<!-- NEW4 — TEST 4 · THE QUILT · part 350 -->
t=null] - The render target to use.
	 * @return {WebGLRenderTarget} The resulting PMREM.
	 */
	fromEquirectangular( equirectangular, renderTarget = null ) {

		return this._fromTexture( equirectangular, renderTarget );

	}

	/**
	 * Generates a PMREM from an cubemap texture, which can be either LDR
	 * or HDR. The ideal input cube size is 256 x 256, as this matches best
	 * with the 256 x 256 cubemap output. The minimum supported input cube
	 * size is 16 x 16 per face.
	 *
	 * @param {Texture} cubemap - The cubemap texture to be converted.
	 * @param {?WebGLRenderTarget} [renderTarget=null] - The render target to use.
	 * @return {WebGLRenderTarget} The resulting PMREM.
	 */
	fromCubemap( cubemap, renderTarget = null ) {

		return this._fromTexture( cubemap, renderTarget );

	}

	/**
	 * Pre-compiles the cubemap shader. You can get faster start-up by invoking this method during
	 * your texture's network fetch for increased concurrency.
	 */
	compileCubemapShader() {

		if ( this._cubemapMaterial === null ) {

			this._cubemapMaterial = _getCubemapMaterial();
			this._compileMaterial( this._cubemapMaterial );

		}

	}

	/**
	 * Pre-compiles the equirectangular shader. You can get faster start-up by invoking this method during
	 * your texture's network fetch for increased concurrency.
	 */
	compileEquirectangularShader() {

		if ( this._equirectMaterial === null ) {

			this._equirectMaterial = _getEquirectMaterial();
			this._compileMaterial( this._equirectMaterial );

		}

	}

	/**
	 * Disposes of the PMREMGenerator's internal memory. Note that PMREMGenerator is a static class,
	 * so you should not need more than one PMREMGenerator object. If you do, calling dispose() on
	 * one of them will cause any others to also become unusable.
	 */
	dispose() {

		this._dispose();

		if ( this._cubemapMaterial !== null ) this._cubemapMaterial.dispose();
		if ( this._equirectMaterial !== null ) this._equirectMaterial.dispose();

		if ( this._backgroundBox !== null ) {

			this._backgroundBox.geometry.dispose();
			this._backgroundBox.material.dispose();

		}

	}

	// private interface

	_setSize( cubeSize ) {

		this._lodMax = Math.floor( Math.log2( cubeSize ) );
		this._cubeSize = Math.pow( 2, this._lodMax );

	}

	_dispose() {

		if ( this._blurMaterial !== null ) this._blurMaterial.dispose();
		if ( this._ggxMaterial !== null ) this._ggxMaterial.dispose();

		if ( this._pingPongRenderTarget !== null ) this._pingPongRenderTarget.dispose();

		for ( let i = 0; i < this._lodMeshes.length; i ++ ) {

			this._lodMeshes[ i ].geometry.dispose();

		}

	}

	_cleanup( outputTarget ) {

		this._renderer.setRenderTarget( _oldTarget, _oldActiveCubeFace, _oldActiveMipmapLevel );
		this._renderer.xr.enabled = _oldXrEnabled;

		outputTarget.scissorTest = false;
		_setViewport( outputTarget, 0, 0, outputTarget.width, outputTarget.height );

	}

	_fromTexture( texture, renderTarget ) {

		if ( texture.mapping === CubeReflectionMapping || texture.mapping === CubeRefractionMapping ) {

			this._setSize( texture.image.length === 0 ? 16 : ( texture.image[ 0 ].width || texture.image[ 0 ].image.width ) );

		} else { // Equirectangular

			this._setSize( texture.image.width / 4 );

		}

		_oldTarget = this._renderer.getRenderTarget();
		_oldActiveCubeFace = this._renderer.getActiveCubeFace();
		_oldActiveMipmapLevel = this._renderer.getActiveMipmapLevel();
		_oldXrEnabled = this._renderer.xr.enabled;

		this._renderer.xr.enabled = false;

		const cubeUVRenderTarget = renderTarget || this._allocateTargets();
		this._textureToCubeUV( texture, cubeUVRenderTarget );
		this._applyPMREM( cubeUVRenderTarget );
		this._cleanup( cubeUVRenderTarget );

		return cubeUVRenderTarget;

	}

	_allocateTargets() {

		const width = 3 * Math.max( this._cubeSize, 16 * 7 );
		const height = 4 * this._cubeSize;

		const params = {
			magFilter: LinearFilter,
			minFilter: LinearFilter,
			generateMipmaps: false,
			type: HalfFloatType,
			format: RGBAFormat,
			colorSpace: LinearSRGBColorSpace,
			depthBuffer: false
		};

		const cubeUVRenderTarget = _createRenderTarget( width, height, params );

		if ( this._pingPongRenderTarget === null || this._pingPongRenderTarget.width !== width || this._pingPongRenderTarget.height !== height ) {

			if ( this._pingPongRenderTarget !== null ) {

				this._dispose();

			}

			this._pingPongRenderTarget = _createRenderTarget( width, height, params );

			const { _lodMax } = this;
			( { lodMeshes: this._lodMeshes, sizeLods: this._sizeLods } = _createPlanes( _lodMax ) );

			this._blurMaterial = _getBlurShader( _lodMax, width, height );
			this._ggxMaterial = _getGGXShader( _lodMax, width, height );

		}

		return cubeUVRenderTarget;

	}

	_compileMaterial( material ) {

		const mesh = new Mesh( new BufferGeometry(), material );
		this._renderer.compile( mesh, _flatCamera );

	}

	_sceneToCubeUV( scene, near, far, cubeUVRenderTarget, position ) {

		const fov = 90;
		const