gfx2d_circle.rs

            const STEPS: usize = 16;
            let pos = vec2(collider.x, collider.y);
            let mut vertices = Vec::with_capacity(STEPS);
            for step in 0..STEPS {
                let m = Transform::FromOrigin {
                    pos,
                    scale: vec2(1.0, 1.0),
                    rot: ((2. * PI / STEPS as f32) * step as f32, Vec2::zero()),
                }
                .matrix();

                vertices.push(m * vec2(collider.diameter / 2., 0.0));
            }

            for (i, &vert) in vertices.iter().enumerate() {
                let next = vertices[(i + 1) % STEPS];
                graphics.add_debug_geometry(
                    None,
                    &[
                        vertex(pos, Vec2::zero(), rgba(255, 0, 0, 192)),
                        vertex(vert, Vec2::zero(), rgba(255, 0, 0, 128)),
                        vertex(next, Vec2::zero(), rgba(255, 0, 0, 128)),
                    ],
                );
            }