1 ! Copyright (C) 2007, 2008 Alex Chapman
2 ! See http://factorcode.org/license.txt for BSD license.
3 USING: accessors arrays colors combinators fry jamshred.oint
4 kernel literals locals math math.constants math.matrices
5 math.order math.quadratic math.ranges math.vectors random
6 sequences specialized-arrays.float vectors ;
7 FROM: jamshred.oint => distance ;
10 CONSTANT: n-segments 5000
12 TUPLE: segment < oint number color radius ;
15 : segment-number++ ( segment -- )
16 [ number>> 1+ ] keep (>>number) ;
18 : clamp-length ( n seq -- n' )
21 : random-color ( -- color )
22 { 100 100 100 } [ random 100 / >float ] map first3 1.0 <rgba> ;
24 CONSTANT: tunnel-segment-distance 0.4
25 CONSTANT: random-rotation-angle $[ pi 20 / ]
27 : random-segment ( previous-segment -- segment )
28 clone dup random-rotation-angle random-turn
29 tunnel-segment-distance over go-forward
30 random-color >>color dup segment-number++ ;
32 : (random-segments) ( segments n -- segments )
34 [ dup last random-segment over push ] dip 1- (random-segments)
37 CONSTANT: default-segment-radius 1
39 : initial-segment ( -- segment )
40 float-array{ 0 0 0 } float-array{ 0 0 -1 } float-array{ 0 1 0 } float-array{ -1 0 0 }
41 0 random-color default-segment-radius <segment> ;
43 : random-segments ( n -- segments )
44 initial-segment 1vector swap (random-segments) ;
46 : simple-segment ( n -- segment )
47 [ float-array{ 0 0 -1 } n*v float-array{ 0 0 -1 } float-array{ 0 1 0 } float-array{ -1 0 0 } ] keep
48 random-color default-segment-radius <segment> ;
50 : simple-segments ( n -- segments )
51 [ simple-segment ] map ;
53 : <random-tunnel> ( -- segments )
54 n-segments random-segments ;
56 : <straight-tunnel> ( -- segments )
57 n-segments simple-segments ;
59 : sub-tunnel ( from to segments -- segments )
60 #! return segments between from and to, after clamping from and to to
62 [ '[ _ clamp-length ] bi@ ] keep <slice> ;
64 : nearer-segment ( segment segment oint -- segment )
65 #! return whichever of the two segments is nearer to the oint
66 [ 2dup ] dip tuck distance [ distance ] dip < -rot ? ;
68 : (find-nearest-segment) ( nearest next oint -- nearest ? )
69 #! find the nearest of 'next' and 'nearest' to 'oint', and return
70 #! t if the nearest hasn't changed
71 pick [ nearer-segment dup ] dip = ;
73 : find-nearest-segment ( oint segments -- segment )
74 dup first swap rest-slice rot [ (find-nearest-segment) ] curry
77 : nearest-segment-forward ( segments oint start -- segment )
78 rot dup length swap <slice> find-nearest-segment ;
80 : nearest-segment-backward ( segments oint start -- segment )
81 swapd 1+ 0 spin <slice> <reversed> find-nearest-segment ;
83 : nearest-segment ( segments oint start-segment -- segment )
84 #! find the segment nearest to 'oint', and return it.
85 #! start looking at segment 'start-segment'
87 [ nearest-segment-forward ] 3keep nearest-segment-backward
88 ] dip nearer-segment ;
90 : get-segment ( segments n -- segment )
91 over clamp-length swap nth ;
93 : next-segment ( segments current-segment -- segment )
94 number>> 1+ get-segment ;
96 : previous-segment ( segments current-segment -- segment )
97 number>> 1- get-segment ;
99 : heading-segment ( segments current-segment heading -- segment )
100 #! the next segment on the given heading
101 over forward>> v. 0 <=> {
102 { +gt+ [ next-segment ] }
103 { +lt+ [ previous-segment ] }
104 { +eq+ [ nip ] } ! current segment
107 :: distance-to-next-segment ( current next location heading -- distance )
108 [let | cf [ current forward>> ] |
109 cf next location>> v. cf location v. - cf heading v. / ] ;
111 :: distance-to-next-segment-area ( current next location heading -- distance )
112 [let | cf [ current forward>> ]
113 h [ next current half-way-between-oints ] |
114 cf h v. cf location v. - cf heading v. / ] ;
116 : vector-to-centre ( seg loc -- v )
117 over location>> swap v- swap forward>> proj-perp ;
119 : distance-from-centre ( seg loc -- distance )
120 vector-to-centre norm ;
122 : wall-normal ( seg oint -- n )
123 location>> vector-to-centre normalize ;
125 CONSTANT: distant 1000
127 : max-real ( a b -- c )
128 #! sometimes collision-coefficient yields complex roots, so we ignore these (hack)
130 over real? [ max ] [ nip ] if
132 drop dup real? [ drop distant ] unless
135 :: collision-coefficient ( v w r -- c )
139 [let* | a [ v dup v. ]
141 c [ w dup v. r sq - ] |
142 c b a quadratic max-real ]
145 : sideways-heading ( oint segment -- v )
146 [ forward>> ] bi@ proj-perp ;
148 : sideways-relative-location ( oint segment -- loc )
149 [ [ location>> ] bi@ v- ] keep forward>> proj-perp ;
151 : (distance-to-collision) ( oint segment -- distance )
152 [ sideways-heading ] [ sideways-relative-location ]
153 [ nip radius>> ] 2tri collision-coefficient ;
155 : collision-vector ( oint segment -- v )
156 dupd (distance-to-collision) swap forward>> n*v ;
158 : bounce-forward ( segment oint -- )
159 [ wall-normal ] [ forward>> swap reflect ] [ (>>forward) ] tri ;
161 : bounce-left ( segment oint -- )
162 #! must be done after forward
163 [ forward>> vneg ] dip [ left>> swap reflect ]
164 [ forward>> proj-perp normalize ] [ (>>left) ] tri ;
166 : bounce-up ( segment oint -- )
167 #! must be done after forward and left!
168 nip [ forward>> ] [ left>> cross ] [ (>>up) ] tri ;
170 : bounce-off-wall ( oint segment -- )
171 swap [ bounce-forward ] [ bounce-left ] [ bounce-up ] 2tri ;