This is great but when do we get the holy grail of poly->voxels?? :)
On Feb 2, 2010, at 10:04 AM, Dave Griffiths wrote:
Hi all,
I've added a (voxel->blobby) command to so we can use the marching
cubes
meshing algorithm to create polygon solids from voxels. I've also
updated the documentation a little for the voxels.
I also stumbled across some strange new effects:
http://www.pawfal.org/dave/blog/category/accidental-art/
Here is a script for converting polygons into voxels - thus completing
the circle:
(clear)
(clear-colour 0.5)
; load the polygon object
(define poly (with-state
(scale 2) ; make it fit nicely within the voxels area
(load-primitive "bot.obj")))
; apply the fitting transform
(with-primitive poly (apply-transform))
; make some voxels
(define v
(with-state
(blend-mode 'src-alpha 'one)
(hint-nozwrite)
(texture (load-texture "splat.png"))
; move around the polygon object
(scale 8)
(translate (vector -0.5 -0.5 -0.5))
(build-voxels 50 50 50)))
; utils - need to put these somewhere else
(define (voxels-index x y z)
(+ x (* y (voxels-width)) (* z (voxels-width) (voxels-height))))
(define (voxels-pos i)
(vdiv (vector (modulo i (voxels-width))
(modulo (quotient i (voxels-width)) (voxels-height))
(quotient i (* (voxels-width) (voxels-height)))) (voxels-
width)))
; for each voxel, check for odd or even intersection counts against
the poly
(with-primitive v
(pdata-index-map!
(lambda (i c)
(let ((p (vtransform (voxels-pos i) (get-transform))))
(if (odd? (length (with-primitive poly (geo/line-
intersect (vector 0 1 -1000) p))))
(vector 1 1 1 1) ; inside
(vector 0 0 0 0)))) ; outside
"c")
; the rest of this is to make it look pretty for previewing
(voxels-calc-gradient)
(pdata-copy "g" "c")
(pdata-map!
(lambda (c)
(if (< (vmag c) 0.1)
(vector 0 0 0 0) c))
"c"))
(destroy poly)
; convert to a blobby
(define bp
(with-state
(hint-unlit) ; again all this
(colour 1) ; just for
(hint-wire) ; preview rendering
(voxels->blobby v)))
(destroy v)
(define pp (blobby->poly bp))
(destroy bp)
(with-primitive pp
(recalc-normals 1))
