pub fn world_step(world: &mut World, time_step: f32, sub_step_count: i32)Expand description
Simulate a world for one time step. (b2World_Step — takes &mut World; the C resolves the world from an id)
Examples found in repository?
examples/demo_scenes.rs (line 74)
50fn main() {
51 // === Bodies demo scene ===
52 let mut wd = default_world_def();
53 wd.gravity = m::Vec2 { x: 0.0, y: -10.0 };
54 let mut world = World::new(&wd);
55
56 add_static_box(&mut world, 0.0, -0.5, 13.0, 0.5);
57 add_static_box(&mut world, -12.2, 2.0, 0.3, 2.0);
58 add_static_box(&mut world, 12.2, 2.0, 0.3, 2.0);
59
60 let mut tracked = Vec::new();
61 for i in 0..24usize {
62 let x = -6.0 + (i % 8) as f32 * 1.7 + 0.13 * (i % 3) as f32;
63 let y = 5.0 + (i / 8) as f32 * 1.6;
64 if i % 2 == 0 {
65 let hx = 0.25 + 0.2 * ((i * 7) % 3) as f32 * 0.5;
66 tracked.push(add_box(&mut world, x, y, hx, hx));
67 } else {
68 let r = 0.22 + 0.16 * ((i * 5) % 3) as f32 * 0.5;
69 tracked.push(add_circle(&mut world, x, y, r, 1.0));
70 }
71 }
72
73 for step in 0..600 {
74 world_step(&mut world, 1.0 / 60.0, 4);
75 if step % 100 == 0 {
76 let t = get_body_transform(&world, tracked[0]);
77 println!(
78 "bodies step {step}: body0 = ({:.3}, {:.3}), contacts = {}",
79 t.p.x,
80 t.p.y,
81 world.contact_id_pool.id_count()
82 );
83 }
84 }
85 println!("BODIES SCENE OK");
86
87 // === Stacking demo scene ===
88 let mut world = World::new(&wd);
89 add_static_box(&mut world, 0.0, -0.5, 11.0, 0.5);
90 let h = 0.4f32;
91 let base = 9i32;
92 for row in 0..base {
93 let count = base - row;
94 let y = h + row as f32 * 2.0 * h;
95 for i in 0..count {
96 let x = (i as f32 - (count - 1) as f32 / 2.0) * 2.05 * h;
97 add_box(&mut world, x, y, h, h);
98 }
99 }
100 for _ in 0..600 {
101 world_step(&mut world, 1.0 / 60.0, 4);
102 }
103 println!(
104 "stacking settled: awake = {}",
105 world.solver_sets[box2d_rust::solver_set::AWAKE_SET as usize]
106 .body_sims
107 .len()
108 );
109 // Drop the heavy ball
110 add_circle(&mut world, 0.3, 9.0, 0.5, 4.0);
111 for _ in 0..600 {
112 world_step(&mut world, 1.0 / 60.0, 4);
113 }
114 println!("STACKING SCENE OK");
115}