WGSLNodeBuilder: Fix `pow()` with negative base on Windows (#28971)

* WGSLNodeBuilder: Fix pow() with negative base on Windows

* restore tsl galaxy example

* Update webgpu_tsl_galaxy.jpg

* puppeteer: add webgpu_tsl_galaxy

examples/webgpu_tsl_galaxy.html

@@ -27,7 +27,7 @@
 		<script type="module">
 
 			import * as THREE from 'three';
-			import { color, cos, float, mix, range, sin, timerLocal, uniform, uv, vec3, vec4, PI, PI2, tslFn } from 'three/tsl';
+			import { color, cos, float, mix, range, sin, timerLocal, uniform, uv, vec3, vec4, PI2 } from 'three/tsl';
 
 			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';
 			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
@@ -70,22 +70,7 @@
 					sin( angle )
 				).mul( radius );
 
-				const sphericalToVec3 = tslFn( ( [ phi, theta ] ) => {
-
-					const sinPhiRadius = sin( phi );
-
-					return vec3(
-						sinPhiRadius.mul( sin( theta ) ),
-						cos( phi ),
-						sinPhiRadius.mul( cos( theta ) )
-					);
-
-				} );
-
-				const phi = range( 0, PI2 );
-				const theta = range( 0, PI );
-				const offsetRadius = range( 0, 1 ).pow( 2 ).mul( radiusRatio ).mul( 1.25 );
-				const randomOffset = sphericalToVec3( phi, theta ).mul( offsetRadius );
+				const randomOffset = range( vec3( - 1 ), vec3( 1 ) ).pow( 3 ).mul( radiusRatio ).add( 0.2 );
 
 				material.positionNode = position.add( randomOffset );
 

src/renderers/webgpu/nodes/WGSLNodeBuilder.js

@@ -72,23 +72,6 @@ const wgslTypeLib = {
 	bmat4: 'mat4x4<bool>'
 };
 
-const wgslMethods = {
-	dFdx: 'dpdx',
-	dFdy: '- dpdy',
-	mod_float: 'threejs_mod_float',
-	mod_vec2: 'threejs_mod_vec2',
-	mod_vec3: 'threejs_mod_vec3',
-	mod_vec4: 'threejs_mod_vec4',
-	equals_bool: 'threejs_equals_bool',
-	equals_bvec2: 'threejs_equals_bvec2',
-	equals_bvec3: 'threejs_equals_bvec3',
-	equals_bvec4: 'threejs_equals_bvec4',
-	lessThanEqual: 'threejs_lessThanEqual',
-	greaterThan: 'threejs_greaterThan',
-	inversesqrt: 'inverseSqrt',
-	bitcast: 'bitcast<f32>'
-};
-
 const wgslPolyfill = {
 	threejs_xor: new CodeNode( `
 fn threejs_xor( a : bool, b : bool ) -> bool {
@@ -153,6 +136,41 @@ fn threejs_biquadraticTexture( map : texture_2d<f32>, coord : vec2f, level : i32
 ` )
 };
 
+const wgslMethods = {
+	dFdx: 'dpdx',
+	dFdy: '- dpdy',
+	mod_float: 'threejs_mod_float',
+	mod_vec2: 'threejs_mod_vec2',
+	mod_vec3: 'threejs_mod_vec3',
+	mod_vec4: 'threejs_mod_vec4',
+	equals_bool: 'threejs_equals_bool',
+	equals_bvec2: 'threejs_equals_bvec2',
+	equals_bvec3: 'threejs_equals_bvec3',
+	equals_bvec4: 'threejs_equals_bvec4',
+	lessThanEqual: 'threejs_lessThanEqual',
+	greaterThan: 'threejs_greaterThan',
+	inversesqrt: 'inverseSqrt',
+	bitcast: 'bitcast<f32>'
+};
+
+// WebGPU issue: does not support pow() with negative base on Windows
+
+if ( /Windows/g.test( navigator.userAgent ) ) {
+
+	wgslPolyfill.pow_float = new CodeNode( 'fn threejs_pow_float( a : f32, b : f32 ) -> f32 { return select( -pow( -a, b ), pow( a, b ), a > 0.0 ); }' );
+	wgslPolyfill.pow_vec2 = new CodeNode( 'fn threejs_pow_vec2( a : vec2f, b : vec2f ) -> vec2f { return vec2f( threejs_pow_float( a.x, b.x ), threejs_pow_float( a.y, b.y ) ); }', [ wgslPolyfill.pow_float ] );
+	wgslPolyfill.pow_vec3 = new CodeNode( 'fn threejs_pow_vec3( a : vec3f, b : vec3f ) -> vec3f { return vec3f( threejs_pow_float( a.x, b.x ), threejs_pow_float( a.y, b.y ), threejs_pow_float( a.z, b.z ) ); }', [ wgslPolyfill.pow_float ] );
+	wgslPolyfill.pow_vec4 = new CodeNode( 'fn threejs_pow_vec4( a : vec4f, b : vec4f ) -> vec4f { return vec4f( threejs_pow_float( a.x, b.x ), threejs_pow_float( a.y, b.y ), threejs_pow_float( a.z, b.z ), threejs_pow_float( a.w, b.w ) ); }', [ wgslPolyfill.pow_float ] );
+
+	wgslMethods.pow_float = 'threejs_pow_float';
+	wgslMethods.pow_vec2 = 'threejs_pow_vec2';
+	wgslMethods.pow_vec3 = 'threejs_pow_vec3';
+	wgslMethods.pow_vec4 = 'threejs_pow_vec4';
+
+}
+
+//
+
 class WGSLNodeBuilder extends NodeBuilder {
 
 	constructor( object, renderer ) {

test/e2e/puppeteer.js

@@ -150,6 +150,7 @@ const exceptionList = [
 	'webgpu_performance_renderbundle',
 	'webgpu_lights_rectarealight',
 	'webgpu_tsl_vfx_flames',
+	'webgpu_tsl_galaxy',
 
 	// WebGPU idleTime and parseTime too low
 	'webgpu_compute_particles',