From fb6ef1d20fdfaecef3f3b4792386acd6a31f58b5 Mon Sep 17 00:00:00 2001
From: Enrico Turri <enricoturri@seznam.cz>
Date: Thu, 31 Jan 2019 14:25:11 +0100
Subject: [PATCH] Keeps modifier transparent while layer editing tool is
 enabled

---
 src/slic3r/GUI/3DScene.cpp    | 4 ++++
 src/slic3r/GUI/3DScene.hpp    | 2 ++
 src/slic3r/GUI/GLCanvas3D.cpp | 7 +++++++
 3 files changed, 13 insertions(+)

diff --git a/src/slic3r/GUI/3DScene.cpp b/src/slic3r/GUI/3DScene.cpp
index fd1645c9e..6b1df6ab3 100644
--- a/src/slic3r/GUI/3DScene.cpp
+++ b/src/slic3r/GUI/3DScene.cpp
@@ -252,6 +252,7 @@ GLVolume::GLVolume(float r, float g, float b, float a)
     , is_modifier(false)
     , is_wipe_tower(false)
     , is_extrusion_path(false)
+    , force_transparent(false)
     , tverts_range(0, size_t(-1))
     , qverts_range(0, size_t(-1))
 {
@@ -293,6 +294,9 @@ void GLVolume::set_render_color()
         set_render_color(OUTSIDE_COLOR, 4);
     else
         set_render_color(color, 4);
+
+    if (force_transparent)
+        render_color[3] = color[3];
 }
 
 void GLVolume::set_color_from_model_volume(const ModelVolume *model_volume)
diff --git a/src/slic3r/GUI/3DScene.hpp b/src/slic3r/GUI/3DScene.hpp
index 7430ff4aa..2732b5a13 100644
--- a/src/slic3r/GUI/3DScene.hpp
+++ b/src/slic3r/GUI/3DScene.hpp
@@ -295,6 +295,8 @@ public:
     bool                is_wipe_tower;
     // Wheter or not this volume has been generated from an extrusion path
     bool                is_extrusion_path;
+    // Wheter or not to always render this volume using its own alpha 
+    bool                force_transparent;
 
     // Interleaved triangles & normals with indexed triangles & quads.
     GLIndexedVertexArray        indexed_vertex_array;
diff --git a/src/slic3r/GUI/GLCanvas3D.cpp b/src/slic3r/GUI/GLCanvas3D.cpp
index 72dfe52bd..33f62f205 100644
--- a/src/slic3r/GUI/GLCanvas3D.cpp
+++ b/src/slic3r/GUI/GLCanvas3D.cpp
@@ -4286,6 +4286,13 @@ bool GLCanvas3D::is_reload_delayed() const
 void GLCanvas3D::enable_layers_editing(bool enable)
 {
     m_layers_editing.set_enabled(enable);
+    const Selection::IndicesList& idxs = m_selection.get_volume_idxs();
+    for (unsigned int idx : idxs)
+    {
+        GLVolume* v = m_volumes.volumes[idx];
+        if (v->is_modifier)
+            v->force_transparent = enable;
+    }
 }
 
 void GLCanvas3D::enable_warning_texture(bool enable)