v1 charge and grav

src/main.moon

@@ -0,0 +1,62 @@
+import random from love.math
+
+types = setmetatable {}, {
+  __index: (t, k) ->
+    t[k] = {
+      mass: k
+      charge: 1 / k - random!
+      color: { random!, random!, random!, 1 }
+      radius: 0.42 + k^0.13
+    }
+    return t[k]
+}
+
+class Particle
+  new: (@x, @y, @vx, @vy, mass) =>
+    for stat, value in pairs types[mass]
+      @[stat] = value
+  update: (dt) =>
+    @x += @vx * dt
+    @y += @vy * dt
+
+particles = {}
+
+--   2   2 -- repel 4 (2 - 2 = 0)
+--   2  -2 -- attract 4 (2 - -2 = 4)
+--   -2  2 -- attract 4 (-2 - 2 = -4)
+--   -2 -2 -- repel 4 (-2 - -2 = 0)
+-- add abs values
+
+do_physics = (A, B, dt) ->
+  dx = A.x - B.x
+  dy = A.y - B.y
+  d2 = dx * dx + dy * dy
+  a = math.atan2 dy, dx
+  x = math.cos a
+  y = math.sin a
+
+  g = (A.mass + B.mass) / d2 / 100
+  c = (math.abs(A.charge) + math.abs(B.charge)) / 10
+  c *= -1 if (A.charge < 0 and B.charge > 0) or (A.charge > 0 and B.charge < 0)
+  f = g + c
+
+  A.vx -= f * x * dt
+  A.vy -= f * y * dt
+  B.vx += f * x * dt
+  B.vy += f * y * dt
+
+love.update = (dt) ->
+  for i = 1, #particles - 1
+    for j = i + 1, #particles
+      a, b = particles[i], particles[j]
+      do_physics a, b, dt
+      a\update dt
+      b\update dt
+
+love.draw = ->
+  for particle in *particles
+    love.graphics.setColor particle.color
+    love.graphics.circle "fill", particle.x, particle.y, particle.radius
+
+love.mousepressed = (x, y, btn) ->
+  table.insert particles, Particle(x, y, 0, 0, math.floor 100 * random!)