Add snapping to projection surface editor

example/bin/data/surfaces.xml

@@ -36,16 +36,16 @@
     <surface>
         <vertices>
             <vertex>
-                <x>160.000000000</x>
-                <y>28.000000000</y>
+                <x>24.396121979</x>
+                <y>259.170288086</y>
             </vertex>
             <vertex>
-                <x>260.000000000</x>
-                <y>209.000000000</y>
+                <x>250.000000000</x>
+                <y>34.000000000</y>
             </vertex>
             <vertex>
-                <x>42.000000000</x>
-                <y>206.000000000</y>
+                <x>214.630920410</x>
+                <y>282.926849365</y>
             </vertex>
         </vertices>
         <texCoords>

src/ofxBaseJoint.cpp

@@ -64,6 +64,11 @@ void ofxBaseJoint::unselect()
     selected = false;
 }
 
+void ofxBaseJoint::setClickDistance(ofVec2f newClickDistance)
+{
+    clickDistance = newClickDistance;
+}
+
 bool ofxBaseJoint::isDragged()
 {
     return bDrag;

src/ofxBaseJoint.h

@@ -23,6 +23,7 @@ public:
     void stopDrag();
     void select();
     void unselect();
+    void setClickDistance(ofVec2f newClickDistance);
     bool isDragged();
     bool isSelected();
     

src/ofxProjectionEditor.cpp

@@ -4,6 +4,7 @@ ofxProjectionEditor::ofxProjectionEditor()
 {
     surfaceManager = NULL;
     bShiftKeyDown = false;
+    fSnapDistance = 10.0f;
     enable();
 }
 
@@ -84,7 +85,36 @@ void ofxProjectionEditor::draw()
 
 void ofxProjectionEditor::mouseDragged(ofMouseEventArgs &args)
 {
-    //
+    ofVec2f mousePosition = ofVec2f(args.x, args.y);
+    
+    // Collect all vertices of the projection surfaces
+    vector<ofVec3f*> allVertices;
+    for ( int i=0; i<surfaceManager->size(); i++ ) {
+        ofxBaseSurface* surface = surfaceManager->getSurface(i);
+        if ( surface == surfaceManager->getSelectedSurface() ) {
+            continue; // Don't add vertices of selected surface
+        }
+        for ( int j=0; j<surface->getVertices().size(); j++ ) {
+            allVertices.push_back(&surface->getVertices()[j]);
+        }
+    }
+    
+    // Snap currently dragged joint to nearest vertex
+    for ( int i=0; i<joints.size(); i++ ) {
+        if ( joints[i]->isDragged() ) {
+            // Snap it!
+            for ( int j=0; j<allVertices.size(); j++ ) {
+                float distance = mousePosition.distance(*allVertices[j]);
+                //cout << "distance: " << distance << endl;
+                if ( distance < fSnapDistance ) {
+                    joints[i]->position = *allVertices[j];
+                    ofVec2f clickDistance = joints[i]->position - ofVec2f(args.x, args.y);
+                    joints[i]->setClickDistance(clickDistance);
+                    break;
+                }
+            }
+        }
+    }
 }
 
 void ofxProjectionEditor::keyPressed(ofKeyEventArgs &args)
@@ -205,6 +235,11 @@ void ofxProjectionEditor::moveSelection(ofVec2f by)
     }
 }
 
+void ofxProjectionEditor::setSnapDistance(float newSnapDistance)
+{
+    fSnapDistance = newSnapDistance;
+}
+
 ofxCircleJoint* ofxProjectionEditor::hitTestJoints(ofVec2f pos)
 {
     for ( int i=0; i<joints.size(); i++ ) {

src/ofxProjectionEditor.h

@@ -35,12 +35,14 @@ public:
     void stopDragJoints();
     void updateVertices();
     void moveSelection(ofVec2f by);
+    void setSnapDistance(float newSnapDistance);
     ofxCircleJoint* hitTestJoints(ofVec2f pos);
     
 private:
     ofxSurfaceManager* surfaceManager;
     vector<ofxCircleJoint*> joints;
     bool bShiftKeyDown;
+    float fSnapDistance;
     
     void drawJoints();
 };