Forcing shader precision for ints to address Issue #3146. Also enabling...

Forcing shader precision for ints to address Issue #3146. Also enabling program log to determine cause of linking errors

src/renderers/WebGLRenderer.js

@@ -6247,6 +6247,7 @@ THREE.WebGLRenderer = function ( parameters ) {
 		var prefix_vertex = [
 
 			"precision " + _precision + " float;",
+			"precision " + _precision + " int;",
 
 			customDefines,
 
@@ -6349,6 +6350,7 @@ THREE.WebGLRenderer = function ( parameters ) {
 		var prefix_fragment = [
 
 			"precision " + _precision + " float;",
+			"precision " + _precision + " int;",
 
 			( parameters.bumpMap || parameters.normalMap ) ? "#extension GL_OES_standard_derivatives : enable" : "",
 
@@ -6406,7 +6408,7 @@ THREE.WebGLRenderer = function ( parameters ) {
 		if ( !_gl.getProgramParameter( program, _gl.LINK_STATUS ) ) {
 
 			console.error( "Could not initialise shader\n" + "VALIDATE_STATUS: " + _gl.getProgramParameter( program, _gl.VALIDATE_STATUS ) + ", gl error [" + _gl.getError() + "]" );
-
+			console.error( "Program Info Log: " + _gl.getProgramInfoLog( program ) );
 		}
 
 		// clean up