mesh.lisp

   1 (in-package :mixamesh)
   2
   3 ;; -- define a few common types of mesh for luck --------------------------
   4
   5 ;; abstract base mesh
   6
   7 ;; simple mesh w vertices
   8 (def-mesh-type simple-mesh (base-mesh) ((vertex vertices-of vertex3d)))
   9
  10 ;; simple mesh with normals for lighting
  11 (def-mesh-type mesh (simple-mesh) ((normal normals-of vector3d) (face-normals face-normals-of vector3d)))
  12
  13 ;; mesh with textures
  14 (def-mesh-type textured-mesh (simple-mesh) ((texcoord uvs-of vector2d)))
  15
  16 ;; mesh with vertex colours or other attributes
  17 (def-mesh-type coloured-mesh (simple-mesh) ((colour colours-of colour)))
  18
  19
  20 ;; -- operations on normals et al --------------------
  21
  22 (def-tuple-op calc-face-normal*
  23         ((vertex-a vertex3d (ax ay az aw))
  24          (vertex-b vertex3d (bx by bz bw))
  25          (vertex-c vertex3d (cx cy cz cw)))
  26   "return the normal of a face"
  27   (:return vector3d
  28                    (vector3d-normal*
  29                         (vector3d-cross*
  30                          (delta-vector3d* vertex-a vertex-b)
  31                          (delta-vector3d* vertex-a vertex-c)))))
  32
  33 (def-tuple-op vector3d-sum*
  34         ((vector-a vector3d (ax ay az))
  35          (vector-b vector3d (bx by bz)))
  36   "return the sum of two vectors"
  37   (:return vector3d
  38                    (vector3d-values* (+ ax bx) (+ ay by) (+ az bz))))
  39
  40 ;; declarations to allow the iterate macro to iterate over the
  41 ;; triangles in a mesh or the vertices
  42 (defclause-sequence in-triangles* index-of-triangle
  43   :access-fn 'triangle-aref*
  44   :size-fn 'triangle-array-dimensions
  45   :sequence-type 'vector
  46   :element-type '(values  (unsigned-byte 16) (unsigned-byte 16) (unsigned-byte 16)))
  47
  48
  49 (defclause-sequence in-vertices* index-of-vertex
  50   :access-fn 'vertex3d-aref*
  51   :size-fn 'vertex3d-array-dimensions
  52   :sequence-type 'vector
  53   :element-type '(values (unsigned-byte 16) (unsigned-byte 16) (unsigned-byte 16) (unsigned-byte 16)))
  54
  55 (defgeneric calc-face-normals (mesh))
  56
  57 (defmethod calc-face-normals ((self mesh))
  58   "Calculate the face normals of a mesh."
  59   (let* ((face-normals (make-vector3d-array (triangle-array-dimensions (faces-of self)))))
  60         (iterate
  61           (for (values a b c) in-triangles* (faces-of self))
  62           (for triangle-index upfrom 0)
  63           (setf (vector3d-aref* face-normals triangle-index)
  64                         (calc-face-normal*
  65                          (vertex3d-aref* (vertices-of self) a)
  66                          (vertex3d-aref* (vertices-of self) b)
  67                          (vertex3d-aref* (vertices-of self) c))))
  68         (setf (face-normals-of self) face-normals)))
  69
  70 (defgeneric calc-vertex-normals (mesh))
  71
  72 (defmethod calc-vertex-normals ((self mesh))
  73   "Calculate the vertex normals of a mesh."
  74   (let ((vertex-normals (make-vector3d-array (length (vertices-of self)))))
  75         (iterate
  76           (for index index-of-vertex (vertices-of self))
  77           (let ((normal (new-vector3d)))
  78                 (iterate
  79                   (for (values a b c) in-triangles* (faces-of self))
  80                   (for face-index upfrom 0)
  81                   (when (or (= a index) (= b index) (= c index))
  82                         (setf (vector3d* normal)
  83                                   (vector3d-sum* (vector3d* normal)
  84                                                                  (vector3d-aref* (face-normals-of self) face-index))))
  85                   (setf (vector3d-aref vertex-normals index) normal))))
  86         (setf (normals-of self) vertex-normals)))
  87
  88
  89 ;; mesh geometry calculation ---------------------------------------------
  90
  91 (defgeneric box-of (mesh))
  92
  93 (defmethod box-of ((self simple-mesh))
  94   "Return a bounding box for the mesh."
  95   (let ((maxx most-negative-single-float)
  96                 (minx most-positive-single-float)
  97                 (maxy most-negative-single-float)
  98                 (miny most-positive-single-float)
  99                 (maxz most-negative-single-float)
 100                 (minz most-positive-single-float))
 101         (iterate
 102           (for (values x y z nil) in-vertices* (vertices-of self))
 103           (cond
 104                 ((< x minx) (setf minx x))
 105                 ((> x maxx) (setf maxx x))
 106                 ((< y miny) (setf miny y))
 107                 ((> y maxy) (setf maxy y))
 108                 ((< z minz) (setf minz z))
 109                 ((> z maxz) (setf maxz z))))
 110         (make-aabb  minx maxx miny maxy minz maxz)))
 111
 112 (defun bound-mesh (mesh)
 113   (setf (gethash mesh *bounding-boxes*) (box-of (gethash mesh *meshes*))))
 114
 115 ;; squeeze into unit bounds (for brushes?) ---------------------------------
 116
 117 (defgeneric normalize-scale (mesh))
 118
 119 (defmethod normalize-scale ((self mesh))
 120   "Rescale geometry to fit into a 1:1:1 bounding box"
 121   (multiple-value-bind
 122                 (minx maxx miny maxy minz maxz)
 123           (box-of self)
 124         (let ((dx (- maxx minx))
 125                   (dy (- maxy miny))
 126                   (dz (- maxz minz))
 127                   (scale))
 128           (cond
 129                 ((and  (> dx dz) (> dx dy))
 130                  ;; dx is largest dimension
 131                  (setf scale (/ 1 (- maxx minx))))
 132                 ;; dy is largest dimension
 133                 ((and (> dy dz) (> dy dx))
 134                  (setf scale (/ 1 (- maxy miny))))
 135                 ;; dz is largest dimension
 136                 ((and (> dz dy) (> dz dx))
 137                  (setf scale (/ 1 (- maxy miny)))))
 138           (iterate
 139                 (for index index-of-vertex (vertices-of self))
 140                 (with-vertex3d*
 141                         (vertex3d-aref* (vertices-of self) index)
 142                         (x y z w)
 143                   (setf (vertex3d-aref* (vertices-of self) index)
 144                                 (vertex3d-values* (* x scale) (* y scale) (* z scale) w)))))))
 145
 146
 147 ;; to do -- this hierarchy should mirror the def-mesh hierarchy and
 148 ;; be automatically expanded out by def-mesh
 149
 150 ;; compiled mesh -- methods defined elsehwhere
 151 (defclass compiled-mesh ()
 152   ((vertex-buffer :initform 0 :type (unsigned-byte 32) :reader vertex-buffer-of)
 153    (triangle-buffer :initform 0 :type (unsigned-byte 32) :reader triangle-buffer-of)
 154    (element-count :initform 0 :type fixnum :reader element-count-of)))
 155
 156 (defclass textured-compiled-mesh ()
 157   ((vertex-buffer :initform 0 :type (unsigned-byte 32) :reader vertex-buffer-of)
 158    (uv-buffer :initform 0 :type (unsigned-byte 32) :reader uv-buffer-of)
 159    (texture :accessor texture-of :initform nil)
 160    (element-count :initform 0 :type fixnum :reader element-count-of)))
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