1 #include "rogueviz.h"
2
3 /** A physics visualization of balls in a shell.
4 *
5 * Compile with HyperRogue, enable a 3D geometry (e.g. Nil), and watch.
6 * This is not configurable yet... you may need to manually change the gravity direction, or the number of balls
7 * (it is not optimized, and it does not work in real time with the default number of balls).
8 */
9
10 namespace rogueviz {
11
12 namespace balls {
13
14 bool on = true;
15
16 struct ball {
17 hyperpoint at;
18 hyperpoint vel;
19 };
20
21 vector<ball> balls;
22
23 ld r_small_ball = .1;
24 ld r_big_ball = 1;
25
26 hpcshape shSmallBall, shBigBall, shShell;
27
initialize(int max_ball)28 void initialize(int max_ball) {
29 on = true;
30
31 cgi.make_ball(shSmallBall, r_small_ball, 2);
32 cgi.make_ball(shBigBall, r_big_ball, 4);
33
34 cgi.bshape(shShell, PPR::WALL);
35 shShell.flags |= POLY_TRIANGLES;
36
37 auto pt = [] (int i, int j) {
38 cgi.hpcpush(direct_exp(/* cspin(0, 2, -30*degree) **/ cspin(2, 1, 90*degree) * cspin(0, 1, j * degree) * cspin(0, 2, i * M_PI / 2 / 16) * ztangent(r_big_ball)));
39 };
40
41 for(int i=0; i<16; i++)
42 for(int j=0; j<360; j++) {
43 pt(i, j);
44 pt(i, j+1);
45 pt(i+1, j);
46 pt(i, j+1);
47 pt(i+1, j);
48 pt(i+1, j+1);
49 }
50 cgi.finishshape();
51 cgi.extra_vertices();
52
53 for(int a=-max_ball; a<=max_ball; a++)
54 for(int b=-max_ball; b<=max_ball; b++)
55 for(int c=-max_ball; c<=max_ball; c++)
56 {
57 hyperpoint h = point3(0.21*a + 1e-2, 0.21*b, 0.21*c);
58
59 if(hypot_d(3, h) > r_big_ball - r_small_ball) continue;
60
61 transmatrix T = rgpushxto0(direct_exp(h));
62
63 balls.emplace_back(ball{T*C0, T*ztangent(1e-3)});
64 }
65
66 }
67
draw_balls(cell * c,const shiftmatrix & V)68 bool draw_balls(cell *c, const shiftmatrix& V) {
69 if(!on) return false;
70
71 if(c == currentmap->gamestart()) {
72 for(auto& b: balls)
73 queuepoly(V * rgpushxto0(b.at), shSmallBall, 0xFFFFFFFF);
74 queuepoly(V, shShell, 0x0000F0FF);
75 }
76
77 return false;
78 }
79
inner(hyperpoint a,hyperpoint b)80 ld inner(hyperpoint a, hyperpoint b) {
81 ld s = a[0] * b[0] + a[1] * b[1] + a[2] * b[2];
82 if(hyperbolic) return s - a[3] * b[3];
83 if(sphere) return s + a[3] * b[3];
84 return s;
85 }
86
geodesic_steps(hyperpoint & at,hyperpoint & vel,int qty)87 void geodesic_steps(hyperpoint& at, hyperpoint& vel, int qty) {
88 if(nonisotropic) {
89 vel /= qty;
90 for(int i=0; i<qty; i++)
91 nisot::geodesic_step(at, vel);
92 vel *= qty;
93 }
94 else {
95 ld d = sqrt(inner(vel, vel));
96 tie(at, vel) = make_pair(
97 at * cos_auto(d) + vel * sin_auto(d)/d,
98 vel * cos_auto(d) - at * sin_auto(d) * sig(3) * d
99 );
100 }
101 }
102
103 ld elastic_in = .2;
104 ld elastic_out = .2;
105
106 ld gravity = 1;
107
turn(int delta)108 bool turn(int delta) {
109 if(!on) return false;
110 for(int i=0; i<delta; i++) {
111 for(auto& b: balls) {
112 /* gravity direction: z */
113 b.vel += ctangent(2, 1e-6) * gravity;
114
115 geodesic_steps(b.at, b.vel, 1);
116
117 if(!nonisotropic && !euclid) {
118 ld e = sqrt(abs(inner(b.at, b.at)));
119 b.at /= e;
120 ld e2 = inner(b.at, b.vel) * sig(3);
121 b.vel -= b.at * e2;
122 }
123
124 hyperpoint v = inverse_exp(shiftless(b.at));
125 ld d = hypot_d(3, v);
126 ld rbs = r_big_ball - r_small_ball;
127 if(d > rbs) {
128 hyperpoint c = C0, ve = v * rbs / d;
129 geodesic_steps(c, ve, 20);
130 hyperpoint ort = ve / d;
131 transmatrix T = gpushxto0(b.at);
132 b.vel -= inner(T*b.vel, T*ort) * ort * (1 + elastic_out);
133
134 b.at = c;
135 if(!nonisotropic && !euclid) {
136 ld e2 = inner(b.at, b.vel) * sig(3);
137 b.vel -= b.at * e2;
138 }
139 }
140 }
141
142 /* This is not optimized. It should use a partition of the space,
143 * to tell which balls have a chance to touch each other. */
144
145 for(auto& b1: balls)
146 for(auto& b2: balls) {
147 if(&b2 == &b1) break;
148 hyperpoint dif = inverse_exp(shiftless(gpushxto0(b1.at) * b2.at));
149 ld d = hypot_d(3, dif);
150 if(d < r_small_ball * 2) {
151 hyperpoint ort1 = (dif / d);
152 ld vel1 = +inner(gpushxto0(b1.at) * b1.vel, ort1);
153 hyperpoint ort2 = inverse_exp(shiftless(gpushxto0(b2.at) * b1.at)) / d;
154 ld vel2 = +inner(gpushxto0(b2.at) * b2.vel, ort2);
155 ld vels = vel1 + vel2;
156 if(vels < 0) continue;
157
158 vels *= (1 + elastic_in) / 2;
159
160 b1.vel -= rgpushxto0(b1.at) * (vels * ort1);
161 b2.vel -= rgpushxto0(b2.at) * (vels * ort2);
162 }
163 }
164 }
165 return false;
166 }
167
args()168 int args() {
169 using namespace arg;
170
171 if(0) ;
172
173 else if(argis("-ball-physics")) {
174 start_game();
175 check_cgi();
176 cgi.require_shapes();
177 shift();
178 initialize(argi());
179 View = cspin(1, 2, M_PI/2);
180 }
181
182 else return 1;
183 return 0;
184 }
185
186
187 auto celldemo = addHook(hooks_drawcell, 100, draw_balls) +
188 addHook(shmup::hooks_turn, 100, turn) +
189 addHook(hooks_args, 100, args) +
__anon2a412fb50202() 190 addHook(hooks_clearmemory, 40, [] () {
191 balls.clear();
192 on = false;
193 });
194
195 }
196 }
197