indexing

	description: "[

		This class describes the arrow pointing to the target

	]"
	date: "$Date$"
	revision: "$Revision$"

		"This class describes the arrow pointing to the target"

	date: "$Date$"
	revision: "$Revision$"

class ARROW

inherit

	EM_3D_OBJECT

	EM_TIME_SINGLETON
		export {NONE} all end

	DOUBLE_MATH
		export {NONE} all end

create

	make

feature {NONE} -- Initialization

	make is
			-- Create arrow
		local
			obj_loader: EM_3D_OBJ_LOADER
		do
			create obj_loader.make
			obj_loader.load_file ("objects/arrow.obj")
			obj_loader.set_color (0, 1, 1, 1)
			model := obj_loader.create_object
			scale.set(1,1,1)
			width := model.width
			height := model.height
			depth := model.depth

			set_scale (0.2, 0.2, 0.2)
		end

feature -- Commands

	update (a_start_location: EM_3D_VECT; a_target_location: EM_3D_VECT) is
			-- Update arrow to be at a_start_location and point in direction to a_target_location.
		local
			direction: EM_3D_VECT
			angle: DOUBLE
		do
			direction := a_target_location - a_start_location

			-- at the moment only the case in the x-z plane is handled
			-- TODO handle all cases
			direction.set (direction.x, 0, direction.z)

			if
				direction.x < 0
			then
				angle := 270+(arc_sine (direction.z/direction.length)/(2*pi)*360)
			else
				angle := 90-(arc_sine (direction.z/direction.length)/(2*pi)*360)
			end

			set_rotation (0, angle, 0)
			set_origin (a_start_location.x, a_start_location.y+1, a_start_location.z)
		end

feature {NONE} -- Implementation

	model: EM_3D_OBJECT
		-- The arrow model

feature {EM_3D_OBJECT} -- Implementation of the 3d object

	draw_object	is
		do
			model.draw_object
		end

end