From 06059eb522f33574680bb75bb73f28e2b0f6e836 Mon Sep 17 00:00:00 2001
From: Tim Vaughan <timv@ughan.xyz>
Date: Mon, 20 Mar 2023 11:40:50 +0100
Subject: [PATCH] Colours are now Vectors, added rainbow pigment.

---
 Colours.lua      | 15 +++++++++------
 Primitives.lua   |  3 ++-
 Textures.lua     | 16 ++++++++++++++++
 mandelbulb.lua   |  6 ++++--
 rainbow_wall.lua | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 65 insertions(+), 9 deletions(-)
 create mode 100644 rainbow_wall.lua

diff --git a/Colours.lua b/Colours.lua
index 8a71cbe..eec5bb5 100644
--- a/Colours.lua
+++ b/Colours.lua
@@ -1,12 +1,15 @@
 --- Some pre-defined colours
 
+require "Vector"
+local V = Vector
+
 Colours = {
-   red = {1,0,0},
-   green = {0,1,0},
-   blue = {0,0,1},
-   yellow = {1,1,0},
-   magenta = {1,0,1},
-   cyan = {0,1,1}
+   red = V.new{1,0,0},
+   green = V.new{0,1,0},
+   blue = V.new{0,0,1},
+   yellow = V.new{1,1,0},
+   magenta = V.new{1,0,1},
+   cyan = V.new{0,1,1}
 }
 
 return Colours
diff --git a/Primitives.lua b/Primitives.lua
index b1efbfb..1648392 100644
--- a/Primitives.lua
+++ b/Primitives.lua
@@ -63,7 +63,8 @@ end
 Primitives = {
    make_sphere = make_sphere,
    make_plane = make_plane,
-   make_pipe = make_pipe
+   make_pipe = make_pipe,
+   make_mandelbulb = make_mandelbulb
 }
 
 return Primitives
diff --git a/Textures.lua b/Textures.lua
index ad805a6..324a2d2 100644
--- a/Textures.lua
+++ b/Textures.lua
@@ -3,6 +3,9 @@
 require "Vector"
 local V = Vector
 
+require "Colours"
+local C = Colours
+
 local function make_phong_texture(lights, mapped_pigment, amb, diff, spec, shiny)
    local normalize = V.normalize
 
@@ -140,6 +143,18 @@ local function make_mandelbrot_pigment(set_pigment, nonset_pigment, max_iter)
    end
 end
 
+local function make_rainbow_pigment(scale)
+   return function (x,y)
+
+      local Ired = math.sin(x/math.pi/scale)^2 * math.sin(y/math.pi/scale)^2
+      local Igreen = math.cos(x/math.pi/scale)^2 * math.sin(y/math.pi/scale)^2
+      local Iblue = math.sin(x/math.pi/scale)^2 * math.cos(y/math.pi/scale)^2
+
+      return C.red*Ired + C.green*Igreen + C.blue*Iblue
+   end
+end
+
+
 -- Mapping functions
 
 -- These functions define mappings from 3D world coordinates to 2D
@@ -170,6 +185,7 @@ Textures = {
    make_solid_pigment = make_solid_pigment,
    make_checkered_pigment = make_checkered_pigment,
    make_image_pigment = make_image_pigment,
+   make_rainbow_pigment = make_rainbow_pigment,
    make_mandelbrot_pigment = make_mandelbrot_pigment,
    map_rectangular = map_rectangular,
    map_spherical = map_spherical
diff --git a/mandelbulb.lua b/mandelbulb.lua
index 7d7a011..f39c67b 100644
--- a/mandelbulb.lua
+++ b/mandelbulb.lua
@@ -18,7 +18,8 @@ local scene = {
    sdf = P.make_mandelbulb(V.origin, 100, 8,
                            T.make_phong_texture(
                               {V.new{3,-5,3}},
-                              T.make_solid_pigment{0,0.5,1.0},
+                              -- T.make_solid_pigment{0,0.5,1.0},
+                              T.map_spherical(T.make_rainbow_pigment(0.1), V.origin, 1, 1),
                               0.1, 1.0, 0.0, 30)),
 
    camera = {location = V.new{0,-5,0},
@@ -28,4 +29,5 @@ local scene = {
 
 Render.eps = 0.001
 Render.bg_col = {0,0,0}
-Render.render(scene, 2560, 1440, "out/mandelbulb.ppm")
+Render.render(scene, 2560, 1440, "out/mandelbulb_rainbow.ppm")
+-- Render.render(scene, 2560, 1440, "out/mandelbulb_rainbow.ppm")
diff --git a/rainbow_wall.lua b/rainbow_wall.lua
new file mode 100644
index 0000000..ad84b68
--- /dev/null
+++ b/rainbow_wall.lua
@@ -0,0 +1,34 @@
+require "Vector"
+local V = Vector
+
+require "Primitives"
+local P = Primitives
+
+require "Operations"
+local O = Operations
+
+require "Textures"
+local T = Textures
+
+require "Render"
+
+local lights = {V.new{1,-1,1}}
+
+local plane_normal = V.normalize(V.new{0.0,-1,0.0})
+local texture_y = V.normalize(V.cross(plane_normal,V.x))
+local texture_x = V.cross(texture_y,plane_normal)
+
+local scene = {
+   sdf = P.make_plane(V.new{0,0,0}, plane_normal,
+                      T.make_phong_texture(lights,
+                                           T.map_rectangular(
+                                              T.make_rainbow_pigment(0.1),
+                                              texture_x, texture_y),
+                                           0.2, 1.0, 0, 1)),
+
+   camera = {location = V.new{-0.5,-5,0},
+             point_at = V.new{-0.5,0,0},
+             right = V.x,
+             fov = 1}}
+
+Render.render(scene, 320, 200, "out/rainbow_wall.ppm")
-- 
2.20.1