[Bf-blender-cvs] [9b5cf593a60] blender2.8: Gizmo: tweak sorting to avoid view-aligned shear

[Campbell Barton]

Commit: 9b5cf593a6068c9415b28eb24ba2d4ab17a2bed8
Author: Campbell Barton
Date:   Thu Oct 18 12:58:54 2018 +1100
Branches: blender2.8
https://developer.blender.org/rB9b5cf593a6068c9415b28eb24ba2d4ab17a2bed8

Gizmo: tweak sorting to avoid view-aligned shear

===================================================================

M	source/blender/editors/transform/transform_gizmo_3d.c

===================================================================

diff --git a/source/blender/editors/transform/transform_gizmo_3d.c b/source/blender/editors/transform/transform_gizmo_3d.c
index 6297cb57c03..4c1be88904d 100644
--- a/source/blender/editors/transform/transform_gizmo_3d.c
+++ b/source/blender/editors/transform/transform_gizmo_3d.c
@@ -2100,7 +2100,17 @@ static void WIDGETGROUP_xform_shear_draw_prepare(const bContext *C, wmGizmoGroup
 	/* Basic ordering for drawing only. */
 	{
 		LISTBASE_FOREACH (wmGizmo *, gz, &gzgroup->gizmos) {
-			gz->temp.f = dot_v3v3(rv3d->viewinv[2], gz->matrix_basis[2]);
+			/* Since we have two pairs of each axis,
+			 * bias the values so gizmos that are orthogonal to the view get priority.
+			 * This means we never default to shearing along the view axis in the case of an overlap. */
+			float axis_order[3], axis_bias[3];
+			copy_v3_v3(axis_order, gz->matrix_basis[2]);
+			copy_v3_v3(axis_bias, gz->matrix_basis[1]);
+			if (dot_v3v3(axis_bias, rv3d->viewinv[2]) < 0.0f) {
+				negate_v3(axis_bias);
+			}
+			madd_v3_v3fl(axis_order, axis_bias, 0.01f);
+			gz->temp.f = dot_v3v3(rv3d->viewinv[2], axis_order);
 		}
 		BLI_listbase_sort(&gzgroup->gizmos, WM_gizmo_cmp_temp_fl_reverse);
 	}