Multi-Objects Metaball: Selection refactor - fix pick and box selection

This is inspired/based on the code we use for armature bone selection.
Both pick selection, and box selection should be working now.

1 files changed, 35 insertions, 11 deletions

diff --git a/source/blender/editors/space_view3d/view3d_select.c b/source/blender/editors/space_view3d/view3d_select.c
index 230bbd11450..c421c96e530 100644
--- a/source/blender/editors/space_view3d/view3d_select.c
+++ b/source/blender/editors/space_view3d/view3d_select.c
@@ -2169,7 +2169,8 @@ static int do_meta_box_select(
         ViewContext *vc,
         const rcti *rect, const eSelectOp sel_op)
 {
-	MetaBall *mb = (MetaBall *)vc->obedit->data;
+	Object *ob = vc->obedit;
+	MetaBall *mb = (MetaBall *)ob->data;
 	MetaElem *ml;
 	int a;
 
@@ -2184,27 +2185,50 @@ static int do_meta_box_select(
 		BKE_mball_deselect_all(mb);
 	}
 
-	for (ml = mb->editelems->first; ml; ml = ml->next) {
-		bool is_inside_1 = false;
-		bool is_inside_2 = false;
+	int metaelem_id = 0;
+	for (ml = mb->editelems->first; ml; ml = ml->next, metaelem_id += 0x10000) {
+		bool is_inside_radius = false;
+		bool is_inside_stiff = false;
+
 		for (a = 0; a < hits; a++) {
-			if (ml->selcol1 == buffer[(4 * a) + 3]) {
-				is_inside_1 = true;
+			int hitresult = buffer[(4 * a) + 3];
+
+			if (hitresult == -1) {
+				continue;
+			}
+			else if (hitresult & MBALL_NOSEL) {
+				continue;
+			}
+
+			const uint hit_object = hitresult & 0xFFFF;
+			if (vc->obedit->select_color != hit_object) {
+				continue;
+			}
+
+			if (metaelem_id != (hitresult & 0xFFFF0000 & ~(MBALLSEL_ANY))) {
+				continue;
+			}
+
+			if (hitresult & MBALLSEL_RADIUS) {
+				is_inside_radius = true;
 				break;
 			}
-			if (ml->selcol2 == buffer[(4 * a) + 3]) {
-				is_inside_2 = true;
+
+			if (hitresult & MBALLSEL_STIFF) {
+				is_inside_stiff = true;
 				break;
 			}
 		}
-		if (is_inside_1) {
+		if (is_inside_radius) {
 			ml->flag |= MB_SCALE_RAD;
 		}
-		if (is_inside_2) {
+		if (is_inside_stiff) {
 			ml->flag &= ~MB_SCALE_RAD;
 		}
+
 		const bool is_select = (ml->flag & SELECT);
-		const bool is_inside = is_inside_1 || is_inside_2;
+		const bool is_inside = is_inside_radius || is_inside_stiff;
+
 		const int sel_op_result = ED_select_op_action_deselected(sel_op, is_select, is_inside);
 		if (sel_op_result != -1) {
 			SET_FLAG_FROM_TEST(ml->flag, sel_op_result, SELECT);