Update WebGLRenderer.html

docs/api/renderers/WebGLRenderer.html

@@ -175,11 +175,17 @@
 		Return a [page:Boolean] true if the context supports vertex textures.
 		</div>
 
+		<h3>[method:number getPixelRatio]()</h3>
+		<div>Returns current device pixel ratio used.</div>
+
+		<h3>[method:null setPixelRatio]( [page:number value] )</h3>
+		<div>Sets device pixel ratio. This is usually used for HiDPI device to prevent bluring output canvas.</div>
+
 		<h3>[method:Object getSize]()</h3>
 		<div>Returns an object containing the width and height of the renderer's output canvas, in pixels.</div>
 
 		<h3>[method:null setSize]( [page:Integer width], [page:Integer height], [page:Boolean updateStyle] )</h3>
-		<div>Resizes the output canvas to (width, height), and also sets the viewport to fit that size, starting in (0, 0). Setting updateStyle to true adds explicit pixel units to the output canvas style.</div>
+		<div>Resizes the output canvas to (width, height) with device pixel ratio taken into account, and also sets the viewport to fit that size, starting in (0, 0). Setting updateStyle to true adds explicit pixel units to the output canvas style.</div>
 
 		<h3>[method:null setViewport]( [page:Integer x], [page:Integer y], [page:Integer width], [page:Integer height] )</h3>
 		<div>Sets the viewport to render from (x, y) to (x + width, y + height).</div>