/** Uint16Array depth buffer for early-Z rejection. */
export class DepthBuffer {
	#width: number;
	#height: number;
	#data: Uint16Array;

	constructor(width: number, height: number) {
		this.#width = width;
		this.#height = height;
		this.#data = new Uint16Array(width * height);
		this.#data.fill(0xffff);
	}

	get width(): number {
		return this.#width;
	}

	get height(): number {
		return this.#height;
	}

	get data(): Uint16Array {
		return this.#data;
	}

	/** Clears all depth values to far plane (0xFFFF). */
	clear(): void {
		this.#data.fill(0xffff);
	}

	/**
	 * Tests a fragment's depth against the stored value and updates if closer.
	 * @param depth Uint16 depth value (0 = near, 65535 = far)
	 * @returns true if the fragment passes (is closer than stored)
	 */
	testAndSet(x: number, y: number, depth: number): boolean {
		const idx = y * this.#width + x;
		if (depth > this.#data[idx]) return false;
		this.#data[idx] = depth;
		return true;
	}

	resize(width: number, height: number): void {
		this.#width = width;
		this.#height = height;
		this.#data = new Uint16Array(width * height);
		this.#data.fill(0xffff);
	}
}