Fix T99248: GPencil Sculpt Grab/Push don't work with one point

There were two problems:

1) The checking of the collision was not working with one point only.
2) For one point, the masking was checked always and if the masking was not activated, the stroke was skipped.

1 files changed, 6 insertions, 3 deletions

diff --git a/source/blender/editors/gpencil/gpencil_sculpt_paint.c b/source/blender/editors/gpencil/gpencil_sculpt_paint.c
index 6d0848de36d..f25d5937ac4 100644
--- a/source/blender/editors/gpencil/gpencil_sculpt_paint.c
+++ b/source/blender/editors/gpencil/gpencil_sculpt_paint.c
@@ -1161,6 +1161,7 @@ static bool gpencil_sculpt_brush_init(bContext *C, wmOperator *op)
 
   gso->is_painting = false;
   gso->first = true;
+  gso->mval_prev[0] = -1.0f;
 
   gso->gpd = ED_gpencil_data_get_active(C);
   gso->cfra = INT_MAX; /* NOTE: So that first stroke will get handled in init_stroke() */
@@ -1442,6 +1443,7 @@ static bool gpencil_sculpt_brush_do_stroke(tGP_BrushEditData *gso,
   char tool = gso->brush->gpencil_sculpt_tool;
   const int radius = (brush->flag & GP_BRUSH_USE_PRESSURE) ? gso->brush->size * gso->pressure :
                                                              gso->brush->size;
+  const bool is_masking = GPENCIL_ANY_SCULPT_MASK(gso->mask);
 
   bGPDstroke *gps_active = (gps->runtime.gps_orig) ? gps->runtime.gps_orig : gps;
   bGPDspoint *pt_active = NULL;
@@ -1459,7 +1461,7 @@ static bool gpencil_sculpt_brush_do_stroke(tGP_BrushEditData *gso,
   if (gps->totpoints == 1) {
     bGPDspoint pt_temp;
     pt = &gps->points[0];
-    if (GPENCIL_ANY_SCULPT_MASK(gso->mask) && (pt->flag & GP_SPOINT_SELECT) != 0) {
+    if ((is_masking && (pt->flag & GP_SPOINT_SELECT) != 0) || (!is_masking)) {
       gpencil_point_to_parent_space(gps->points, diff_mat, &pt_temp);
       gpencil_point_to_xy(gsc, gps, &pt_temp, &pc1[0], &pc1[1]);
 
@@ -1618,7 +1620,8 @@ static bool gpencil_sculpt_brush_do_frame(bContext *C,
     }
 
     /* Check if the stroke collide with brush. */
-    if (!ED_gpencil_stroke_check_collision(gsc, gps, gso->mval, radius, bound_mat)) {
+    if ((gps->totpoints > 1) &&
+        (!ED_gpencil_stroke_check_collision(gsc, gps, gso->mval, radius, bound_mat))) {
       continue;
     }
 
@@ -1982,7 +1985,7 @@ static void gpencil_sculpt_brush_apply(bContext *C, wmOperator *op, PointerRNA *
   }
 
   /* Store coordinates as reference, if operator just started running */
-  if (gso->first) {
+  if (gso->mval_prev[0] == -1.0f) {
     gso->mval_prev[0] = gso->mval[0];
     gso->mval_prev[1] = gso->mval[1];
     gso->pressure_prev = gso->pressure;