1 files changed, 37 insertions, 19 deletions

diff --git a/source/blender/editors/gpencil/gpencil_utils.c b/source/blender/editors/gpencil/gpencil_utils.c
index 5a45afe9c5a..28a90a26a9d 100644
--- a/source/blender/editors/gpencil/gpencil_utils.c
+++ b/source/blender/editors/gpencil/gpencil_utils.c
@@ -2916,6 +2916,40 @@ void ED_gpencil_sbuffer_vertex_color_set(Depsgraph *depsgraph,
   }
 }
 
+/* Helper to get the bigger 2D bound box points. */
+static void gpencil_projected_2d_bound_box(GP_SpaceConversion *gsc,
+                                           bGPDstroke *gps,
+                                           const float diff_mat[4][4],
+                                           float r_min[2],
+                                           float r_max[2])
+{
+  float bounds[8][2];
+  BoundBox bb;
+  BKE_boundbox_init_from_minmax(&bb, gps->boundbox_min, gps->boundbox_max);
+
+  /* Project 8 vertices in 2D. */
+  for (int i = 0; i < 8; i++) {
+    bGPDspoint pt_dummy, pt_dummy_ps;
+    copy_v3_v3(&pt_dummy.x, bb.vec[i]);
+    gpencil_point_to_parent_space(&pt_dummy, diff_mat, &pt_dummy_ps);
+    gpencil_point_to_xy_fl(gsc, gps, &pt_dummy_ps, &bounds[i][0], &bounds[i][1]);
+  }
+
+  /* Take extremes. */
+  INIT_MINMAX2(r_min, r_max);
+  for (int i = 0; i < 8; i++) {
+    minmax_v2v2_v2(r_min, r_max, bounds[i]);
+  }
+
+  /* Ensure the bounding box is oriented to axis. */
+  if (r_max[0] < r_min[0]) {
+    SWAP(float, r_min[0], r_max[0]);
+  }
+  if (r_max[1] < r_min[1]) {
+    SWAP(float, r_min[1], r_max[1]);
+  }
+}
+
 /* Check if the stroke collides with brush. */
 bool ED_gpencil_stroke_check_collision(GP_SpaceConversion *gsc,
                                        bGPDstroke *gps,
@@ -2924,31 +2958,15 @@ bool ED_gpencil_stroke_check_collision(GP_SpaceConversion *gsc,
                                        const float diff_mat[4][4])
 {
   const int offset = (int)ceil(sqrt((radius * radius) * 2));
-  bGPDspoint pt_dummy, pt_dummy_ps;
-  float boundbox_min[2] = {0.0f};
-  float boundbox_max[2] = {0.0f};
+  float boundbox_min[2];
+  float boundbox_max[2];
 
   /* Check we have something to use (only for old files). */
   if (is_zero_v3(gps->boundbox_min)) {
     BKE_gpencil_stroke_boundingbox_calc(gps);
   }
 
-  /* Convert bound box to 2d */
-  copy_v3_v3(&pt_dummy.x, gps->boundbox_min);
-  gpencil_point_to_parent_space(&pt_dummy, diff_mat, &pt_dummy_ps);
-  gpencil_point_to_xy_fl(gsc, gps, &pt_dummy_ps, &boundbox_min[0], &boundbox_min[1]);
-
-  copy_v3_v3(&pt_dummy.x, gps->boundbox_max);
-  gpencil_point_to_parent_space(&pt_dummy, diff_mat, &pt_dummy_ps);
-  gpencil_point_to_xy_fl(gsc, gps, &pt_dummy_ps, &boundbox_max[0], &boundbox_max[1]);
-
-  /* Ensure the bounding box is oriented to axis. */
-  if (boundbox_max[0] < boundbox_min[0]) {
-    SWAP(float, boundbox_min[0], boundbox_max[0]);
-  }
-  if (boundbox_max[1] < boundbox_min[1]) {
-    SWAP(float, boundbox_min[1], boundbox_max[1]);
-  }
+  gpencil_projected_2d_bound_box(gsc, gps, diff_mat, boundbox_min, boundbox_max);
 
   rcti rect_stroke = {boundbox_min[0], boundbox_max[0], boundbox_min[1], boundbox_max[1]};