fix/workaround [#33493] checker de-select and edge loops

Checker de-select by default would give uneven selection on a circle, this isnt really a bug but the offset used would give unevenly spaced selection even if the 3rd vertex for eg could be evenly selected on a circle.

Change how the offset works so the active element always remains selected when the offset is set to zero, this tends to give more even de-selection.

diff --git a/source/blender/editors/mesh/editmesh_select.c b/source/blender/editors/mesh/editmesh_select.c
index a8f6ccc6c2cb6834875b795e91319d07fdb9d25a..6ca7777f8e26f7be82da6f94dbdba9c0cc8a5256 100644 (file)
--- a/source/blender/editors/mesh/editmesh_select.c
+++ b/source/blender/editors/mesh/editmesh_select.c
@@ -2630,7 +2630,8 @@ static int edbm_select_nth_exec(bContext *C, wmOperator *op)
        int nth = RNA_int_get(op->ptr, "nth");
        int offset = RNA_int_get(op->ptr, "offset");
 
-       offset = MIN2(nth, offset);
+       /* so input of offset zero ends up being (nth - 1) */
+       offset = (offset + (nth - 1)) % nth;
 
        if (edbm_deselect_nth(em, nth, offset) == 0) {
                BKE_report(op->reports, RPT_ERROR, "Mesh has no active vert/edge/face");