From eb6de2d4fcd6df0555a46fdca546f94bb5c799e6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cle=CC=81ment=20Foucault?= <foucault.clem@gmail.com>
Date: Mon, 2 Dec 2024 13:21:04 +0100
Subject: [PATCH] Fix #131239: Grease Pencil: Last stroke in drawing uses wrong
 layer opacity

Flush was being done on the wrong pass. It was also creating errors.
---
 source/blender/draw/engines/gpencil/gpencil_engine_c.cc | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/source/blender/draw/engines/gpencil/gpencil_engine_c.cc b/source/blender/draw/engines/gpencil/gpencil_engine_c.cc
index 01e7b318c60..6600828cb4e 100644
--- a/source/blender/draw/engines/gpencil/gpencil_engine_c.cc
+++ b/source/blender/draw/engines/gpencil/gpencil_engine_c.cc
@@ -483,13 +483,15 @@ static GPENCIL_tObject *grease_pencil_object_cache_populate(
       continue;
     }
 
+    if (last_pass) {
+      drawcall_flush(*last_pass);
+    }
+
     GPENCIL_tLayer *tgp_layer = grease_pencil_layer_cache_add(
         pd, ob, layer, info.onion_id, is_layer_used_as_mask, tgp_ob);
     PassSimple &pass = *tgp_layer->geom_ps;
     last_pass = &pass;
 
-    drawcall_flush(pass);
-
     const bool use_lights = pd->use_lighting &&
                             ((layer.base.flag & GP_LAYER_TREE_NODE_USE_LIGHTS) != 0) &&
                             (ob->dtx & OB_USE_GPENCIL_LIGHTS);