Camera API: Client-Side Interpolation

init.lua

local vec = vector.new
local vec_round = vector.round
local cam, player
local hud, init_hud, smiley
local old_rot

minetest.register_on_joinplayer(function(player)
	player = player

	init_hud = player:hud_add {
		hud_elem_type = "text",
		position      = {x = 0.5, y = 0.5},
		offset        = {x = 0,   y = -95},
		alignment     = {x = 0,   y = 1},
		size          = {x = 3,   y = 3},
		number        = 0xffffff,
		text          = "Jean-Patrick Guerrero presents...",
		z_index       = 0xDEAD,
		style         = 1,
	}

	local flags = player:hud_get_flags()
	flags.crosshair = false
	flags.hotbar    = false
	flags.healthbar = false
	flags.wielditem = false
	flags.breathbar = false
	flags.minimap   = true

	player:hud_set_flags(flags)
end)

core.after(3, function()
	cam = Camera()
	cam:set_pos(vec(-68, 7, 1))
	cam:set_target(vec(-25, 7, 1))

	cam:set_speed{fov = 2, zoom = 10, move = 3, rotate = 5}
	cam:set_zoom{min = 10, max = 1000}

	player = core.get_player_by_name"singleplayer"
	player:set_active_camera(cam:get_id())

	hud = player:hud_add {
		hud_elem_type = "text",
		position      = {x = 0.5, y = 0.5},
		offset        = {x = 0,   y = 25},
		alignment     = {x = 0,   y = 1},
		size          = {x = 4,   y = 4},
		number        = 0xffff00,
		text          = "",
		z_index       = 0xDEAD,
		style         = 1,
	}

	player:hud_change(hud, "text", "The Camera API")

	core.after(5, function()
		player:hud_remove(init_hud)
		player:hud_change(hud, "offset", {x = 0, y = 320})
		player:hud_change(hud, "size", {x = 3, y = 3})
		player:hud_change(hud, "text", "Translation interpolated")
		cam:set_pos(vec(0, 25, 1), true)
	--	cam:set_fov(100, true)
	end)
end)

core.register_globalstep(function()
	if not cam then return end
	local cam_pos = vec_round(cam:get_pos())
--	print(dump(cam_pos))

	if cam_pos == vec(0, 25, 1) then
		player:hud_change(hud, "text", "Rotation interpolated")
		cam:set_pos(vec(0, 25, 1))
		cam:add_rotation360({x = 180, y = 0}, true)

		core.after(4, function()
			player:hud_change(hud, "text", "FOV interpolated (speed: " .. cam:get_speed().fov .. ")")
			cam:set_fov(100, true)
		end)	
	end

	if cam:get_fov() == 100 then
		cam:set_speed{fov = 5}
		player:hud_change(hud, "text", "FOV interpolated (speed: " .. cam:get_speed().fov .. ")")
		cam:set_fov(72, true)

		core.after(2, function()
			player:hud_change(hud, "text", "Translation interpolated (speed: " .. cam:get_speed().move .. ")")
			cam:set_pos(vec(-68, 9, 1), true)
			cam:set_target(vec(-68, 9, 1))

			core.after(3, function()
				cam:set_speed{move = 8}
				player:hud_change(hud, "text", "Translation interpolated (speed: " .. cam:get_speed().move .. ")")

				core.after(3, function()
					cam:set_speed{move = 4}
					player:hud_change(hud, "text", "Translation interpolated (speed: " .. cam:get_speed().move .. ")")
				end)
			end)
		end)
	end

	if cam_pos == vec(-68, 9, 1) then
		core.after(1, function()
			cam:set_speed{move = 1}
			player:hud_change(hud, "text", "Translation interpolated (speed: " .. cam:get_speed().move .. ")")
			cam:set_pos(vec(-88, 8, 1), true)
			cam:set_target(vec(-88, 8, 1))
		end)
	end

	if cam_pos == vec(-88, 8, 1) then
		core.after(1, function()
			if not smiley then
				smiley = player:hud_add {
					hud_elem_type = "image",
					position      = {x = 0.8, y = 0.5},
					scale         = {x = 2,    y = 2},
					text          = "smiley.png",
					z_index       = 0xDEAD,
				}
			end

			core.after(2, function()
				if smiley then
					player:hud_remove(smiley)
				end

				if not old_rot then
					old_rot = cam:get_rotation360()
					cam:set_target(vec(-88, 8, 1))
					cam:add_rotation360({x = 180, y = 0}, true)
				end

				core.after(3, function()
					cam:set_pos(vec(-68, 10, 1), true)
					cam:set_target(vec(-68, 10, 1))
				end)
			end)
		end)
	end

	if cam_pos == vec(-68, 10, 1) then
		player:hud_change(hud, "text", "ObjectRef Attachment")

		local ppos = player:get_pos()
		local cam_pos = vec(ppos)
		cam_pos.x = cam_pos.x + 5
		cam_pos.y = cam_pos.y + 5
		cam_pos.z = cam_pos.z - 5
		cam:set_pos(cam_pos)

		local cam_target = vec(ppos)
		cam_target.y = cam_target.y + 1.4

		cam:set_target(cam_target)
		cam:set_zoom{min = 10, max = 1000}
		cam:set_controls{mouse = true}

		player:attach_camera(cam:get_id())
	end
end)