possibly adding separate texture upload thread

EscapeTimeVisualWidget.cpp

@@ -14,9 +14,17 @@
 
 ETVImage::ETVImage(EscapeTimeVisualWidget& owner,
                    const Bitmap<float>& img) :
+    ETVImage{ owner, owner.context(), img }
+{
+}
+
+
+ETVImage::ETVImage(EscapeTimeVisualWidget& owner,
+                   QOpenGLContext* context,
+                   const Bitmap<float>& img) :
     owner{ owner }
 {
-    auto& gl = *QOpenGLContext::currentContext()->functions();
+    auto& gl = *context->functions();
     gl.glGenTextures(1, &textureId);
     gl.glActiveTexture(GL_TEXTURE0);
     gl.glBindTexture(GL_TEXTURE_2D, textureId);

EscapeTimeVisualWidget.h

@@ -17,6 +17,9 @@ class ETVImage
 public:
     ETVImage(EscapeTimeVisualWidget& owner,
              const Bitmap<float>& img);
+    ETVImage(EscapeTimeVisualWidget& owner,
+             QOpenGLContext* context,
+             const Bitmap<float>& img);
     ~ETVImage(void);
 
     void draw(float x, float y, float w, float h,

FractalZoomWidget.cpp

@@ -149,16 +149,24 @@ TextureUploader::TextureUploader(EscapeTimeVisualWidget& shareWith, QObject* par
     owner{ shareWith }
 {
     this->context = new QOpenGLContext(this);
+    this->surface = new QOffscreenSurface(owner.context()->screen(), this);
+    surface->create();
     this->context->setFormat(owner.context()->format());
     this->context->setScreen(owner.context()->screen());
     this->context->setShareContext(owner.context());
     bool created = this->context->create();
+    printf("is created: %d\n", created);
 }
 
 
 void TextureUploader::upload(int level, GridIndex i, GridIndex j, Bitmap<float>* bmp)
 {
-    auto etvImg = std::make_shared<ETVImage>(owner, *bmp);
+    bool isCurrent = context->makeCurrent(surface);
+    if (!isCurrent) {
+        printf("texture redirected");
+        return;
+    }
+    auto etvImg = std::make_shared<ETVImage>(owner, context, *bmp);
     delete bmp;
     bmp = nullptr;
     uploaded(level, i, j, std::move(etvImg));
@@ -412,10 +420,10 @@ void FractalZoomWidget::initializeGL(void)
 
 
     if (useUploadThread) {
-        uploader = new TextureUploader(*this, this);
+        uploader = new TextureUploader(*this);
         uploadeThread = new QThread(this);
-        uploader->moveToThread(uploadeThread);
         uploadeThread->start();
+        uploader->moveToThread(uploadeThread);
         connect(&calcer, &Calcer::done, uploader, &TextureUploader::upload);
         connect(uploader, &TextureUploader::uploaded, this, &FractalZoomWidget::cellReadyTex);
     }

FractalZoomWidget.h

@@ -7,6 +7,7 @@
 
 #include <QThreadPool>
 #include <QMutex>
+#include <QOffscreenSurface>
 
 class FractalZoomWidget;
 
@@ -73,6 +74,7 @@ class TextureUploader :
     Q_OBJECT
 
     QOpenGLContext* context;
+    QOffscreenSurface* surface;
     EscapeTimeVisualWidget& owner;
 public:
     TextureUploader(EscapeTimeVisualWidget& shareWith, QObject* parent = nullptr);
@@ -97,7 +99,7 @@ class FractalZoomWidget :
 
     ETVImage* emptyImage;
 
-    const bool useUploadThread = true;
+    const bool useUploadThread = false;
     TextureUploader* uploader;
     QThread* uploadeThread;