Nodes: Add lengthSq to MathNodes (#27568)

* add lengthSq to math nodes

* forgot lengthSq doesn't exist in glsl

* cleanup

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examples/jsm/nodes/Nodes.js

@@ -39,7 +39,7 @@ import * as NodeUtils from './core/NodeUtils.js';
 export { NodeUtils };
 
 // math
-export { default as MathNode, EPSILON, INFINITY, radians, degrees, exp, exp2, log, log2, sqrt, inverseSqrt, floor, ceil, normalize, fract, sin, cos, tan, asin, acos, atan, abs, sign, length, negate, oneMinus, dFdx, dFdy, round, reciprocal, trunc, fwidth, bitcast, atan2, min, max, mod, step, reflect, distance, difference, dot, cross, pow, pow2, pow3, pow4, transformDirection, mix, clamp, saturate, refract, smoothstep, faceForward, cbrt } from './math/MathNode.js';
+export { default as MathNode, EPSILON, INFINITY, radians, degrees, exp, exp2, log, log2, sqrt, inverseSqrt, floor, ceil, normalize, fract, sin, cos, tan, asin, acos, atan, abs, sign, length, lengthSq, negate, oneMinus, dFdx, dFdy, round, reciprocal, trunc, fwidth, bitcast, atan2, min, max, mod, step, reflect, distance, difference, dot, cross, pow, pow2, pow3, pow4, transformDirection, mix, clamp, saturate, refract, smoothstep, faceForward, cbrt } from './math/MathNode.js';
 export { parabola, gain, pcurve, sinc } from './math/MathNode.js';
 
 export { default as OperatorNode, add, sub, mul, div, remainder, equal, lessThan, greaterThan, lessThanEqual, greaterThanEqual, and, or, xor, bitAnd, bitOr, bitXor, shiftLeft, shiftRight } from './math/OperatorNode.js';

examples/jsm/nodes/math/MathNode.js

@@ -310,6 +310,7 @@ export const pcurve = ( x, a, b ) => pow( div( pow( x, a ), add( pow( x, a ), po
 export const sinc = ( x, k ) => sin( PI.mul( k.mul( x ).sub( 1.0 ) ) ).div( PI.mul( k.mul( x ).sub( 1.0 ) ) );
 
 export const cbrt = ( a ) => mul( sign( a ), pow( abs( a ), 1.0 / 3.0 ) );
+export const lengthSq = ( a ) => dot( a, a );
 export const mix = nodeProxy( MathNode, MathNode.MIX );
 export const clamp = ( value, low = 0, high = 1 ) => nodeObject( new MathNode( MathNode.CLAMP, nodeObject( value ), nodeObject( low ), nodeObject( high ) ) );
 export const saturate = ( value ) => clamp( value );
@@ -341,6 +342,7 @@ addNodeElement( 'atan', atan );
 addNodeElement( 'abs', abs );
 addNodeElement( 'sign', sign );
 addNodeElement( 'length', length );
+addNodeElement( 'lengthSq', lengthSq );
 addNodeElement( 'negate', negate );
 addNodeElement( 'oneMinus', oneMinus );
 addNodeElement( 'dFdx', dFdx );