-- Textures for raymarcher
require "Vector"
local V = Vector

local function make_phong(lights, colour, amb, spec, shiny)
   return function (location, ray_dir, normal, count)
      local thiscol = {0, 0, 0}
      local reflected_ray = V.normalize(normal*(ray_dir*normal*2) - ray_dir)
      for _,light in ipairs(lights) do
         local light_dir = V.normalize(light-location)
         local Iamb = math.max(normal*light_dir, 0)
         local Ispec = math.pow(math.max(light_dir*reflected_ray,0),shiny)
            
         thiscol[1] = thiscol[1] + colour[1]*Iamb*amb + Ispec*spec
         thiscol[2] = thiscol[2] + colour[2]*Iamb*amb + Ispec*spec
         thiscol[3] = thiscol[3] + colour[3]*Iamb*amb + Ispec*spec
      end

      return thiscol
   end
end

local function make_count_texture()
   return function (location, ray_dir, normal, count)
      return {count/10, count/10, count/10}
   end
end

   
Textures = {
   make_phong = make_phong,
   make_count_texture = make_count_texture
}

return Textures