Fixed vertex normals of CylinderGeometry.

src/extras/geometries/CylinderGeometry.js

@@ -45,21 +45,37 @@ THREE.CylinderGeometry = function ( radiusTop, radiusBottom, height, segmentsRad
 
 	}
 
-	for ( y = 0; y < segmentsY; y ++ ) {
+	var tanTheta = ( radiusBottom - radiusTop ) / height;
+	var na, nb;
 
-		for ( x = 0; x < segmentsX; x ++ ) {
+	for ( x = 0; x < segmentsX; x ++ ) {
+
+		if ( radiusTop !== 0 ) {
+
+			na = this.vertices[ vertices[ 0 ][ x ] ].clone();
+			nb = this.vertices[ vertices[ 0 ][ x + 1 ] ].clone();
+
+		} else {
+
+			na = this.vertices[ vertices[ 1 ][ x ] ].clone();
+			nb = this.vertices[ vertices[ 1 ][ x + 1 ] ].clone();
+
+		}
+		
+		na.setY( Math.sqrt( na.x * na.x + na.z * na.z ) * tanTheta ).normalize();
+		nb.setY( Math.sqrt( nb.x * nb.x + nb.z * nb.z ) * tanTheta ).normalize();
+
+		for ( y = 0; y < segmentsY; y ++ ) {
 
 			var v1 = vertices[ y ][ x ];
 			var v2 = vertices[ y + 1 ][ x ];
 			var v3 = vertices[ y + 1 ][ x + 1 ];
 			var v4 = vertices[ y ][ x + 1 ];
 
-			// FIXME: These normals aren't right for cones.
-
-			var n1 = this.vertices[ v1 ].clone().setY( 0 ).normalize();
-			var n2 = this.vertices[ v2 ].clone().setY( 0 ).normalize();
-			var n3 = this.vertices[ v3 ].clone().setY( 0 ).normalize();
-			var n4 = this.vertices[ v4 ].clone().setY( 0 ).normalize();
+			var n1 = na.clone();
+			var n2 = na.clone();
+			var n3 = nb.clone();
+			var n4 = nb.clone();
 
 			var uv1 = uvs[ y ][ x ].clone();
 			var uv2 = uvs[ y + 1 ][ x ].clone();