Add axes w/ rotation sync w/ main model viewer

axes.scad

@@ -0,0 +1,46 @@
+module arrow(length=30, shaft_radius=1, head_radius=2, head_length=5) {
+    cylinder(h=length-head_length, r=shaft_radius, center=false);
+
+    translate([0, 0, length-head_length])
+        cylinder(h=head_length, r1=head_radius, r2=0, center=false);
+}
+
+color("red")
+    rotate([0, 90, 0])
+        arrow();
+
+color("green")
+    rotate([-90, 0, 0])
+        arrow();
+
+color("blue")
+    rotate([0, 0, 90])
+        arrow();
+
+module letter(text)
+    linear_extrude(1) text(text, halign="center", valign="center");
+
+letter_dist = 38;
+union() {
+    color("red")
+        translate([letter_dist, 0, 0])
+            rotate([45, 0, 45])
+                letter("X");
+    color("green")
+        rotate([0, 0, 90])
+            translate([letter_dist, 0, 0])
+                rotate([45, 0, -45])
+                    letter("Y");
+    color("blue")
+        rotate([0, -90, 0])
+            translate([letter_dist, 0, 0])
+                rotate([90+45, 0, 0])
+                    rotate([0, 0, -90])
+                        letter("Z");
+}
+
+color("grey")
+    cube(10, center=true);
+
+color([0, 0, 0, $preview ? 0.05 : 0])
+    sphere(r=43);

src/components/ViewerPanel.tsx

@@ -1,10 +1,7 @@
 // Portions of this file are Copyright 2021 Google LLC, and licensed under GPL2+. See COPYING.
 
-import { CSSProperties, useContext, useRef } from 'react';
+import { CSSProperties, useContext, useEffect, useRef, useState } from 'react';
 import { ModelContext } from './contexts';
-import { StlViewer} from "react-stl-viewer";
-import { ColorPicker } from 'primereact/colorpicker';
-import { defaultModelColor } from '../state/initial-state';
 
 declare global {
   namespace JSX {
@@ -19,34 +16,78 @@ export default function ViewerPanel({className, style}: {className?: string, sty
   if (!model) throw new Error('No model');
 
   const state = model.state;
-  const modelRef = useRef();
+  const modelViewerRef = useRef<any>();
+  const axesViewerRef = useRef<any>();
 
+  for (const ref of [modelViewerRef, axesViewerRef]) {
+    const otherRef = ref === modelViewerRef ? axesViewerRef : modelViewerRef;
+    useEffect(() => {
+      function handleCameraChange(e: any) {
+        if (e.detail.source === 'user-interaction') {
+          const cameraOrbit = ref.current.getCameraOrbit();
+          cameraOrbit.radius = otherRef.current.getCameraOrbit().radius;
+
+          otherRef.current.cameraOrbit = cameraOrbit.toString();
+        }
+      }
+      ref.current.addEventListener('camera-change', handleCameraChange);
+      return () => ref.current.removeEventListener('camera-change', handleCameraChange);
+    }, [ref.current, otherRef.current]);
+  }
+
   return (
     <div className={className}
           style={{
               display: 'flex',
               flexDirection: 'column', 
+              position: 'relative',
               flex: 1, 
               width: '100%',
               ...(style ?? {})
           }}>
-      {(state.output?.displayFileURL || state.output?.outFile && state.output.outFile.name.endsWith('.glb') && state.output?.outFileURL) && (
-            <model-viewer
-              orientation="0deg -90deg 0deg"
-              src={state.output?.displayFileURL ?? state.output?.outFileURL ?? ''}
-              style={{
-                width: '100%',
-                height: '100%',
-              }}
-              environment-image="./skybox-lights.jpg"
-              max-camera-orbit="auto 180deg auto"
-              min-camera-orbit="auto 0deg auto"
-              camera-controls
-              ar
-              ref={(ref: any) => {
-                modelRef.current = ref;
-              }}
-            />
+      <model-viewer
+        orientation="0deg -90deg 0deg"
+        src={state.output?.displayFileURL ?? state.output?.outFileURL ?? ''}
+        style={{
+          width: '100%',
+          height: '100%',
+        }}
+        environment-image="./skybox-lights.jpg"
+        max-camera-orbit="auto 180deg auto"
+        min-camera-orbit="auto 0deg auto"
+        camera-controls
+        ar
+        ref={modelViewerRef}
+      >
+        <span slot="progress-bar"></span>
+      </model-viewer>
+      {state.view.showAxes && (
+        <model-viewer
+                orientation="0deg -90deg 0deg"
+                src="./axes.glb"
+                style={{
+                  position: 'absolute',
+                  bottom: 0,
+                  right: 0,
+                  zIndex: 10,
+                  height: '200px',
+                  width: '200px',
+                }}
+                loading="eager"
+                interpolation-decay="0"
+                environment-image="./skybox-lights.jpg"
+                max-camera-orbit="auto 180deg auto"
+                min-camera-orbit="auto 0deg auto"
+                orbit-sensitivity="5"
+                interaction-prompt="none"
+                disable-zoom
+                camera-controls="false"
+                disable-tap 
+                disable-pan
+                ref={axesViewerRef}
+        >
+          <span slot="progress-bar"></span>
+        </model-viewer>
       )}
     </div>
   )