1.1 --- a/org/touch.org	Sun Feb 12 10:45:38 2012 -0700
     1.2 +++ b/org/touch.org	Sun Feb 12 12:10:51 2012 -0700
     1.3 @@ -50,7 +50,8 @@
     1.4  itself is grayscale, with black meaning a hair length of 0 (no hair is
     1.5  present) and white meaning a hair length of =scale=, which is a float
     1.6  stored under the key "scale". If the pixel is gray then the resultant
     1.7 -hair length is linearly interpolated between 0 and =scale=.
     1.8 +hair length is linearly interpolated between 0 and =scale=. I call
     1.9 +these "hairs" /feelers/.
    1.10  
    1.11  #+name: meta-data
    1.12  #+begin_src clojure
    1.13 @@ -86,6 +87,24 @@
    1.14  
    1.15  #+end_src
    1.16  
    1.17 +
    1.18 +=(touch-kernel)= generates the functions which implement the sense of
    1.19 +touch for a creature. These functions must do 6 things to obtain touch
    1.20 +data.
    1.21 +
    1.22 +  - Get the tactile profile image and scale paramaters which describe
    1.23 +    the layout of feelers along the object's surface.
    1.24 +  - Get the lengths of each feeler by analyzing the color of the
    1.25 +    pixels in the tactile profile image.
    1.26 +  - Find the triangles which make up the mesh in pixel-space and in
    1.27 +    world-space.
    1.28 +  - Find the coordinates of each pixel in world-space. These
    1.29 +    coordinates are the origins of the feelers.
    1.30 +  - Calculate the normals of the triangles in world space, and add
    1.31 +    them to each of the origins of the feelers. These are the
    1.32 +    normalized coordinates of the tips of the feelers.
    1.33 +  - Generate some sort of topology for the sensors.
    1.34 +
    1.35  #+name: kernel
    1.36  #+begin_src clojure
    1.37  (in-ns 'cortex.touch)
    1.38 @@ -173,6 +192,64 @@
    1.39                  (node-seq creature)))))
    1.40  #+end_src
    1.41  
    1.42 +* Sensor Related Functions
    1.43 +
    1.44 +These functions analyze the touch-sensor-profile image convert the
    1.45 +location of each touch sensor from pixel coordinates to UV-coordinates
    1.46 +and XYZ-coordinates.
    1.47 +
    1.48 +#+name: sensors
    1.49 +#+begin_src clojure
    1.50 +(defn sensors-in-triangle
    1.51 +  "Locate the touch sensors in the triangle, returning a map of their
    1.52 +   UV and geometry-relative coordinates."
    1.53 +  [image mesh tri-index]
    1.54 +  (let [width (.getWidth image)
    1.55 +        height (.getHeight image)
    1.56 +        UV-vertex-coords (triangle-UV-coord mesh width height tri-index)
    1.57 +        bounds (convex-bounds UV-vertex-coords)
    1.58 +        
    1.59 +        cutout-triangle (points->triangle UV-vertex-coords)
    1.60 +        UV-sensor-coords
    1.61 +        (filter (comp (partial inside-triangle? cutout-triangle)
    1.62 +                      (fn [[u v]] (Vector3f. u v 0)))
    1.63 +                (white-coordinates image bounds))
    1.64 +        UV->geometry (triangle-transformation
    1.65 +                      cutout-triangle
    1.66 +                      (mesh-triangle mesh tri-index))
    1.67 +        geometry-sensor-coords
    1.68 +        (map (fn [[u v]] (.mult UV->geometry (Vector3f. u v 0)))
    1.69 +             UV-sensor-coords)]
    1.70 +  {:UV UV-sensor-coords :geometry geometry-sensor-coords}))
    1.71 +
    1.72 +(defn-memo locate-feelers
    1.73 +  "Search the geometry's tactile UV profile for touch sensors,
    1.74 +   returning their positions in geometry-relative coordinates."
    1.75 +  [#^Geometry geo]
    1.76 +  (let [mesh (.getMesh geo)
    1.77 +        num-triangles (.getTriangleCount mesh)]
    1.78 +    (if-let [image (tactile-sensor-profile geo)]
    1.79 +      (map
    1.80 +       (partial sensors-in-triangle image mesh)
    1.81 +       (range num-triangles))
    1.82 +      (repeat (.getTriangleCount mesh) {:UV nil :geometry nil}))))
    1.83 +
    1.84 +(defn-memo touch-topology
    1.85 +  "Return a sequence of vectors of the form [x y] describing the
    1.86 +   \"topology\" of the tactile sensors. Points that are close together
    1.87 +   in the touch-topology are generally close together in the simulation."
    1.88 +  [#^Gemoetry geo]
    1.89 +  (vec (collapse (reduce concat (map :UV (locate-feelers geo))))))
    1.90 +
    1.91 +(defn-memo feeler-coordinates
    1.92 +  "The location of the touch sensors in world-space coordinates."
    1.93 +  [#^Geometry geo]
    1.94 +  (vec (map :geometry (locate-feelers geo))))
    1.95 +#+end_src
    1.96 +
    1.97 +
    1.98 +
    1.99 +
   1.100  * Visualizing Touch
   1.101  #+name: visualization
   1.102  #+begin_src clojure
   1.103 @@ -393,61 +470,6 @@
   1.104  #+end_src
   1.105  
   1.106  
   1.107 -* Sensor Related Functions
   1.108 -
   1.109 -These functions analyze the touch-sensor-profile image convert the
   1.110 -location of each touch sensor from pixel coordinates to UV-coordinates
   1.111 -and XYZ-coordinates.
   1.112 -
   1.113 -#+name: sensors
   1.114 -#+begin_src clojure
   1.115 -(defn sensors-in-triangle
   1.116 -  "Locate the touch sensors in the triangle, returning a map of their
   1.117 -   UV and geometry-relative coordinates."
   1.118 -  [image mesh tri-index]
   1.119 -  (let [width (.getWidth image)
   1.120 -        height (.getHeight image)
   1.121 -        UV-vertex-coords (triangle-UV-coord mesh width height tri-index)
   1.122 -        bounds (convex-bounds UV-vertex-coords)
   1.123 -        
   1.124 -        cutout-triangle (points->triangle UV-vertex-coords)
   1.125 -        UV-sensor-coords
   1.126 -        (filter (comp (partial inside-triangle? cutout-triangle)
   1.127 -                      (fn [[u v]] (Vector3f. u v 0)))
   1.128 -                (white-coordinates image bounds))
   1.129 -        UV->geometry (triangle-transformation
   1.130 -                      cutout-triangle
   1.131 -                      (mesh-triangle mesh tri-index))
   1.132 -        geometry-sensor-coords
   1.133 -        (map (fn [[u v]] (.mult UV->geometry (Vector3f. u v 0)))
   1.134 -             UV-sensor-coords)]
   1.135 -  {:UV UV-sensor-coords :geometry geometry-sensor-coords}))
   1.136 -
   1.137 -(defn-memo locate-feelers
   1.138 -  "Search the geometry's tactile UV profile for touch sensors,
   1.139 -   returning their positions in geometry-relative coordinates."
   1.140 -  [#^Geometry geo]
   1.141 -  (let [mesh (.getMesh geo)
   1.142 -        num-triangles (.getTriangleCount mesh)]
   1.143 -    (if-let [image (tactile-sensor-profile geo)]
   1.144 -      (map
   1.145 -       (partial sensors-in-triangle image mesh)
   1.146 -       (range num-triangles))
   1.147 -      (repeat (.getTriangleCount mesh) {:UV nil :geometry nil}))))
   1.148 -
   1.149 -(defn-memo touch-topology
   1.150 -  "Return a sequence of vectors of the form [x y] describing the
   1.151 -   \"topology\" of the tactile sensors. Points that are close together
   1.152 -   in the touch-topology are generally close together in the simulation."
   1.153 -  [#^Gemoetry geo]
   1.154 -  (vec (collapse (reduce concat (map :UV (locate-feelers geo))))))
   1.155 -
   1.156 -(defn-memo feeler-coordinates
   1.157 -  "The location of the touch sensors in world-space coordinates."
   1.158 -  [#^Geometry geo]
   1.159 -  (vec (map :geometry (locate-feelers geo))))
   1.160 -#+end_src
   1.161 -
   1.162  * Physics Collision Objects
   1.163  
   1.164  The "hairs" are actually =Rays= which extend  from a point on a