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 vectors ;
7 FROM: jamshred.oint => distance ;
8 FROM: alien.c-types => float ;
9 SPECIALIZED-ARRAY: float
12 CONSTANT: n-segments 5000
14 TUPLE: segment < oint number color radius ;
17 : segment-number++ ( segment -- )
18 [ number>> 1 + ] keep (>>number) ;
20 : clamp-length ( n seq -- n' )
23 : random-color ( -- color )
24 { 100 100 100 } [ random 100 / >float ] map first3 1.0 <rgba> ;
26 CONSTANT: tunnel-segment-distance 0.4
27 CONSTANT: random-rotation-angle $[ pi 20 / ]
29 : random-segment ( previous-segment -- segment )
30 clone dup random-rotation-angle random-turn
31 tunnel-segment-distance over go-forward
32 random-color >>color dup segment-number++ ;
34 : (random-segments) ( segments n -- segments )
36 [ dup last random-segment over push ] dip 1 - (random-segments)
39 CONSTANT: default-segment-radius 1
41 : initial-segment ( -- segment )
42 float-array{ 0 0 0 } float-array{ 0 0 -1 } float-array{ 0 1 0 } float-array{ -1 0 0 }
43 0 random-color default-segment-radius <segment> ;
45 : random-segments ( n -- segments )
46 initial-segment 1vector swap (random-segments) ;
48 : simple-segment ( n -- segment )
49 [ float-array{ 0 0 -1 } n*v float-array{ 0 0 -1 } float-array{ 0 1 0 } float-array{ -1 0 0 } ] keep
50 random-color default-segment-radius <segment> ;
52 : simple-segments ( n -- segments )
53 [ simple-segment ] map ;
55 : <random-tunnel> ( -- segments )
56 n-segments random-segments ;
58 : <straight-tunnel> ( -- segments )
59 n-segments simple-segments ;
61 : sub-tunnel ( from to segments -- segments )
62 #! return segments between from and to, after clamping from and to to
64 [ '[ _ clamp-length ] bi@ ] keep <slice> ;
66 :: nearer-segment ( seg-a seg-b oint -- segment )
71 : (find-nearest-segment) ( nearest next oint -- nearest ? )
72 #! find the nearest of 'next' and 'nearest' to 'oint', and return
73 #! t if the nearest hasn't changed
74 pick [ nearer-segment dup ] dip = ;
76 : find-nearest-segment ( oint segments -- segment )
77 dup first swap rest-slice rot [ (find-nearest-segment) ] curry
80 : nearest-segment-forward ( segments oint start -- segment )
81 rot tail-slice find-nearest-segment ;
83 : nearest-segment-backward ( segments oint start -- segment )
84 1 + rot head-slice <reversed> find-nearest-segment ;
86 : nearest-segment ( segments oint start-segment -- segment )
87 #! find the segment nearest to 'oint', and return it.
88 #! start looking at segment 'start-segment'
90 [ nearest-segment-forward ] 3keep nearest-segment-backward
91 ] dip nearer-segment ;
93 : get-segment ( segments n -- segment )
94 over clamp-length swap nth ;
96 : next-segment ( segments current-segment -- segment )
97 number>> 1 + get-segment ;
99 : previous-segment ( segments current-segment -- segment )
100 number>> 1 - get-segment ;
102 : heading-segment ( segments current-segment heading -- segment )
103 #! the next segment on the given heading
104 over forward>> v. 0 <=> {
105 { +gt+ [ next-segment ] }
106 { +lt+ [ previous-segment ] }
107 { +eq+ [ nip ] } ! current segment
110 :: distance-to-next-segment ( current next location heading -- distance )
111 current forward>> :> cf
112 cf next location>> v. cf location v. - cf heading v. / ;
114 :: distance-to-next-segment-area ( current next location heading -- distance )
115 current forward>> :> cf
116 next current half-way-between-oints :> h
117 cf h v. cf location v. - cf heading v. / ;
119 : vector-to-centre ( seg loc -- v )
120 over location>> swap v- swap forward>> proj-perp ;
122 : distance-from-centre ( seg loc -- distance )
123 vector-to-centre norm ;
125 : wall-normal ( seg oint -- n )
126 location>> vector-to-centre normalize ;
128 CONSTANT: distant 1000
130 : max-real ( a b -- c )
131 #! sometimes collision-coefficient yields complex roots, so we ignore these (hack)
133 over real? [ max ] [ nip ] if
135 drop dup real? [ drop distant ] unless
138 :: collision-coefficient ( v w r -- c )
145 c b a quadratic max-real
148 : sideways-heading ( oint segment -- v )
149 [ forward>> ] bi@ proj-perp ;
151 : sideways-relative-location ( oint segment -- loc )
152 [ [ location>> ] bi@ v- ] keep forward>> proj-perp ;
154 : (distance-to-collision) ( oint segment -- distance )
155 [ sideways-heading ] [ sideways-relative-location ]
156 [ nip radius>> ] 2tri collision-coefficient ;
158 : collision-vector ( oint segment -- v )
159 dupd (distance-to-collision) swap forward>> n*v ;
161 : bounce-forward ( segment oint -- )
162 [ wall-normal ] [ forward>> swap reflect ] [ (>>forward) ] tri ;
164 : bounce-left ( segment oint -- )
165 #! must be done after forward
166 [ forward>> vneg ] dip [ left>> swap reflect ]
167 [ forward>> proj-perp normalize ] [ (>>left) ] tri ;
169 : bounce-up ( segment oint -- )
170 #! must be done after forward and left!
171 nip [ forward>> ] [ left>> cross ] [ (>>up) ] tri ;
173 : bounce-off-wall ( oint segment -- )
174 swap [ bounce-forward ] [ bounce-left ] [ bounce-up ] 2tri ;