Clear the canvas before starting to draw (#27092)

Co-authored-by: Antonio Pisano <apisano@wu.ac.at>

examples/jsm/interactive/HTMLMesh.js

@@ -501,6 +501,8 @@ function html2canvas( element ) {
 
 	// console.time( 'drawElement' );
 
+	context.clearRect(0, 0, canvas.width, canvas.height);
+
 	drawElement( element );
 
 	// console.timeEnd( 'drawElement' );