X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=Textures.lua;h=2b2e70151f24eaec9150152a01ebc27792ccab5c;hb=f564e0e7248f977ea2397ea49e3d2e1804a65f7c;hp=cee3dd9f715d371071ad053acfab3ea386e480cf;hpb=46c1311e546ae5cefc4f596ed13476c649f12f66;p=raymarcher.git

diff --git a/Textures.lua b/Textures.lua
index cee3dd9..2b2e701 100644
--- a/Textures.lua
+++ b/Textures.lua
@@ -1,22 +1,41 @@
 -- Textures for raymarcher
+
 require "Vector"
 local V = Vector
 
-local function make_phong_texture(lights, pigment, amb, diff, spec, shiny)
+local function make_phong_texture(lights, mapped_pigment, amb, diff, spec, shiny)
    local normalize = V.normalize
-   return function (location, ray_dir, normal, count)
-      local colour = pigment(location[1],location[3])
+
+   local eps = 0.0001
+   local function light_visibility(location, light_dir, pos, dest, res, sdf)
+      local p = sdf(location)
+      if pos + p.dist > dest then
+         return res
+      elseif p.dist < eps then
+         return 0.0
+      else
+         return light_visibility(location + light_dir*p.dist, light_dir, pos+p.dist,
+                                 dest, math.min(res, 30*p.dist/(pos+p.dist)), sdf)
+      end
+   end
+   
+   return function (location, ray_dir, normal, count, sdf)
+      local colour = mapped_pigment(location)
       local thiscol = {colour[1]*amb, colour[2]*amb, colour[3]*amb}
 
       local reflected_ray = ray_dir - normal*(ray_dir*normal*2)
       for _,light in ipairs(lights) do
-         local light_dir = V.normalize(light-location)
+         local light_dist = V.norm(light-location)
+         local light_dir = (light-location)/light_dist
+
+         local vis = light_visibility(location + light_dir*eps, light_dir, eps, light_dist, 1, sdf)
+
          local Idiff = math.max(normal*light_dir, 0)
          local Ispec = math.pow(math.max(light_dir*reflected_ray,0),shiny)
             
-         thiscol[1] = thiscol[1] + colour[1]*Idiff*diff + Ispec*spec
-         thiscol[2] = thiscol[2] + colour[2]*Idiff*diff + Ispec*spec
-         thiscol[3] = thiscol[3] + colour[3]*Idiff*diff + Ispec*spec
+         thiscol[1] = thiscol[1] + vis*(colour[1]*Idiff*diff + Ispec*spec)
+         thiscol[2] = thiscol[2] + vis*(colour[2]*Idiff*diff + Ispec*spec)
+         thiscol[3] = thiscol[3] + vis*(colour[3]*Idiff*diff + Ispec*spec)
       end
 
       return thiscol
@@ -24,25 +43,28 @@ local function make_phong_texture(lights, pigment, amb, diff, spec, shiny)
 end
 
 local function make_count_texture(scale)
-   return function (location, ray_dir, normal, count)
+   return function (location, ray_dir, normal, count, sdf)
       return {count*scale, count*scale, count*scale}
    end
 end
 
-local function make_flat_texture(pigment)
-   return function (location, ray_dir, normal, count)
-      return pigment(location[1], location[2])
+local function make_flat_texture(mapped_pigment)
+   return function (location, ray_dir, normal, count, sdf)
+      return mapped_pigment(location)
    end
 end
 
+
+-- Pigments
+
 local function make_solid_pigment(colour)
-   return function (x,y)
+   return function(x,y)
       return colour
    end
 end
 
 local function make_checkered_pigment(colour1, colour2)
-   return function (x,y)
+   return function(x,y)
       if (x%1 < 0.5 and y%1 < 0.5) or (x%1 > 0.5 and y%1 > 0.5) then
          return colour1
       else
@@ -50,13 +72,58 @@ local function make_checkered_pigment(colour1, colour2)
       end
    end
 end
+
+local function make_mandelbrot_pigment(set_pigment, nonset_pigment, max_iter)
+
+   local function get_col(x,y,cx,cy,iter)
+      if iter == 0 then
+         return set_pigment(cx, cy)
+      elseif x^2 + y^2 > 4 then
+         return nonset_pigment(cx, cy)
+      else
+         return get_col(x^2 - y^2 + cx,
+                        2*x*y + cy,
+                        cx, cy, iter-1)
+      end
+   end
+
+   return function (x,y)
+      return get_col(0,0,x,y,max_iter)
+   end
+end
+
+-- Mapping functions
+
+-- These functions define mappings from 3D world coordinates to 2D
+-- texture/pigment coordinates
+
+local function map_rectangular(pigment, xvec, yvec)
+   return function(location)
+      return pigment(location*xvec, location*yvec)
+   end
+end
+
+local function map_spherical(pigment, centre, scale_theta, scale_phi)
+   return function(location)
+      local r = location-centre
+      local rnorm = V.norm(r)
+      
+      local phi = math.acos((V.z*r)/rnorm)
+      local theta = math.acos((V.x*r)/V.norm(V.cross(V.z,r)))
+
+      return pigment(theta*scale_theta/math.pi, phi*scale_phi/math.pi)
+   end
+end
    
 Textures = {
    make_phong_texture = make_phong_texture,
    make_flat_texture = make_flat_texture,
    make_count_texture = make_count_texture,
    make_solid_pigment = make_solid_pigment,
-   make_checkered_pigment = make_checkered_pigment
+   make_checkered_pigment = make_checkered_pigment,
+   make_mandelbrot_pigment = make_mandelbrot_pigment,
+   map_rectangular = map_rectangular,
+   map_spherical = map_spherical
 }
 
 return Textures