Drivers: support explicit euler rotation order for transform channels.

The meaning of the euler angles completely depends on the rotation
order. Currently the rotation order is taken from the target of the
driver variable, which somewhat makes sense if it uses euler, but if
it's quaternion, then the order is always set to XYZ.

Add a new option for the rotation channels of the Transform Channel
driver variables that defaults to the old behavior, but allows setting
an explicit rotation order.

1 files changed, 17 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_fcurve.c b/source/blender/makesrna/intern/rna_fcurve.c
index 6c546940e6d..6cb3a18605c 100644
--- a/source/blender/makesrna/intern/rna_fcurve.c
+++ b/source/blender/makesrna/intern/rna_fcurve.c
@@ -1701,6 +1701,17 @@ static void rna_def_drivertarget(BlenderRNA *brna)
       {0, NULL, 0, NULL, NULL},
   };
 
+  static const EnumPropertyItem prop_rotation_mode_items[] = {
+      {DTAR_ROTMODE_AUTO, "AUTO", 0, "Auto Euler", "Euler using the rotation order of the target"},
+      {DTAR_ROTMODE_EULER_XYZ, "XYZ", 0, "XYZ Euler", "Euler using the XYZ rotation order"},
+      {DTAR_ROTMODE_EULER_XZY, "XZY", 0, "XZY Euler", "Euler using the XZY rotation order"},
+      {DTAR_ROTMODE_EULER_YXZ, "YXZ", 0, "YXZ Euler", "Euler using the YXZ rotation order"},
+      {DTAR_ROTMODE_EULER_YZX, "YZX", 0, "YZX Euler", "Euler using the YZX rotation order"},
+      {DTAR_ROTMODE_EULER_ZXY, "ZXY", 0, "ZXY Euler", "Euler using the ZXY rotation order"},
+      {DTAR_ROTMODE_EULER_ZYX, "ZYX", 0, "ZYX Euler", "Euler using the ZYX rotation order"},
+      {0, NULL, 0, NULL, NULL},
+  };
+
   srna = RNA_def_struct(brna, "DriverTarget", NULL);
   RNA_def_struct_ui_text(srna, "Driver Target", "Source of input values for driver variables");
 
@@ -1749,6 +1760,12 @@ static void rna_def_drivertarget(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Type", "Driver variable type");
   RNA_def_property_update(prop, 0, "rna_DriverTarget_update_data");
 
+  prop = RNA_def_property(srna, "rotation_mode", PROP_ENUM, PROP_NONE);
+  RNA_def_property_enum_sdna(prop, NULL, "rotation_mode");
+  RNA_def_property_enum_items(prop, prop_rotation_mode_items);
+  RNA_def_property_ui_text(prop, "Rotation Mode", "Mode for calculating rotation channel values");
+  RNA_def_property_update(prop, 0, "rna_DriverTarget_update_data");
+
   prop = RNA_def_property(srna, "transform_space", PROP_ENUM, PROP_NONE);
   RNA_def_property_enum_bitflag_sdna(prop, NULL, "flag");
   RNA_def_property_enum_items(prop, prop_local_space_items);