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local world = require "world"
local util = require "util"
local pi = math.pi
local obj = {}
obj.max_size = 20
local types = {}
function obj.load_types()
for _, f in ipairs(love.filesystem.getDirectoryItems "objects") do
local ts = assert(love.filesystem.load("objects/"..f))()
for t, v in pairs(ts) do
types[t] = v
end
end
end
function obj.new(type, pos, data, ...)
world.last_id = world.last_id + 1
local o = setmetatable(
{id = world.last_id, data = data or {}, type = type}, obj)
o.data.pos = pos
o:init(...)
return o
end
function obj.load(id, data)
local o = setmetatable({id = id, data = data, type = data.type}, obj)
o:init()
return o
end
function obj.get(id)
return world.objects[id]
end
function obj.is_obj(v)
return getmetatable(v) == obj
end
function obj.in_box(x1, y1, x2, y2)
return coroutine.wrap(function()
for x = x1, x2 + world.chunk_size, world.chunk_size do
for y = y1, y2 + world.chunk_size, world.chunk_size do
for _, o in pairs(world.chunk(x, y).objects) do
local x, y = unpack(o.data.pos)
if x >= x1 and x <= x2 and y >= y1 and y <= y2 then
coroutine.yield(o)
end
end
end
end
end)
end
function obj.in_circle(x1, y1, r)
return coroutine.wrap(function()
for o in obj.in_box(x1-r, y1-r, x1+r, y1+r) do
if (x1-o.data.pos[1])^2 + (y1-o.data.pos[2])^2 <= r^2 then
coroutine.yield(o)
end
end
end)
end
function obj.at(x, y)
return coroutine.wrap(function()
for o in obj.in_box(
x - obj.max_size, y - obj.max_size,
x + obj.max_size, y + obj.max_size) do
if o:in_hitbox(x, y) then
coroutine.yield(o)
end
end
end)
end
function obj.all()
return coroutine.wrap(function()
for _, o in pairs(world.objects) do
coroutine.yield(o)
end
end)
end
function obj.total_energy()
local res = 0
for obj in obj.all() do
res = res + obj:energy()
end
return res
end
function obj:__index(v)
if obj[v] then
return obj[v]
else
return types[rawget(self, "type")][v]
end
end
function obj:overload(m, ...)
if types[self.type][m] then
return types[self.type][m](self, ...)
end
end
function obj:init(...)
self.chunk = world.chunk(unpack(self.data.pos))
self.chunk.objects[self.id] = self
world.objects[self.id] = self
self.data.vel = self.data.vel or {0, 0}
self.data.avel = self.data.avel or 0
return self:overload("init", ...)
end
function obj:set_pos(x, y)
self.data.pos[1] = x
self.data.pos[2] = y
local chunk = world.chunk(unpack(self.data.pos))
if chunk ~= self.chunk then
self.chunk.objects[self.id] = nil
chunk.objects[self.id] = self
self.chunk = chunk
end
end
function obj:tick(...)
local vx, vy = unpack(self.data.vel)
self:set_pos(self.data.pos[1] + vx, self.data.pos[2] + vy)
self.data.angle = (self.data.angle or 0) + self.data.avel / pi
if self.hitbox then
local x, y = unpack(self.data.pos)
for o in obj.in_box(
x - obj.max_size, y - obj.max_size,
x + obj.max_size, y + obj.max_size) do
if o.hitbox and o ~= self then
local dist = o.hitbox + self.hitbox
local ox, oy = unpack(o.data.pos)
local dx, dy = ox - x, oy - y
if dx*dx + dy*dy < dist*dist then
-- local ke = self:energy() + o:energy()
self:collision(o)
o:collision(self)
local angle = math.atan2(dy, dx)
-- reposition self outside of collided object
self:set_pos(
self.data.pos[1] - math.cos(angle) * dist + dx,
self.data.pos[2] - math.sin(angle) * dist + dy)
local av1, av2 = self.data.avel, o.data.avel
-- transfer angular velocity conserving energy
local avel = math.sqrt((av1*av1 + av2*av2) / 2)
self.data.avel = avel * (av1 > av2 and 1 or -1)
o.data.avel = avel * (av1 > av2 and -1 or 1)
local vx, vy = unpack(self.data.vel)
local ovx, ovy = unpack(o.data.vel)
-- exchange the components of the velocities towards the
-- angle of collision
local rovx, rvy = util.rot(angle, vx, vy)
local rvx, rovy = util.rot(angle, ovx, ovy)
self.data.vel[1], self.data.vel[2] = util.rot(-angle, rvx, rvy)
o.data.vel[1], o.data.vel[2] = util.rot(-angle, rovx, rovy)
self:collision_exit(o)
o:collision_exit(self)
-- assert(ke - (self:energy() + o:energy()) < 0.00001)
end
end
end
end
self:overload("tick", ...)
end
function obj:draw(...)
love.graphics.push()
love.graphics.translate(unpack(self.data.pos))
if self.data.angle then
love.graphics.rotate(self.data.angle)
end
self:overload("draw", ...)
love.graphics.pop()
end
function obj:collision(...)
return self:overload("collision", ...)
end
function obj:collision_exit(...)
return self:overload("collision_exit", ...)
end
function obj:energy()
local vx, vy = unpack(self.data.vel)
local avel = self.data.avel
return 1 + avel*avel + vx*vx + vy*vy
end
function obj:observe_avel(o)
return o.data.avel - util.magnitude(self.data.vel)
end
function obj:observe_vel(o)
local vx, vy = unpack(self.data.vel)
local ovx, ovy = unpack(o.data.vel)
return ovx - vx, ovy - vy
end
function obj:observe_pos(o)
local px, py = unpack(self.data.pos)
local opx, opy = unpack(o.data.pos)
return opx - px, opy - py
end
function obj:avel_to_accel(o, ax, ay)
local ovx, ovy = self:observe_vel(o)
local nvx, nvy = ovx + ax, ovy + ay
local v = util.magnitude{ovx, ovy}
local nv = util.magnitude{nvx, nvy}
local ne = v*v - nv*nv
local avel = self:observe_avel(o)
local ave = avel*avel + ne
if ave < 0 then
return false
end
local vx, vy = unpack(self.data.vel)
o.data.avel =
util.magnitude{vx, vy} + (math.sqrt(ave) * (avel >= 0 and 1 or -1))
o.data.vel = {vx + nvx, vy + nvy}
return true
end
function obj:in_hitbox(px, py)
local x, y = unpack(self.data.pos)
local dx, dy = x - px, y - py
return dx*dx + dy*dy < self.hitbox*self.hitbox
end
function obj:remove()
self.chunk.objects[self.id] = nil
world.objects[self.id] = nil
return self:overload "remove"
end
return obj
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