thanks.

[unikronsoftware]

You'll need to translate the camera while zooming. Basically if you know the offset to the point is P when zoomFactor = 1, you will need to move the camera appropriately, scaled by the difference where the camera would be at the zoomScale vs when its one. Don't have any code handy, sorry.

[edb]

Got it working!  If anybody's curious, here's the bit in my code where the zoom happens:

Code: [Select]

Touch touchZero = Input.GetTouch(0);
Touch touchOne = Input.GetTouch(1);

// A finger was lifted, reset some stuff
if (touchZero.phase == TouchPhase.Ended  ||  touchOne.phase == TouchPhase.Ended)
{
initialPinchCenterHasBeenSet = false;
return;
}


// Find the position in the previous frame of each touch.
Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;

// Find the magnitude of the vector (the distance) between the touches in each frame.
float prevTouchDeltaMag = (touchZeroPrevPos - touchOnePrevPos).magnitude;
float touchDeltaMag = (touchZero.position - touchOne.position).magnitude;

// Find the difference in the distances between each frame.
float deltaMagnitudeDiff = prevTouchDeltaMag - touchDeltaMag;

// Save the initial pinch points
Vector2 pinchCenterScreenPt = (touchZeroPrevPos + touchOnePrevPos) / 2.0f;
if (initialPinchCenterHasBeenSet == false)
{
initialPinchCenterScreenPt = pinchCenterScreenPt;

// Clamp initialPinchCenterScreenPt to be within the playfield
Vector3 lowerRightCornerScreenPt = gameplayManager.mainTk2dCamera.camera.WorldToScreenPoint(lowerRightMostCornerOfGridcels);
Vector3 upperLeftCornerScreenPt = gameplayManager.mainTk2dCamera.camera.WorldToScreenPoint(upperLeftMostCornerOfGridcels);
initialPinchCenterScreenPt.x = Mathf.Clamp(initialPinchCenterScreenPt.x, upperLeftCornerScreenPt.x, lowerRightCornerScreenPt.x);
initialPinchCenterScreenPt.y = Mathf.Clamp(initialPinchCenterScreenPt.y, lowerRightCornerScreenPt.y, upperLeftCornerScreenPt.y);

                        initialPinchCenterWorldPt = gameplayManager.mainTk2dCamera.camera.ScreenToWorldPoint(initialPinchCenterScreenPt);
initialPinchCenterHasBeenSet = true;

initialCameraScreenPt = gameplayManager.mainTk2dCamera.camera.WorldToScreenPoint(gameplayManager.mainTk2dCamera.transform.position);
                 }



//#### ZOOM PART 1.   ZOOMFACTOR change
float maxZoomFactor = 2.0f;

// Get a zoomFactor by multiplying the pinch distance by a speed
valForPinchZeroToOne = valForPinchZeroToOne - deltaMagnitudeDiff*multitouchPinchZoomSpeed;
valForPinchZeroToOne = Mathf.Clamp(valForPinchZeroToOne, 0, 1);
float valForZoomFactor = Mathf.Lerp(gameplayManager.zoomFactorSave, maxZoomFactor, valForPinchZeroToOne);
gameplayManager.mainTk2dCamera.ZoomFactor = valForZoomFactor;

// CLAMP ZoomFactor
gameplayManager.mainTk2dCamera.ZoomFactor = Mathf.Clamp(gameplayManager.mainTk2dCamera.ZoomFactor, gameplayManager.zoomFactorSave, maxZoomFactor);

gameplayManager.mainTk2dCamera.UpdateCameraMatrix();
//####




//++++ ZOOM PART 2.  MOVE the Tk2dCamera's position.
if ( Mathf.Abs(deltaMagnitudeDiff) > 0) // Only do the move when there was a zoom
{

Vector3 originalOffsetScreen = initialPinchCenterScreenPt - initialCameraScreenPt;
Vector3 curOffsetScreen = mainCamera.WorldToScreenPoint(initialPinchCenterWorldPt) - initialCameraScreenPt;
Vector3 difference = curOffsetScreen-originalOffsetScreen;
Vector3 moveTowardPinchScreenPt = new Vector3();
moveTowardPinchScreenPt = initialCameraScreenPt + difference;

gameplayManager.mainTk2dCamera.transform.position = gameplayManager.mainTk2dCamera.ScreenToWorldPoint(moveTowardPinchScreenPt);
gameplayManager.mainTk2dCamera.UpdateCameraMatrix();
}
//++++