main.dart

import 'package:vector_math/vector_math_64.dart';

void main() {
  Matrix4 transform = Matrix4(
    1.0,   0.0,   0.0,   0.0, // nodartfmt
    0.0,   1.0,   0.0,   0.0, // nodartfmt
    0.0,   0.0,   1.0,   500, // nodartfmt
    0.0,   0.0, 0.001,   1.5, // nodartfmt
  );

  // I want to find the source point that will yield destination point 1305,676
  // when the transform is applied.

  Vector3 points = transform.perspectiveTransform(Vector3(1305, 676, 0));

  print('${points.x.truncate()},${points.y.truncate()}'); // 870,450

  // So now we know that 1305,676 will transform to 870,450
  // ... but what opint will transform to 1305,676?

  // An inverse transform would seem to make sense...
  Matrix4 inverse = Matrix4.inverted(transform);
  Vector3 inversePoints = inverse.perspectiveTransform(Vector3(1305, 676, 0));
  print('${inversePoints.x.truncate()},${inversePoints.y.truncate()}');
  
  // wat?? that prints 1305,676, which is the source point!
  // But we know that the source point transforms to 870,450
  // So... what gives?
}