add two missing shader functions (#26237)

Co-authored-by: aardgoose <angus.sawyer@email.com>

examples/jsm/nodes/Nodes.js

@@ -35,7 +35,7 @@ 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, atan2, min, max, mod, step, reflect, distance, difference, dot, cross, pow, pow2, pow3, pow4, transformDirection, mix, clamp, saturate, refract, smoothstep, faceForward } 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, negate, oneMinus, dFdx, dFdy, round, reciprocal, trunc, fwidth, atan2, min, max, mod, step, reflect, distance, difference, dot, cross, pow, pow2, pow3, pow4, transformDirection, mix, clamp, saturate, refract, smoothstep, faceForward } from './math/MathNode.js';
 export { default as OperatorNode, add, sub, mul, div, remainder, equal, assign, lessThan, greaterThan, lessThanEqual, greaterThanEqual, and, or, xor, bitAnd, bitOr, bitXor, shiftLeft, shiftRight } from './math/OperatorNode.js';
 export { default as CondNode, cond } from './math/CondNode.js';
 

examples/jsm/nodes/math/MathNode.js

@@ -218,6 +218,8 @@ MathNode.DFDX = 'dFdx';
 MathNode.DFDY = 'dFdy';
 MathNode.ROUND = 'round';
 MathNode.RECIPROCAL = 'reciprocal';
+MathNode.TRUNC = 'trunc';
+MathNode.FWIDTH = 'fwidth';
 
 // 2 inputs
 
@@ -274,6 +276,8 @@ export const dFdx = nodeProxy( MathNode, MathNode.DFDX );
 export const dFdy = nodeProxy( MathNode, MathNode.DFDY );
 export const round = nodeProxy( MathNode, MathNode.ROUND );
 export const reciprocal = nodeProxy( MathNode, MathNode.RECIPROCAL );
+export const trunc = nodeProxy( MathNode, MathNode.TRUNC );
+export const fwidth = nodeProxy( MathNode, MathNode.FWIDTH );
 
 export const atan2 = nodeProxy( MathNode, MathNode.ATAN2 );
 export const min = nodeProxy( MathNode, MathNode.MIN );
@@ -328,6 +332,8 @@ addNodeElement( 'dFdx', dFdx );
 addNodeElement( 'dFdy', dFdy );
 addNodeElement( 'round', round );
 addNodeElement( 'reciprocal', reciprocal );
+addNodeElement( 'trunc', trunc );
+addNodeElement( 'fwidth', fwidth );
 addNodeElement( 'atan2', atan2 );
 addNodeElement( 'min', min );
 addNodeElement( 'max', max );