ToriEngine - ECS Metroidvania Engine

entity_that_moves={

pos = {x=30,y=64} --position component

move = {vel_x=1,vel_y=0,max_vel_x=3,max_vel_y=2,acc_x=1, acc_y=3, friction=0.8} --movement component
}

function(ent)
	ent.move.vel_x=mid(-ent.move.max_vel_x,ent.move.vel_x+ent.move.acc_x,ent.move.max_vel_x)
	ent.move.vel_y= --yadda yadda yadda you get the point
end

-- basic
function _has(e, ks)
  for n in all(ks) do
    if e[n]==nil then
      return false
    end
  end
  return true
end

function system(ks, f)
  return function(es)
    for e in all(es) do
      if _has(e, ks) then
        f(e)
      end
    end
  end
end

--extras

function tag(e,k,v)
    if (not v) v=true
    e[k]=v
end

function untag(e,k)
    e[k]=nil
end

function filter(es,k,v)
    local res={}
    for e in all(es) do
        if e[k]==v then
            add(res,e)
        end
    end
    return res
end

function find(es,k,v)
    local res=filter(es,k,v)
    if (#res>0) return res[1]
    return nil
end

function filter_tagged(es,t)
    local res={}
    for e in all(es) do
        if e[t]!=nil then
            add(res,e)
        end
    end
    return res
end

function _update60()
    -- these are the updater
    -- systems we need (for now)

    _animate(world)

    --_behaviour_system(world)
    _ai_behaviour(world)

    _move_input(world)
    _jump_input(world)
    _atk_input(world)

    _gravity(world)

    _grounded(world)

    _movement(world)

    _map_collisions(world)
    _ent_collisions(world)

    _damaged(world)
    _death(world)

end

function _draw()
    palt(11,true) 
    palt(0,false)
    cls(5)

    colorize(128,133,141,134)
    map()

    -- these are the render systems
    -- we need (for now)

    colorize(129,2,15,7)
    _animspr(world)
    _camera(world)
    pal()
    _ui(world)

    -- just debug stuff
    if debug then
        _debug_vectors(world)

	for p in all(debug_collision_pixels) do 
	    pset(p[1],p[2],p[3])
        end
    end
end

-- update systems

_map_collisions = system({"pos","size","mcoll","jump"},
 function(e)

  collide_side(e)

  collide_roof(e)

  if collide_floor(e) then
   tag(e,"grounded")
  else
   --self:set_anim("jump")
   untag(e,"grounded")
  end

 end)

_ent_collisions = system({"pos","move","ecoll"},
    function(e)
        for typ,tg in pairs(e.ecoll.all) do

        local es=filter(world,"type",typ)
            for e2 in all(es) do

                if e2!=e and overlaps_box_box(
                    e.pos,e.size,
                    e2.pos,e2.size) then

                    --entity collided will become
                    --e[tg]
                    if (not e[tg]) tag(e,tg,{by=e2})

                end
            end
        end
    end
)

-- custom handlers

function collide_side(e)

 local offset=e.size.x/3
 for i=-(e.size.x/3),(e.size.x/3),2 do
 --if e.move.vx>0 then
 if fget(mget((e.pos.x+(offset))/8,(e.pos.y+i)/8),0) then
   e.move.vx=0
   e.pos.x=(flr(((e.pos.x+(offset))/8))*8)-(offset)
   return true
  end
 --elseif e.move.vx<0 then
  if fget(mget((e.pos.x-(offset))/8,(e.pos.y+i)/8),0) then
   e.move.vx=0
   e.pos.x=(flr((e.pos.x-(offset))/8)*8)+8+(offset)
   return true
  end
-- end
 end
 --didn't hit a solid tile.
 return false
end

--check if pushing into floor tile and resolve.
--requires e.move.vx,e.pos.x,e.pos.y,self.grounded,self.airtime and 
--assumes tile flag 0 or 1 == solid
function collide_floor(e)
 --only check for ground when falling.
 if e.move.vy<0 then
  return false
 end
 local landed=false

 --check for collision at multiple points along the bottom
 --of the sprite: left, center, and right.
 for i=-(e.size.x/3),(e.size.x/3),2 do
  local tile=mget((e.pos.x+i)/8,(e.pos.y+(e.size.y/2))/8)
  if fget(tile,0) or (fget(tile,1) and e.move.vy>=0) then
   e.move.vy=0
   e.pos.y=(flr((e.pos.y+(e.size.y/2))/8)*8)-(e.size.y/2)
   landed=true
  end
 end
 return landed
end

--check if pushing into roof tile and resolve.
--requires e.move.vy,e.pos.x,e.pos.y, and 
--assumes tile flag 0 == solid
function collide_roof(e)
 --check for collision at multiple points along the top
 --of the sprite: left, center, and right.
 for i=-(e.size.x/3),(e.size.x/3),2 do
  if fget(mget((e.pos.x+i)/8,(e.pos.y-(e.size.y/2))/8),0) then
   e.move.vy=0
   e.pos.y=flr((e.pos.y-(e.size.y/2))/8)*8+8+(e.size.y/2)
   e.jump.jump_hold_time=0
  end
 end
end