private void SetElement(UIPoolScrollElement element, int contentIndex, float position, bool addHeight, int topChange)
{
if (contentIndex < 0 || contentIndex >= mTotalElementCount)
{
return;
}
element.SetIndex(contentIndex);
element.SetData(mData[contentIndex]);
if (addHeight)
{
position += element.Height;
}
element.SetPosition(position);
mCurrentTopElement += topChange;
if (mCurrentTopElement < 0)
{
mCurrentTopElement += mElementPool.Length;
}
if (mCurrentTopElement >= mElementPool.Length)
{
mCurrentTopElement -= mElementPool.Length;
}
}
private void UpdateLooping()
{
int currentBot = mCurrentTopElement + mElementPool.Length - 1;
currentBot %= mElementPool.Length;
UIPoolScrollElement topElement = mElementPool[mCurrentTopElement];
UIPoolScrollElement botElement = mElementPool[currentBot];
if (topElement.IsOnScreen() > 0)
{
// Current top element is above the screen top, it can be moved to the bot
float contentBotPosition = botElement.Bot - mSpacing;
int newContentIndex = botElement.Index + 1;
SetElement(topElement, newContentIndex, contentBotPosition, false, 1);
}
else if (topElement.Top < -mSpacing)
{
// Current top element's top has scrolled below the screen top, a new element need to be moved to the top
float contentTopPosition = topElement.Top + mSpacing;
int newContentIndex = topElement.Index - 1;
SetElement(botElement, newContentIndex, contentTopPosition, true, -1);
}
}
private void UpdateElastic()
{
int currentBot = mCurrentTopElement + mElementPool.Length - 1;
currentBot %= mElementPool.Length;
UIPoolScrollElement topElement = mElementPool[mCurrentTopElement];
UIPoolScrollElement botElement = mElementPool[currentBot];
float offset = 0;
// Elastic clamp at top
if (topElement.Index <= 0)
{
if (topElement.Top < -mSpacing)
{
offset = -mSpacing - topElement.Top;
}
}
// Elastic clamp at bot
if (Mathf.Approximately(offset, 0) && botElement.Index >= mTotalElementCount - 1)
{
if (botElement.Bot > -mScrollHeight - mSpacing)
{
offset = -(botElement.Bot + mScrollHeight - mSpacing);
}
}
if (Mathf.Approximately(offset, 0))
{
return; // No clamp required
}
float elasticBase = 300f;
float sign = Mathf.Sign(offset);
float offRatio = Mathf.Clamp01(Mathf.Abs(offset) / elasticBase);
float correction = 1f - (offRatio * offRatio);
if (mHasInput)
{
// Is currently dragging
if (offset > 0 != mVelocity > 0)
{
// Velocity is pulling elements off screen - apply velocity dampening
mVelocity *= correction;
}
}
else
{
// Not dragging, set velocity to return to screen
mVelocity = sign * correction * elasticBase * mElasticity;
float move = mVelocity * Time.deltaTime;
if (Mathf.Abs(offset) < Mathf.Abs(move))
{
// The next move with velocity will go past the wanted position, set the position exactly and stop velocity
mVelocity = 0;
Move(offset);
}
}
}
