Save screenshot image in a separate background thread (#546)

src/graphics/engine/engine.cpp

@@ -52,6 +52,7 @@
 #include "ui/interface.h"
 
 #include <iomanip>
+#include <SDL_thread.h>
 
 template<> Gfx::CEngine* CSingleton<Gfx::CEngine>::m_instance = nullptr;
 
@@ -483,24 +484,42 @@ void CEngine::FrameUpdate()
     }
 }
 
+struct WriteScreenShotData
+{
+    std::unique_ptr<CImage> img;
+    std::string fileName;
+};
+
 bool CEngine::WriteScreenShot(const std::string& fileName, int width, int height)
 {
-    void *pixels = m_device->GetFrameBufferPixels();
+    WriteScreenShotData* data = new WriteScreenShotData();
-    CImage img({width, height});
+    data->img = MakeUnique<CImage>(Math::IntPoint(width, height));
 
-    img.SetDataPixels(pixels);
+    data->img->SetDataPixels(m_device->GetFrameBufferPixels());
-    img.FlipVertically();
+    data->img->FlipVertically();
 
-    if ( img.SavePNG(fileName.c_str()) )
+    data->fileName = fileName;
+    SDL_CreateThread(CEngine::WriteScreenShotThread, data);
+    return true;
+}
+
+int CEngine::WriteScreenShotThread(void* data_ptr)
+{
+    WriteScreenShotData* data = static_cast<WriteScreenShotData*>(data_ptr);
+
+    if ( data->img->SavePNG(data->fileName.c_str()) )
     {
        GetLogger()->Debug("Save screenshot saved successfully\n");
-       return true;
     }
     else
     {
-       GetLogger()->Error("%s!\n", img.GetError().c_str());
+       GetLogger()->Error("%s!\n", data->img->GetError().c_str());
-       return false;
     }
+
+    delete data;
+
+    CRobotMain::GetInstancePointer()->IOWriteSceneFinished();
+    return 0;
 }
 
 bool CEngine::GetPause()

src/graphics/engine/engine.h

@@ -1348,6 +1348,8 @@ protected:
 
     int GetEngineState(const ModelTriangle& triangle);
 
+    static int WriteScreenShotThread(void* data_ptr);
+
 protected:
     CApplication*     m_app;
     CSoundInterface*  m_sound;

src/object/robotmain.cpp

@@ -179,7 +179,6 @@ CRobotMain::CRobotMain(CController* controller)
     m_satcomRepeat = true;
     m_editorTrack  = "";
     m_editorRepeat = true;
-    m_delayWriteMessage = 0;
     m_selectObject = 0;
     m_infoUsed     = 0;
 
@@ -2754,15 +2753,6 @@ bool CRobotMain::EventFrame(const Event &event)
         }
     }
 
-    if (m_delayWriteMessage > 0)
-    {
-        m_delayWriteMessage --;
-        if (m_delayWriteMessage == 0)
-        {
-            m_displayText->DisplayError(INFO_WRITEOK, Math::Vector(0.0f,0.0f,0.0f));
-        }
-    }
-
     if (GetMissionType() == MISSION_CODE_BATTLE)
     {
         if (!m_codeBattleInit)
@@ -5128,10 +5118,15 @@ bool CRobotMain::IOWriteScene(const char *filename, const char *filecbot, char *
     CBotClass::SaveStaticState(file);
     fClose(file);
 
-    m_delayWriteMessage = 4;  // displays message in 3 frames
     return true;
 }
 
+//! Notifies the user that scene write is finished
+void CRobotMain::IOWriteSceneFinished()
+{
+    m_displayText->DisplayError(INFO_WRITEOK, Math::Vector(0.0f,0.0f,0.0f));
+}
+
 //! Resumes the game
 CObject* CRobotMain::IOReadObject(CLevelParserLine *line, const char* filename, int objRank)
 {

src/object/robotmain.h

@@ -299,6 +299,7 @@ public:
 
     bool        IsBusy();
     bool        IOWriteScene(const char *filename, const char *filecbot, char *info);
+    void        IOWriteSceneFinished();
     CObject*    IOReadScene(const char *filename, const char *filecbot);
     void        IOWriteObject(CLevelParserLine *line, CObject* obj);
     CObject*    IOReadObject(CLevelParserLine *line, const char* filename, int objRank);
@@ -479,7 +480,6 @@ protected:
     bool            m_satcomRepeat;
     std::string     m_editorTrack;
     bool            m_editorRepeat;
-    int             m_delayWriteMessage;
     int             m_movieInfoIndex;
 
     CObject*        m_controller;