WebGPURenderer: Add Enable Directive/Enable-Extension Support (#28615)

* Added directive support to WGSLNodeBuilder

* fix mr doob style issues

* fix compatibility with r166, add dual source blending

* Change function name and add enableDualSourceBlending function

* minor

src/renderers/webgpu/nodes/WGSLNodeBuilder.js

@@ -163,6 +163,8 @@ class WGSLNodeBuilder extends NodeBuilder {
 
 		this.builtins = {};
 
+		this.directives = {};
+
 	}
 
 	needsColorSpaceToLinear( texture ) {
@@ -655,6 +657,50 @@ ${ flowData.code }
 
 	}
 
+	enableDirective( name, shaderStage = this.shaderStage ) {
+
+		const stage = this.directives[ shaderStage ] || ( this.directives[ shaderStage ] = [] );
+		stage.push( name );
+
+	}
+
+	getDirectives( shaderStage ) {
+
+		const snippets = [];
+		const directives = this.directives[ shaderStage ];
+
+		if ( directives !== undefined ) {
+
+			for ( const directive of directives ) {
+
+				snippets.push( `enable ${directive}` );
+
+			}
+
+		}
+
+		return snippets.join( '\n' );
+
+	}
+
+	enableClipDistances() {
+
+		this.enableDirective( 'clip_distances' );
+
+	}
+
+	enableShaderF16() {
+
+		this.enableDirective( 'f16' );
+
+	}
+
+	enableDualSourceBlending() {
+
+		this.enableDirective( 'dual_source_blending' );
+
+	}
+
 	getBuiltins( shaderStage ) {
 
 		const snippets = [];
@@ -970,6 +1016,7 @@ ${ flowData.code }
 			stageData.structs = this.getStructs( shaderStage );
 			stageData.vars = this.getVars( shaderStage );
 			stageData.codes = this.getCodes( shaderStage );
+			stageData.directives = this.getDirectives( shaderStage );
 
 			//
 
@@ -1129,6 +1176,8 @@ ${ flowData.code }
 	_getWGSLVertexCode( shaderData ) {
 
 		return `${ this.getSignature() }
+// directives
+${shaderData.directives};
 
 // uniforms
 ${shaderData.uniforms}
@@ -1188,6 +1237,9 @@ fn main( ${shaderData.varyings} ) -> ${shaderData.returnType} {
 	_getWGSLComputeCode( shaderData, workgroupSize ) {
 
 		return `${ this.getSignature() }
+// directives
+${shaderData.directives}
+
 // system
 var<private> instanceIndex : u32;
 

src/renderers/webgpu/utils/WebGPUConstants.js

@@ -326,5 +326,7 @@ export const GPUFeatureName = {
 	ShaderF16: 'shader-f16',
 	RG11B10UFloat: 'rg11b10ufloat-renderable',
 	BGRA8UNormStorage: 'bgra8unorm-storage',
-	Float32Filterable: 'float32-filterable'
+	Float32Filterable: 'float32-filterable',
+	ClipDistances: 'clip-distances',
+	DualSourceBlending: 'dual-source-blending'
 };