Fix T69814: Grease Pencil Onion Skin Loop doesn't work as expected

The first element of the loop was not calculated for all onion modes. For select mode the first selected is used, for other modes the first frame in the layer is used.

1 files changed, 5 insertions, 6 deletions

diff --git a/source/blender/draw/engines/gpencil/gpencil_draw_utils.c b/source/blender/draw/engines/gpencil/gpencil_draw_utils.c
index 743a2fb546c..ce5d8cbf732 100644
--- a/source/blender/draw/engines/gpencil/gpencil_draw_utils.c
+++ b/source/blender/draw/engines/gpencil/gpencil_draw_utils.c
@@ -1355,19 +1355,19 @@ static void gpencil_draw_onionskins(GpencilBatchCache *cache,
   int idx;
   float fac = 1.0f;
   int step = 0;
-  int mode = 0;
   bool colflag = false;
-  bGPDframe *gpf_loop = NULL;
+  const int mode = gpd->onion_mode;
+  bGPDframe *gpf_loop = ((gpd->onion_flag & GP_ONION_LOOP) && (mode != GP_ONION_MODE_SELECTED)) ?
+                            gpl->frames.first :
+                            NULL;
   int last = gpf->framenum;
 
   colflag = (bool)gpd->onion_flag & GP_ONION_GHOST_PREVCOL;
   const short onion_keytype = gpd->onion_keytype;
-
   /* -------------------------------
    * 1) Draw Previous Frames First
    * ------------------------------- */
   step = gpd->gstep;
-  mode = gpd->onion_mode;
 
   if (gpd->onion_flag & GP_ONION_GHOST_PREVCOL) {
     copy_v3_v3(color, gpd->gcolor_prev);
@@ -1416,7 +1416,7 @@ static void gpencil_draw_onionskins(GpencilBatchCache *cache,
     }
 
     /* if loop option, save the frame to use later */
-    if ((mode != GP_ONION_MODE_ABSOLUTE) && (gpd->onion_flag & GP_ONION_LOOP)) {
+    if ((mode == GP_ONION_MODE_SELECTED) && (gpd->onion_flag & GP_ONION_LOOP)) {
       gpf_loop = gf;
     }
 
@@ -1427,7 +1427,6 @@ static void gpencil_draw_onionskins(GpencilBatchCache *cache,
    * 2) Now draw next frames
    * ------------------------------- */
   step = gpd->gstep_next;
-  mode = gpd->onion_mode;
 
   if (gpd->onion_flag & GP_ONION_GHOST_NEXTCOL) {
     copy_v3_v3(color, gpd->gcolor_next);