init

.gitignore

@@ -0,0 +1 @@
+*.lua

src/main.moon

@@ -0,0 +1,96 @@
+width, height = love.graphics.getDimensions!
+radius = (width + height) / 4
+
+class Particle
+  new: (n=1, x, y, r=radius) =>
+    rng = love.math.newRandomGenerator n
+    @color = { rng\random!, rng\random!, rng\random!, 1 }
+    @mass = n
+    @charge = n % math.log(n)
+    @radius = math.log(n + 8)
+    if x and y
+      @x = x
+      @y = y
+    else
+      d = love.math.random! * r
+      r = love.math.random! * math.pi * 2
+      @x = d * math.sin r
+      @y = d * math.cos r
+    @vx = 0
+    @vy = 0
+
+universe = {}
+new = {}
+for i=1,800
+  table.insert universe, Particle nil, nil, nil, 200
+
+physics = (a, b) ->
+  dx = a.x - b.x
+  dy = a.y - b.y
+  d2 = dx * dx + dy * dy
+  theta = math.atan2 dy, dx
+  x = math.cos theta
+  y = math.sin theta
+  r2 = (a.radius + b.radius)^2
+  m = a.mass + b.mass
+  if d2 > r2
+    g = 1 / d2
+    a.vx -= b.mass * g * x
+    a.vy -= b.mass * g * y
+    b.vx += a.mass * g * x
+    b.vy += a.mass * g * y
+  -- elseif d2 < math.log(r2) / m^2
+  --   p = Particle m
+  --   p.vx = a.vx / a.mass + b.vx / b.mass
+  --   p.vy = a.vy / a.mass + b.vy / b.mass
+  --   p.x = (a.x * a.mass + b.x * b.mass) / m
+  --   p.y = (a.y * a.mass + b.y * b.mass) / m
+  --   a.dirty = true
+  --   b.dirty = true
+  --   table.insert new, p
+  else
+    f = math.min 1, 100 / math.max d2, 0.01
+    a.vx += f * x
+    a.vy += f * y
+    b.vx -= f * x
+    b.vy -= f * y
+    a.vx *= 0.99
+    a.vy *= 0.99
+    b.vx *= 0.99
+    b.vy *= 0.99
+    -- a.x += x
+    -- a.y += y
+    -- b.x -= x
+    -- b.y -= y
+
+love.update = (dt) ->
+  for a = 1, #universe - 1
+    for b = a + 1, #universe
+      physics(universe[a], universe[b])
+
+  for i = #universe, 1, -1
+    if universe[i].dirty
+      table.remove universe, i
+      i += 1
+
+  while next new
+    table.insert universe, table.remove new, 1
+
+  for particle in *universe
+    particle.x += particle.vx * dt
+    particle.y += particle.vy * dt
+
+love.mousepressed = (x, y) ->
+  for i = 1, 25
+    X = x - width / 2 + love.math.random -25, 25
+    Y = y - height / 2 + love.math.random -25, 25
+    table.insert universe, Particle 1, X, Y
+
+love.draw = ->
+  love.graphics.translate width / 2, height / 2
+  for particle in *universe
+    love.graphics.setColor particle.color
+    love.graphics.circle "fill", particle.x, particle.y, particle.radius
+
+love.keypressed = (key) ->
+  love.event.quit! if key == "escape"

src/old.moon

@@ -0,0 +1,121 @@
+-- particle type influences attractive/repulsive forces
+-- heat
+width, height = love.graphics.getDimensions!
+clamp = (n, x, y) -> math.max x, math.min y, n
+sign = (n) -> math.abs(n) == n and 1 or -1
+
+class Particle
+  new: (n=1, x, y) =>
+    rng = love.math.newRandomGenerator n
+    @color = { rng\random!, rng\random!, rng\random!, 1 }
+    @mass = n
+    @charge = n % 5 - 2
+    @radius = math.log(n + 10)
+    @x = x or love.math.random 0, width
+    @y = y or love.math.random 0, height
+    @vx = 0
+    @vy = 0
+
+universe = {}
+new = {}
+for i=1,500
+  table.insert universe, Particle love.math.random 1, 5
+-- table.insert universe, Particle 1, width / 2 - 4, height / 2 - 200
+-- table.insert universe, Particle 5, width / 2 + 4, height / 2 - 200
+-- table.insert universe, Particle 1, width / 2 - 4, height / 2 + 200
+-- table.insert universe, Particle 1, width / 2 + 4, height / 2 + 200
+
+physics = (a, b) ->
+  -- distance, direction, collision checks
+  dx = a.x - b.x
+  dy = a.y - b.y
+  d2 = dx * dx + dy * dy
+  theta = math.atan2 dy, dx
+  x = math.cos theta
+  y = math.sin theta
+  r2 = (a.radius + b.radius)^2
+  m = a.mass + b.mass
+  if d2 > r2
+    -- gravitational force
+    g = 1 / d2
+    a.vx -= b.mass * g * x
+    a.vy -= b.mass * g * y
+    b.vx += a.mass * g * x
+    b.vy += a.mass * g * y
+    -- electromotive force
+    unless a.charge == 0 or b.charge == 0
+      e = (math.abs(a.charge) + math.abs(b.charge))^3 / d2^2
+      -- print a.charge, b.charge, e
+      if sign(a.charge) == sign(b.charge)
+        a.vx -= b.charge * e * x
+        a.vy -= b.charge * e * y
+        b.vx += a.charge * e * x
+        b.vy += a.charge * e * y
+      else
+        a.vx -= b.charge * e * x
+        a.vy -= b.charge * e * y
+        b.vx -= a.charge * e * x
+        b.vy -= a.charge * e * y
+  elseif d2 < math.log(r2) / m^3 / 10
+    -- making new elements
+    p = Particle m
+    p.vx = a.vx / a.mass + b.vx / b.mass
+    p.vy = a.vy / a.mass + b.vy / b.mass
+    p.x = (a.x * a.mass + b.x * b.mass) / m
+    p.y = (a.y * a.mass + b.y * b.mass) / m
+    a.dirty = true
+    b.dirty = true
+    table.insert new, p
+  else
+    -- anti-collision force
+    f = math.min 0.4, 100 / math.max d2, 0.01
+    a.vx += b.mass * f * x
+    a.vy += b.mass * f * y
+    b.vx -= a.mass * f * x
+    b.vy -= a.mass * f * y
+
+love.update = (dt) ->
+  for a = 1, #universe - 1
+    for b = a + 1, #universe
+      physics(universe[a], universe[b])
+
+  for i=#universe, 1, -1
+    if universe[i].dirty
+      table.remove universe, i
+      i += 1
+
+  while next new
+    table.insert universe, table.remove new, 1
+
+  for particle in *universe
+    -- particle.vx *= 0.9
+    -- particle.vy *= 0.9
+    particle.x += particle.vx * dt
+    particle.y += particle.vy * dt
+
+love.draw = ->
+  types = {}
+  for particle in *universe
+    if types[particle.mass]
+      types[particle.mass] += 1
+    else
+      types[particle.mass] = 1
+    love.graphics.setColor particle.color
+    love.graphics.circle "fill", particle.x, particle.y, particle.radius
+
+  -- love.graphics.setColor 1, 1, 1, 0.5
+  -- love.graphics.line width / 2, 0, width / 2, height
+  love.graphics.setColor 1, 1, 1, 1
+  love.graphics.print #universe
+  for i,v in ipairs types
+    love.graphics.print "#{i}->#{v}", 0, i * 12
+
+love.mousepressed = (x, y) ->
+  for i=1,50
+    a = x + love.math.random -25, 25
+    b = y + love.math.random -25, 25
+    table.insert universe, Particle 1, a, b
+
+love.keypressed = (key) ->
+  love.event.quit! if key == "escape"
+  table.insert universe, Particle!