Function cuboid_support_map_find_local_separating_normal_oneway

pub fn cuboid_support_map_find_local_separating_normal_oneway<S: SupportMap>(
    cube1: &Cuboid,
    shape2: &S,
    pos12: &Isometry<f32>,
) -> (f32, Vector<f32>)

Finds the best separating axis by testing the face normals of a cuboid against a support map shape.

This function tests all face normals (X, Y, and Z axes in both positive and negative directions) of the cuboid to find which direction gives the maximum separation from the support map shape.

Parameters

• cube1: The cuboid whose face normals will be tested
• shape2: Any convex shape implementing SupportMap
• pos12: The position of shape2 relative to cube1

Returns

A tuple containing:

• Real: The maximum separation found among the cuboid’s face normals
  • Positive: Shapes are separated
  • Negative: Shapes are overlapping
• Vector<Real>: The face normal direction that gives this separation

Usage in Complete SAT

This function tests only the face normals of the cuboid. For a complete SAT collision test between a cuboid and another shape, you typically need to:

1. Test cuboid’s face normals (this function)
2. Test the other shape’s face normals (if applicable)
3. Test edge-edge cross products in 3D (if both shapes have edges)

Example

use parry2d::shape::{Cuboid, Ball};
use parry2d::query::sat::cuboid_support_map_find_local_separating_normal_oneway;
use nalgebra::{Isometry2, Vector2};

let cube = Cuboid::new(Vector2::new(1.0, 1.0));
let sphere = Ball::new(0.5);

// Position sphere to the right of the cube
let pos12 = Isometry2::translation(2.0, 0.0);

let (separation, normal) = cuboid_support_map_find_local_separating_normal_oneway(
    &cube,
    &sphere,
    &pos12
);

if separation > 0.0 {
    println!("Shapes separated by {} along normal {}", separation, normal);
} else {
    println!("Shapes overlapping by {} along normal {}", -separation, normal);
}

Performance

This function is more efficient than cuboid_support_map_compute_separation_wrt_local_line for face normals because it can directly compute the separation without testing both directions. It tests 2×DIM axes (where DIM is 2 or 3).