Add 3d model short command

Sources/Generator/Generators/PageContentGenerator.swift

@@ -104,6 +104,7 @@ struct PageContentGenerator {
         // For svg with custom area: ![x,y,width,height](file.svg)
         // For downloads: ![download](file1, text1; file2, text2, (download-name); ...)
         // For a simple box: ![box](title;body)
+        // For 3D models: ![3d](file;Description)
         // A fancy page link: ![page](page_id)
         // External pages: ![external](url1, text1; url2, text2, ...)
         guard let fileAndTitle = markdown.between(first: "](", andLast: ")").removingPercentEncoding else {
@@ -147,6 +148,8 @@ struct PageContentGenerator {
             return handleSimpleBox(page: page, content: content)
         case .pageLink:
             return handlePageLink(page: page, language: language, pageId: content)
+        case .model3d:
+            return handle3dModel(page: page, content: content)
         }
     }
 
@@ -399,4 +402,26 @@ struct PageContentGenerator {
         // We assume that the thumbnail images are already required by overview pages.
         return factory.pageLink.generate(content)
     }
+
+    private func handle3dModel(page: Element, content: String) -> String {
+        let parts = content.components(separatedBy: ";")
+        guard parts.count > 1 else {
+            results.warning("Invalid 3d model specification", source: page.path)
+            return ""
+        }
+        let file = parts[0]
+        guard file.hasSuffix(".glb") else {
+            results.warning("Invalid 3d model file \(file) (must be .glb)", source: page.path)
+            return ""
+        }
+
+        // Ensure that file is available
+        let filePath = page.pathRelativeToRootForContainedInputFile(file)
+        results.require(file: filePath, source: page.path)
+
+        let description = parts.dropFirst().joined(separator: ";")
+        return """
+        <model-viewer alt="\(description)" src="\(file)" ar shadow-intensity="1" camera-controls touch-action="pan-y"></model-viewer>
+        """
+    }
 }

Sources/Generator/Generators/ShorthandMarkdownKey.swift

@@ -26,4 +26,9 @@ enum ShorthandMarkdownKey: String {
      A pretty link to another page on the site.
      */
     case pageLink = "page"
+
+    /**
+     A 3D model to display
+     */
+    case model3d = "3d"
 }