Add cap support to CreateCylinder

See https://forum.babylonjs.com/t/meshbuilder-cap-parameter-for-cylinder-extrudepolygon-sides-parameter-for-box/2959/4

src/Meshes/Builders/cylinderBuilder.ts

@@ -4,7 +4,7 @@ import { VertexData } from "../mesh.vertexData";
 import { Scene } from "../../scene";
 import { Nullable } from "../../types";
 
-VertexData.CreateCylinder = function(options: { height?: number, diameterTop?: number, diameterBottom?: number, diameter?: number, tessellation?: number, subdivisions?: number, arc?: number, faceColors?: Color4[], faceUV?: Vector4[], hasRings?: boolean, enclose?: boolean, sideOrientation?: number, frontUVs?: Vector4, backUVs?: Vector4 }): VertexData {
+VertexData.CreateCylinder = function(options: { height?: number, diameterTop?: number, diameterBottom?: number, diameter?: number, tessellation?: number, subdivisions?: number, arc?: number, faceColors?: Color4[], faceUV?: Vector4[], hasRings?: boolean, enclose?: boolean, cap?: number, sideOrientation?: number, frontUVs?: Vector4, backUVs?: Vector4 }): VertexData {
     var height: number = options.height || 2;
     var diameterTop: number = (options.diameterTop === 0) ? 0 : options.diameterTop || options.diameter || 1;
     var diameterBottom: number = (options.diameterBottom === 0) ? 0 : options.diameterBottom || options.diameter || 1;
@@ -12,6 +12,7 @@ VertexData.CreateCylinder = function(options: { height?: number, diameterTop?: n
     var subdivisions: number = options.subdivisions || 1;
     var hasRings: boolean = options.hasRings ? true : false;
     var enclose: boolean = options.enclose ? true : false;
+    var cap = options.cap || Mesh.CAP_ALL;
     var arc: number = options.arc && (options.arc <= 0 || options.arc > 1) ? 1.0 : options.arc || 1.0;
     var sideOrientation: number = (options.sideOrientation === 0) ? 0 : options.sideOrientation || VertexData.DEFAULTSIDE;
     var faceUV: Vector4[] = options.faceUV || new Array<Vector4>(3);
@@ -235,9 +236,13 @@ VertexData.CreateCylinder = function(options: { height?: number, diameterTop?: n
         }
     };
 
-    // add caps to geometry
-    createCylinderCap(false);
-    createCylinderCap(true);
+    // add caps to geometry based on cap parameter
+    if ((cap === Mesh.CAP_START)
+        || (cap === Mesh.CAP_ALL))
+        createCylinderCap(false);
+    if ((cap === Mesh.CAP_END)
+        || (cap === Mesh.CAP_ALL))
+        createCylinderCap(true);
 
     // Sides
     VertexData._ComputeSides(sideOrientation, positions, indices, normals, uvs, options.frontUVs, options.backUVs);
@@ -291,6 +296,7 @@ export class CylinderBuilder {
      * * The parameter `subdivisions` sets the number of rings along the cylinder height (positive integer, default 1).
      * * The parameter `hasRings` (boolean, default false) makes the subdivisions independent from each other, so they become different faces.
      * * The parameter `enclose`  (boolean, default false) adds two extra faces per subdivision to a sliced cylinder to close it around its height axis.
+     * * The parameter `cap` sets the way the cylinder is capped. Possible values : BABYLON.Mesh.NO_CAP, BABYLON.Mesh.CAP_START, BABYLON.Mesh.CAP_END, BABYLON.Mesh.CAP_ALL (default).
      * * The parameter `arc` (float, default 1) is the ratio (max 1) to apply to the circumference to slice the cylinder.
      * * You can set different colors and different images to each box side by using the parameters `faceColors` (an array of n Color3 elements) and `faceUV` (an array of n Vector4 elements).
      * * The value of n is the number of cylinder faces. If the cylinder has only 1 subdivisions, n equals : top face + cylinder surface + bottom face = 3
@@ -309,7 +315,7 @@ export class CylinderBuilder {
      * @returns the cylinder mesh
      * @see https://doc.babylonjs.com/how_to/set_shapes#cylinder-or-cone
      */
-    public static CreateCylinder(name: string, options: { height?: number, diameterTop?: number, diameterBottom?: number, diameter?: number, tessellation?: number, subdivisions?: number, arc?: number, faceColors?: Color4[], faceUV?: Vector4[], updatable?: boolean, hasRings?: boolean, enclose?: boolean, sideOrientation?: number, frontUVs?: Vector4, backUVs?: Vector4 }, scene: any): Mesh {
+    public static CreateCylinder(name: string, options: { height?: number, diameterTop?: number, diameterBottom?: number, diameter?: number, tessellation?: number, subdivisions?: number, arc?: number, faceColors?: Color4[], faceUV?: Vector4[], updatable?: boolean, hasRings?: boolean, enclose?: boolean, cap?: number, sideOrientation?: number, frontUVs?: Vector4, backUVs?: Vector4 }, scene: any): Mesh {
         var cylinder = new Mesh(name, scene);
 
         options.sideOrientation = Mesh._GetDefaultSideOrientation(options.sideOrientation);
@@ -321,4 +327,4 @@ export class CylinderBuilder {
 
         return cylinder;
     }
-}
+}