package iron.culling;

class ContributionCull {

	public static var minPixelRadius: Float = 2.0;
	public static var enabled: Bool = false;

	public static function passes(
		centerX: Float, centerY: Float, centerZ: Float,
		radius: Float,
		camX: Float, camY: Float, camZ: Float,
		focalLengthPx: Float
	): Bool {
		if (!enabled || minPixelRadius <= 0.0 || focalLengthPx <= 0.0) return true;

		var dx = centerX - camX;
		var dy = centerY - camY;
		var dz = centerZ - camZ;
		var dist = Math.sqrt(dx * dx + dy * dy + dz * dz);

		if (dist <= radius) return true; 

		var projectedRadiusPx = focalLengthPx * radius / dist;
		return projectedRadiusPx >= minPixelRadius;
	}

	public static function passesNode(
		node: BVHNode,
		camX: Float, camY: Float, camZ: Float,
		focalLengthPx: Float
	): Bool {
		if (!enabled || minPixelRadius <= 0.0 || focalLengthPx <= 0.0) return true;

		var cx = (node.minX + node.maxX) * 0.5;
		var cy = (node.minY + node.maxY) * 0.5;
		var cz = (node.minZ + node.maxZ) * 0.5;
		var ex = (node.maxX - node.minX) * 0.5;
		var ey = (node.maxY - node.minY) * 0.5;
		var ez = (node.maxZ - node.minZ) * 0.5;
		var radius = Math.sqrt(ex * ex + ey * ey + ez * ez);

		if (camX >= node.minX && camX <= node.maxX &&
			camY >= node.minY && camY <= node.maxY &&
			camZ >= node.minZ && camZ <= node.maxZ) {
			return true;
		}

		var dx = cx - camX;
		var dy = cy - camY;
		var dz = cz - camZ;
		var dist = Math.sqrt(dx * dx + dy * dy + dz * dz);

		if (dist <= radius) return true;

		var projectedRadiusPx = focalLengthPx * radius / dist;
		return projectedRadiusPx >= minPixelRadius;
	}

	public static function computeFocalLengthPx(fov: Float, screenHeight: Int): Float {
		return screenHeight / (2.0 * Math.tan(fov * 0.5));
	}
}