love.graphics.inverseTransformPoint
Converts the given 2D position from screen-space into global coordinates.

This effectively applies the reverse of the current graphics transformations to the given position. A similar Transform:inverseTransformPoint method exists for Transform objects.
globalX, globalY = love.graphics.inverseTransformPoint( screenX, screenY )
screenX number The x component of the screen-space position.
screenY number The y component of the screen-space position.
globalX number The x component of the position in global coordinates.
globalY number The y component of the position in global coordinates.