formalizing..?

src/main.moon

@@ -1,57 +1,70 @@
-import graphics from love
-import cos, sin, pi from math
-export t = 0
-tau = 2 * math.pi
-w, h = graphics.getDimensions!
-
 tiny = require "tiny"
 
-MapDisplay = tiny.sortedSystem {
+IDTracker = tiny.system {
-  compare: (a, b) =>
+  filter: tiny.requireAll "id"
-    a.orbit.hierarchy < b.orbit.hierarchy
+  onAdd: (entity) =>
-  filter: tiny.requireAll "orbit"
+    @[entity.id] = entity
-  draw: =>
+  onRemove: (entity) =>
-    graphics.translate w / 2, h / 2
+    @[entity.id] = nil
-    for e in *@entities
-      entity = e.orbit
-      -- orbital period
-      --  real: T = 2pi * sqrt(a^3 / G*M)
-      --  sim:  T = 2pi * speed_parameter
-      entity.x = entity.radius * cos(t / entity.speed_parameter) + entity.offset
-      entity.y = entity.radius * sin(t / entity.speed_parameter) + entity.offset
-      if entity.parent
-        entity.x += entity.parent.x
-        entity.y += entity.parent.y
-      graphics.circle "fill", entity.x, entity.y, 5
 }
 
-world = tiny.world MapDisplay
+Time = tiny.processingSystem {
+  filter: tiny.requireAll "time"
+  process: (entity, dt) =>
+    entity.time += dt
+}
+
+import graphics from love
+import cos, sin from math
+w, h = graphics.getDimensions!
+MapDisplay = tiny.sortedSystem {
+  compare: (a, b) =>
+    if a.orbit and b.orbit
+      a.orbit.hierarchy <= b.orbit.hierarchy
+    else
+      true
+  filter: tiny.requireAny "orbit", tiny.requireAll("x", "y")
+  draw: (t) =>
+    graphics.translate w / 2, h / 2
+    for entity in *@entities
+      if orbit = entity.orbit
+        orbit = entity.orbit
+        -- orbital period
+        --  real: T = 2pi * sqrt(a^3 / G*M)
+        --  sim:  T = 2pi * speed_parameter
+        entity.x = orbit.radius * cos(t / orbit.speed_parameter) + orbit.offset
+        entity.y = orbit.radius * sin(t / orbit.speed_parameter) + orbit.offset
+        if orbit.parent_id
+          parent = IDTracker[orbit.parent_id]
+          entity.x += parent.x
+          entity.y += parent.y
+      graphics.circle "fill", entity.x, entity.y, 5 -- TEMP radius
+}
 
 -- TEMP demo
 sun = {
+  id: 0
   x: 0,
-  y: 0,
+  y: 0
-  orbit: { hierarchy: 0, radius: 0, offset: 0, speed_parameter: 1 }
 }
-
 planet = {
+  id: 1
   orbit: {
     hierarchy: 1
     radius: 20
-    parent: sun
+    parent_id: 0
     offset: love.math.random!
     speed_parameter: 0.5
   }
 }
-
+game = { time: 0 }
-world\add planet, sun
+world = tiny.world MapDisplay, IDTracker, planet, sun, Time, game
 
 love.update = (dt) ->
-  t += dt
   world\update dt
 
 love.draw = ->
-  MapDisplay\draw!
+  MapDisplay\draw game.time
 
 love.keypressed = (key) ->
   if key == "escape" love.event.quit!