Clarified & optimized shader prefix concatenation.

src/renderers/webgl/WebGLProgram.js

@@ -154,16 +154,16 @@ THREE.WebGLProgram = ( function () {
 
 		var program = gl.createProgram();
 
-		var prefix_vertex, prefix_fragment;
+		var prefixVertex, prefixFragment;
 
 		if ( material instanceof THREE.RawShaderMaterial ) {
 
-			prefix_vertex = '';
-			prefix_fragment = '';
+			prefixVertex = '';
+			prefixFragment = '';
 
 		} else {
 
-			prefix_vertex = [
+			prefixVertex = [
 
 				'precision ' + parameters.precision + ' float;',
 				'precision ' + parameters.precision + ' int;',
@@ -270,7 +270,7 @@ THREE.WebGLProgram = ( function () {
 
 			].filter( filterEmptyLine ).join( '\n' );
 
-			prefix_fragment = [
+			prefixFragment = [
 
 				( parameters.bumpMap || parameters.normalMap || parameters.flatShading || material.derivatives ) ? '#extension GL_OES_standard_derivatives : enable' : '',
 
@@ -331,8 +331,11 @@ THREE.WebGLProgram = ( function () {
 
 		}
 
-		var glVertexShader = new THREE.WebGLShader( gl, gl.VERTEX_SHADER, prefix_vertex + vertexShader );
-		var glFragmentShader = new THREE.WebGLShader( gl, gl.FRAGMENT_SHADER, prefix_fragment + fragmentShader );
+		var vertexGlsl = prefixVertex + vertexShader;
+		var fragmentGlsl = prefixFragment + fragmentShader;
+
+		var glVertexShader = new THREE.WebGLShader( gl, gl.VERTEX_SHADER, vertexGlsl );
+		var glFragmentShader = new THREE.WebGLShader( gl, gl.FRAGMENT_SHADER, fragmentGlsl );
 
 		gl.attachShader( program, glVertexShader );
 		gl.attachShader( program, glFragmentShader );