<!-- SOLUV · part 355 -->
itionSize = 3;

		const position = new Float32Array( positionSize * vertices * cubeFaces );
		const outputDirection = new Float32Array( positionSize * vertices * cubeFaces );

		for ( let face = 0; face < cubeFaces; face ++ ) {

			const x = ( face % 3 ) * 2 / 3 - 1;
			const y = face > 2 ? 0 : -1;
			const coordinates = [
				x, y, 0,
				x + 2 / 3, y, 0,
				x + 2 / 3, y + 1, 0,
				x, y, 0,
				x + 2 / 3, y + 1, 0,
				x, y + 1, 0
			];
			position.set( coordinates, positionSize * vertices * face );

			for ( let vertex = 0; vertex < vertices; vertex ++ ) {

				const u = uv1[ vertex * 2 ] * 2 - 1;
				const v = uv1[ vertex * 2 + 1 ] * 2 - 1;

				// RH coordinate system; PMREM face-indexing convention
				if ( face === 0 ) {

					_direction.set( 1, v, u ); // pos x

				} else if ( face === 1 ) {

					_direction.set( - u, 1, - v ); // pos y

				} else if ( face === 2 ) {

					_direction.set( - u, v, 1 ); // pos z

				} else if ( face === 3 ) {

					_direction.set( -1, v, - u ); // neg x

				} else if ( face === 4 ) {

					_direction.set( - u, -1, v ); // neg y

				} else {

					_direction.set( u, v, -1 ); // neg z

				}

				_direction.toArray( outputDirection, ( face * vertices + vertex ) * positionSize );

			}

		}

		const planes = new BufferGeometry();
		planes.setAttribute( 'position', new BufferAttribute( position, positionSize ) );
		planes.setAttribute( 'outputDirection', new BufferAttribute( outputDirection, positionSize ) );
		lodMeshes.push( new Mesh( planes, null ) );

		if ( lod > LOD_MIN ) {

			lod --;

		}

	}

	return { lodMeshes, sizeLods };

}

function _createRenderTarget( width, height, params ) {

	const cubeUVRenderTarget = new WebGLRenderTarget( width, height, params );
	cubeUVRenderTarget.texture.mapping = CubeUVReflectionMapping;
	cubeUVRenderTarget.texture.name = 'PMREM.cubeUv';
	cubeUVRenderTarget.scissorTest = true;
	return cubeUVRenderTarget;

}

function _setViewport( target, x, y, width, height ) {

	target.viewport.set( x, y, width, height );
	target.scissor.set( x, y, width, height );

}

function _getGGXShader( lodMax, width, height ) {

	const shaderMaterial = new ShaderMaterial( {

		name: 'PMREMGGXConvolution',

		defines: {
			'GGX_SAMPLES': GGX_SAMPLES,
			'CUBEUV_TEXEL_WIDTH': 1.0 / width,
			'CUBEUV_TEXEL_HEIGHT': 1.0 / height,
			'CUBEUV_MAX_MIP': `${lodMax}.0`,
		},

		uniforms: {
			'envMap': { value: null },
			'roughness': { value: 0.0 },
			'mipInt': { value: 0 }
		},

		vertexShader: _getCommonVertexShader(),

		fragmentShader: /* glsl */`

			precision highp float;
			precision highp int;

			varying vec3 vOutputDirection;

			uniform sampler2D envMap;
			uniform float roughness;
			uniform float mipInt;

			#define ENVMAP_TYPE_CUBE_UV
			#include <cube_uv_reflection_fragment>

			#define PI 3.14159265359

			// Van der Corput radical inverse
			float radicalInverse_VdC(uint bits) {
				bits = (bits << 16u) | (bits >> 16u);
				bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
				bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
				bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
				bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
				return float(bits) * 2.3283064365386963e-10; // / 0x100000000
			}

			// Hammersley sequence
			vec2 hammersley(uint i, uint N) {
				return vec2(float(i) / float(N), radicalInverse_VdC(i));
			}

			// GGX VNDF importance sampling (Eric Heitz 2018)
			// "Sampling the GGX Distribution of Visible Normals"
			// https://jcgt.org/published/0007/04/01/
			vec3 importanceSampleGGX_VNDF(vec2 Xi, vec3 V, float roughness) {
				float alpha = roughness * roughness;

				// Section 4.1: Orthonormal basis
				vec3 T1 = vec3(1.0, 0.0, 0.0);
				vec3 T2 = cross(V, T1);

				// Section 4.2: Parameterization of projected area
				float r = sqrt(Xi.x);
				float phi = 2.0 * PI * Xi.y;
				float t1 = r * cos(phi);
				float t2 = r * sin(phi);
				float s = 0.5 * (1.0 + V.z);
				t2 = (1.0 - s) * sqrt(1.0 - t1 * t1) + s * t2;

				// Section 4.3: Reprojection onto hemisphere
				vec3 Nh = t1 * T1 + t2 * T2 + sqrt(max(0.0, 1.0 - t1 * t1 - t2 * t2)) * V;

				// Section 3.4: Transform back to ellipsoid configuration
				return normalize(vec3(alpha * Nh.x, alpha * Nh.y, max(0.0, Nh.z)));
			}

			void main() {
				vec3 N = normalize(vOutputDirection);
				vec3 V = N; // Assume view direction equals normal for pre-filtering

				vec3 prefilteredColor = vec3(0.0);
				float totalWeight = 0.0;

				// For very low roughness, just sample the environment directly
				if (roughness < 0.001) {
					gl_FragColor = vec4(bilinearCubeUV(envMap, N, mipInt), 1.0);
					return;
				}

				// Tangent space basis for VNDF sampling
				vec3 up = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
				vec3 tangent = normalize(cross(up, N));
				vec3 bitangent = cross(N, tangent);

				for(uint i = 0u; i < uint(GGX_SAMPLES); i++) {