Fix for segv on gui start

applications/gui/src/screen.cpp

@@ -337,7 +337,7 @@ void ftl::gui::Screen::draw(NVGcontext *ctx) {
 
 		mImageID = camera_->captureFrame().texture();
 
-		if (imageSize[0] > 0) {
+		if (mImageID < std::numeric_limits<unsigned int>::max() && imageSize[0] > 0) {
 			auto mScale = (screenSize.cwiseQuotient(imageSize).minCoeff());
 			Vector2f scaleFactor = mScale * imageSize.cwiseQuotient(screenSize);
 			Vector2f positionInScreen(0.0f, 0.0f);

components/rgbd-sources/src/middlebury_source.cpp

@@ -194,7 +194,7 @@ void MiddleburySource::_performDisparity() {
 }
 
 bool MiddleburySource::grab(int n, int b) {
-	_performDisparity();
+	//_performDisparity();
 	return true;
 }