From 2f806dedc762c1ee810be44820aaff8de8cb5d07 Mon Sep 17 00:00:00 2001
From: Enrico Turri <enricoturri@seznam.cz>
Date: Tue, 25 Jun 2019 09:51:43 +0200
Subject: [PATCH] Fixed rendering of selection rectangle with perspective
 camera

---
 src/slic3r/GUI/GLSelectionRectangle.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/slic3r/GUI/GLSelectionRectangle.cpp b/src/slic3r/GUI/GLSelectionRectangle.cpp
index 327cb1fde..684563bff 100644
--- a/src/slic3r/GUI/GLSelectionRectangle.cpp
+++ b/src/slic3r/GUI/GLSelectionRectangle.cpp
@@ -68,7 +68,8 @@ namespace GUI {
         if (!is_dragging())
             return;
 
-        float zoom = (float)canvas.get_camera().get_zoom();
+        const Camera& camera = canvas.get_camera();
+        float zoom = (float)camera.get_zoom();
         float inv_zoom = (zoom != 0.0f) ? 1.0f / zoom : 0.0f;
 
         Size cnv_size = canvas.get_canvas_size();
@@ -96,6 +97,11 @@ namespace GUI {
 
         glsafe(::glPushMatrix());
         glsafe(::glLoadIdentity());
+        // ensure that the rectangle is renderered inside the frustrum
+        glsafe(::glTranslated(0.0, 0.0, -(camera.get_near_z() + 0.5)));
+        // ensure that the overlay fits the frustrum near z plane
+        double gui_scale = camera.get_gui_scale();
+        glsafe(::glScaled(gui_scale, gui_scale, 1.0));
 
         glsafe(::glPushAttrib(GL_ENABLE_BIT));
         glsafe(::glLineStipple(4, 0xAAAA));