Armature: Add Display Axis Offset

Display the bone axes at the head (root) of the bone by default, instead
of the tail (tip), and add a slider so that it's possible to adjust this
position.

Versioning code is in place to ensure existing files behave the same
(axes shown at tail), whereas new Armatures will be using the new
default (axes shown at head).

Reviewed By: #animation_rigging, #user_interface, Severin, Sybren

Differential Revision: https://developer.blender.org/D7685

1 files changed, 5 insertions, 1 deletions

diff --git a/source/blender/draw/engines/overlay/overlay_armature.c b/source/blender/draw/engines/overlay/overlay_armature.c
index 7042d095b56..54224071d23 100644
--- a/source/blender/draw/engines/overlay/overlay_armature.c
+++ b/source/blender/draw/engines/overlay/overlay_armature.c
@@ -1293,11 +1293,15 @@ static void draw_axes(ArmatureDrawContext *ctx,
     float length = pchan->bone->length;
     copy_m4_m4(axis_mat, pchan->custom_tx ? pchan->custom_tx->pose_mat : pchan->pose_mat);
     rescale_m4(axis_mat, (float[3]){length, length, length});
+    translate_m4(axis_mat, 0.0, arm->axes_position - 1.0, 0.0);
 
     drw_shgroup_bone_axes(ctx, axis_mat, final_col);
   }
   else {
-    drw_shgroup_bone_axes(ctx, BONE_VAR(eBone, pchan, disp_mat), final_col);
+    float disp_mat[4][4];
+    copy_m4_m4(disp_mat, BONE_VAR(eBone, pchan, disp_mat));
+    translate_m4(disp_mat, 0.0, arm->axes_position - 1.0, 0.0);
+    drw_shgroup_bone_axes(ctx, disp_mat, final_col);
   }
 }