toolhead: Changed the threshold calculation for straight segments

Signed-off-by: Dmitry Butyugin <[email protected]>

klippy/toolhead.py

@@ -72,23 +72,27 @@ def calc_junction(self, prev_move):
                                + axes_r[2] * prev_axes_r[2])
         if junction_cos_theta > 0.999999:
             return
+        sin_theta_d2 = math.sqrt(0.5*(1.0-junction_cos_theta))
+        cos_theta_d2 = math.sqrt(0.5*(1.0+junction_cos_theta))
         # Apply limits
         self.max_start_v2 = min(
             extruder_v2, self.max_cruise_v2, prev_move.max_cruise_v2,
             prev_move.max_start_v2 + prev_move.delta_v2)
         if junction_cos_theta >= -0.999999:
-            sin_theta_d2 = math.sqrt(0.5*(1.0-junction_cos_theta))
             R_jd = sin_theta_d2 / (1. - sin_theta_d2)
+            self.max_start_v2 = min(
+                self.max_start_v2,
+                R_jd * self.junction_deviation * self.accel,
+                R_jd * prev_move.junction_deviation * prev_move.accel)
+        # Check that the radius of curvature for this junction is finite
+        if max(self.move_d, prev_move.move_d) < 99999999.9 * cos_theta_d2:
             # Approximated circle must contact moves no further than mid-move
-            tan_theta_d2 = sin_theta_d2 / math.sqrt(.5*(1.0+junction_cos_theta))
+            tan_theta_d2 = sin_theta_d2 / cos_theta_d2
             move_centripetal_v2 = .5 * self.move_d * tan_theta_d2 * self.accel
             prev_move_centripetal_v2 = (.5 * prev_move.move_d * tan_theta_d2
                                         * prev_move.accel)
-            self.max_start_v2 = min(
-                self.max_start_v2,
-                R_jd * self.junction_deviation * self.accel,
-                R_jd * prev_move.junction_deviation * prev_move.accel,
-                move_centripetal_v2, prev_move_centripetal_v2)
+            self.max_start_v2 = min(self.max_start_v2, move_centripetal_v2,
+                                    prev_move_centripetal_v2)
         self.max_smoothed_v2 = min(
             self.max_start_v2
             , prev_move.max_smoothed_v2 + prev_move.smooth_delta_v2)