lib/middleware/lens_disto.rb in tracksperanto-2.9.9 vs lib/middleware/lens_disto.rb in tracksperanto-2.10.0

@@ -1,22 +1,10 @@
 # -*- encoding : utf-8 -*-
 class Tracksperanto::Middleware::LensDisto < Tracksperanto::Middleware::Base
   include Tracksperanto::UVCoordinates
+
   
-  class Vector2 < Struct.new(:x, :y)
-  end
-  
-  class RF < Struct.new(:r, :f)
-    def inspect
-      '(%0.3f %0.3f)' % [r, f]
-    end
-    
-    def m
-      r * f
-    end
-  end
-  
   parameter :k,  :cast => :float, :desc => "Quartic distortion coefficient", :default => 0
   parameter :kcube,  :cast => :float, :desc => "Cubic distortion coefficient", :default => 0
   parameter :remove, :cast => :bool, :desc => "Remove distortion instead of adding it"
   
   STEPS = 256
@@ -27,72 +15,77 @@
   
   def start_export(w, h)
     @width, @height = w, h
     @aspect = @width.to_f / @height
     
+    generate_lut
+    super
+  end
+  
+  def export_point(frame, float_x, float_y, float_residual)
+    x, y =  remove ? undisto(float_x, float_y) : disto(float_x, float_y)
+    super(frame, x, y, float_residual)
+  end
+  
+  private
+  
+  class Vector2 < Struct.new(:x, :y)
+  end
+  
+  class RF < Struct.new(:r, :f)
+    def inspect
+      '(%0.3f %0.3f)' % [r, f]
+    end
+    
+    def m
+      r * f
+    end
+  end
+  
+  # We apply disto using a lookup table of y = f(r)
+  def generate_lut
     # Generate the lookup table
     @lut = [RF.new(0.0, 1.0)]
     max_r = @aspect + 1
     
     increment = max_r / STEPS
     r = 0
     STEPS.times do | mult |
       r += increment
-      @lut.push(RF.new(r, disto_radius(r)))
+      @lut.push(RF.new(r, distort_radius(r)))
     end
-    
-    @lut.inspect
-    super
   end
   
-  def export_point(frame, float_x, float_y, float_residual)
-    x, y =  remove ? undisto(float_x, float_y) : disto(float_x, float_y)
-    super(frame, x, y, float_residual)
-  end
-  
-  private
-  
   def with_uv(x, y)
     vec = Vector2.new(convert_to_uv(x, @width), convert_to_uv(y, @height))
     yield(vec)
     [convert_from_uv(@width, vec.x), convert_from_uv(@height, vec.y)]
   end
   
   # Radius is equal to aspect at the rightmost extremity
-  def disto_radius(r)
-    r2 = r ** 2
-    # Skipping the square root speeds things up if we don't need it
-    f = if kcube.abs > 0.00001
-      1 + (r2 * (k + kcube * Math.sqrt(r2)));
-    else
-      1 + (r2 * k);
-    end
+  def distort_radius(r)
+    1 + (r*r*(k + kcube * r))
   end
   
   def disto(x, y)
     with_uv(x, y) do | pt |
-      # Get the radius of the point
-      x = pt.x * @aspect
-      r = Math.sqrt(x.abs**2 + pt.y.abs**2)
-      
       # Find the good tuples to interpolate on
-      f = disto_interpolated(r)
-      
+      f = disto_interpolated(get_radius(pt))
       pt.x = pt.x * f
       pt.y = pt.y * f
     end
   end
   
+  def get_radius(pt)
+    # Get the radius of the point
+    x = pt.x * @aspect
+    r = Math.sqrt(x.abs**2 + pt.y.abs**2)
+  end
   
   def undisto(x, y)
     with_uv(x, y) do | pt |
-      # Get the radius of the point
-      x = pt.x * @aspect
-      r = Math.sqrt(x.abs**2 + pt.y.abs**2)
-      
       # Find the good tuples to interpolate on
-      f = undisto_interpolated(r)
-      
+      f = undisto_interpolated(get_radius(pt))
       pt.x = pt.x / f
       pt.y = pt.y / f
     end
   end