Removed error dialog when texture file does not exist

xs/src/slic3r/GUI/GLTexture.cpp

@@ -4,6 +4,8 @@
 
 #include <wx/image.h>
 
+#include <boost/filesystem.hpp>
+
 #include <vector>
 #include <algorithm>
 
@@ -27,6 +29,9 @@ bool GLTexture::load_from_file(const std::string& filename, bool generate_mipmap
 {
     reset();
 
+    if (!boost::filesystem::exists(filename))
+        return false;
+
     // Load a PNG with an alpha channel.
     wxImage image;
     if (!image.LoadFile(filename, wxBITMAP_TYPE_PNG))