[vtk-developers] Problem in VTK 8.2 with defaultFormat() and QVTKOpenGLWidget on Windows 10/Intel

[Elvis Stansvik]

Hi all,

I'm in the process of porting our application to VTK 8.2.0, so
switching to the new QVTKOpenGLWidget where possible (and staying with
QVTKOpenGLNativeWidget where necessary).

I'm struggling with a problem I'm seeing on Windows 10 / Intel
graphics in the new QVTKOpenGLWidget.

When we add some actors to the renderer during runtime and then call
Render(), the rendering seems ineffective (nothing shows up) until the
user resizes the widget a little (causing a second render). The
problem can be "worked around" of course by simply issuing two
successive Render() calls, but this is obviously an ugly workaround.

The problem is not appearing on our Linux or macOS test machines, only
on the Windows 10 machine (Intel graphics, though not sure that
matters).

I started digging around, and it seems the problem can also be "fixed"
by using a OpenGL compatibility profile instead of core profile (which
is what QVTKOpenGLWidget::defaultFormat() returns).

So instead of

  QSurfaceFormat::setDefaultFormat(QVTKOpenGLWidget::defaultFormat());

if I do

  auto format = QVTKOpenGLWidget::defaultFormat();
  format.setProfile(QSurfaceFormat::CompatibilityProfile);
  QSurfaceFormat::setDefaultFormat(format);

that seems to "solve" the problem.

Below is a minimal test case where I simply show a QVTKOpenGLWidget,
and 2 seconds later I set the renderer background to red and call
Render(). For me, the window will not turn red until I resize it a
little (or if I uncomment either of the two commented lines).

Has anyone seen this problem before?

I have not tested with VTK master yet, and I know there has been some
changes, but we would really like to stick to a released version
(8.2.0).

Versions used:

- Windows 10
- Intel UHD Graphics 620 (driver 24.20.100.6344)
- VTK 8.2.0
- Qt 5.12.3 (5.11.1 also tested)

Many thanks in advance for any tips/advice.

Elvis

renderbug.cpp:

#include <QApplication>
#include <QSurfaceFormat>
#include <QTimer>
#include <QtDebug>

#include <QVTKOpenGLWidget.h>

#include <vtkGenericOpenGLRenderWindow.h>
#include <vtkNew.h>
#include <vtkRenderer.h>

int main(int argc, char *argv[])
{
    auto format = QVTKOpenGLWidget::defaultFormat();
    //format.setProfile(QSurfaceFormat::CompatibilityProfile);
    QSurfaceFormat::setDefaultFormat(format);

    QApplication app(argc, argv);

    vtkNew<vtkRenderer> renderer;

    vtkNew<vtkGenericOpenGLRenderWindow> window;
    window->AddRenderer(renderer);

    QVTKOpenGLWidget widget;
    widget.SetRenderWindow(window);

    QTimer::singleShot(2000, [&window, &renderer]() {
        qDebug() << "Setting background to red and rendering";
        renderer->SetBackground(1.0, 0.0, 0.0);
        window->Render();
        //window->Render();
    });

    widget.show();

    return app.exec();
}

CMakeLists.txt:

cmake_minimum_required(VERSION 3.5)

project(renderbug)

find_package(Qt5Widgets REQUIRED)

find_package(VTK 8.2.0 REQUIRED COMPONENTS
    vtkGUISupportQt
    vtkInteractionStyle
    vtkRenderingCore
    vtkRenderingOpenGL2
)

add_executable(renderbug WIN32
    renderbug.cpp
)

target_link_libraries(renderbug PRIVATE
    Qt5::Widgets
    vtkGUISupportQt
    vtkInteractionStyle
    vtkRenderingCore
    vtkRenderingOpenGL2
)

target_include_directories(renderbug SYSTEM PRIVATE
    ${VTK_INCLUDE_DIRS}
)

target_compile_definitions(renderbug PRIVATE
    ${VTK_DEFINITIONS}
)