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Add check to avoid degenerate planes in BSP tree build

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Please merge to release
(cherry picked from commit de0b181913)
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Neil Toronto 2014-04-24 10:54:40 -06:00 committed by Ryan Culpepper
parent 9cf6659bf0
commit 3261aacdfa
1 changed files with 16 additions and 6 deletions
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22
pkgs/plot-pkgs/plot-lib/plot/private/plot3d/bsp.rkt
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@ -427,15 +427,25 @@
(let* ([ss (canonicalize-shapes ss)])
(build-bsp-tree* ss)))
(: bad-plane? (-> FlVector Boolean))
(define (bad-plane? plane)
(define a (flvector-ref plane 0))
(define b (flvector-ref plane 1))
(define c (flvector-ref plane 2))
(define d (flvector-ref plane 3))
(or (and ((abs a) . < . 1e-16) ((abs b) . < . 1e-16) ((abs c) . < . 1e-16))
(not (flrational? a)) (not (flrational? b)) (not (flrational? c)) (not (flrational? d))))
(: try-bsp-split (-> (Listof BSP-Shape) FlVector Boolean (-> (U #f BSP-Tree)) (U #f BSP-Tree)))
(define (try-bsp-split ss plane disjoint? k)
(define-values (neg-ss pos-ss) (bin-shapes ss plane disjoint?))
(cond [(not (and neg-ss pos-ss)) (k)]
[(empty? neg-ss) (k)]
[(empty? pos-ss) (k)]
[(and disjoint? ((+ (length neg-ss) (length pos-ss)) . > . (length ss))) (k)]
(cond [(bad-plane? plane) (k)]
[else
(bsp-node plane (build-bsp-tree* neg-ss) (build-bsp-tree* pos-ss))]))
(define-values (neg-ss pos-ss) (bin-shapes ss plane disjoint?))
(cond [(not (and neg-ss pos-ss)) (k)]
[(empty? neg-ss) (k)]
[(empty? pos-ss) (k)]
[(and disjoint? ((+ (length neg-ss) (length pos-ss)) . > . (length ss))) (k)]
[else (bsp-node plane (build-bsp-tree* neg-ss) (build-bsp-tree* pos-ss))])]))
(: try-bsp-split/axial-planes (-> (Listof BSP-Shape) (Listof axis) (U #f BSP-Tree)))
(define (try-bsp-split/axial-planes ss axes)