Fix #59: add HC.shapesAt(x,y)

docs/MainModule.rst

@@ -217,7 +217,7 @@ You can iterate over the shapes using ``pairs`` (see example).
 .. function:: HC.neighbors(shape)
 
    :param Shape shape: Query shape.
-   :returns: Table of neighboring shapes, where the keys of the table are the shape.
+   :returns: Table of neighboring shapes, where the keys of the table are the shapes.
 
 Get other shapes in that are close to ``shape``.
 The table is a *set*, meaning that the shapes are stored in *keys* of the table.
@@ -238,6 +238,22 @@ You can iterate over the shapes using ``pairs`` (see example).
         end
     end
 
+.. function:: HC.shapesAt(x, y)
+
+   :param numbers x,y: Point to query.
+   :returns: Table of shapes at the point, where the keys of the table are the shapes.
+
+Get shapes that contain the point (x,y).
+The table is a *set*, meaning that the shapes are stored in *keys* of the table.
+You can iterate over the shapes using ``pairs`` (see example).
+
+**Example**::
+
+    local shapes = HC.shapesAt(love.mouse.getPosition)
+    for s in pairs(shapes) do
+        game.selectUnit(s)
+    end
+
 
 .. function:: HC.hash()
 

init.lua

@@ -118,6 +118,16 @@ function HC:collisions(shape)
 	return candidates
 end
 
+function HC:shapesAt(x, y)
+	local candidates = {}
+	for c in pairs(self._hash:cellAt(x, y)) do
+		if c:contains(x, y) then
+			rawset(candidates, c, c)
+		end
+	end
+	return candidates
+end
+
 -- the class and the instance
 HC = common_local.class('HardonCollider', HC)
 local instance = common_local.instance(HC)
@@ -136,5 +146,6 @@ return setmetatable({
 
 	neighbors  = function(...) return instance:neighbors(...) end,
 	collisions = function(...) return instance:collisions(...) end,
+	shapesAt   = function(...) return instance:shapesAt(...) end,
 	hash       = function() return instance.hash() end,
 }, {__call = function(_, ...) return common_local.instance(HC, ...) end})