require "Vector"
local V = Vector

require "Primitives"
local P = Primitives

require "Operations"
local O = Operations

require "Textures"
local T = Textures

require "Render"

local function make_mandelbulb(max_iter, power, texture)
   return function(p)
      local z = V.new(p)
      local dr = 1.0
      local r = 0.0

      for i=1,max_iter do
         r = V.norm(z)
         if r>2.0 then
            break
         end
         
         -- convert to polar coordinates
         theta = math.acos(z[3]/r)
         phi = math.atan(z[2],z[1])
         dr =  math.pow(r, power-1.0)*power*dr + 1.0
         
         -- scale and rotate the point
         zr = math.pow(r ,power)
         theta = theta*power
         phi = phi*power
         
         -- convert back to cartesian coordinates
         z = V.new{math.sin(theta)*math.cos(phi),
                   math.sin(phi)*math.sin(theta),
                   math.cos(theta)} * zr
         z = z + p
      end
   
      return {dist = 0.5*math.log(r)*r/dr,
              texture = texture}
   end
end

local scene = {
   -- sdf = make_mandelbulb(T.make_count_texture(0.1)),
   sdf = make_mandelbulb(100, 8,
                         T.make_phong_texture(
                            {V.new{3,-5,3}},
                            T.make_solid_pigment{0,0.5,1.0},
                            0.1, 1.0, 0.0, 30)),

   camera = {location = V.new{0,-5,0},
             point_at = V.origin,
             right = V.x,
             fov = 1}}

Render.eps = 0.001
Render.bg_col = {0,0,0}
Render.render(scene, 640, 480, "out/mandelbulb.ppm")