target.addScaledVector( coeff[ 8 ], 0.429043 * ( x * x - y * y ) ); // ( π / 4 ) * 0.546274 return target; } /** * Adds the given SH to this instance. * * @param {SphericalHarmonics3} sh - The SH to add. * @return {SphericalHarmonics3} A reference to this spherical harmonics. */ add( sh ) { for ( let i = 0; i < 9; i ++ ) { this.coefficients[ i ].add( sh.coefficients[ i ] ); } return this; } /** * A convenience method for performing {@link SphericalHarmonics3#add} and * {@link SphericalHarmonics3#scale} at once. * * @param {SphericalHarmonics3} sh - The SH to add. * @param {number} s - The scale factor. * @return {SphericalHarmonics3} A reference to this spherical harmonics. */ addScaledSH( sh, s ) { for ( let i = 0; i < 9; i ++ ) { this.coefficients[ i ].addScaledVector( sh.coefficients[ i ], s ); } return this; } /** * Scales this SH by the given scale factor. * * @param {number} s - The scale factor. * @return {SphericalHarmonics3} A reference to this spherical harmonics. */ scale( s ) { for ( let i = 0; i < 9; i ++ ) { this.coefficients[ i ].multiplyScalar( s ); } return this; } /** * Linear interpolates between the given SH and this instance by the given * alpha factor. * * @param {SphericalHarmonics3} sh - The SH to interpolate with. * @param {number} alpha - The alpha factor. * @return {SphericalHarmonics3} A reference to this spherical harmonics. */ lerp( sh, alpha ) { for ( let i = 0; i < 9; i ++ ) { this.coefficients[ i ].lerp( sh.coefficients[ i ], alpha ); } return this; } /** * Returns `true` if this spherical harmonics is equal with the given one. * * @param {SphericalHarmonics3} sh - The spherical harmonics to test for equality. * @return {boolean} Whether this spherical harmonics is equal with the given one. */ equals( sh ) { for ( let i = 0; i < 9; i ++ ) { if ( ! this.coefficients[ i ].equals( sh.coefficients[ i ] ) ) { return false; } } return true; } /** * Copies the values of the given spherical harmonics to this instance. * * @param {SphericalHarmonics3} sh - The spherical harmonics to copy. * @return {SphericalHarmonics3} A reference to this spherical harmonics. */ copy( sh ) { return this.set( sh.coefficients ); } /** * Returns a new spherical harmonics with copied values from this instance. * * @return {SphericalHarmonics3} A clone of this instance. */ clone() { return new this.constructor().copy( this ); } /** * Sets the SH coefficients of this instance from the given array. * * @param {Array} array - An array holding the SH coefficients. * @param {number} [offset=0] - The array offset where to start copying. * @return {SphericalHarmonics3} A clone of this instance. */ fromArray( array, offset = 0 ) { const coefficients = this.coefficients; for ( let i = 0; i < 9; i ++ ) { coefficients[ i ].fromArray( array, offset + ( i * 3 ) ); } return this; } /** * Returns an array with the SH coefficients, or copies them into the provided * array. The coefficients are represented as numbers. * * @param {Array} [array=[]] - The target array. * @param {number} [offset=0] - The array offset where to start copying. * @return {Array} An array with flat SH coefficients. */ toArray( array = [], offset = 0 ) { const coefficients = this.coefficients; for ( let i = 0; i < 9; i ++ ) { coefficients[ i ].toArray( array, offset + ( i * 3 ) ); } return array; } /** * Computes the SH basis for the given normal vector. * * @param {Vector3} normal - The normal. * @param {Array} shBasis - The target array holding the SH basis. */ static getBasisAt( normal, shBasis ) { // normal is assumed to be unit length const x = normal.x, y = normal.y, z = normal.z; // band 0 shBasis[ 0 ] = 0.282095; // band 1 shBasis[ 1 ] = 0.488603 * y; shBasis[ 2 ] = 0.488603 * z; shBasis[ 3 ] = 0.488603 * x; // band 2 shBasis[ 4 ] = 1.092548 * x * y; shBasis[ 5 ] = 1.092548 * y * z; shBasis[ 6 ] = 0.315392 * ( 3 * z * z - 1 ); shBasis[ 7 ] = 1.092548 * x * z; shBasis[ 8 ] = 0.546274 * ( x * x - y * y ); } } /** * Light probes are an alternative way of adding light to a 3D scene. Unlike * classical light sources (e.g. directional, point or spot lights), light * probes do not emit light. Instead they store information about light * passing through 3D space. During rendering, the light that hits a 3D * object is approximated by using the data from the light probe. * * Light probes are usually created from (radiance) environment maps. The * class {@link LightProbeGenerator} can be used to create light probes from * cube textures or render targets. However, light estimation data could also * be provided in other forms e.g. by WebXR. T