Imgui Images, missing attributes

[mielsense]

in the sfml backend for imgui there is no option to set the uv coordinates of the top left and bottom right corners

where in imgui

IMGUI_API void Image(
ImTextureID user_texture_id,
const ImVec2& image_size,
const ImVec2& uv0 = ImVec2(0, 0),
const ImVec2& uv1 = ImVec2(1, 1),
const ImVec4& tint_col = ImVec4(1, 1, 1, 1),
const ImVec4& border_col = ImVec4(0, 0, 0, 0)
);

this is a problem because the defaults are flipped compared to sfml, and so this mage the rendered image flipped with no way to be un-flipped ..

would it be possible to add the uv coordinated options to the imgui-sfml backend overloads please ?

[EllySp]

Has this been solved already? I was looking into it but I can't really replicate the issue, plus there's this lines on the Image() implementation that seem to be there to fix this specific issue:

If you still have this problem I'll like to see your code, I just replicated it by doing the following and it didn't flip the image:

    sf::Texture const texture("my_texture.png");
    sf::Sprite sprite(texture);
    while (window.isOpen())
    {
        while (const auto event = window.pollEvent())
        {
            ImGui::SFML::ProcessEvent(window, *event);

            if (event->is<sf::Event::Closed>())
            {
                window.close();
            }
        }

        ImGui::SFML::Update(window, deltaClock.restart());

        ImGui::Begin("Hello, world!");
        // Image within a window, not flipped
        ImGui::Image(texture);
        ImGui::End();

        window.clear();
        // Background image, also not fliped
        window.draw(sprite);
        ImGui::SFML::Render(window);
        window.display();
    }

[mielsense]

Hey !
I should have been more clear sorry, the problem does not occur with textures but with renderTextures (used as a framebuffer in my project) :

Here is a simple demo showcasing the flipped render texture :

sf::RenderTexture frameBuffer;
    if (!frameBuffer.create(800, 600)) {
        return -1;
    }

    sf::Texture texture;
    if (!texture.loadFromFile("texture.png")) {
        return -1;
    }

    sf::Sprite sprite(texture);

    while (window.isOpen()) {
        sf::Event event;
        while (window.pollEvent(event)) {
            ImGui::SFML::ProcessEvent(window, event);

            if (event.type == sf::Event::Closed) {
                window.close();
            }
        }

        ImGui::SFML::Update(window, deltaClock.restart());

        frameBuffer.clear(sf::Color::White);
        frameBuffer.draw(sprite);
        frameBuffer.display();

        sf::Sprite frameBufferSprite(frameBuffer.getTexture());

        ImGui::Begin("Frame Buffer View");
        ImGui::Image(frameBuffer.getTexture(), sf::Vector2f(400, 300));
        ImGui::End();

        ImGui::Begin("Original Texture View");
        ImGui::Image(texture, sf::Vector2f(400, 300));
        ImGui::End();

        window.clear(sf::Color::White);
        window.draw(frameBufferSprite);
        ImGui::SFML::Render(window);
        window.display();
    

[eliasdaler]

By calling this:

ImGui::Image(frameBuffer.getTexture(), sf::Vector2f(400, 300));

you're calling a wrong overload. Instead, it should be called like this:

ImGui::Image(frameBuffer, sf::Vector2f(400, 300));

RenderTextures are stored flipped in VRAM, there's nothing we can do to detect that if you just pass an sf::Texture

@ChrisThrasher - we discussed this in some previous issue, but this thing can be solved better if Texture::m_pixelsFlipped ever gets a public getter.

[ChrisThrasher]

@ChrisThrasher - we discussed this in some previous issue, but this thing can be solved better if Texture::m_pixelsFlipped ever gets a public getter.

SFML/SFML#1770 (comment)

I'll see if there is any desire amongst the team to make this happen. It's mostly up to Binary and Exploiter. I'm not opposed to it.

[mielsense]

Thank you for the help !