bounds2.lua

-- TODO: Don't use class system...

local TObject = require "class"
local vec2 = require "vector"[2]

local bounds2 = TObject:inherit("bounds2")

function bounds2:create(a, b)
  local f = self.fields
  f._a = b and a:copy() or vec2(1)
  f._b = b and b:copy() or a and a:copy() or vec2(1)
end

bounds2.properties = {
  a = {
    get = function(self)
      return self._a
    end,
    set = function(self, value)
      self._a:assign(value)
    end
  },
  b = {
    get = function(self)
      return self._b
    end,
    set = function(self, value)
      self._b:assign(value)
    end
  },
  pos = {
    get = function(self)
      return self._a
    end,
    set = function(self, value)
      -- braces for speed
      self:assign(self + (value - self._a))
    end
  },
  size = {
    get = function(self)
      return self._b - self._a + 1
    end,
    set = function(self, value)
      self._b = self._a + value - 1
    end
  },
  width = {
    get = function(self)
      return self.size.x
    end,
    set = function(self, value)
      self._b.x = self._a.x + value - 1
    end
  },
  height = {
    get = function(self)
      return self.size.y
    end,
    set = function(self, value)
      self._b.y = self._a.y + value - 1
    end
  },
  left = {
    get = function(self)
      return self.a.x
    end,
    set = function(self, value)
      self._a.x = value
    end
  },
  top = {
    get = function(self)
      return self.a.y
    end,
    set = function(self, value)
      self._a.y = value
    end
  },
  right = {
    get = function(self)
      return self.b.x
    end,
    set = function(self, value)
      self._b.x = value
    end
  },
  bottom = {
    get = function(self)
      return self.b.y
    end,
    set = function(self, value)
      self._b.y = value
    end
  }
}

local function clamp(vec, bounds)
  return vec2(
    math.min(math.max(vec.x, bounds.a.x), bounds.b.x),
    math.min(math.max(vec.y, bounds.a.y), bounds.b.y)
  )
end

function bounds2:clamp(bounds)
  return bounds2(
    clamp(self.a, bounds),
    clamp(self.b, bounds)
  )
end

function bounds2.mt:add(vec)
  return bounds2(self.a + vec, self.b + vec)
end

function bounds2.mt:sub(vec)
  return bounds2(self.a - vec, self.b - vec)
end

function bounds2.mt:equal(other)
  return self.a == other.a and self.b == other.b
end

function bounds2:assign(other)
  self.a = other.a
  self.b = other.b
end

function bounds2:copy()
  return bounds2(self.a, self.b)
end

function bounds2:contains(vec)
  return vec >= self.a and vec <= self.b
end

return bounds2