Mercurial > cortex

annotate org/touch.org @ 241:f2e583be8584

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
saving progress...
author Robert McIntyre <rlm@mit.edu>
date Sun, 12 Feb 2012 13:30:42 -0700
parents 6961377c4554
children a7f26a074071
rev   line source
rlm@37 1 #+title: Simulated Sense of Touch
rlm@0 2 #+author: Robert McIntyre
rlm@0 3 #+email: rlm@mit.edu
rlm@37 4 #+description: Simulated touch for AI research using JMonkeyEngine and clojure.
rlm@37 5 #+keywords: simulation, tactile sense, jMonkeyEngine3, clojure
rlm@4 6 #+SETUPFILE: ../../aurellem/org/setup.org
rlm@4 7 #+INCLUDE: ../../aurellem/org/level-0.org
rlm@0 8
rlm@229 9
rlm@229 10
rlm@37 11 * Touch
rlm@0 12
rlm@226 13 Touch is critical to navigation and spatial reasoning and as such I
rlm@226 14 need a simulated version of it to give to my AI creatures.
rlm@0 15
rlm@228 16 However, touch in my virtual can not exactly correspond to human touch
rlm@228 17 because my creatures are made out of completely rigid segments that
rlm@228 18 don't deform like human skin.
rlm@228 19
rlm@228 20 Human skin has a wide array of touch sensors, each of which speciliaze
rlm@228 21 in detecting different vibrational modes and pressures. These sensors
rlm@228 22 can integrate a vast expanse of skin (i.e. your entire palm), or a
rlm@228 23 tiny patch of skin at the tip of your finger. The hairs of the skin
rlm@228 24 help detect objects before they even come into contact with the skin
rlm@228 25 proper.
rlm@228 26
rlm@228 27 Instead of measuring deformation or vibration, I surround each rigid
rlm@228 28 part with a plenitude of hair-like objects which do not interact with
rlm@228 29 the physical world. Physical objects can pass through them with no
rlm@228 30 effect. The hairs are able to measure contact with other objects, and
rlm@228 31 constantly report how much of their extent is covered. So, even though
rlm@228 32 the creature's body parts do not deform, the hairs create a margin
rlm@228 33 around those body parts which achieves a sense of touch which is a
rlm@228 34 hybrid between a human's sense of deformation and sense from hairs.
rlm@228 35
rlm@228 36 Implementing touch in jMonkeyEngine follows a different techinal route
rlm@228 37 than vision and hearing. Those two senses piggybacked off
rlm@228 38 jMonkeyEngine's 3D audio and video rendering subsystems. To simulate
rlm@228 39 Touch, I use jMonkeyEngine's physics system to execute many small
rlm@229 40 collision detections, one for each "hair". The placement of the
rlm@229 41 "hairs" is determined by a UV-mapped image which shows where each hair
rlm@229 42 should be on the 3D surface of the body.
rlm@228 43
rlm@229 44
rlm@229 45 * Defining Touch Meta-Data in Blender
rlm@229 46
rlm@229 47 Each geometry can have a single UV map which describes the position
rlm@229 48 and length of the "hairs" which will constitute its sense of
rlm@229 49 touch. This image path is stored under the "touch" key. The image
rlm@229 50 itself is grayscale, with black meaning a hair length of 0 (no hair is
rlm@229 51 present) and white meaning a hair length of =scale=, which is a float
rlm@229 52 stored under the key "scale". If the pixel is gray then the resultant
rlm@238 53 hair length is linearly interpolated between 0 and =scale=. I call
rlm@238 54 these "hairs" /feelers/.
rlm@229 55
rlm@231 56 #+name: meta-data
rlm@0 57 #+begin_src clojure
rlm@229 58 (defn tactile-sensor-profile
rlm@229 59 "Return the touch-sensor distribution image in BufferedImage format,
rlm@229 60 or nil if it does not exist."
rlm@229 61 [#^Geometry obj]
rlm@229 62 (if-let [image-path (meta-data obj "touch")]
rlm@229 63 (load-image image-path)))
rlm@233 64
rlm@233 65 (defn tactile-scale
rlm@233 66 "Return the maximum length of a hair. All hairs are scalled between
rlm@233 67 0.0 and this length, depending on their color. Black is 0, and
rlm@233 68 white is maximum length, and everything in between is scalled
rlm@233 69 linearlly. Default scale is 0.01 jMonkeyEngine units."
rlm@233 70 [#^Geometry obj]
rlm@233 71 (if-let [scale (meta-data obj "scale")]
rlm@233 72 scale 0.1))
rlm@228 73 #+end_src
rlm@156 74
rlm@229 75 ** TODO add image showing example touch-uv map
rlm@229 76 ** TODO add metadata display for worm
rlm@229 77
rlm@234 78
rlm@233 79 * Skin Creation
rlm@234 80 * TODO get the actual lengths for each hair
rlm@234 81
rlm@234 82 #+begin_src clojure
rlm@234 83 pixel-triangles
rlm@234 84 xyz-triangles
rlm@234 85 conversions (map triangles->affine-transform pixel-triangles
rlm@234 86 xyz-triangles)
rlm@234 87
rlm@234 88 #+end_src
rlm@234 89
rlm@238 90
rlm@238 91 =(touch-kernel)= generates the functions which implement the sense of
rlm@238 92 touch for a creature. These functions must do 6 things to obtain touch
rlm@238 93 data.
rlm@238 94
rlm@238 95 - Get the tactile profile image and scale paramaters which describe
rlm@238 96 the layout of feelers along the object's surface.
rlm@239 97 =(tactile-sensor-profile)=, =(tactile-scale)=
rlm@239 98
rlm@238 99 - Get the lengths of each feeler by analyzing the color of the
rlm@238 100 pixels in the tactile profile image.
rlm@239 101 NOT IMPLEMENTED YET
rlm@239 102
rlm@238 103 - Find the triangles which make up the mesh in pixel-space and in
rlm@238 104 world-space.
rlm@239 105 =(triangles)= =(pixel-triangles)=
rlm@239 106
rlm@239 107 - Find the coordinates of each pixel in pixel space. These
rlm@239 108 coordinates are used to make the touch-topology.
rlm@240 109 =(feeler-pixel-coords)=
rlm@239 110
rlm@238 111 - Find the coordinates of each pixel in world-space. These
rlm@240 112 coordinates are the origins of the feelers. =(feeler-origins)=
rlm@239 113
rlm@238 114 - Calculate the normals of the triangles in world space, and add
rlm@238 115 them to each of the origins of the feelers. These are the
rlm@238 116 normalized coordinates of the tips of the feelers.
rlm@240 117 For both of these, =(feeler-tips)=
rlm@239 118
rlm@238 119 - Generate some sort of topology for the sensors.
rlm@239 120 =(touch-topology)=
rlm@239 121
rlm@239 122 #+begin_src clojure
rlm@239 123
rlm@239 124
rlm@239 125
rlm@239 126
rlm@239 127 #+end_src
rlm@239 128
rlm@239 129
rlm@238 130
rlm@233 131 #+name: kernel
rlm@233 132 #+begin_src clojure
rlm@233 133 (in-ns 'cortex.touch)
rlm@233 134
rlm@239 135 (declare touch-topology feelers set-ray)
rlm@234 136
rlm@233 137 (defn touch-kernel
rlm@234 138 "Constructs a function which will return tactile sensory data from
rlm@234 139 'geo when called from inside a running simulation"
rlm@234 140 [#^Geometry geo]
rlm@234 141 (let [[ray-reference-origins
rlm@234 142 ray-reference-tips
rlm@239 143 ray-lengths] (feelers geo)
rlm@234 144 current-rays (map (fn [] (Ray.)) ray-reference-origins)
rlm@234 145 topology (touch-topology geo)]
rlm@234 146 (if (empty? ray-reference-origins) nil
rlm@234 147 (fn [node]
rlm@234 148 (let [transform (.getWorldMatrix geo)]
rlm@234 149 (dorun
rlm@234 150 (map (fn [ray ref-origin ref-tip length]
rlm@234 151 (set-ray ray transform ref-origin ref-tip length))
rlm@234 152 current-rays ray-reference-origins
rlm@234 153 ray-reference-tips ray-lengths))
rlm@234 154 (vector
rlm@234 155 topology
rlm@234 156 (vec
rlm@234 157 (for [ray current-rays]
rlm@234 158 (do
rlm@234 159 (let [results (CollisionResults.)]
rlm@234 160 (.collideWith node ray results)
rlm@234 161 (let [touch-objects
rlm@234 162 (filter #(not (= geo (.getGeometry %)))
rlm@234 163 results)]
rlm@234 164 [(if (empty? touch-objects)
rlm@234 165 (.getLimit ray)
rlm@234 166 (.getDistance (first touch-objects)))
rlm@234 167 (.getLimit ray)])))))))))))
rlm@234 168
rlm@234 169 (defn touch-kernel*
rlm@233 170 "Returns a function which returns tactile sensory data when called
rlm@233 171 inside a running simulation."
rlm@233 172 [#^Geometry geo]
rlm@233 173 (let [feeler-coords (feeler-coordinates geo)
rlm@233 174 tris (triangles geo)
rlm@233 175 limit (tactile-scale geo)]
rlm@233 176 (if (empty? (touch-topology geo))
rlm@233 177 nil
rlm@233 178 (fn [node]
rlm@233 179 (let [sensor-origins
rlm@233 180 (map
rlm@233 181 #(map (partial local-to-world geo) %)
rlm@233 182 feeler-coords)
rlm@233 183 triangle-normals
rlm@233 184 (map (partial get-ray-direction geo)
rlm@233 185 tris)
rlm@233 186 rays
rlm@233 187 (flatten
rlm@233 188 (map (fn [origins norm]
rlm@233 189 (map #(doto (Ray. % norm)
rlm@233 190 (.setLimit limit)) origins))
rlm@233 191 sensor-origins triangle-normals))]
rlm@233 192 (vector
rlm@233 193 (touch-topology geo)
rlm@233 194 (vec
rlm@233 195 (for [ray rays]
rlm@233 196 (do
rlm@233 197 (let [results (CollisionResults.)]
rlm@233 198 (.collideWith node ray results)
rlm@233 199 (let [touch-objects
rlm@233 200 (filter #(not (= geo (.getGeometry %)))
rlm@233 201 results)]
rlm@233 202 [(if (empty? touch-objects)
rlm@233 203 limit (.getDistance (first touch-objects)))
rlm@233 204 limit])))))))))))
rlm@233 205
rlm@233 206 (defn touch!
rlm@233 207 "Endow the creature with the sense of touch. Returns a sequence of
rlm@233 208 functions, one for each body part with a tactile-sensor-proile,
rlm@233 209 each of which when called returns sensory data for that body part."
rlm@233 210 [#^Node creature]
rlm@233 211 (filter
rlm@233 212 (comp not nil?)
rlm@233 213 (map touch-kernel
rlm@233 214 (filter #(isa? (class %) Geometry)
rlm@233 215 (node-seq creature)))))
rlm@233 216 #+end_src
rlm@233 217
rlm@238 218 * Sensor Related Functions
rlm@238 219
rlm@238 220 These functions analyze the touch-sensor-profile image convert the
rlm@238 221 location of each touch sensor from pixel coordinates to UV-coordinates
rlm@238 222 and XYZ-coordinates.
rlm@238 223
rlm@238 224 #+name: sensors
rlm@238 225 #+begin_src clojure
rlm@240 226 (in-ns 'cortex.touch)
rlm@240 227
rlm@240 228 (defn feeler-pixel-coords
rlm@239 229 "Returns the coordinates of the feelers in pixel space in lists, one
rlm@239 230 list for each triangle, ordered in the same way as (triangles) and
rlm@239 231 (pixel-triangles)."
rlm@239 232 [#^Geometry geo image]
rlm@240 233 (map
rlm@240 234 (fn [pixel-triangle]
rlm@240 235 (filter
rlm@240 236 (fn [coord]
rlm@240 237 (inside-triangle? (->triangle pixel-triangle)
rlm@240 238 (->vector3f coord)))
rlm@240 239 (white-coordinates image (convex-bounds pixel-triangle))))
rlm@240 240 (pixel-triangles geo image)))
rlm@239 241
rlm@240 242 (defn feeler-origins [#^Geometry geo image]
rlm@240 243 (let [transforms
rlm@240 244 (map #(triangles->affine-transform
rlm@240 245 (->triangle %1) (->triangle %2))
rlm@240 246 (pixel-triangles geo image)
rlm@240 247 (triangles geo))]
rlm@240 248 (mapcat (fn [transform coords]
rlm@240 249 (map #(.mult transform (->vector3f %)) coords))
rlm@240 250 transforms (feeler-pixel-coords geo image))))
rlm@239 251
rlm@240 252 (defn feeler-tips [#^Geometry geo image]
rlm@241 253 (let [origins (feeler-origins geo image)
rlm@241 254 normals
rlm@241 255 (map
rlm@241 256 (fn [triangle]
rlm@241 257 (.calculateNormal triangle)
rlm@241 258 (.clone (.getNormal triangle)))
rlm@241 259 (map ->triangle (triangles geo)))]
rlm@241 260 (map #(.add %1 %2) origins normals)))
rlm@241 261
rlm@241 262 (defn touch-topology [#^Geometry geo image]
rlm@241 263 (collapse (feeler-pixel-coords geo image)))
rlm@240 264
rlm@239 265
rlm@238 266 (defn sensors-in-triangle
rlm@238 267 "Locate the touch sensors in the triangle, returning a map of their
rlm@238 268 UV and geometry-relative coordinates."
rlm@238 269 [image mesh tri-index]
rlm@238 270 (let [width (.getWidth image)
rlm@238 271 height (.getHeight image)
rlm@238 272 UV-vertex-coords (triangle-UV-coord mesh width height tri-index)
rlm@238 273 bounds (convex-bounds UV-vertex-coords)
rlm@238 274
rlm@238 275 cutout-triangle (points->triangle UV-vertex-coords)
rlm@238 276 UV-sensor-coords
rlm@238 277 (filter (comp (partial inside-triangle? cutout-triangle)
rlm@238 278 (fn [[u v]] (Vector3f. u v 0)))
rlm@238 279 (white-coordinates image bounds))
rlm@238 280 UV->geometry (triangle-transformation
rlm@238 281 cutout-triangle
rlm@238 282 (mesh-triangle mesh tri-index))
rlm@238 283 geometry-sensor-coords
rlm@238 284 (map (fn [[u v]] (.mult UV->geometry (Vector3f. u v 0)))
rlm@238 285 UV-sensor-coords)]
rlm@238 286 {:UV UV-sensor-coords :geometry geometry-sensor-coords}))
rlm@238 287
rlm@238 288 (defn-memo locate-feelers
rlm@238 289 "Search the geometry's tactile UV profile for touch sensors,
rlm@238 290 returning their positions in geometry-relative coordinates."
rlm@238 291 [#^Geometry geo]
rlm@238 292 (let [mesh (.getMesh geo)
rlm@238 293 num-triangles (.getTriangleCount mesh)]
rlm@238 294 (if-let [image (tactile-sensor-profile geo)]
rlm@238 295 (map
rlm@238 296 (partial sensors-in-triangle image mesh)
rlm@238 297 (range num-triangles))
rlm@238 298 (repeat (.getTriangleCount mesh) {:UV nil :geometry nil}))))
rlm@238 299
rlm@238 300 (defn-memo touch-topology
rlm@238 301 "Return a sequence of vectors of the form [x y] describing the
rlm@238 302 \"topology\" of the tactile sensors. Points that are close together
rlm@238 303 in the touch-topology are generally close together in the simulation."
rlm@238 304 [#^Gemoetry geo]
rlm@238 305 (vec (collapse (reduce concat (map :UV (locate-feelers geo))))))
rlm@238 306
rlm@238 307 (defn-memo feeler-coordinates
rlm@238 308 "The location of the touch sensors in world-space coordinates."
rlm@238 309 [#^Geometry geo]
rlm@238 310 (vec (map :geometry (locate-feelers geo))))
rlm@238 311 #+end_src
rlm@238 312
rlm@238 313
rlm@238 314
rlm@238 315
rlm@233 316 * Visualizing Touch
rlm@233 317 #+name: visualization
rlm@233 318 #+begin_src clojure
rlm@233 319 (in-ns 'cortex.touch)
rlm@233 320
rlm@233 321 (defn touch->gray
rlm@233 322 "Convert a pair of [distance, max-distance] into a grayscale pixel"
rlm@233 323 [distance max-distance]
rlm@233 324 (gray
rlm@233 325 (- 255
rlm@233 326 (rem
rlm@233 327 (int
rlm@233 328 (* 255 (/ distance max-distance)))
rlm@233 329 256))))
rlm@233 330
rlm@233 331 (defn view-touch
rlm@233 332 "Creates a function which accepts a list of touch sensor-data and
rlm@233 333 displays each element to the screen."
rlm@233 334 []
rlm@233 335 (view-sense
rlm@233 336 (fn
rlm@233 337 [[coords sensor-data]]
rlm@233 338 (let [image (points->image coords)]
rlm@233 339 (dorun
rlm@233 340 (for [i (range (count coords))]
rlm@233 341 (.setRGB image ((coords i) 0) ((coords i) 1)
rlm@233 342 (apply touch->gray (sensor-data i)))))
rlm@233 343 image))))
rlm@233 344 #+end_src
rlm@233 345
rlm@233 346
rlm@233 347
rlm@228 348 * Triangle Manipulation Functions
rlm@228 349
rlm@229 350 The rigid bodies which make up a creature have an underlying
rlm@229 351 =Geometry=, which is a =Mesh= plus a =Material= and other important
rlm@229 352 data involved with displaying the body.
rlm@229 353
rlm@229 354 A =Mesh= is composed of =Triangles=, and each =Triangle= has three
rlm@229 355 verticies which have coordinates in XYZ space and UV space.
rlm@229 356
rlm@229 357 Here, =(triangles)= gets all the triangles which compose a mesh, and
rlm@229 358 =(triangle-UV-coord)= returns the the UV coordinates of the verticies
rlm@229 359 of a triangle.
rlm@229 360
rlm@231 361 #+name: triangles-1
rlm@228 362 #+begin_src clojure
rlm@239 363 (in-ns 'cortex.touch)
rlm@239 364
rlm@239 365 (defn vector3f-seq [#^Vector3f v]
rlm@239 366 [(.getX v) (.getY v) (.getZ v)])
rlm@239 367
rlm@239 368 (defn triangle-seq [#^Triangle tri]
rlm@239 369 [(vector3f-seq (.get1 tri))
rlm@239 370 (vector3f-seq (.get2 tri))
rlm@239 371 (vector3f-seq (.get3 tri))])
rlm@239 372
rlm@240 373 (defn ->vector3f
rlm@240 374 ([coords] (Vector3f. (nth coords 0 0)
rlm@240 375 (nth coords 1 0)
rlm@240 376 (nth coords 2 0))))
rlm@239 377
rlm@239 378 (defn ->triangle [points]
rlm@239 379 (apply #(Triangle. %1 %2 %3) (map ->vector3f points)))
rlm@239 380
rlm@239 381 (defn triangle
rlm@239 382 "Get the triangle specified by triangle-index from the mesh within
rlm@239 383 bounds."
rlm@239 384 [#^Geometry geo triangle-index]
rlm@239 385 (triangle-seq
rlm@239 386 (let [scratch (Triangle.)]
rlm@239 387 (.getTriangle (.getMesh geo) triangle-index scratch) scratch)))
rlm@239 388
rlm@228 389 (defn triangles
rlm@228 390 "Return a sequence of all the Triangles which compose a given
rlm@228 391 Geometry."
rlm@239 392 [#^Geometry geo]
rlm@239 393 (map (partial triangle geo) (range (.getTriangleCount (.getMesh geo)))))
rlm@228 394
rlm@228 395 (defn triangle-vertex-indices
rlm@228 396 "Get the triangle vertex indices of a given triangle from a given
rlm@228 397 mesh."
rlm@228 398 [#^Mesh mesh triangle-index]
rlm@228 399 (let [indices (int-array 3)]
rlm@228 400 (.getTriangle mesh triangle-index indices)
rlm@228 401 (vec indices)))
rlm@228 402
rlm@228 403 (defn vertex-UV-coord
rlm@228 404 "Get the UV-coordinates of the vertex named by vertex-index"
rlm@228 405 [#^Mesh mesh vertex-index]
rlm@228 406 (let [UV-buffer
rlm@228 407 (.getData
rlm@228 408 (.getBuffer
rlm@228 409 mesh
rlm@228 410 VertexBuffer$Type/TexCoord))]
rlm@228 411 [(.get UV-buffer (* vertex-index 2))
rlm@228 412 (.get UV-buffer (+ 1 (* vertex-index 2)))]))
rlm@228 413
rlm@239 414 (defn pixel-triangle [#^Geometry geo image index]
rlm@239 415 (let [mesh (.getMesh geo)
rlm@239 416 width (.getWidth image)
rlm@239 417 height (.getHeight image)]
rlm@239 418 (vec (map (fn [[u v]] (vector (* width u) (* height v)))
rlm@239 419 (map (partial vertex-UV-coord mesh)
rlm@239 420 (triangle-vertex-indices mesh index))))))
rlm@228 421
rlm@239 422 (defn pixel-triangles [#^Geometry geo image]
rlm@239 423 (let [height (.getHeight image)
rlm@239 424 width (.getWidth image)]
rlm@239 425 (map (partial pixel-triangle geo image)
rlm@239 426 (range (.getTriangleCount (.getMesh geo))))))
rlm@229 427
rlm@228 428 #+end_src
rlm@228 429
rlm@228 430 * Triangle Affine Transforms
rlm@228 431
rlm@229 432 The position of each hair is stored in a 2D image in UV
rlm@229 433 coordinates. To place the hair in 3D space we must convert from UV
rlm@229 434 coordinates to XYZ coordinates. Each =Triangle= has coordinates in
rlm@229 435 both UV-space and XYZ-space, which defines a unique [[http://mathworld.wolfram.com/AffineTransformation.html ][Affine Transform]]
rlm@229 436 for translating any coordinate within the UV triangle to the
rlm@229 437 cooresponding coordinate in the XYZ triangle.
rlm@229 438
rlm@231 439 #+name: triangles-3
rlm@228 440 #+begin_src clojure
rlm@228 441 (defn triangle->matrix4f
rlm@228 442 "Converts the triangle into a 4x4 matrix: The first three columns
rlm@228 443 contain the vertices of the triangle; the last contains the unit
rlm@228 444 normal of the triangle. The bottom row is filled with 1s."
rlm@228 445 [#^Triangle t]
rlm@228 446 (let [mat (Matrix4f.)
rlm@228 447 [vert-1 vert-2 vert-3]
rlm@228 448 ((comp vec map) #(.get t %) (range 3))
rlm@228 449 unit-normal (do (.calculateNormal t)(.getNormal t))
rlm@228 450 vertices [vert-1 vert-2 vert-3 unit-normal]]
rlm@228 451 (dorun
rlm@228 452 (for [row (range 4) col (range 3)]
rlm@228 453 (do
rlm@228 454 (.set mat col row (.get (vertices row)col))
rlm@228 455 (.set mat 3 row 1))))
rlm@228 456 mat))
rlm@228 457
rlm@240 458 (defn triangles->affine-transform
rlm@228 459 "Returns the affine transformation that converts each vertex in the
rlm@228 460 first triangle into the corresponding vertex in the second
rlm@228 461 triangle."
rlm@228 462 [#^Triangle tri-1 #^Triangle tri-2]
rlm@228 463 (.mult
rlm@228 464 (triangle->matrix4f tri-2)
rlm@228 465 (.invert (triangle->matrix4f tri-1))))
rlm@228 466 #+end_src
rlm@228 467
rlm@239 468
rlm@239 469 * Schrapnel Conversion Functions
rlm@239 470
rlm@239 471 It is convienent to treat a =Triangle= as a sequence of verticies, and
rlm@239 472 a =Vector2f= and =Vector3f= as a sequence of floats. These conversion
rlm@239 473 functions make this easy. If these classes implemented =Iterable= then
rlm@239 474 this code would not be necessary. Hopefully they will in the future.
rlm@239 475
rlm@239 476 #+name: triangles-2
rlm@239 477 #+begin_src clojure
rlm@239 478 (defn point->vector2f [[u v]]
rlm@239 479 (Vector2f. u v))
rlm@239 480
rlm@239 481 (defn vector2f->vector3f [v]
rlm@239 482 (Vector3f. (.getX v) (.getY v) 0))
rlm@239 483
rlm@239 484 (defn map-triangle [f #^Triangle tri]
rlm@239 485 (Triangle.
rlm@239 486 (f 0 (.get1 tri))
rlm@239 487 (f 1 (.get2 tri))
rlm@239 488 (f 2 (.get3 tri))))
rlm@239 489
rlm@239 490 (defn points->triangle
rlm@239 491 "Convert a list of points into a triangle."
rlm@239 492 [points]
rlm@239 493 (apply #(Triangle. %1 %2 %3)
rlm@239 494 (map (fn [point]
rlm@239 495 (let [point (vec point)]
rlm@239 496 (Vector3f. (get point 0 0)
rlm@239 497 (get point 1 0)
rlm@239 498 (get point 2 0))))
rlm@239 499 (take 3 points))))
rlm@239 500 #+end_src
rlm@239 501
rlm@239 502
rlm@229 503 * Triangle Boundaries
rlm@229 504
rlm@229 505 For efficiency's sake I will divide the UV-image into small squares
rlm@229 506 which inscribe each UV-triangle, then extract the points which lie
rlm@229 507 inside the triangle and map them to 3D-space using
rlm@229 508 =(triangle-transform)= above. To do this I need a function,
rlm@229 509 =(inside-triangle?)=, which determines whether a point is inside a
rlm@229 510 triangle in 2D UV-space.
rlm@228 511
rlm@231 512 #+name: triangles-4
rlm@228 513 #+begin_src clojure
rlm@229 514 (defn convex-bounds
rlm@229 515 "Returns the smallest square containing the given vertices, as a
rlm@229 516 vector of integers [left top width height]."
rlm@240 517 [verts]
rlm@240 518 (let [xs (map first verts)
rlm@240 519 ys (map second verts)
rlm@229 520 x0 (Math/floor (apply min xs))
rlm@229 521 y0 (Math/floor (apply min ys))
rlm@229 522 x1 (Math/ceil (apply max xs))
rlm@229 523 y1 (Math/ceil (apply max ys))]
rlm@229 524 [x0 y0 (- x1 x0) (- y1 y0)]))
rlm@229 525
rlm@229 526 (defn same-side?
rlm@229 527 "Given the points p1 and p2 and the reference point ref, is point p
rlm@229 528 on the same side of the line that goes through p1 and p2 as ref is?"
rlm@229 529 [p1 p2 ref p]
rlm@229 530 (<=
rlm@229 531 0
rlm@229 532 (.dot
rlm@229 533 (.cross (.subtract p2 p1) (.subtract p p1))
rlm@229 534 (.cross (.subtract p2 p1) (.subtract ref p1)))))
rlm@229 535
rlm@229 536 (defn inside-triangle?
rlm@229 537 "Is the point inside the triangle?"
rlm@229 538 {:author "Dylan Holmes"}
rlm@229 539 [#^Triangle tri #^Vector3f p]
rlm@240 540 (let [[vert-1 vert-2 vert-3] [(.get1 tri) (.get2 tri) (.get3 tri)]]
rlm@229 541 (and
rlm@229 542 (same-side? vert-1 vert-2 vert-3 p)
rlm@229 543 (same-side? vert-2 vert-3 vert-1 p)
rlm@229 544 (same-side? vert-3 vert-1 vert-2 p))))
rlm@229 545 #+end_src
rlm@229 546
rlm@240 547 #+results: triangles-4
rlm@240 548 : #'cortex.touch/inside-triangle?
rlm@240 549
rlm@229 550
rlm@228 551 * Physics Collision Objects
rlm@230 552
rlm@234 553 The "hairs" are actually =Rays= which extend from a point on a
rlm@230 554 =Triangle= in the =Mesh= normal to the =Triangle's= surface.
rlm@230 555
rlm@231 556 #+name: rays
rlm@228 557 #+begin_src clojure
rlm@228 558 (defn get-ray-origin
rlm@228 559 "Return the origin which a Ray would have to have to be in the exact
rlm@228 560 center of a particular Triangle in the Geometry in World
rlm@228 561 Coordinates."
rlm@228 562 [geom tri]
rlm@228 563 (let [new (Vector3f.)]
rlm@228 564 (.calculateCenter tri)
rlm@228 565 (.localToWorld geom (.getCenter tri) new) new))
rlm@228 566
rlm@228 567 (defn get-ray-direction
rlm@228 568 "Return the direction which a Ray would have to have to be to point
rlm@228 569 normal to the Triangle, in coordinates relative to the center of the
rlm@228 570 Triangle."
rlm@228 571 [geom tri]
rlm@228 572 (let [n+c (Vector3f.)]
rlm@228 573 (.calculateNormal tri)
rlm@228 574 (.calculateCenter tri)
rlm@228 575 (.localToWorld
rlm@228 576 geom
rlm@228 577 (.add (.getCenter tri) (.getNormal tri)) n+c)
rlm@228 578 (.subtract n+c (get-ray-origin geom tri))))
rlm@228 579 #+end_src
rlm@226 580 * Headers
rlm@231 581
rlm@231 582 #+name: touch-header
rlm@226 583 #+begin_src clojure
rlm@226 584 (ns cortex.touch
rlm@226 585 "Simulate the sense of touch in jMonkeyEngine3. Enables any Geometry
rlm@226 586 to be outfitted with touch sensors with density determined by a UV
rlm@226 587 image. In this way a Geometry can know what parts of itself are
rlm@226 588 touching nearby objects. Reads specially prepared blender files to
rlm@226 589 construct this sense automatically."
rlm@226 590 {:author "Robert McIntyre"}
rlm@226 591 (:use (cortex world util sense))
rlm@226 592 (:use clojure.contrib.def)
rlm@226 593 (:import (com.jme3.scene Geometry Node Mesh))
rlm@226 594 (:import com.jme3.collision.CollisionResults)
rlm@226 595 (:import com.jme3.scene.VertexBuffer$Type)
rlm@226 596 (:import (com.jme3.math Triangle Vector3f Vector2f Ray Matrix4f)))
rlm@226 597 #+end_src
rlm@37 598
rlm@232 599 * Adding Touch to the Worm
rlm@232 600
rlm@232 601 #+name: test-touch
rlm@232 602 #+begin_src clojure
rlm@232 603 (ns cortex.test.touch
rlm@232 604 (:use (cortex world util sense body touch))
rlm@232 605 (:use cortex.test.body))
rlm@232 606
rlm@232 607 (cortex.import/mega-import-jme3)
rlm@232 608
rlm@232 609 (defn test-touch []
rlm@232 610 (let [the-worm (doto (worm) (body!))
rlm@232 611 touch (touch! the-worm)
rlm@232 612 touch-display (view-touch)]
rlm@232 613 (world (nodify [the-worm (floor)])
rlm@232 614 standard-debug-controls
rlm@232 615
rlm@232 616 (fn [world]
rlm@232 617 (light-up-everything world))
rlm@232 618
rlm@232 619 (fn [world tpf]
rlm@232 620 (touch-display (map #(% (.getRootNode world)) touch))))))
rlm@232 621 #+end_src
rlm@228 622 * Source Listing
rlm@228 623 * Next
rlm@228 624
rlm@228 625
rlm@226 626 * COMMENT Code Generation
rlm@39 627 #+begin_src clojure :tangle ../src/cortex/touch.clj
rlm@231 628 <<touch-header>>
rlm@231 629 <<meta-data>>
rlm@231 630 <<triangles-1>>
rlm@231 631 <<triangles-2>>
rlm@231 632 <<triangles-3>>
rlm@231 633 <<triangles-4>>
rlm@231 634 <<sensors>>
rlm@231 635 <<rays>>
rlm@231 636 <<kernel>>
rlm@231 637 <<visualization>>
rlm@0 638 #+end_src
rlm@0 639
rlm@232 640
rlm@68 641 #+begin_src clojure :tangle ../src/cortex/test/touch.clj
rlm@232 642 <<test-touch>>
rlm@39 643 #+end_src
rlm@39 644
rlm@0 645
rlm@0 646
rlm@0 647
rlm@32 648
rlm@32 649
rlm@226 650