Monoidally-managed Minetest state modifications
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player_monoids/standard_monoids.lua

156 lines
3.2 KiB

-- Standard effect monoids, to provide canonicity.
local function mult(x, y) return x * y end
local function mult_fold(elems)
local tot = 1
for _, v in pairs(elems) do
tot = tot * v
end
return tot
end
local function v_mult(v1, v2)
local res = {}
for k, v in pairs(v1) do
res[k] = v * v2[k]
end
return res
end
local function v_mult_fold(identity)
return function(elems)
local tot = identity
for _, v in pairs(elems) do
tot = v_mult(tot, v)
end
return tot
end
end
local monoid = player_monoids.make_monoid
-- Speed monoid. Effect values are speed multipliers. Must be nonnegative
-- numbers.
player_monoids.speed = monoid({
combine = mult,
fold = mult_fold,
identity = 1,
apply = function(multiplier, player)
local ov = player:get_physics_override()
ov.speed = multiplier
player:set_physics_override(ov)
end,
})
-- Jump monoid. Effect values are jump multipliers. Must be nonnegative
-- numbers.
player_monoids.jump = monoid({
combine = mult,
fold = mult_fold,
identity = 1,
apply = function(multiplier, player)
local ov = player:get_physics_override()
ov.jump = multiplier
player:set_physics_override(ov)
end,
})
-- Gravity monoid. Effect values are gravity multipliers.
player_monoids.gravity = monoid({
combine = mult,
fold = mult_fold,
identity = 1,
apply = function(multiplier, player)
local ov = player:get_physics_override()
ov.gravity = multiplier
player:set_physics_override(ov)
end,
})
-- Fly ability monoid. The values are booleans, which are combined by or. A true
-- value indicates having the ability to fly.
player_monoids.fly = monoid({
combine = function(p, q) return p or q end,
fold = function(elems)
for _, v in pairs(elems) do
if v then return true end
end
return false
end,
identity = false,
apply = function(can_fly, player)
local p_name = player:get_player_name()
local privs = minetest.get_player_privs(p_name)
if can_fly then
privs.fly = true
else
privs.fly = nil
end
minetest.set_player_privs(p_name, privs)
end,
})
-- Noclip ability monoid. Works the same as fly monoid.
player_monoids.noclip = monoid({
combine = function(p, q) return p or q end,
fold = function(elems)
for _, v in pairs(elems) do
if v then return true end
end
return false
end,
identity = false,
apply = function(can_noclip, player)
local p_name = player:get_player_name()
local privs = minetest.get_player_privs(p_name)
if can_noclip then
privs.noclip = true
else
privs.noclip = nil
end
minetest.set_player_privs(p_name, privs)
end,
})
local def_col_scale = { x=0.3, y=1, z=0.3 }
-- Collisionbox scaling factor. Values are a vector of x, y, z multipliers.
player_monoids.collisionbox = monoid({
combine = v_mult,
fold = v_mult_fold({x=1, y=1, z=1}),
identity = {x=1, y=1, z=1},
apply = function(multiplier, player)
local v = vector.multiply(def_col_scale, multiplier)
player:set_properties({
collisionbox = { -v.x, -v.y, -v.z, v.z, v.y, v.z }
})
end,
})
player_monoids.visual_size = monoid({
combine = v_mult,
fold = v_mult_fold({x=1, y=1}),
identity = {x=1, y=1},
apply = function(multiplier, player)
player:set_properties({
visual_size = multiplier
})
end,
})