From a6cedbc429fa504e09859598d04c5b180187c5c4 Mon Sep 17 00:00:00 2001
From: David Allemang <david.allemang@kitware.com>
Date: Mon, 6 Jul 2026 14:15:04 -0400
Subject: [PATCH] zoom issue.

---
 engine.js  | 6 +++++-
 index.html | 8 ++++----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/engine.js b/engine.js
index f1921e2b..743647c9 100644
--- a/engine.js
+++ b/engine.js
@@ -381,9 +381,13 @@ export class Engine {
                 this.canvas.height = Math.max(this.canvas.height, targetH);
             }
 
-            gl.viewport(0, 0, targetW, targetH);
+            const viewportY = this.canvas.height - targetH;
+            gl.viewport(0, viewportY, targetW, targetH);
+            gl.enable(gl.SCISSOR_TEST);
+            gl.scissor(0, viewportY, targetW, targetH);
             gl.clearColor(0.0, 0.0, 0.0, 0.0);
             gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
+            gl.disable(gl.SCISSOR_TEST);
 
             const aspect = rect.width / rect.height;
             const viewProj = diorama.updateMatrices(aspect);
diff --git a/index.html b/index.html
index d724a94f..578b7de2 100644
--- a/index.html
+++ b/index.html
@@ -40,8 +40,8 @@
 
     <h2>Static Sub-Figures</h2>
     <div style="display: grid; grid-template-columns: 1fr 1fr;">
-        <div class="figure" id="demo-2"></div>
-        <div class="figure" id="demo-3"></div>
+        <div class="figure" id="demo-top-static"></div>
+        <div class="figure" id="demo-iso"></div>
     </div>
 
     <div id="atlas-container" style="position: absolute; right: 0; top: 0"></div>
@@ -66,14 +66,14 @@
                 p 0 -2 0 piston facing=north extended=false
             `)
             const f_static = new WorldFrame(w_static);
-            const d_static_top = new Diorama('demo-2', f_static, () => engine.requestRender());
+            const d_static_top = new Diorama('demo-top-static', f_static, () => engine.requestRender());
             d_static_top.radius = 5;
             d_static_top.theta = 180;
             d_static_top.phi = 90;
             d_static_top.centerView();
             d_static_top.saveState();
             engine.addDiorama(d_static_top)
-            const d_static_iso = new Diorama('demo-3', f_static, () => engine.requestRender());
+            const d_static_iso = new Diorama('demo-iso', f_static, () => engine.requestRender());
             d_static_iso.radius = 5;
             d_static_iso.centerView();
             d_static_iso.saveState();