Made normal map shader consistent with Phong shader.

Transplanted hemisphere specular from Phong. Also had to go back to using varying for view position as computing it in the fragment shader wasn't really working :S

src/extras/ShaderUtils.js

@@ -219,14 +219,13 @@ THREE.ShaderUtils = {
 				"#endif",
 
 				"varying vec3 vWorldPosition;",
+				"varying vec3 vViewPosition;",
 
 				THREE.ShaderChunk[ "shadowmap_pars_fragment" ],
 				THREE.ShaderChunk[ "fog_pars_fragment" ],
 
 				"void main() {",
 
-					"vec3 vViewPosition = cameraPosition - vWorldPosition;",
-
 					"gl_FragColor = vec4( vec3( 1.0 ), uOpacity );",
 
 					"vec3 specularTex = vec3( 1.0 );",
@@ -483,15 +482,16 @@ THREE.ShaderUtils = {
 							"float dotProduct = dot( normal, lVector );",
 							"float hemiDiffuseWeight = 0.5 * dotProduct + 0.5;",
 
-							"hemiDiffuse += uDiffuseColor * mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight );",
+							"vec3 hemiColor = mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight );",
+
+							"hemiDiffuse += uDiffuseColor * hemiColor;",
 
 							// specular (sky light)
 
-							"float hemiSpecularWeight = 0.0;",
 
 							"vec3 hemiHalfVectorSky = normalize( lVector + viewPosition );",
 							"float hemiDotNormalHalfSky = 0.5 * dot( normal, hemiHalfVectorSky ) + 0.5;",
-							"hemiSpecularWeight += specularTex.r * max( pow( hemiDotNormalHalfSky, uShininess ), 0.0 );",
+							"float hemiSpecularWeightSky = specularTex.r * max( pow( hemiDotNormalHalfSky, uShininess ), 0.0 );",
 
 							// specular (ground light)
 
@@ -499,21 +499,23 @@ THREE.ShaderUtils = {
 
 							"vec3 hemiHalfVectorGround = normalize( lVectorGround + viewPosition );",
 							"float hemiDotNormalHalfGround = 0.5 * dot( normal, hemiHalfVectorGround ) + 0.5;",
-							"hemiSpecularWeight += specularTex.r * max( pow( hemiDotNormalHalfGround, uShininess ), 0.0 );",
+							"float hemiSpecularWeightGround = specularTex.r * max( pow( hemiDotNormalHalfGround, uShininess ), 0.0 );",
 
 							"#ifdef PHYSICALLY_BASED_SHADING",
 
+								"float dotProductGround = dot( normal, lVectorGround );",
+
 								// 2.0 => 2.0001 is hack to work around ANGLE bug
 
 								"float specularNormalization = ( uShininess + 2.0001 ) / 8.0;",
 
 								"vec3 schlickSky = uSpecularColor + vec3( 1.0 - uSpecularColor ) * pow( 1.0 - dot( lVector, hemiHalfVectorSky ), 5.0 );",
 								"vec3 schlickGround = uSpecularColor + vec3( 1.0 - uSpecularColor ) * pow( 1.0 - dot( lVectorGround, hemiHalfVectorGround ), 5.0 );",
-								"hemiSpecular += ( schlickSky + schlickGround ) * mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight ) * hemiSpecularWeight * hemiDiffuseWeight * specularNormalization;",
+								"hemiSpecular += hemiColor * specularNormalization * ( schlickSky * hemiSpecularWeightSky * max( dotProduct, 0.0 ) + schlickGround * hemiSpecularWeightGround * max( dotProductGround, 0.0 ) );",
 
 							"#else",
 
-								"hemiSpecular += uSpecularColor * mix( hemisphereLightGroundColor[ i ], hemisphereLightSkyColor[ i ], hemiDiffuseWeight ) * hemiSpecularWeight * hemiDiffuseWeight;",
+								"hemiSpecular += uSpecularColor * hemiColor * ( hemiSpecularWeightSky + hemiSpecularWeightGround ) * hemiDiffuseWeight;",
 
 							"#endif",
 
@@ -622,6 +624,7 @@ THREE.ShaderUtils = {
 				"varying vec2 vUv;",
 
 				"varying vec3 vWorldPosition;",
+				"varying vec3 vViewPosition;",
 
 				THREE.ShaderChunk[ "skinning_pars_vertex" ],
 				THREE.ShaderChunk[ "shadowmap_pars_vertex" ],
@@ -711,6 +714,7 @@ THREE.ShaderUtils = {
 					//
 
 					"vWorldPosition = mPosition.xyz;",
+					"vViewPosition = -mvPosition.xyz;",
 
 					// shadows