diff --git a/src/drone_controller.cc b/src/drone_controller.cc
index 588ac23..f6edfb6 100644
--- a/src/drone_controller.cc
+++ b/src/drone_controller.cc
@@ -2,6 +2,7 @@
 #include "opengl_widget.hh"
 
 #include <QJsonArray>
+#include <QDebug>
 
 
 DroneController::DroneController(const QJsonObject &json)
@@ -99,15 +100,18 @@ void DroneController::seek(int frame) {
 void DroneController::computeCollisions(double sphere_radius) {
 	double sqDist = sphere_radius * sphere_radius * 2;
 	for (int i = 0; i < duration; i++) {
-		for (const Drone &a : drones) {
-			for (const Drone &b : drones) {
+		for (Drone &a : drones) {
+			a.setTo(i);
+			for (Drone &b : drones) {
+				b.setTo(i);
 				if (&a == &b) continue;
 				if (collides(a, b, sqDist)) {
-					emit collision(a.getId(), b.getId(), frame);
+					emit collision(a.getId(), b.getId(), i);
 				}
 			}
 		}
 	}
+	seek(frame);
 }