Update 3DM Viewer

Author: GitHubDragonFly

viewers/templates/3DM Viewer.html

@@ -343,7 +343,7 @@
         <button title="URL of the remote 3DM model" id="btn_url" onclick="show_url();" style="background-color: transparent; min-width: 34px;">URL</button>
         <input type="file" title="Browse Local Files" id="file_input" onchange="init();" accept=".3dm, image/png, image/jpeg, image/bmp, image/gif, image/svg+xml, image/webp" multiple />
         <label for="file_image_input" title="Background Image" style="color: #553801;">BGND</label>
-        <input type="file" title="Background Image" id="file_image_input" accept=".exr, .hdr, image/png, image/jpeg, image/bmp, image/gif, image/svg+xml, image/webp" onchange="set_scene_image()" disabled />
+        <input type="file" title="Background Image" id="file_image_input" accept=".exr, .hdr, .ktx2, image/png, image/jpeg, image/bmp, image/gif, image/svg+xml, image/webp" onchange="set_scene_image()" disabled />
         <button title="Toggle Gradient Color Background" id="btn_bgnd_linear_gradient" onclick="set_bgnd_linear_gradient();" style="background-color: transparent; color: blue;" disabled>G</button>
         <button title="Model Opacity - double click to enable/disable" id="btn_dc_opacity" class="dropdown" style="text-align: center; border: 1px solid blue; -webkit-border-radius: 3px; border-radius: 3px;" ondblclick="set_opacity();" onclick="show_hide_dropdown_opacity();">O
           <div id="dc_opacity" class="dropdown-content" style="display: none;" onfocusout="if (enable_opacity === true) hide_dropdown_opacity();">
@@ -1793,7 +1793,7 @@
 
           let fn_uc = fii.name.toUpperCase();
 
-          if (fii.type.startsWith('image/') && ! (fn_uc.endsWith('.SVG') || fn_uc.endsWith('.EXR') || fn_uc.endsWith('.HDR'))) {
+          if (fii.type.startsWith('image/') && ! (fn_uc.endsWith('.SVG') || fn_uc.endsWith('.KTX2') || fn_uc.endsWith('.EXR') || fn_uc.endsWith('.HDR'))) {
             hdrJPGLoader.load( URL.createObjectURL( fii ) , async function( texture ) {
               URL.revokeObjectURL( fii );