Placing Furniture on drag in AR Core - unity3d

Question

I am new to ARCore in Unity. My colleague has already made this app on iOS. But I am having some problems dragging the object around and set it on a position. Also you can rotate it with 2 fingers. Here I am giving the ARKit equivalent code of m dragging. Can anyone help me with doing the same on AR Core
switch (Input.touchCount) {
case 1:
if (touch.phase == TouchPhase.Began || touch.phase == TouchPhase.Moved) {
var screenPosition = Camera.main.ScreenToViewportPoint(touch.position);
ARPoint point = new ARPoint {
x = screenPosition.x,
y = screenPosition.y
};
// prioritize reults types
ARHitTestResultType[] resultTypes = {
//ARHitTestResultType.ARHitTestResultTypeExistingPlaneUsingExtent,
// if you want to use infinite planes use this:
ARHitTestResultType.ARHitTestResultTypeExistingPlane,
ARHitTestResultType.ARHitTestResultTypeHorizontalPlane,
ARHitTestResultType.ARHitTestResultTypeFeaturePoint
};
foreach (ARHitTestResultType resultType in resultTypes) {
if (HitTestWithResultType(point, resultType)) {
return;
}
}
}
break;
case 2:
if (touch.phase == TouchPhase.Moved || touch.phase == TouchPhase.Ended) {
Vector2 direction = touch.deltaPosition;
float yAngleIncrementVal = touch.deltaPosition.magnitude;
Vector3 currentRotation = transform.rotation.eulerAngles;
if (direction.x > 0) {
currentRotation.y += (yAngleIncrementVal * rotationScale);
}
else {
currentRotation.y -= (yAngleIncrementVal * rotationScale);
}
transform.rotation = Quaternion.Euler(currentRotation);
}
break;
}
}
This script will attached to the gameobject which will move across the plane. How can I drag a gameobject and update the anchors so that it stays on the plane. Thank You

Answer 1

I am pretty much doing the same thing, and this is a simplified version of my own code:
case 1:
if (Input.GetTouch(0).phase == TouchPhase.Began)
{
touchOffset = ARCamera.WorldToScreenPoint(gameObject.position) - new Vector3(Input.GetTouch(0).position.x, Input.GetTouch(0).position.y, 0);
}
RaycastHit hit;
LayerMask layers = (1 << LayerMask.NameToLayer(layersOfGroundObjects))
Ray ray = ARCamera.ScreenPointToRay(Input.GetTouch(0).position + new Vector2(mouseOffset.x, mouseOffset.y));
if (!ClickedOnUI && Physics.Raycast(ray, out hit, Mathf.Infinity, layers))
{
if(Input.GetTouch(0).phase == TouchPhase.Began)
{
touchOffset = hit.point - gameObject.position;
}
if (Input.GetTouch(0).phase == TouchPhase.Moved)
{
gameObject.position = hit.point - touchOffset ;
}
}
case 2:
float currentTouchDistance = Vector2.Distance(touches[0].position, touches[1].position);
float diff_y = touches[0].position.y - touches[1].position.y;
float diff_x = touches[0].position.x - touches[1].position.x;
float currentTouchAngle = Mathf.Atan2(diff_y, diff_x) * Mathf.Rad2Deg;
if (isFirstFrameWithTwoTouches)
{
cachedTouchDistance = currentTouchDistance;
cachedTouchAngle = currentTouchAngle;
isFirstFrameWithTwoTouches = false;
}
float angleDelta = currentTouchAngle - cachedTouchAngle;
float scaleMultiplier = (currentTouchDistance / cachedTouchDistance);
float scaleAmount = cachedAugmentationScale * scaleMultiplier;
float scaleAmountClamped = Mathf.Clamp(scaleAmount, scaleRangeMin, scaleRangeMax);
if (enableRotation)
{
gameObject.localEulerAngles = cachedAugmentationRotation - new Vector3(0, angleDelta * 3f, 0);
}
if (enableRotation && enableScaling)
{
gameObject.localScale = new Vector3(scaleAmountClamped, scaleAmountClamped, scaleAmountClamped);
}
I also use a touchOffset which is the distance away from the object's pivot (position) that the user has clicked to start dragging. I apply that offset to the final position every time it is dragged. It makes dragging feels much more natural. I also use it for a lot more in my own code, therefore it was quite important for me, but that is irrelevant for this question so I removed the rest of the code.
Moreover, I use many layers for what is considered ground, because I can put my furniture on more surfaces other than the ARCore tracked plane. If you only care about the tracked plane then either assign a layer to it, or use ARCore's raycast instead of Unity's one. Or just use my Eazy ARCore Interface plugin that can do both (uses layers for tracked planes and makes things easier with raycasting for multiple surfaces)