Asset initial

// A normalized incident Gaussian packet on a 192 x 160 lattice.
// Coordinates here match scene.json: x = position.x + 96, j = position.y + 80.
// Fixed-grid normalization, validated against the independent numerical reference.
use models { Wave };
let normalization = 37.27485898801376;

fn absorber(x: Int, j: Int) -> Float {
	if x >= 152 {
		let ramp = (x - 151) / 40.0;
		return exp(-0.3 * ramp * ramp * 0.4 / 2.0);
	}
	let edge = max(0.0, max((16 - x) / 16.0, max((16 - j) / 16.0, (j - 143) / 16.0)));
	return exp(-0.3 * edge * edge * 0.4 / 2.0);
}

fn aperture(x: Int, y: Float) -> Float {
	if x < 56 || x >= 58 || abs(y - 14.0) < 4.0 || abs(y + 14.0) < 4.0 { return 1.0; }
	return 0.0;
}

fn envelope(x: Int, y: Float) -> Float {
	if x >= 56 { return 0.0; }
	let dx = (x - 32) / 7.0;
	let dy = y / 32.0;
	return exp(-(dx * dx) / 4.0 - (dy * dy) / 4.0);
}

fn detector(x: Int) -> Float {
	if x >= 152 { return 1.0; }
	return 0.0;
}

place Wave in box([-96, -80, 0], [96, 80, 1]) {
	let x = position.x + 96;
	let j = position.y + 80;
	let y = j - 79.5;
	let packet = envelope(x, y);
	set target.absorb = absorber(x, j);
	set target.detector = detector(x);
	set target.open = aperture(x, y);
	set target.real = packet * cos(0.55 * x) / normalization;
	set target.imag = packet * sin(0.55 * x) / normalization;
	set target.xEven = 1.0 - (x % 2);
	set target.yEven = 1.0 - (j % 2);
}