-! Copyright (C) 2007, 2008 Alex Chapman
-! See http://factorcode.org/license.txt for BSD license.
-USING: accessors arrays combinators float-arrays kernel jamshred.oint locals math math.constants math.matrices math.order math.ranges math.vectors math.quadratic random sequences vectors ;
-USE: tools.walker
-IN: jamshred.tunnel
-
-: n-segments ( -- n ) 5000 ; inline
-
-TUPLE: segment < oint number color radius ;
-C: <segment> segment
-
-: segment-number++ ( segment -- )
- [ number>> 1+ ] keep (>>number) ;
-
-: random-color ( -- color )
- { 100 100 100 } [ random 100 / >float ] map { 1.0 } append ;
-
-: tunnel-segment-distance ( -- n ) 0.4 ;
-: random-rotation-angle ( -- theta ) pi 20 / ;
-
-: random-segment ( previous-segment -- segment )
- clone dup random-rotation-angle random-turn
- tunnel-segment-distance over go-forward
- random-color over set-segment-color dup segment-number++ ;
-
-: (random-segments) ( segments n -- segments )
- dup 0 > [
- >r dup peek random-segment over push r> 1- (random-segments)
- ] [ drop ] if ;
-
-: default-segment-radius ( -- r ) 1 ;
-
-: initial-segment ( -- segment )
- F{ 0 0 0 } F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 }
- 0 random-color default-segment-radius <segment> ;
-
-: random-segments ( n -- segments )
- initial-segment 1vector swap (random-segments) ;
-
-: simple-segment ( n -- segment )
- [ F{ 0 0 -1 } n*v F{ 0 0 -1 } F{ 0 1 0 } F{ -1 0 0 } ] keep
- random-color default-segment-radius <segment> ;
-
-: simple-segments ( n -- segments )
- [ simple-segment ] map ;
-
-: <random-tunnel> ( -- segments )
- n-segments random-segments ;
-
-: <straight-tunnel> ( -- segments )
- n-segments simple-segments ;
-
-: sub-tunnel ( from to segments -- segments )
- #! return segments between from and to, after clamping from and to to
- #! valid values
- [ sequence-index-range [ clamp-to-range ] curry bi@ ] keep <slice> ;
-
-: nearer-segment ( segment segment oint -- segment )
- #! return whichever of the two segments is nearer to the oint
- >r 2dup r> tuck distance >r distance r> < -rot ? ;
-
-: (find-nearest-segment) ( nearest next oint -- nearest ? )
- #! find the nearest of 'next' and 'nearest' to 'oint', and return
- #! t if the nearest hasn't changed
- pick >r nearer-segment dup r> = ;
-
-: find-nearest-segment ( oint segments -- segment )
- dup first swap rest-slice rot [ (find-nearest-segment) ] curry
- find 2drop ;
-
-: nearest-segment-forward ( segments oint start -- segment )
- rot dup length swap <slice> find-nearest-segment ;
-
-: nearest-segment-backward ( segments oint start -- segment )
- swapd 1+ 0 spin <slice> <reversed> find-nearest-segment ;
-
-: nearest-segment ( segments oint start-segment -- segment )
- #! find the segment nearest to 'oint', and return it.
- #! start looking at segment 'start-segment'
- segment-number over >r
- [ nearest-segment-forward ] 3keep
- nearest-segment-backward r> nearer-segment ;
-
-: get-segment ( segments n -- segment )
- over sequence-index-range clamp-to-range swap nth ;
-
-: next-segment ( segments current-segment -- segment )
- number>> 1+ get-segment ;
-
-: previous-segment ( segments current-segment -- segment )
- number>> 1- get-segment ;
-
-: heading-segment ( segments current-segment heading -- segment )
- #! the next segment on the given heading
- over forward>> v. 0 <=> {
- { +gt+ [ next-segment ] }
- { +lt+ [ previous-segment ] }
- { +eq+ [ nip ] } ! current segment
- } case ;
-
-:: distance-to-next-segment ( current next location heading -- distance )
- [let | cf [ current forward>> ] |
- cf next location>> v. cf location v. - cf heading v. / ] ;
-
-:: distance-to-next-segment-area ( current next location heading -- distance )
- [let | cf [ current forward>> ]
- h [ next current half-way-between-oints ] |
- cf h v. cf location v. - cf heading v. / ] ;
-
-: vector-to-centre ( seg loc -- v )
- over location>> swap v- swap forward>> proj-perp ;
-
-: distance-from-centre ( seg loc -- distance )
- vector-to-centre norm ;
-
-: wall-normal ( seg oint -- n )
- location>> vector-to-centre normalize ;
-
-: distant ( -- n ) 1000 ;
-
-: max-real ( a b -- c )
- #! sometimes collision-coefficient yields complex roots, so we ignore these (hack)
- dup real? [
- over real? [ max ] [ nip ] if
- ] [
- drop dup real? [ drop distant ] unless
- ] if ;
-
-:: collision-coefficient ( v w r -- c )
- v norm 0 = [
- distant
- ] [
- [let* | a [ v dup v. ]
- b [ v w v. 2 * ]
- c [ w dup v. r sq - ] |
- c b a quadratic max-real ]
- ] if ;
-
-: sideways-heading ( oint segment -- v )
- [ forward>> ] bi@ proj-perp ;
-
-: sideways-relative-location ( oint segment -- loc )
- [ [ location>> ] bi@ v- ] keep forward>> proj-perp ;
-
-: (distance-to-collision) ( oint segment -- distance )
- [ sideways-heading ] [ sideways-relative-location ]
- [ nip radius>> ] 2tri collision-coefficient ;
-
-: collision-vector ( oint segment -- v )
- dupd (distance-to-collision) swap forward>> n*v ;
-
-: bounce-forward ( segment oint -- )
- [ wall-normal ] [ forward>> swap reflect ] [ (>>forward) ] tri ;
-
-: bounce-left ( segment oint -- )
- #! must be done after forward
- [ forward>> vneg ] dip [ left>> swap reflect ]
- [ forward>> proj-perp normalize ] [ (>>left) ] tri ;
-
-: bounce-up ( segment oint -- )
- #! must be done after forward and left!
- nip [ forward>> ] [ left>> cross ] [ (>>up) ] tri ;
-
-: bounce-off-wall ( oint segment -- )
- swap [ bounce-forward ] [ bounce-left ] [ bounce-up ] 2tri ;
-