diff --git a/examples/lesson02.js b/examples/lesson02.js
index 3629aa7..9cad745 100644
--- a/examples/lesson02.js
+++ b/examples/lesson02.js
@@ -14,6 +14,7 @@ webgl.canvas = document;
 const canvas = document.createElement('canvas');
 const frame = document.requestAnimationFrame;
 
+webgl.init(); // optional
 let gl;
 
 document.title = 'Lesson02';
diff --git a/index.d.ts b/index.d.ts
index dd100d1..98c218c 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -60,6 +60,8 @@ declare module "webgl-raub" {
 	export default webgl;
 	
 	export interface WebGL {
+		init: ()=> void;
+		
 		contextAttributes: TContextAttributes;
 		getContextAttributes: () => TContextAttributes;
 		
@@ -132,11 +134,6 @@ declare module "webgl-raub" {
 			srcOffset?: number,
 			length?: number,
 		) => void;
-		bufferSubData: (
-			target: number,
-			offset: number,
-			arr: Float32Array,
-		) => void;
 		copyBufferSubData: (
 			readTarget: number,
 			writeTarget: number,
diff --git a/js/webgl.js b/js/webgl.js
index 8beb689..b1e4230 100644
--- a/js/webgl.js
+++ b/js/webgl.js
@@ -15,10 +15,6 @@ const unfoldBool = (x) => typeof x === 'boolean' ? (x ? 1 : 0) : x;
 if (!gl.__isInited) {
 	gl.__isInited = true;
 	
-	if (!global.__skipGlewInit) {
-		gl.init();
-	}
-	
 	// WebGL constructors
 	gl.WebGLRenderingContext = function WebGLRenderingContext(_) { this._ = _; };
 	gl.WebGLProgram = function WebGLProgram(_) { this._ = _; };
diff --git a/test/index.test.js b/test/index.test.js
index 5bfaeb7..b69fff2 100644
--- a/test/index.test.js
+++ b/test/index.test.js
@@ -1,6 +1,5 @@
 'use strict';
 
-global.__skipGlewInit = true;
 const webgl = require('..');
 
 
diff --git a/test/setup.js b/test/setup.js
index 287b0e3..cc1451c 100644
--- a/test/setup.js
+++ b/test/setup.js
@@ -1,5 +1,3 @@
 'use strict';
 
-global.__skipGlewInit = true;
-
 module.exports = async () => require('..');