relative_position.lua

---------------------------------------------
--[[
	Utility method to get the position in front of a creature.

	orientation: WoW's orientation is a radian, because WoW's circle starts at
	 the top we need the radian_start to make sure we're counting from the top.
     This is typically the orientation of the calling unit.

	yards: The distance in front of the unit to target.

	useLandHeight: If true will attempt to get the X, Y map height at the 
	 target position for the Z axis.
]] ---------------------------------------------
local RadiansConvConstant = math.pi / 180
local RadianStart = 0.5 * math.pi

function GetPositionRelative(self, orientation, yards, useLandHeight)
    local UNIT_RADIANS = RadianStart + orientation
    -- WoW has switched the x and y axis, x is from bottom to top, y from right to left
    -- meaning y counts up if going to left, counts down if going to right, x counts up top, bottom: down
    -- multiply by the yards we want to move as it'll return a number based on a circle which consists of 1 to each side (unit circle?)
    local UNIT_Y = math.cos(UNIT_RADIANS) * -yards
    local UNIT_X = math.sin(UNIT_RADIANS) * yards
    if useLandHeight then
        return self:GetX() + UNIT_X, self:GetY() + UNIT_Y,
            self:GetMap():GetHeight(self:GetX() + UNIT_X, self:GetY() + UNIT_Y), self:GetO()
    else
        return self:GetX() + UNIT_X, self:GetY() + UNIT_Y, self:GetZ(), self:GetO()
    end
end

function DegreesToRadians(degrees)
    return degrees * RadiansConvConstant
end