From 99ec668aa013994f9c67c46c9bc37a8af57b0d18 Mon Sep 17 00:00:00 2001
From: "jiangkai.zhao" <jiangkai.zhao@bambulab.com>
Date: Tue, 11 Mar 2025 16:14:49 +0800
Subject: [PATCH] Fix:crash when multicolor printing

jira: none
Change-Id: I6289934a897644fb025acd20b59bea1a69995f89
(cherry picked from commit 576d931475c4b42582d78092e75ce0b0b7394ca7)
---
 src/slic3r/GUI/3DScene.cpp | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/src/slic3r/GUI/3DScene.cpp b/src/slic3r/GUI/3DScene.cpp
index 851fde8bd3..462fc08932 100644
--- a/src/slic3r/GUI/3DScene.cpp
+++ b/src/slic3r/GUI/3DScene.cpp
@@ -823,25 +823,24 @@ int GLVolumeCollection::load_real_wipe_tower_preview(
     if (wt_mesh.its.vertices.empty()) return int(this->volumes.size() - 1);
 
     std::vector<Slic3r::ColorRGBA> extruder_colors = GUI::wxGetApp().plater()->get_extruders_colors();
-    std::vector<Slic3r::ColorRGBA> colors;
     GUI::PartPlateList               &ppl              = GUI::wxGetApp().plater()->get_partplate_list();
     std::vector<int>                  plate_extruders  = ppl.get_plate(plate_idx)->get_extruders(true);
-
-    for (int extruder_id : plate_extruders) {
-        if (extruder_id <= extruder_colors.size())
-            colors.push_back(extruder_colors[extruder_id - 1]);
+    std::vector<Slic3r::ColorRGBA>    colors;
+    if (!plate_extruders.empty()) {
+        if (plate_extruders.front() <= extruder_colors.size())
+            colors.push_back(extruder_colors[plate_extruders.front() - 1]);
         else
             colors.push_back(extruder_colors[0]);
     }
-
-    volumes.emplace_back(new GLWipeTowerVolume(colors));
+    if (colors.empty()) return int(this->volumes.size() - 1);
+    volumes.emplace_back(new GLWipeTowerVolume({colors}));
     GLWipeTowerVolume &v = *dynamic_cast<GLWipeTowerVolume *>(volumes.back());
-    v.model_per_colors.resize(colors.size());
     auto mesh = wt_mesh;
     if (render_brim) {
         mesh.merge(brim_mesh);
     }
     if (!colors.empty()) {
+        v.model_per_colors.resize(1);
         v.model_per_colors[0].init_from(mesh);
     }
     TriangleMesh wipe_tower_shell = mesh.convex_hull_3d();