nalgebra/tests/core/cg.rs

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2020-07-03 01:31:30 +08:00
use na::{Matrix3, Matrix4, Point2, Point3, Vector2, Vector3};
/// See Example 3.4 of "Graphics and Visualization: Principles & Algorithms"
/// by Theoharis, Papaioannou, Platis, Patrikalakis.
#[test]
fn test_scaling_wrt_point_1() {
let a = Point2::new(0.0, 0.0);
let b = Point2::new(1.0, 1.0);
let c = Point2::new(5.0, 2.0);
let scaling = Vector2::new(2.0, 2.0);
let scale_about = Matrix3::new_nonuniform_scaling_wrt_point(scaling, c);
let expected_a = Point2::new(-5.0, -2.0);
let expected_b = Point2::new(-3.0, 0.0);
let result_a = scale_about.transform_point(&a);
let result_b = scale_about.transform_point(&b);
let result_c = scale_about.transform_point(&c);
assert!(expected_a == result_a);
assert!(expected_b == result_b);
assert!(c == result_c);
}
/// Based on the same example as the test above.
#[test]
fn test_scaling_wrt_point_2() {
let a = Point3::new(0.0, 0.0, 1.0);
let b = Point3::new(1.0, 1.0, 1.0);
let c = Point3::new(5.0, 2.0, 1.0);
let scaling = Vector3::new(2.0, 2.0, 1.0);
let scale_about = Matrix4::new_nonuniform_scaling_wrt_point(scaling, c);
let expected_a = Point3::new(-5.0, -2.0, 1.0);
let expected_b = Point3::new(-3.0, 0.0, 1.0);
let result_a = scale_about.transform_point(&a);
let result_b = scale_about.transform_point(&b);
let result_c = scale_about.transform_point(&c);
assert!(expected_a == result_a);
assert!(expected_b == result_b);
assert!(c == result_c);
}
/// Based on https://github.com/emlowry/AiE/blob/50bae4068edb686cf8ffacdf6fab8e7cb22e7eb1/Year%201%20Classwork/MathTest/Matrix4x4TestGroup.cpp#L145
#[test]
fn test_scaling_wrt_point_3() {
let about = Point3::new(2.0, 1.0, -2.0);
let scale = Vector3::new(2.0, 0.5, -1.0);
let pt = Point3::new(1.0, 2.0, 3.0);
let scale_about = Matrix4::new_nonuniform_scaling_wrt_point(scale, about);
let expected = Point3::new(0.0, 1.5, -7.0);
let result = scale_about.transform_point(&pt);
assert!(result == expected);
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}