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 ( segment segment oint -- segment )
67 #! return whichever of the two segments is nearer to the oint
68 [ 2dup ] dip tuck distance [ distance ] dip < -rot ? ;
70 : (find-nearest-segment) ( nearest next oint -- nearest ? )
71 #! find the nearest of 'next' and 'nearest' to 'oint', and return
72 #! t if the nearest hasn't changed
73 pick [ nearer-segment dup ] dip = ;
75 : find-nearest-segment ( oint segments -- segment )
76 dup first swap rest-slice rot [ (find-nearest-segment) ] curry
79 : nearest-segment-forward ( segments oint start -- segment )
80 rot dup length swap <slice> find-nearest-segment ;
82 : nearest-segment-backward ( segments oint start -- segment )
83 swapd 1 + 0 spin <slice> <reversed> find-nearest-segment ;
85 : nearest-segment ( segments oint start-segment -- segment )
86 #! find the segment nearest to 'oint', and return it.
87 #! start looking at segment 'start-segment'
89 [ nearest-segment-forward ] 3keep nearest-segment-backward
90 ] dip nearer-segment ;
92 : get-segment ( segments n -- segment )
93 over clamp-length swap nth ;
95 : next-segment ( segments current-segment -- segment )
96 number>> 1 + get-segment ;
98 : previous-segment ( segments current-segment -- segment )
99 number>> 1 - get-segment ;
101 : heading-segment ( segments current-segment heading -- segment )
102 #! the next segment on the given heading
103 over forward>> v. 0 <=> {
104 { +gt+ [ next-segment ] }
105 { +lt+ [ previous-segment ] }
106 { +eq+ [ nip ] } ! current segment
109 :: distance-to-next-segment ( current next location heading -- distance )
110 [let | cf [ current forward>> ] |
111 cf next location>> v. cf location v. - cf heading v. / ] ;
113 :: distance-to-next-segment-area ( current next location heading -- distance )
114 [let | cf [ current forward>> ]
115 h [ next current half-way-between-oints ] |
116 cf h v. cf location v. - cf heading v. / ] ;
118 : vector-to-centre ( seg loc -- v )
119 over location>> swap v- swap forward>> proj-perp ;
121 : distance-from-centre ( seg loc -- distance )
122 vector-to-centre norm ;
124 : wall-normal ( seg oint -- n )
125 location>> vector-to-centre normalize ;
127 CONSTANT: distant 1000
129 : max-real ( a b -- c )
130 #! sometimes collision-coefficient yields complex roots, so we ignore these (hack)
132 over real? [ max ] [ nip ] if
134 drop dup real? [ drop distant ] unless
137 :: collision-coefficient ( v w r -- c )
141 [let* | a [ v dup v. ]
143 c [ w dup v. r sq - ] |
144 c b a quadratic max-real ]
147 : sideways-heading ( oint segment -- v )
148 [ forward>> ] bi@ proj-perp ;
150 : sideways-relative-location ( oint segment -- loc )
151 [ [ location>> ] bi@ v- ] keep forward>> proj-perp ;
153 : (distance-to-collision) ( oint segment -- distance )
154 [ sideways-heading ] [ sideways-relative-location ]
155 [ nip radius>> ] 2tri collision-coefficient ;
157 : collision-vector ( oint segment -- v )
158 dupd (distance-to-collision) swap forward>> n*v ;
160 : bounce-forward ( segment oint -- )
161 [ wall-normal ] [ forward>> swap reflect ] [ (>>forward) ] tri ;
163 : bounce-left ( segment oint -- )
164 #! must be done after forward
165 [ forward>> vneg ] dip [ left>> swap reflect ]
166 [ forward>> proj-perp normalize ] [ (>>left) ] tri ;
168 : bounce-up ( segment oint -- )
169 #! must be done after forward and left!
170 nip [ forward>> ] [ left>> cross ] [ (>>up) ] tri ;
172 : bounce-off-wall ( oint segment -- )
173 swap [ bounce-forward ] [ bounce-left ] [ bounce-up ] 2tri ;