mesh.lisp

   1
   2 (in-package :mixamesh)
   3
   4 (defparameter *meshes* (make-hash-table :test 'equalp)
   5   "A table of loaded meshes to use as brushes.")
   6
   7 (unless (find-package :mesh-names)
   8   (make-package :mesh-names))
   9
  10
  11 (def-mesh-type wire-mesh base-mesh (colours colours-of colour))
  12 (def-mesh-type textured-mesh mesh (texcoord uvs-of vector2d))
  13 (def-mesh-type coloured-mesh mesh (colour colours-of colour))
  14
  15
  16 ;; mesh - building protocol
  17 (defgeneric mesh-builder (mesh op data))
  18
  19 ;; constructor
  20 (defmethod initialize-instance :after ((self base-mesh) &rest args)
  21   (declare (ignore args))
  22   ;; treat the object as a function
  23   (closer-mop:set-funcallable-instance-function
  24    self
  25    #'(lambda (op data) (mesh-builder self op data))))
  26
  27
  28
  29 (def-tuple-op calc-face-normal
  30      ((vertex-a vertex3d (ax ay az aw))
  31       (vertex-b vertex3d (bx by bz bw))
  32       (vertex-c vertex3d (cx cy cz cw)))
  33   "return the normal of a face"
  34   (:return vector3d
  35            (vector3d-normal
  36             (vector3d-cross
  37              (delta-vector3d vertex-a vertex-b)
  38              (delta-vector3d vertex-a vertex-c)))))
  39
  40 (def-tuple-op vector3d-sum
  41      ((vector-a vector3d (ax ay az))
  42       (vector-b vector3d (bx by bz)))
  43   "return the sum of two vectors"
  44   (:return vector3d
  45            (vector3d-tuple (+ ax bx) (+ ay by) (+ az bz))))
  46
  47 ;; declarations to allow the iterate macro to iterate over the
  48 ;; triangles in a mesh or the vertices
  49 (defclause-sequence in-triangles index-of-triangle
  50   :access-fn 'triangle-aref
  51   :size-fn 'triangle-array-dimensions
  52   :sequence-type 'vector
  53   :element-type '(values  (unsigned-byte 16) (unsigned-byte 16) (unsigned-byte 16)))
  54
  55
  56 (defclause-sequence in-vertices index-of-vertex
  57   :access-fn 'vertex3d-aref
  58   :size-fn 'vertex3d-array-dimensions
  59   :sequence-type 'vector
  60   :element-type '(values (unsigned-byte 16) (unsigned-byte 16) (unsigned-byte 16) (unsigned-byte 16)))
  61
  62
  63 (defmethod calc-face-normals ((self mesh))
  64    "Calculate the face normals of a mesh."
  65    (let* ((face-normals (make-vector3d-array (triangle-array-dimensions (faces-of self)))))
  66      (iterate
  67        (for (values a b c) in-triangles (faces-of self))
  68        (for triangle-index upfrom 0)
  69        (setf (vector3d-aref face-normals triangle-index)
  70              (calc-face-normal
  71               (vertex3d-aref (vertices-of self) a)
  72               (vertex3d-aref (vertices-of self) b)
  73               (vertex3d-aref (vertices-of self) c))))
  74      (setf (face-normals-of self) face-normals)))
  75
  76 (defmethod calc-vertex-normals ((self mesh))
  77   "Calculate the vertex normals of a mesh."
  78   (let ((vertex-normals (make-vector3d-array (length (vertices-of self)))))
  79     (iterate
  80       (for index index-of-vertex (vertices-of self))
  81       (let ((normal (new-vector3d)))
  82         (iterate
  83           (for (values a b c) in-triangles (faces-of self))
  84           (for face-index upfrom 0)
  85           (when (or (= a index) (= b index) (= c index))
  86             (setf (vector3d normal)
  87                   (vector3d-sum (vector3d normal)
  88                                 (vector3d-aref (face-normals-of self) face-index))))
  89           (setf (vector3d-aref vertex-normals  index) (vertex3d normal)))))
  90     (setf (normals-of self) vertex-normals)))
  91
  92
  93 ;; mesh geometry calculation ---------------------------------------------
  94
  95 (defmethod box-of ((self mesh))
  96   "Return a bounding box for the mesh."
  97   (let ((maxx most-negative-single-float)
  98         (minx most-positive-single-float)
  99         (maxy most-negative-single-float)
 100         (miny most-positive-single-float)
 101         (maxz most-negative-single-float)
 102         (minz most-positive-single-float))
 103     (iterate
 104       (for index index-of-vertex (vertices-of self))
 105       (with-vertex3d
 106        (vertex3d-aref (vertices-of self) index)
 107        (x y z w)
 108        (cond
 109         ((< x minx) (setf minx x))
 110         ((> x maxx) (setf maxx x))
 111         ((< y miny) (setf miny y))
 112         ((> y maxy) (setf maxy y))
 113         ((< z minz) (setf minz z))
 114         ((< z minz) (setf minz z)))))
 115     (values minx maxx miny maxy minz maxz)))
 116
 117 (defmethod normalize-scale ((self mesh))
 118   "Rescale geometry to fit into a 1:1:1 bounding box"
 119   (multiple-value-bind
 120         (minx maxx miny maxy minz maxz)
 121       (box-of self)
 122     (let ((dx (- maxx minx))
 123           (dy (- maxy miny))
 124           (dz (- maxz minz))
 125         (scale))
 126     (cond
 127       ((and  (> dx dz) (> dx dy))
 128        ;; dx is largest dimension
 129        (setf scale (/ 1 (- maxx minx))))
 130       ;; dy is largest dimension
 131       ((and (> dy dz) (> dy dx))
 132        (setf scale (/ 1 (- maxy miny))))
 133       ;; dz is largest dimension
 134       ((and (> dz dy) (> dz dx))
 135        (setf scale (/ 1 (- maxy miny)))))
 136     (iterate
 137       (for index index-of-vertex (vertices-of self))
 138       (with-vertex3d
 139        (vertex3d-aref (vertices-of self) index)
 140        (x y z w)
 141        (setf (vertex3d-aref (vertices-of self) index) (vertex3d-tuple (* x scale) (* y scale) (* z scale) w)))))))
 142
 143
 144 (defmethod stripify ((self mesh))
 145   "Stripify mesh")
 146
 147 ;; (defmethod decompilation ((self compiled-mesh))
 148 ;;   "Create a modifiable mesh from a compiled mesh")
 149
 150 ;; (defmethod compilation ((self mesh))
 151 ;;   "Given a mesh return a compiled mesh, which is a non-modifiable mesh optimised for rendering in foreign memory."
 152 ;; )
 153
 154