Function inv_rotate_vector 

pub fn inv_rotate_vector(q: Rot, v: Vec2) -> Vec2

Inverse rotate a vector

Examples found in repository

examples/benchmark/scenes/machines.rs (line 310)

pub fn create_washer(world: &mut World) {
    let kinematic = true;

    {
        let body_def = default_body_def();
        // groundId is only used to anchor the (disabled) revolute joint branch.
        let _ground_id = create_body(world, &body_def);
    }

    {
        let motor_speed = 25.0;

        let mut body_def = default_body_def();
        body_def.position = to_pos(Vec2 { x: 0.0, y: 10.0 });

        if kinematic {
            body_def.type_ = BodyType::Kinematic;
            body_def.angular_velocity = (PI / 180.0) * motor_speed;
            body_def.linear_velocity = Vec2 {
                x: 0.001,
                y: -0.002,
            };
        } else {
            body_def.type_ = BodyType::Dynamic;
        }

        let body_id = create_body(world, &body_def);

        let shape_def = default_shape_def();

        let r0 = 14.0;
        let r1 = 16.0;
        let r2 = 18.0;

        let angle = PI / 18.0;
        let q = Rot {
            c: angle.cos(),
            s: angle.sin(),
        };
        let qo = Rot {
            c: (0.1 * angle).cos(),
            s: (0.1 * angle).sin(),
        };
        let mut u1 = Vec2 { x: 1.0, y: 0.0 };
        for i in 0..36 {
            let u2 = if i == 35 {
                Vec2 { x: 1.0, y: 0.0 }
            } else {
                rotate_vector(q, u1)
            };

            {
                let a1 = inv_rotate_vector(qo, u1);
                let a2 = rotate_vector(qo, u2);

                let p1 = mul_sv(r1, a1);
                let p2 = mul_sv(r2, a1);
                let p3 = mul_sv(r1, a2);
                let p4 = mul_sv(r2, a2);

                let points = [p1, p2, p3, p4];
                let hull = compute_hull(&points);

                let polygon = make_polygon(&hull, 0.0);
                create_polygon_shape(world, body_id, &shape_def, &polygon);
            }

            if i % 9 == 0 {
                let p1 = mul_sv(r0, u1);
                let p2 = mul_sv(r1, u1);
                let p3 = mul_sv(r0, u2);
                let p4 = mul_sv(r1, u2);

                let points = [p1, p2, p3, p4];
                let hull = compute_hull(&points);

                let polygon = make_polygon(&hull, 0.0);
                create_polygon_shape(world, body_id, &shape_def, &polygon);
            }

            u1 = u2;
        }
    }

    let grid_count: i32 = if BENCHMARK_DEBUG { 20 } else { 90 };
    let a = 0.1;

    let polygon = make_square(a);
    let mut body_def = default_body_def();
    body_def.type_ = BodyType::Dynamic;
    let mut shape_def = default_shape_def();
    shape_def.enable_hit_events = true;

    let mut y = -1.1 * a * grid_count as f32 + 10.0;
    for _ in 0..grid_count {
        let mut x = -1.1 * a * grid_count as f32;

        for _ in 0..grid_count {
            body_def.position = to_pos(Vec2 { x, y });
            let body_id = create_body(world, &body_def);

            create_polygon_shape(world, body_id, &shape_def, &polygon);

            x += 2.1 * a;
        }

        y += 2.1 * a;
    }
}