Fix crash when removing surface after releasing mouse outside window

src/ofxBaseSurface.cpp

@@ -64,4 +64,9 @@ void ofxBaseSurface::setTexture(ofTexture *texturePtr)
 ofTexture* ofxBaseSurface::getTexture()
 {
     return texture;
+}
+
+ofTexture* ofxBaseSurface::getDefaultTexture()
+{
+    return &defaultTexture;
 }

src/ofxBaseSurface.h

@@ -26,6 +26,7 @@ public:
     void setTexture(ofTexture* texturePtr);
     
     ofTexture* getTexture();
+    ofTexture* getDefaultTexture();
     
 protected:
     ofMesh mesh;

src/ofxProjectionEditor.cpp

@@ -68,8 +68,16 @@ void ofxProjectionEditor::update(ofEventArgs &args)
     // update surface if one of the joints is being dragged
     for ( int i=0; i<joints.size(); i++ ) {
         if ( joints[i]->isDragged() || joints[i]->isSelected() ) {
-            // update vertex to new location
-            surfaceManager->getSelectedSurface()->setVertex(i, joints[i]->position);
+            
+            if ( surfaceManager->getSelectedSurface() != NULL ) {
+                // update vertex to new location
+                surfaceManager->getSelectedSurface()->setVertex(i, joints[i]->position);
+            } else {
+                // clear joints if there is no surface selected
+                // as the remove selected surface in the surface manager
+                // is not supposed to access joints here
+                joints.clear();
+            }
             break;
         }
     }