/// <summary>
/// When a row is marked for deletion
/// </summary>
private void RemoveRow(TileRow row)
{
// UnityEngine.Object.Destroy removes whatever is given out of the runtime context, effectively deleting it
Destroy(row.gameObject);
// we implicitly assume that the row to be deleted is in front the queue
// this could very well cause wrong behaviour and the interface is ambiguous
rows.Dequeue();
// and then we add for each tile a new one, so we don't run out of tiles
AddRow();
}
/// <summary>
/// Composited function to check if a TileRow intersects with a character
/// </summary>
private bool IntersectionHit(TileRow row)
{
// sometimes the selected row already has been "deleted" in the sense of removal from the scene.
// In Unity the MonoBehaviour Null Equality operator is overwritten to make this check like this:
if (row == null)
{
return(false);
}
// does a characters bounding box intersects enough of a tiles bounding box?
return(Intersection.NormalizedIntersectionAmount(runCharacterController, row) > hitThreshold);
}
/// <summary>
/// Returns the percentage of an intersection of the character sprite with a tile.
/// </summary>
public static float NormalizedIntersectionAmount(RunCharacterController character, TileRow tile)
{
// get the bounds
var tileBounds = RetrieveBounds(tile);
var characterBounds = RetrieveBounds(character);
// calculate the x/y overlap
var xOverlap = max(0,
min(tileBounds.max.x, characterBounds.max.x) - max(tileBounds.min.x, characterBounds.min.x));
var yOverlap = max(0,
min(tileBounds.max.y, characterBounds.max.y) - max(tileBounds.min.y, characterBounds.min.y));
// an overlap is also just a rectangle - so calculate the area occupied
var overlapArea = xOverlap * yOverlap;
// similarly calculate the area of the character occupied
var characterArea = characterBounds.size.x * characterBounds.size.y;
// return the fraction of how much overlap occurs on the character sprite
return(overlapArea / characterArea);
}
/// <summary>
/// Extracts the correct bounds of the top-most tile on a TileRow
/// </summary>
private static Bounds RetrieveBounds(TileRow tile)
{
return(tile.TopSprite.bounds);
}