From 8554d210dfb7d5e385305aef61903286407965be Mon Sep 17 00:00:00 2001
From: binary1248 <binary1248@hotmail.com>
Date: Sat, 15 Sep 2018 21:36:53 +0200
Subject: [PATCH] Ensure the proper default framebuffer is bound when
 activating a RenderWindow. Fixes #1471.

---
 include/SFML/Graphics/RenderWindow.hpp |  7 +++++++
 src/SFML/Graphics/RenderWindow.cpp     | 18 ++++++++++++++----
 2 files changed, 21 insertions(+), 4 deletions(-)

diff --git a/include/SFML/Graphics/RenderWindow.hpp b/include/SFML/Graphics/RenderWindow.hpp
index 2b3b6bce4a..01f07828bd 100644
--- a/include/SFML/Graphics/RenderWindow.hpp
+++ b/include/SFML/Graphics/RenderWindow.hpp
@@ -177,6 +177,13 @@ class SFML_GRAPHICS_API RenderWindow : public Window, public RenderTarget
     ///
     ////////////////////////////////////////////////////////////
     virtual void onResize();
+
+private:
+
+    ////////////////////////////////////////////////////////////
+    // Member data
+    ////////////////////////////////////////////////////////////
+    unsigned int m_defaultFrameBuffer; ///< Framebuffer to bind when targeting this window
 };
 
 } // namespace sf
diff --git a/src/SFML/Graphics/RenderWindow.cpp b/src/SFML/Graphics/RenderWindow.cpp
index 446e906097..42f4ffeafa 100644
--- a/src/SFML/Graphics/RenderWindow.cpp
+++ b/src/SFML/Graphics/RenderWindow.cpp
@@ -34,14 +34,16 @@
 namespace sf
 {
 ////////////////////////////////////////////////////////////
-RenderWindow::RenderWindow()
+RenderWindow::RenderWindow() :
+m_defaultFrameBuffer(0)
 {
     // Nothing to do
 }
 
 
 ////////////////////////////////////////////////////////////
-RenderWindow::RenderWindow(VideoMode mode, const String& title, Uint32 style, const ContextSettings& settings)
+RenderWindow::RenderWindow(VideoMode mode, const String& title, Uint32 style, const ContextSettings& settings) :
+m_defaultFrameBuffer(0)
 {
     // Don't call the base class constructor because it contains virtual function calls
     create(mode, title, style, settings);
@@ -49,7 +51,8 @@ RenderWindow::RenderWindow(VideoMode mode, const String& title, Uint32 style, co
 
 
 ////////////////////////////////////////////////////////////
-RenderWindow::RenderWindow(WindowHandle handle, const ContextSettings& settings)
+RenderWindow::RenderWindow(WindowHandle handle, const ContextSettings& settings) :
+m_defaultFrameBuffer(0)
 {
     // Don't call the base class constructor because it contains virtual function calls
     create(handle, settings);
@@ -83,7 +86,7 @@ bool RenderWindow::setActive(bool active)
     // try to draw to the default framebuffer of the RenderWindow
     if (active && result && priv::RenderTextureImplFBO::isAvailable())
     {
-        priv::RenderTextureImplFBO::unbind();
+        glCheck(GLEXT_glBindFramebuffer(GLEXT_GL_FRAMEBUFFER, m_defaultFrameBuffer));
 
         return true;
     }
@@ -108,6 +111,13 @@ Image RenderWindow::capture() const
 ////////////////////////////////////////////////////////////
 void RenderWindow::onCreate()
 {
+    if (priv::RenderTextureImplFBO::isAvailable())
+    {
+        // Retrieve the framebuffer ID we have to bind when targeting the window for rendering
+        // We assume that this window's context is still active at this point
+        glCheck(glGetIntegerv(GLEXT_GL_FRAMEBUFFER_BINDING, reinterpret_cast<GLint*>(&m_defaultFrameBuffer)));
+    }
+
     // Just initialize the render target part
     RenderTarget::initialize();
 }