basic_impacts.lua

--[[
	Late library for Minetest - Library adding temporary effects.
	(c) Pierre-Yves Rollo

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published
	by the Free Software Foundation, either version 2.1 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program.  If not, see <http://www.gnu.org/licenses/>.
--]]

--- Effects
-----------
-- Alters effects by groups with an intensity multiplier
-- Params: { group_name = intensity multiplier, .. }
late.register_impact_type({'player', 'mob'}, 'effects', {
    reset = function(impact)
            late.get_storage_for_target(impact.target).modifiers = nil
        end,
    update = function(impact)
        local data = late.get_storage_for_target(impact.target)
        data.modifiers = {}

        for _, params in pairs(impact.params) do
            for group, intensity in pairs(params) do
                if group ~= 'intensity' then
                    data.modifiers[group] = (data.modifiers[group] or 1)
                        * (1 - (intensity + 1) * params.intensity)
                end
            end
        end
    end,
})

-- Speed
--------
-- Params :
-- 1: Speed multiplier [0..infinite]. Default: 1

late.register_impact_type('player', 'speed', {
	reset = function(impact)
			late.set_physics_override(impact.target, {speed = 1.0})
		end,
	update = function(impact)
			late.set_physics_override(impact.target, {
				speed = late.multiply_valints(
					late.get_valints(impact.params, 1))
			})
		end,
})

-- Jump
-------
-- Params :
-- 1: Jump multiplier [0..infinite]. Default: 1

late.register_impact_type('player', 'jump', {
	reset = function(impact)
			late.set_physics_override(impact.target, {jump = 1.0})
		end,
		update = function(impact)
			late.set_physics_override(impact.target, {
				jump = late.multiply_valints(
					late.get_valints(impact.params, 1))
			})
		end,
})

-- Gravity
----------
-- Params :
-- 1: Gravity multiplier [0..infinite]. Default: 1

late.register_impact_type('player', 'gravity', {
	reset = function(impact)
			late.set_physics_override(impact.target, {gravity = 1.0})
		end,
	update = function(impact)
			late.set_physics_override(impact.target, {
				gravity = late.multiply_valints(
					late.get_valints(impact.params, 1))
			})
		end,
})

-- Fly
------
-- Params :
-- 1: Put 1 to give fly priv
-- TODO: Try by attaching to an entity

late.register_impact_type('player', 'fly', {
	vars = { original_priv = nil },

	reset = function(impact)
			if impact.vars.original_priv ~= nil then
				local pname = impact.target:get_player_name()
				local privs = minetest.get_player_privs(pname)
				privs.fly = impact.vars.original_priv or nil
				minetest.set_player_privs(pname, privs)
				impact.vars.original_priv = nil
			end
		end,

	update = function(impact)
			local pname = impact.target:get_player_name()
			local privs = minetest.get_player_privs(pname)
			if impact.vars.original_priv == nil then
				impact.vars.original_priv = privs.fly or false
			end
			privs.fly = impact.vars.original_priv or
				late.multiply_valints(late.get_valints(impact.params, 1)) > 0.5
				or false
			minetest.set_player_privs(pname, privs)
		end,
})

-- Damage
---------
-- Params :
-- 1: Health points lost (+) or gained (-) per period
-- 2: Period length in seconds
-- TODO: Use a different armor/damage group for magic ?
-- TODO: Or adapt damage to armor group
late.register_impact_type({'player', 'mob'}, 'damage', {
	step = function(impact, dtime)
		for _, params in pairs(impact.params) do
			params.timer = (params.timer or 0) + dtime
			local times = math.floor(params.timer / (params[2] or 1))
			if times > 0 then
				impact.target:punch(impact.target, nil, {
					full_punch_interval = 1.0,
					damage_groups = {
						fleshy = times * (params[1] or 0) * params.intensity }
				})
				params.timer = params.timer - times * (params[2] or 1)
			end
		end
	end,
})

-- Breath
---------
-- Params :
-- 1: Breath points gained (+) or lost (-) per period
-- 2: Period length in seconds (default 1 second)
-- TODO: Missing an impact preventing from breathing
late.register_impact_type({'player'}, 'breath', {
	step = function(impact, dtime)
		for _, params in pairs(impact.params) do
			params.timer = (params.timer or 0) + dtime
			local times = math.floor(params.timer / (params[2] or 1))
			if times > 0 then
				params.timer = params.timer - times * (params[2] or 1)

				local old = impact.target:get_breath()
				local new = old + times * (params[1] or 0) * params.intensity

				if new < 0 then new = 0 end
				if new > 11 then new = 11 end
				if new == 11 and old < 11 then new = 10 end
				if new ~= old then impact.target:set_breath(new) end
			end
		end
	end,
})

-- Daylight
-----------
-- Params :
-- 1: Daylight aimed [0..1]. 0 = Dark, 1 = Full daylight
-- TODO: Impact should be considered as changed when default daylight changes

-- Function computing default daynight ratio (there is no (yet?) any lua api
-- function to do that). More or less LUA version of C++ time_to_daynight_ratio
-- funtion from minetest/src/daynightratio.h
local function get_default_daynight_ratio()
	local t = minetest.get_timeofday() * 24000
	if t > 12000 then t = 24000 - t end
	local values = {
		{4375, 0.150}, {4875, 0.250}, {5125, 0.350}, {5375, 0.500},
		{5625, 0.675}, {5875, 0.875}, {6125, 1.0}, {6375, 1.0},
	}

	for i, v in ipairs(values) do
		if v[1] > t then
			if i == 1 then
				return v[2]
			else
				local f = (t - values[i-1][1]) / (v[1] - values[i-1][1]);
				return (f * v[2] + (1.0 - f) * values[i-1][2]);
			end
		end
	end
	return 1
end

late.register_impact_type('player', 'daylight', {
	reset = function(impact)
			impact.target:override_day_night_ratio(nil)
		end,
	update = function(impact)
			impact.target:override_day_night_ratio(
				late.superpose_valints(
					late.get_valints(impact.params, 1),
					get_default_daynight_ratio()))
		end,
})

-- Texture
----------
-- Params:
-- colorize - Colorize
-- opacity - Opacity [0..1]

late.register_impact_type({'player', 'mob'}, 'texture', {
	vars = { initial_textures = nil },

	reset = function(impact)
			if impact.vars.initial_textures then
				default.player_set_textures(impact.target,
					impact.vars.initial_textures)
				impact.vars.initial_textures = nil
			end
			impact.target:settexturemod("")
		end,

	update = function(impact)
			local data = late.get_storage_for_target(impact.target)
			local modifier = ""
			local color

			for _, param in pairs(impact.params) do
				if param.colorize and param.intensity then
					color = late.color_to_table(param.colorize)
					color.a = color.a * param.intensity
					modifier = modifier.."^[colorize:"..
						late.color_to_rgba_texture(color)
				end
			end

			local opacity = late.multiply_valints(
				late.get_valints(impact.params, "opacity"))

			if opacity < 1 then
				-- https://github.com/minetest/minetest/pull/7148
				-- Alpha textures on entities to be released in Minetest 0.5
				-- Before 0.5, target is either fully visible or invisible
				modifier = modifier.."^[opacity:"..(opacity * 255)
			end

			if data.type == 'mob' then
				impact.target:settexturemod(modifier)
			end

			if data.type == 'player' then
				local textures = default.player_get_animation(impact.target).textures

				if textures then
					if not impact.vars.initial_textures then
						impact.vars.initial_textures = table.copy(textures)
					end
					for key, _ in pairs(textures) do
						textures[key] = impact.vars.initial_textures[key]
													..modifier
					end
					default.player_set_textures(impact.target, textures)
				end

			end
		end,
	})

-- Nametag (WIP)
----------
-- Params:
-- colorize - Colorize
-- opacity - Opacity [0..1]
-- TODO: Get real nametag color instead of white as default

late.register_impact_type({'player', 'mob'}, 'nametag', {
	reset = function(impact)
			impact.target:set_nametag_attributes({color = "white"})
		end,

	update = function(impact)
			local opacity = late.multiply_valints(
				late.get_valints(impact.params,	"opacity"))
			local color = late.superpose_color_valints(
				late.get_valints(impact.params,	"colorize"), "white")
			color.a = color.a * opacity
			impact.target:set_nametag_attributes({color = color})
		end,
	})

-- Vision (WIP)
---------
-- Params :
-- 1: Vision multiplier [0..1]. 0 = Blind, 1 and above = normal. Default: 1
-- TODO: 2: Mask color (colorstring). Default "black".
-- TODO: Definitely not working, too easy to disable by pressing F1

late.register_impact_type('player', 'vision', {
	vars = { hudid = nil },
	reset = function(impact)
			if impact.vars.hudid then
				impact.target:hud_remove(impact.vars.hudid)
			end
		end,
	update = function(impact)
			local vision = late.multiply_valints(
				late.get_valints(impact.params, 1))
			if vision > 1 then vision = 1 end
			local text = "late_black_pixel.png^[colorize:#000000^[opacity:"..
				math.ceil(255-vision*255)
			if impact.vars.hudid then
				impact.target:hud_change(impact.vars.hudid, 'text', text)
			else
				impact.vars.hudid = impact.target:hud_add({
					hud_elem_type = "image",
					text=text,
					scale = { x=-100, y=-100},
					position = {x = 0.5, y = 0.5},
					alignment = {x = 0, y = 0}
				})
			end
		end,
})