From cb5790513e938b4879b6e66012802c9c5a0a2297 Mon Sep 17 00:00:00 2001
From: Tim Vaughan <timv@ughan.xyz>
Date: Fri, 17 Mar 2023 15:45:47 +0100
Subject: [PATCH] Added mandelbulb!!

---
 mandelbulb.lua | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 mandelbulb.lua

diff --git a/mandelbulb.lua b/mandelbulb.lua
new file mode 100644
index 0000000..eca6da2
--- /dev/null
+++ b/mandelbulb.lua
@@ -0,0 +1,64 @@
+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")
-- 
2.20.1