add taper optional param to threads

src/mesh/api.js

@@ -876,11 +876,12 @@ let add = {
 
     threads() {
         worker.model_gen_threads({
-            height: 50,
+            height: 25,
-            radius: 25,
+            radius: 10,
-            turns: 5,
+            turns: 10,
-            depth: 3,
+            depth: 1,
-            steps: 50
+            steps: 75,
+            taper: true
         }).then(verts => {
             const nmdl = new mesh.model({ file: "gear", mesh: verts.toFloat32() });
             const ngrp = group.new([ nmdl ]);

src/mesh/tool.js

@@ -823,7 +823,7 @@ mesh.tool = class MeshTool {
         return { gear, pitch };
     }
 
-    generateThreads(height, radius, turns, depth, steps) {
+    generateThreads(height, radius, turns, depth, steps, taper) {
         let verts = [];
         let zstep = height / turns;
         let rstep = (Math.PI * 2) / steps;
@@ -839,12 +839,12 @@ mesh.tool = class MeshTool {
                 let itern = iter + steps;
                 let rm = radius - depth;
                 let rx = true &&
-                    iter < mute_min ? rm + (iter / mute_min) * depth :
+                    // iter < mute_min ? rm + (iter / mute_min) * depth :
-                    iter > mute_max ? rm + ((iter_max - iter) / mute_min) * depth :
+                    taper && iter > mute_max ? rm + ((iter_max - iter) / mute_min) * depth :
                     radius;
                 let rxt = true &&
-                    itern < mute_min ? rm + (itern / mute_min) * depth :
+                    // itern < mute_min ? rm + (itern / mute_min) * depth :
-                    itern > mute_max ? rm + ((iter_max - itern) / mute_min) * depth :
+                    taper && itern > mute_max ? rm + ((iter_max - itern) / mute_min) * depth :
                     radius;
                 let angle0 = rstep * step - Math.PI/2;
                 let z0 = (zstep * turn) + (z2step * step);

src/mesh/work.js

@@ -459,7 +459,7 @@ let model = {
     },
 
     gen_threads(data, send) {
-        let { height, radius, turns, depth, steps } = data;
+        let { height, radius, turns, depth, steps, taper } = data;
         let zstep = height / turns;
         height += zstep * 2;
         turns += 2;
@@ -469,6 +469,7 @@ let model = {
             turns,
             depth,
             steps,
+            taper
         );
         // return send.done(verts);
         let s0 = model.split({