bed_mash_fast: Support relative_reference_index

Uses the closest point in the optimized mesh.

README.md

@@ -421,9 +421,11 @@ are listed in [globals.cfg](globals.cfg#L5).
 `BED_MESH_CALIBRATE_FAST`
 
 Wraps the Klipper `BED_MESH_CALIBRATE` command to scale and redistribute the
-probe points so that only the appropriate area in `MESH_MIN` and `MESH_MAX` is probed. This can dramatically reduce probing times for anything that doesn't
-fill the first layer of the bed. `PRINT_START` will automatically use this for
-bed mesh calibration if a `[bed_mesh]` section is detected in your config.
+probe points so that only the appropriate area in `MESH_MIN` and `MESH_MAX` is
+probed. This can dramatically reduce probing times for anything that doesn't
+fill the first layer of the bed. If the `MESH_MIN` and `MESH_MAX` arguments
+are provided to `PRINT_START` it will automatically use this for bed mesh
+calibration (so long as a `[bed_mesh]` section is detected in your config).
 
 The following additional configuration options are available from
 [globals.cfg](globals.cfg#L5).
@@ -437,10 +439,14 @@ The following additional configuration options are available from
 
 > **Note:** See the [optional section](#bed-mesh) for additional macros.
 
-> **Note:** The bed mesh optimizations are silently disabled for delta printers
-  and when the mesh parameters include a [`RELATIVE_REFERENCE_INDEX`
-  ](https://www.klipper3d.org/Bed_Mesh.html#the-relative-reference-index)
-  (which is icnompatible with dynamic mesh generation).
+> **Note:** The bed mesh optimizations are silently disabled for delta printers.
+
+> **Note:** If the `bed_mesh` config includes a [`relative_reference_index`
+  ](https://www.klipper3d.org/Bed_Mesh.html#the-relative-reference-index) then
+  the index point selected in the optimized mesh will be the point closest to
+  the index point in the mesh from the config. However, if a
+  `RELATIVE_REFERENCE_INDEX` parameter is supplied directly to this macro it
+  will be used unmodified.
 
 `BED_MESH_CHECK`
 

bed_mesh_fast.cfg

@@ -19,12 +19,9 @@ gcode:
   {% set probe_count_scale = km.probe_count_scale %}
   {% set bed_mesh = printer.configfile.settings.bed_mesh %}
 
-  # Don't want to duplicate all the math for a delta bed, and still thinking up
-  # a good strategy for relative reference index.
+  # TODO: Handle the math for a delta bed.
   {%if "mesh_radius" not in bed_mesh and
-       "MESH_RADIUS" not in params and
-       "relative_reference_index" not in bed_mesh and
-       "RELATIVE_REFERENCE_INDEX" not in params %}
+       "MESH_RADIUS" not in params %}
     {% set safe_min_x = bed_mesh.mesh_min[0] %}
     {% set safe_min_y = bed_mesh.mesh_min[1] %}
     {% set safe_max_x = bed_mesh.mesh_max[0] %}
@@ -77,6 +74,56 @@ gcode:
       {% set dummy = probe_count.append(probe_count[0]) %}
     {% endif %}
 
+    # If the config includes a relative_reference_index then we need to find the
+    # point in the new mesh that's closest to the index point in the mesh that
+    # the config would have generated.
+    # TODO: Could also adjust the mesh parameters in here to ensure it includes
+    # the original index point, but that would be extra work and would cause
+    # slower probes if the mesh needs to be expanded to include the point.
+    {% if "relative_reference_index" in bed_mesh %}
+      {% set row = (bed_mesh.relative_reference_index / bed_mesh.probe_count[0]
+                    )|int%}
+      {% set rrf_x = (((safe_max_x - safe_min_x) /
+                       (bed_mesh.probe_count[0] - 1))|round(2, 'floor')) *
+                     (bed_mesh.relative_reference_index %
+                      bed_mesh.probe_count[-1]) %}
+      {% if row % 2 %}
+        {% set rrf_x = safe_max_x - rrf_x %}
+      {% else %}
+        {% set rrf_x = safe_min_x + rrf_x %}
+      {% endif %}
+      {% set rrf_y = (((safe_max_y - safe_min_y) /
+                       (bed_mesh.probe_count[-1] - 1))|round(2, 'floor')) *
+                     row + safe_min_x %}
+      {% set x_dist = (mesh_max_x - mesh_min_x) / (probe_count[0] - 1) %}
+      {% set y_dist = (mesh_max_y - mesh_min_y) / (probe_count[1] - 1) %}
+      {% set rrf = {'x':0, 'y':0, 'dist':safe_max_x**2+safe_max_y**2,'pos':0} %}
+      {% for row in range(probe_count[1])%}
+        {% for col in range(probe_count[0])%}
+          {% if row % 2 %}
+            {% set x = mesh_max_x - col * x_dist %}
+          {% else %}
+            {% set x = mesh_min_x + col * x_dist %}
+          {% endif %}
+          {% set y = mesh_min_y + row * y_dist %}
+          {% set dist = ((x - rrf_x)**2 + (y - rrf_y)**2)**0.5 %}
+          {% if dist < rrf.dist %}
+            {% set dummy = rrf.__setitem__("dist", dist) %}
+            {% set dummy = rrf.__setitem__("x", x) %}
+            {% set dummy = rrf.__setitem__("y", y) %}
+            {% set dummy = rrf.__setitem__("pos", row * probe_count[1] + col) %}
+          {% endif %}
+        {% endfor %}
+      {% endfor %}
+      {% if rrf.x != rrf_x or rrf.y != rrf_y %}
+        {action_respond_info("relative_reference_index remapped to"
+                             " %d (%.2f,%.2f) from %d (%.2f,%.2f)" %
+                             (rrf.pos, rrf.x, rrf.y,
+                              bed_mesh.relative_reference_index, rrf_x, rrf_y))}
+      {% endif %}
+      {% set dummy = params.__setitem__("RELATIVE_REFERENCE_INDEX", rrf.pos) %}
+    {% endif %}
+
     {% set dummy = params.__setitem__("MESH_MIN", mesh_min_x~","~mesh_min_y) %}
     {% set dummy = params.__setitem__("MESH_MAX", mesh_max_x~","~mesh_max_y) %}
     {% set dummy = params.__setitem__("PROBE_COUNT", probe_count|join(',')) %}