src/materials/DepthComparisonMaterial.js

import { NoBlending, PerspectiveCamera, RGBADepthPacking, ShaderMaterial, Uniform } from "three";

import fragmentShader from "./glsl/depth-comparison.frag";
import vertexShader from "./glsl/depth-comparison.vert";

/**
 * A depth comparison shader material.
 */

export class DepthComparisonMaterial extends ShaderMaterial {

	/**
	 * Constructs a new depth comparison material.
	 *
	 * @param {Texture} [depthTexture=null] - A depth texture.
	 * @param {PerspectiveCamera} [camera] - A camera.
	 */

	constructor(depthTexture = null, camera) {

		super({
			name: "DepthComparisonMaterial",
			defines: {
				DEPTH_PACKING: "0"
			},
			uniforms: {
				depthBuffer: new Uniform(null),
				cameraNear: new Uniform(0.3),
				cameraFar: new Uniform(1000)
			},
			blending: NoBlending,
			toneMapped: false,
			depthWrite: false,
			depthTest: false,
			fragmentShader,
			vertexShader
		});

		this.depthBuffer = depthTexture;
		this.depthPacking = RGBADepthPacking;
		this.copyCameraSettings(camera);

	}

	/**
	 * The depth buffer.
	 *
	 * @type {Texture}
	 */

	set depthBuffer(value) {

		this.uniforms.depthBuffer.value = value;

	}

	/**
	 * The depth packing strategy.
	 *
	 * @type {DepthPackingStrategies}
	 */

	set depthPacking(value) {

		this.defines.DEPTH_PACKING = value.toFixed(0);
		this.needsUpdate = true;

	}

	/**
	 * Sets the depth buffer.
	 *
	 * @deprecated Use depthBuffer and depthPacking instead.
	 * @param {Texture} buffer - The depth texture.
	 * @param {DepthPackingStrategies} [depthPacking=RGBADepthPacking] - The depth packing strategy.
	 */

	setDepthBuffer(buffer, depthPacking = RGBADepthPacking) {

		this.depthBuffer = buffer;
		this.depthPacking = depthPacking;

	}

	/**
	 * Copies the settings of the given camera.
	 *
	 * @deprecated Use copyCameraSettings instead.
	 * @param {Camera} camera - A camera.
	 */

	adoptCameraSettings(camera) {

		this.copyCameraSettings(camera);

	}

	/**
	 * Copies the settings of the given camera.
	 *
	 * @param {Camera} camera - A camera.
	 */

	copyCameraSettings(camera) {

		if(camera) {

			this.uniforms.cameraNear.value = camera.near;
			this.uniforms.cameraFar.value = camera.far;

			if(camera instanceof PerspectiveCamera) {

				this.defines.PERSPECTIVE_CAMERA = "1";

			} else {

				delete this.defines.PERSPECTIVE_CAMERA;

			}

			this.needsUpdate = true;

		}

	}

}