Mercurial > cortex

     1 #+title: Movement!

     2 #+author: Robert McIntyre

     3 #+email: rlm@mit.edu

     4 #+description: muscles for a simulated creature

     5 #+keywords: simulation, jMonkeyEngine3, clojure

     6 #+SETUPFILE: ../../aurellem/org/setup.org

     7 #+INCLUDE: ../../aurellem/org/level-0.org

     8 

     9 

    10 Surprisingly enough, terristerial creatures only move by using torque

    11 applied about their joints.  There's not a single straight line of

    12 force in the human body at all!  (A straight line of force would

    13 correspond to some sort of jet or rocket propulseion.)

    14 

    15 

    16 Here's how motor-control/ proprioception will work: Each muscle is

    17 defined by a 1-D array of numbers (the "motor pool") each of which

    18 represent muscle fibers. A muscle also has a scalar :strength factor

    19 which determines how strong the muscle as a whole is.  The effector

    20 function for a muscle takes a number < (count motor-pool) and that

    21 number is said to "activate" all the muscle fibers whose index is

    22 lower than the number.  Each fiber will apply force in proportion to

    23 its value in the array.  Lower values cause less force.  The lower

    24 values can be put at the "beginning" of the 1-D array to simulate the

    25 layout of actual human muscles, which are capable of more percise

    26 movements when exerting less force.

    27 

    28 #+name: movement

    29 #+begin_src clojure 

    30 (ns cortex.movement

    31   "Give simulated creatures defined in special blender files the power

    32    to move around in a simulated environment."

    33   {:author "Robert McIntyre"}

    34   (:use (cortex world util sense body))

    35   (:use clojure.contrib.def)

    36   (:import java.awt.image.BufferedImage)

    37   (:import com.jme3.scene.Node)

    38   (:import com.jme3.math.Vector3f)

    39   (:import com.jme3.bullet.control.RigidBodyControl))

    40 

    41 (defn muscle-profile

    42   "Return a vector where each entry is the strength of the \"motor

    43   pool\" at that part in the muscle."

    44   [#^BufferedImage profile]

    45   (vec

    46    (let [width (.getWidth profile)]

    47      (for [x (range width)]

    48        (- 255

    49           (bit-and

    50            0x0000FF

    51            (.getRGB profile x 0)))))))

    52 

    53 (defvar 

    54   ^{:arglists '([creature])}

    55   muscles

    56   (sense-nodes "muscles")

    57   "Return the children of the creature's \"muscles\" node.")

    58 

    59 (defn movement-fn

    60   "Returns a function which when called with a integer value inside a

    61    running simulation will cause movement in the creature according

    62    to the muscle's position and strength profile. Each function

    63    returns the amount of force applied / max force."

    64   [#^Node parts #^Node muscle]

    65   (let [target (closest-node parts muscle)

    66         axis

    67         (.mult (.getWorldRotation muscle) Vector3f/UNIT_Y)

    68         strength (meta-data muscle "strength")

    69         image-name (read-string (meta-data muscle "muscle"))

    70         image (load-image image-name)

    71         fibers (muscle-profile image)

    72         fiber-integral (reductions + fibers)

    73         force-index

    74         (vec (map  #(float (* strength (/ % (last fiber-integral))))

    75               fiber-integral))

    76         control (.getControl target RigidBodyControl)]

    77     (fn [n]

    78       (let [pool-index (max 0 (min n (dec (count fibers))))

    79             force (force-index pool-index)]

    80         (.applyTorque control (.mult axis force))

    81         (float (/ force strength))))))

    82         

    83 

    84 (defn movement!

    85   "Endow the creature with the power of movement. Returns a sequence

    86    of functions, each of which accept an integer value and will

    87    activate their corresponding muscle."

    88   [#^Node creature]

    89     (for [muscle (muscles creature)]

    90       (movement-fn creature muscle)))

    91 

    92 (defn movement-display-kernel

    93   "Display muscle exertion data as a bar filling up with red."

    94   [exertion]

    95      (let [height 20

    96            width 300

    97            image (BufferedImage. width height

    98                                  BufferedImage/TYPE_INT_RGB)

    99            fill (min (int (* width exertion)) width)]

   100        (dorun

   101         (for [x (range fill)

   102               y (range height)]

   103           (.setRGB image x y 0xFF0000)))

   104        image))

   105 

   106 (defn view-movement

   107   "Creates a function which accepts a list of muscle-exertion data and

   108   displays each element of the list to the screen."

   109   []

   110   (view-sense movement-display-kernel))

   111 

   112 #+end_src

   113 

   114 

   115 

   116 

   117 

   118 * COMMENT code generation

   119 #+begin_src clojure :tangle ../src/cortex/movement.clj

   120 <<movement>>

   121 #+end_src
author	Robert McIntyre <rlm@mit.edu>
date	Thu, 09 Feb 2012 08:11:10 -0700
parents	66fbab414d45
children	959127e21f81