1.1 Binary file assets/Models/test-creature/hand.blend has changed

     2.1 --- a/org/body.org	Wed Feb 08 05:50:15 2012 -0700
     2.2 +++ b/org/body.org	Wed Feb 08 08:53:12 2012 -0700
     2.3 @@ -38,14 +38,22 @@
     2.4  
     2.5  The main reason that I use eve-style bodies is so that there will be
     2.6  correspondence between the AI's vision and the physical presence of
     2.7 -its body. 
     2.8 +its body. Each individual section is simulated by a separate rigid
     2.9 +body that corresponds exactly with its visual representation and does
    2.10 +not change. Sections are connected by invisible joints that are well
    2.11 +supported in jMonkyeEngine. Bullet, the physics backend for
    2.12 +jMonkeyEngine, can efficiently simulate hundreds of rigid bodies
    2.13 +connected by joints. Sections do not have to stay as one piece
    2.14 +forever; they can be dynamically replaced with multiple sections to
    2.15 +simulate splitting in two. This could be used to simulate retractable
    2.16 +claws or EVE's hands, which could coalece into one object in the
    2.17 +movie.
    2.18  
    2.19  * Solidifying the Body
    2.20  
    2.21  Here is a hand designed eve-style in blender.
    2.22  
    2.23 -
    2.24 -#+attr_html: width="500"
    2.25 +#+attr_html: width="755"
    2.26  [[../images/hand-screenshot0.png]]
    2.27  
    2.28  If we load it directly into jMonkeyEngine, we get this:
    2.29 @@ -92,10 +100,16 @@
    2.30  #+end_src
    2.31  
    2.32  #+begin_html
    2.33 -<video controls="controls" width="755">
    2.34 +<div class="figure">
    2.35 +<center>
    2.36 +<video controls="controls" width="640">
    2.37    <source src="../video/ghost-hand.ogg" type="video/ogg"
    2.38  	  preload="none" poster="../images/aurellem-1280x480.png" />
    2.39  </video>
    2.40 +</center>
    2.41 +<p>The hand model directly loaded from blender. It has no physical
    2.42 +  presense in the simulation. </p>
    2.43 +</div>
    2.44  #+end_html
    2.45  
    2.46  You will notice that the hand has no physical presence -- it's a
    2.47 @@ -106,7 +120,7 @@
    2.48  specify the mass of each object in blender and construct the physics
    2.49  shape based on the mesh in jMonkeyEngine.
    2.50  
    2.51 -#+name: joints-1
    2.52 +#+name: body-1
    2.53  #+begin_src clojure
    2.54  (defn physical!
    2.55    "Iterate through the nodes in creature and make them real physical
    2.56 @@ -134,6 +148,7 @@
    2.57  CollisionShapes for each geometry with the mass specified in that
    2.58  geometry's meta-data.
    2.59  
    2.60 +#+name: test-1
    2.61  #+begin_src clojure 
    2.62  (in-ns 'cortex.test.body)
    2.63  
    2.64 @@ -160,10 +175,16 @@
    2.65  #+end_src
    2.66  
    2.67  #+begin_html
    2.68 -<video controls="controls" width="755">
    2.69 +<div class="figure">
    2.70 +<center>
    2.71 +<video controls="controls" width="640">
    2.72    <source src="../video/crumbly-hand.ogg" type="video/ogg"
    2.73  	  preload="none" poster="../images/aurellem-1280x480.png" />
    2.74  </video>
    2.75 +</center>
    2.76 +<p>The hand now has a physical presence, but there is nothing to hold
    2.77 +it together.</p>
    2.78 +</div>
    2.79  #+end_html
    2.80  
    2.81  Now that's some progress.
    2.82 @@ -188,12 +209,44 @@
    2.83  has the name "joints". Their orientation and meta-data determine what
    2.84  joint is created.
    2.85  
    2.86 +#+attr_html: width="755"
    2.87 +#+caption: joints hack in blender. Each empty node here will be transformed into a joint in jMonkeyEngine
    2.88  [[../images/hand-screenshot1.png]]
    2.89  
    2.90 +The empty node in the upper right, highlighted in yellow, is the
    2.91 +parent node of all the emptys which represent joints. The following
    2.92 +functions must do three things to translate these into real joints:
    2.93  
    2.94 + - Find the children of the "joints" node.
    2.95 + - Determine the two spatials the joint it meant to connect.
    2.96 + - Create the joint based on the meta-data of the empty node.
    2.97  
    2.98 +** Finding the Joints 
    2.99 +#+name: joints-2 
   2.100 +#+begin_src clojure
   2.101 +(defvar 
   2.102 +  ^{:arglists '([creature])}
   2.103 +  joints
   2.104 +  (sense-nodes "joints")
   2.105 +  "Return the children of the creature's \"joints\" node.")
   2.106 +#+end_src
   2.107  
   2.108 -#+name: joints-2
   2.109 +The higher order function =(sense-nodes)= from cortex.sense makes our
   2.110 +first task very easy.
   2.111 +
   2.112 +** Joint Targets and Orientation
   2.113 +
   2.114 +This technique for finding a joint's targets is very similiar to
   2.115 +=(cortex.sense/closest-node)=.  A small cube, centered around the
   2.116 +empty-node, grows exponentially until it intersects two /physical/
   2.117 +objects. The objects are ordered according to the joint's rotation,
   2.118 +with the first one being the object that has more negative coordinates
   2.119 +in the joint's reference frame. Since the objects must be physical,
   2.120 +the empty-node itself escapes detection. Because the objects must be
   2.121 +physical, =(joint-targets)= must be called /after/ =(physical!)= is
   2.122 +called.
   2.123 +
   2.124 +#+name: joints-3
   2.125  #+begin_src clojure 
   2.126  (defn joint-targets
   2.127    "Return the two closest two objects to the joint object, ordered
   2.128 @@ -222,7 +275,16 @@
   2.129                      v))                  
   2.130             (take 2 targets))
   2.131            (recur (float (* radius 2))))))))
   2.132 +#+end_src
   2.133  
   2.134 +** Generating Joints
   2.135 +
   2.136 +This long chunk of code iterates through all the different ways of
   2.137 +specifying joints using blender meta-data and converts each one to the
   2.138 +appropriate jMonkyeEngine joint.
   2.139 +
   2.140 +#+name: joints-4
   2.141 +#+begin_src clojure
   2.142  (defmulti joint-dispatch
   2.143    "Translate blender pseudo-joints into real JME joints."
   2.144    (fn [constraints & _] 
   2.145 @@ -252,12 +314,7 @@
   2.146         pivot-b
   2.147         false)
   2.148      (.setLinearLowerLimit Vector3f/ZERO)
   2.149 -    (.setLinearUpperLimit Vector3f/ZERO)
   2.150 -    ;;(.setAngularLowerLimit (Vector3f. 1 1 1))
   2.151 -    ;;(.setAngularUpperLimit (Vector3f. 0 0 0))
   2.152 -
   2.153 -))
   2.154 -
   2.155 +    (.setLinearUpperLimit Vector3f/ZERO)))
   2.156  
   2.157  (defmethod joint-dispatch :hinge
   2.158    [constraints control-a control-b pivot-a pivot-b rotation]
   2.159 @@ -345,13 +402,12 @@
   2.160                          pivot-a pivot-b
   2.161                          joint-rotation))
   2.162        (println-repl "could not find joint meta-data!"))))
   2.163 +#+end_src
   2.164  
   2.165 -(defvar 
   2.166 -  ^{:arglists '([creature])}
   2.167 -  joints
   2.168 -  (sense-nodes "joints")
   2.169 -  "Return the children of the creature's \"joints\" node.")
   2.170 +Creating joints is now a matter applying =(connect)= to each joint
   2.171 +node.
   2.172  
   2.173 +#+begin_src clojure
   2.174  (defn joints!
   2.175    "Connect the solid parts of the creature with physical joints. The
   2.176     joints are taken from the \"joints\" node in the creature."
   2.177 @@ -362,7 +418,66 @@
   2.178        (let [[obj-a obj-b] (joint-targets creature joint)]
   2.179          (connect obj-a obj-b joint)))
   2.180      (joints creature))))
   2.181 +#+end_src
   2.182  
   2.183 +
   2.184 +** Round 3
   2.185 +
   2.186 +Now we can test the hand in all its glory.
   2.187 +
   2.188 +#+begin_src clojure 
   2.189 +(in-ns 'cortex.test.body)
   2.190 +
   2.191 +(def debug-control 
   2.192 +  {"key-h" (fn [world val]
   2.193 +             (if val (enable-debug world)))
   2.194 +
   2.195 +   "key-u" (fn [world _] (set-gravity world Vector3f/ZERO))
   2.196 +   })
   2.197 +  
   2.198 +(defn test-three []
   2.199 +  (world (nodify
   2.200 +          [(doto (hand)
   2.201 +           (physical!)
   2.202 +           (joints!) )
   2.203 +           (floor)])
   2.204 +         (merge standard-debug-controls debug-control
   2.205 +                normal-gravity)
   2.206 +         (comp
   2.207 +          #(Capture/captureVideo
   2.208 +            % (File. "/home/r/proj/cortex/render/body/3"))
   2.209 +          #(do (set-gravity % Vector3f/ZERO) %)
   2.210 +          setup)
   2.211 +         no-op))
   2.212 +#+end_src
   2.213 +
   2.214 +=(physical!)= makes the hand solid, then =(joints!)= connects each
   2.215 +piece together. 
   2.216 +
   2.217 +
   2.218 +#+begin_html
   2.219 +<div class="figure">
   2.220 +<center>
   2.221 +<video controls="controls" width="640">
   2.222 +  <source src="../video/full-hand.ogg" type="video/ogg"
   2.223 +	  preload="none" poster="../images/aurellem-1280x480.png" />
   2.224 +</video>
   2.225 +</center>
   2.226 +<p>Now the hand is physical and has joints.</p>
   2.227 +</div>
   2.228 +#+end_html
   2.229 +
   2.230 +The joints are visualized as green connections between each segment
   2.231 +for debug purposes. You can see that they correspond to the empty
   2.232 +nodes in the blender file.
   2.233 +
   2.234 +* Wrap-Up!
   2.235 +
   2.236 +It is convienent to combine =(physical!)= and =(joints!)= into one
   2.237 +function that completely creates the creature's physical body.
   2.238 +
   2.239 +#+name: joints-4
   2.240 +#+begin_src clojure
   2.241  (defn body!
   2.242    "Endow the creature with a physical body connected with joints.  The
   2.243     particulars of the joints and the masses of each pody part are
   2.244 @@ -374,6 +489,8 @@
   2.245  
   2.246  * Bookkeeping
   2.247  
   2.248 +Header; here for completeness.
   2.249 +
   2.250  #+name: body-0
   2.251  #+begin_src clojure
   2.252  (ns cortex.body
   2.253 @@ -397,6 +514,11 @@
   2.254  
   2.255  * Source 
   2.256  
   2.257 +Dylan -- I'll fill these in later
   2.258 +- cortex.body
   2.259 +- cortex.test.body
   2.260 +- blender files
   2.261 +
   2.262  * COMMENT Examples
   2.263  
   2.264  #+name: test-body