Examples: Fix webgl_buffergeometry_instancing_lambert.

examples/webgl_buffergeometry_instancing_lambert.html

@@ -49,6 +49,8 @@
 			#include <logdepthbuf_pars_vertex>
 			#include <clipping_planes_pars_vertex>
 
+			varying vec2 vHighPrecisionZW;
+
 			void main() {
 
 				#include <uv_vertex>
@@ -76,6 +78,8 @@
 				#include <logdepthbuf_vertex>
 				#include <clipping_planes_vertex>
 
+				vHighPrecisionZW = gl_Position.zw;
+
 			}
 			`;