添加关照、全局等高线、修改图层问题

static/sdk/three/jsm/renderers/webgl/utils/WebGLExtensions.js

@@ -0,0 +1,36 @@
+class WebGLExtensions {
+
+	constructor( backend ) {
+
+		this.backend = backend;
+
+		this.gl = this.backend.gl;
+		this.availableExtensions = this.gl.getSupportedExtensions();
+
+		this.extensions = {};
+
+	}
+
+	get( name ) {
+
+		let extension = this.extensions[ name ];
+
+		if ( extension === undefined ) {
+
+			extension = this.gl.getExtension( name );
+
+		}
+
+		return extension;
+
+	}
+
+	has( name ) {
+
+		return this.availableExtensions.includes( name );
+
+	}
+
+}
+
+export default WebGLExtensions;