fixed bug that crashes with empty video slot

1 files changed, 7 insertions, 0 deletions

diff --git a/rotord/graph.cpp b/rotord/graph.cpp
index a6e1603..e3b0669 100644
--- a/rotord/graph.cpp
+++ b/rotord/graph.cpp
@@ -32,6 +32,13 @@ bool Graph::signal_render(string &signal_xml,const float framerate) {
 	 return false;
 }
 bool Graph::video_render(const string &output_filename,const string &audio_filename,const float framerate,float& progress) {
+	vector<Node*> loaders=find_nodes("video_loader");
+	for (auto i:loaders){
+		if (!dynamic_cast<Video_loader*>(i)->isLoaded) {
+			cerr<<"Rotor: all loaders must be populated before rendering"<<endl;
+			return false;
+		}
+	}
 	if (find_node("video_output")) {
 		Video_output *video_output=dynamic_cast<Video_output*>(find_node("video_output"));
 		return video_output->render(duration,framerate,output_filename,audio_filename,progress,outW,outH);