From 12341bf26c962eec2cd6ff683c11bf9fc2ad826c Mon Sep 17 00:00:00 2001
From: Val Erastov <xibyte@gmail.com>
Date: Tue, 30 Oct 2018 22:54:46 -0700
Subject: [PATCH] store coordinate system for a shell and use to derive
 coordinate system of its faces

---
 web/app/cad/model/mface.js             | 7 +++++--
 web/app/cad/model/mopenFace.js         | 1 +
 web/app/cad/model/mshell.js            | 4 +++-
 web/app/cad/scene/wrappers/entityIO.js | 5 +++--
 web/app/math/l3space.js                | 8 ++++----
 5 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/web/app/cad/model/mface.js b/web/app/cad/model/mface.js
index 69a3ce79..595f68fc 100644
--- a/web/app/cad/model/mface.js
+++ b/web/app/cad/model/mface.js
@@ -47,8 +47,11 @@ export class MFace extends MObject {
   evalCSys() {
     if (!this._csys) {
       if (this.isPlaneBased) {
-        let [x, y, z] = this.surface.simpleSurface.basis();
-        let origin = z.multiply(this.surface.simpleSurface.w);
+        let alignCsys = (this.shell && this.shell.csys) || CSys.ORIGIN;
+        let [x, y, z] = BasisForPlane(this.surface.simpleSurface.normal, alignCsys.y, alignCsys.z);
+        let proj = z.dot(alignCsys.origin);
+        proj -= this.surface.simpleSurface.w;
+        let origin  = alignCsys.origin.minus(z.multiply(proj));
         this._csys = new CSys(origin, x, y, z);
       } else {
         let origin = this.surface.southWestPoint();
diff --git a/web/app/cad/model/mopenFace.js b/web/app/cad/model/mopenFace.js
index 07ed97d7..5a1fe3c0 100644
--- a/web/app/cad/model/mopenFace.js
+++ b/web/app/cad/model/mopenFace.js
@@ -6,6 +6,7 @@ export class MOpenFaceShell extends MShell {
   constructor(surfacePrototype, csys) {
     super();
     this.surfacePrototype = surfacePrototype;
+    this.csys = csys;
     this.faces.push(new MFace(this.id + '/SURFACE', this, 
       surfacePrototype.boundTo([], 100, 100), csys));
   }
diff --git a/web/app/cad/model/mshell.js b/web/app/cad/model/mshell.js
index 7a29ceff..021283c4 100644
--- a/web/app/cad/model/mshell.js
+++ b/web/app/cad/model/mshell.js
@@ -2,6 +2,7 @@ import {MObject} from './mobject';
 import {MBrepFace, MFace} from './mface';
 import {MEdge} from './medge';
 import {MVertex} from './mvertex';
+import CSys from '../../math/csys';
 
 export class MShell extends MObject {
 
@@ -18,9 +19,10 @@ export class MShell extends MObject {
 
 export class MBrepShell extends MShell {
 
-  constructor(shell) {
+  constructor(shell, csys) {
     super();
     this.brepShell = shell;
+    this.csys = csys || CSys.ORIGIN;
     
     let faceCounter = 0;
     let edgeCounter = 0;
diff --git a/web/app/cad/scene/wrappers/entityIO.js b/web/app/cad/scene/wrappers/entityIO.js
index a6e4c2d7..314e1d9d 100644
--- a/web/app/cad/scene/wrappers/entityIO.js
+++ b/web/app/cad/scene/wrappers/entityIO.js
@@ -1,7 +1,8 @@
 import {readBrep} from '../../../brep/io/brepIO';
 import {MBrepShell} from '../../model/mshell';
+import CSys from '../../../math/csys';
 
-export function readShellEntityFromJson(data, consumed) {
+export function readShellEntityFromJson(data, consumed, csys) {
   
   let refIndex = indexFacesByRef(consumed);
 
@@ -15,7 +16,7 @@ export function readShellEntityFromJson(data, consumed) {
       }
     }
   }
-  return new MBrepShell(shell);  
+  return new MBrepShell(shell, csys);  
 }
 
 function indexFacesByRef(shells) {
diff --git a/web/app/math/l3space.js b/web/app/math/l3space.js
index 50aa930e..78e20e1e 100644
--- a/web/app/math/l3space.js
+++ b/web/app/math/l3space.js
@@ -262,12 +262,12 @@ Matrix3.rotateMatrix = function(angle, axis, pivot, matrix) {
   return m;
 };
 
-function BasisForPlane(normal) {
+function BasisForPlane(normal, alignY = AXIS.Y, alignZ = AXIS.Z) {
   let alignPlane, x, y;
-  if (Math.abs(normal.dot(AXIS.Y)) < 0.5) {
-    alignPlane = normal.cross(AXIS.Y);
+  if (Math.abs(normal.dot(alignY)) < 0.5) {
+    alignPlane = normal.cross(alignY);
   } else {
-    alignPlane = normal.cross(AXIS.Z);
+    alignPlane = normal.cross(alignZ);
   }
   y = alignPlane.cross(normal);
   x = y.cross(normal);