per_move_pressure_advance extruder flag

README.md

@@ -64,6 +64,7 @@ If I want my printer to light itself on fire, I should be able to make my printe
 
 - [adxl345: improve ACCELEROMETER_QUERY command](https://github.com/DangerKlippers/danger-klipper/pull/124)
 
+- [extruder: add flag to use the PA constant from a trapq move vs a cached value](https://github.com/DangerKlippers/danger-klipper/pull/132)
 If you're feeling adventurous, take a peek at the extra features in the bleeding-edge branch:
 
 - [dmbutyugin's advanced-features branch](https://github.com/DangerKlippers/danger-klipper/pull/69) [dmbutyugin/advanced-features](https://github.com/dmbutyugin/klipper/commits/advanced-features)

docs/Config_Reference.md

@@ -987,6 +987,11 @@ max_temp:
 #   heater and sensor hardware failures. Set this range just wide
 #   enough so that reasonable temperatures do not result in an error.
 #   These parameters must be provided.
+per_move_pressure_advance: False
+#   If true, uses pressure advance constant from trapq when processing moves
+#   This causes changes to pressure advance be taken into account immediately,
+#   for all moves in the current queue, rather than ~250ms later once the queue gets flushed
+
 ```
 
 ### [heater_bed]

klippy/chelper/kin_extruder.c

@@ -59,10 +59,20 @@ pa_move_integrate(struct move *m, double pressure_advance
         start = 0.;
     if (end > m->move_t)
         end = m->move_t;
+    // figure out what to use for pressure advance
+    // use_pa_from_trapq is passed in via the move's axes_r.z field
+    // if this is True (not 0), we use the pressure advance value in the axes_r.y
+    // otherwise, we use the one passed in as an arg to this function (the stored one)
+    int use_pa_from_trapq = m->axes_r.z != 0.;
+    if (use_pa_from_trapq) {
+        pressure_advance = m->axes_r.y;
+    }
+    else {
+        int can_pressure_advance = m->axes_r.y != 0.;
+        if (!can_pressure_advance)
+            pressure_advance = 0.;
+    }
     // Calculate base position and velocity with pressure advance
-    int can_pressure_advance = m->axes_r.y != 0.;
-    if (!can_pressure_advance)
-        pressure_advance = 0.;
     base += pressure_advance * m->start_v;
     double start_v = m->start_v + pressure_advance * 2. * m->half_accel;
     // Calculate definitive integral

klippy/kinematics/extruder.py

@@ -263,6 +263,11 @@ def __init__(self, config, extruder_num):
         self.trapq = ffi_main.gc(ffi_lib.trapq_alloc(), ffi_lib.trapq_free)
         self.trapq_append = ffi_lib.trapq_append
         self.trapq_finalize_moves = ffi_lib.trapq_finalize_moves
+
+        self.per_move_pressure_advance = config.getboolean(
+            "per_move_pressure_advance", False
+        )
+
         # Setup extruder stepper
         self.extruder_stepper = None
         if (
@@ -357,9 +362,10 @@ def move(self, print_time, move):
         accel = move.accel * axis_r
         start_v = move.start_v * axis_r
         cruise_v = move.cruise_v * axis_r
-        can_pressure_advance = False
+        pressure_advance = 0.0
         if axis_r > 0.0 and (move.axes_d[0] or move.axes_d[1]):
-            can_pressure_advance = True
+            pressure_advance = self.extruder_stepper.pressure_advance
+        use_pa_from_trapq = 1.0 if self.per_move_pressure_advance else 0.0
         # Queue movement (x is extruder movement, y is pressure advance flag)
         self.trapq_append(
             self.trapq,
@@ -371,8 +377,8 @@ def move(self, print_time, move):
             0.0,
             0.0,
             1.0,
-            can_pressure_advance,
-            0.0,
+            pressure_advance,
+            use_pa_from_trapq,
             start_v,
             cruise_v,
             accel,