MathNode: Add `rand()`. (#28765)

src/nodes/Nodes.js

@@ -38,7 +38,7 @@ import * as NodeUtils from './core/NodeUtils.js';
 export { NodeUtils };
 
 // math
-export { default as MathNode, PI, PI2, 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, transpose, all, any, equals } from './math/MathNode.js';
+export { default as MathNode, PI, PI2, 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, transpose, all, any, equals, rand } from './math/MathNode.js';
 
 export { default as OperatorNode, add, sub, mul, div, remainder, equal, lessThan, greaterThan, lessThanEqual, greaterThanEqual, and, or, not, xor, bitAnd, bitNot, bitOr, bitXor, shiftLeft, shiftRight } from './math/OperatorNode.js';
 export { default as CondNode, cond } from './math/CondNode.js';

src/nodes/math/MathNode.js

@@ -1,7 +1,7 @@
 import TempNode from '../core/TempNode.js';
 import { sub, mul, div } from './OperatorNode.js';
 import { addNodeClass } from '../core/Node.js';
-import { addNodeElement, nodeObject, nodeProxy, float, vec3, vec4 } from '../shadernode/ShaderNode.js';
+import { addNodeElement, nodeObject, nodeProxy, float, vec2, vec3, vec4, tslFn } from '../shadernode/ShaderNode.js';
 
 class MathNode extends TempNode {
 
@@ -330,6 +330,15 @@ export const refract = nodeProxy( MathNode, MathNode.REFRACT );
 export const smoothstep = nodeProxy( MathNode, MathNode.SMOOTHSTEP );
 export const faceForward = nodeProxy( MathNode, MathNode.FACEFORWARD );
 
+export const rand = tslFn( ( [ uv ] ) => {
+
+	const a = 12.9898, b = 78.233, c = 43758.5453;
+	const dt = dot( uv.xy, vec2( a, b ) ), sn = mod( dt, PI );
+
+	return fract( sin( sn ).mul( c ) );
+
+} );
+
 export const mixElement = ( t, e1, e2 ) => mix( e1, e2, t );
 export const smoothstepElement = ( x, low, high ) => smoothstep( low, high, x );
 
@@ -390,5 +399,6 @@ addNodeElement( 'difference', difference );
 addNodeElement( 'saturate', saturate );
 addNodeElement( 'cbrt', cbrt );
 addNodeElement( 'transpose', transpose );
+addNodeElement( 'rand', rand );
 
 addNodeClass( 'MathNode', MathNode );