diff --git a/trap/animation_renderer.py b/trap/animation_renderer.py
index 6f34dd0..8441b9f 100644
--- a/trap/animation_renderer.py
+++ b/trap/animation_renderer.py
@@ -22,6 +22,7 @@ import math
 from pyglet import shapes
 
 from PIL import Image
+import json
 
 from trap.frame_emitter import DetectionState, Frame, Track
 from trap.preview_renderer import DrawnTrack, PROJECTION_IMG, PROJECTION_MAP
@@ -115,6 +116,26 @@ class AnimationRenderer:
 
         ]
 
+        self.debug_points = []
+        # print(self.config.debug_points_file)
+        if self.config.debug_points_file:
+            with self.config.debug_points_file.open('r') as fp:
+                img_points = np.array(json.load(fp))
+                # to place points accurate I used a 2160p image, but during calibration and
+                # prediction I use(d) a 1440p image, so convert points to different space:
+                img_points = np.array(img_points)
+                # first undistort the points so that lines are actually straight
+                undistorted_img_points = cv2.undistortPoints(np.array([img_points]).astype('float32'), self.config.camera.mtx, self.config.camera.dist, None, self.config.camera.newcameramtx)
+                dst_img_points = cv2.perspectiveTransform(np.array(undistorted_img_points), self.config.camera.H)
+                if dst_img_points.shape[1:] == (1,2):
+                    dst_img_points = np.reshape(dst_img_points, (dst_img_points.shape[0], 2))
+            
+                self.debug_points = [
+                    pyglet.shapes.Circle(p[0], self.window.height - p[1], 3, color=(255,0,0,255), batch=self.batch_overlay) for p in dst_img_points
+                ]
+                
+        
+
         
         self.init_shapes()
 
diff --git a/trap/config.py b/trap/config.py
index d551f0e..77e9a09 100644
--- a/trap/config.py
+++ b/trap/config.py
@@ -326,3 +326,9 @@ render_parser.add_argument("--render-url",
                     type=str,
                     default=None)
 
+
+render_parser.add_argument("--debug-points-file",
+                           help="A json file with points to test projection/homography etc.",
+                           type=Path,
+                           required=False,
+                           )
\ No newline at end of file
diff --git a/trap/frame_emitter.py b/trap/frame_emitter.py
index b3a5c81..c777239 100644
--- a/trap/frame_emitter.py
+++ b/trap/frame_emitter.py
@@ -215,7 +215,6 @@ class FrameEmitter:
                 i = self.config.video_offset
 
 
-
             # if '-' in video_path.path().stem:
             #     path_stem = video_path.stem[:video_path.stem.rfind('-')]
             # else:
diff --git a/trap/preview_renderer.py b/trap/preview_renderer.py
index a5b31cf..4ef4094 100644
--- a/trap/preview_renderer.py
+++ b/trap/preview_renderer.py
@@ -111,20 +111,21 @@ class DrawnTrack:
         if len(self.coords) > len(self.drawn_positions):
             self.drawn_positions.extend(self.coords[len(self.drawn_positions):])
 
-        for a, drawn_prediction in enumerate(self.drawn_predictions):
-            for i, pos in enumerate(drawn_prediction):
-                # TODO: this should be done in polar space starting from origin (i.e. self.drawn_posision[-1])
-                decay = max(3, (18/i) if i else 10) # points further away move with more delay
-                decay = 6
-                origin = self.drawn_positions[-1]
-                drawn_r, drawn_angle = relativePointToPolar(  origin, drawn_prediction[i])
-                pred_r, pred_angle = relativePointToPolar(origin, self.pred_coords[a][i])
-                r = exponentialDecay(drawn_r, pred_r, decay, dt)
-                angle = exponentialDecay(drawn_angle, pred_angle, decay, dt)
-                x, y = relativePolarToPoint(origin, r, angle)
-                self.drawn_predictions[a][i] = int(x), int(y)
-                # self.drawn_predictions[i][0] = int(exponentialDecay(self.drawn_predictions[i][0], self.pred_coords[i][0], decay, dt))
-                # self.drawn_predictions[i][1] = int(exponentialDecay(self.drawn_predictions[i][1], self.pred_coords[i][1], decay, dt))
+        if len(self.pred_coords):
+            for a, drawn_prediction in enumerate(self.drawn_predictions):
+                for i, pos in enumerate(drawn_prediction):
+                    # TODO: this should be done in polar space starting from origin (i.e. self.drawn_posision[-1])
+                    decay = max(3, (18/i) if i else 10) # points further away move with more delay
+                    decay = 6
+                    origin = self.drawn_positions[-1]
+                    drawn_r, drawn_angle = relativePointToPolar(  origin, drawn_prediction[i])
+                    pred_r, pred_angle = relativePointToPolar(origin, self.pred_coords[a][i])
+                    r = exponentialDecay(drawn_r, pred_r, decay, dt)
+                    angle = exponentialDecay(drawn_angle, pred_angle, decay, dt)
+                    x, y = relativePolarToPoint(origin, r, angle)
+                    self.drawn_predictions[a][i] = int(x), int(y)
+                    # self.drawn_predictions[i][0] = int(exponentialDecay(self.drawn_predictions[i][0], self.pred_coords[i][0], decay, dt))
+                    # self.drawn_predictions[i][1] = int(exponentialDecay(self.drawn_predictions[i][1], self.pred_coords[i][1], decay, dt))
 
         if len(self.pred_coords) > len(self.drawn_predictions):
             self.drawn_predictions.extend(self.pred_coords[len(self.drawn_predictions):])