-- Testing meta-circles

FieldMap={}

-- Clear FieldMap
function ClearFieldMap(w,h)
 FieldMap["width"]=w
 FieldMap["height"]=h
 local i, j

 for i=1,w,1 do
  FieldMap[i]={}

  for j=1, h, 1 do
   FieldMap[i][j]=0
  end

 end
end


-- Add Metacircle
function MetaCircle(cx, cy, radius)
 local left, right, top, bottom
 left = cx-radius
 right = cx+radius
 top = cy-radius
 bottom = cy+radius
print("doing: "..cx.." "..cy.." "..radius)

 local i,j

 for i=left, right, 1 do
  for j=top, bottom, 1 do
   local distance_squared = (cx-i)*(cx-i)+(cy-j)*(cy-j)
   local distance = sqrt(distance_squared)
   local inten = (radius - distance) / radius
   if inten<0 then inten=0 end
   if inten>1 then inten=1 end
   if i>=1 and i<=FieldMap["width"] and j>=1 and j<=FieldMap["height"] then
    --print(inten)
    FieldMap[i][j] = FieldMap[i][j] + inten
   end
  end
 end

end

-- Create a list to hold circles that are generated
CircleList = List:new()
ExtentRadius = 0   -- Circle encompassing entire fractal

MinRadius = 3
MaxRadius = 7


-- Randomly choose a circle from the list
function SelectCircle()
  local num = CircleList:len()
  local x,y, radius
  

  local which = RandRange(1, num)
  local circle = CircleList[which]
  return circle
end


-- RandomVector()-- Generate a unit-length vector pointing in a random direction
function RandomVector()
  local x,y

  x = Rand01()
  y = Rand01()

  x = -1 + (x*2)
  y = -1 + (y*2)

  local len = sqrt((x*x)+(y*y))
  x = x/len
  y = y/len

  return x,y
end

function CirclesCollide(circle1, circle2)
 local dist = (circle1.x-circle2.x)*(circle1.x-circle2.x) + (circle1.y-circle2.y)*(circle1.y-circle2.y)
 local max = ((circle1.radius-1)+(circle2.radius-1))*((circle1.radius-1)+(circle2.radius-2))

 if dist<max then return 1
 else return nil
 end
end


function CircleCollidesWithList(circle)
 local num = CircleList:len()
 local i

 for i=1,num,1 do
   circle2 = CircleList[i]
   if CirclesCollide(circle, circle2) then return 1 end
 end

 return nil
end


-- SpawnRandomCircle()
-- Generate a circle outside of the current extents
function SpawnRandomCircle()
  local radius = RandRange(MinRadius, MaxRadius)
  local vx, vy = RandomVector()

  vx = vx * (ExtentRadius + radius + 2)
  vy = vy * (ExtentRadius + radius +2)

  local c={}
  c.x = vx
  c.y = vy
  c.radius = radius

  return c
end


-- InsertCircle()
-- Insert a circle into fractal, and update extent radius if necessary
function InsertCircle(circle)
  CircleList:append(circle)

  local i,j
  for i=circle.x-circle.radius, circle.x+circle.radius,1 do
    for j=circle.y-circle.radius, circle.y+circle.radius, 1 do
      local dist = sqrt( (i*i)+(j*j) )
      if dist > ExtentRadius then ExtentRadius = dist end
    end
  end
end


-- SeedFractal()
-- Seed the fractal with an initial circle (at 0,0) and calculate ExtentRadius
function SeedFractal()
  local radius = RandRange(MinRadius, MaxRadius)
  local c = {}

  c.x = 0
  c.y = 0
  c.radius = radius

  ExtentRadius = radius
  CircleList:append(c)
end

-- AccreteCircle()
-- Spawn a random circle, pick a random circle already in the list, and propagate the circle in 1-unit increments until
-- it hits the fractal
function AccreteCircle()
  local c1 = SpawnRandomCircle()
  local c2 = SelectCircle()

  local vx, vy = (c2.x-c1.x), (c2.y-c1.y)
  local len = sqrt( (vx*vx)+(vy*vy) )
  vx = vx/len
  vy = vy/len

  local collide = CircleCollidesWithList(c1)
  while collide==nil do
    c1.x = c1.x + vx
    c1.y = c1.y + vy
    collide = CircleCollidesWithList(c1)
  end

  c1.x = c1.x + vx
  c1.y = c1.y + vy

  InsertCircle(c1)
end
  

-- Build field
-- Iterate through the list of circles and build the field

function BuildField()
  local num = CircleList:len()
  print("Number of circles: "..num)
  ClearFieldMap(MW, MH)
  
  for i=1,num,1 do
    local c = CircleList[i]
    --print("Check")
    MetaCircle(Int(c.x+(MW/2)), Int(c.y+(MH/2)), c.radius)  -- Add 1/2 map dimensions to shift fractal to center of map
  end
end