Font Displays Corrupted on XSX/PS5

[JOSKevinW]

We've recently integrated Cog into our Unreal Engine using 5.2.1. We've encountered the font looks corrupted when on the XSX and PS5 platforms; they look correct on Windows. When we increase the DpiScale, it still looks incorrect. Do you expect that this would work on these other platforms too?

[arnaud-jamin]

Hello,

I was not able to test on other platforms than PC. I do not have any devkit.

Sorry.

[arnaud-jamin]

Btw, the code handling the font in Cog is very small. Imgui is handling 99% of it.

[JOSKevinW]

This appears to be addressed by replacing the texture loading code in FCogImguiContext::BuildFont.

It's also notable that the texture format is not PF_R8G8B8A8, it is 4 bytes per pixel, not 8.

`FontAtlasTexture = UTexture2D::CreateTransient(TextureWidth, TextureHeight);
FontAtlasTexture->UpdateResource();

auto SrcDataCleanup = [](uint8* Data) { delete[] Data; };

FUpdateTextureRegion2D* TextureRegion = new FUpdateTextureRegion2D(0, 0, 0, 0, TextureWidth, TextureHeight);
auto DataCleanup = [SrcDataCleanup](uint8* Data, const FUpdateTextureRegion2D* UpdateRegion)
{
	delete UpdateRegion;
};
FontAtlasTexture->UpdateTextureRegions(0, 1u, TextureRegion, BytesPerPixel * TextureWidth, BytesPerPixel, TextureDataRaw, DataCleanup);`

As a separate issue, Cog rendered on console is very small as opposed to PC. I adapted SCogImguiWidget::OnPaint's calculation of Transform to match what imGui's Unreal integration does. The original code only accounts for transform and not scale.

FSlateRenderTransform displayPosition(DrawData.DisplayPos); const FSlateRenderTransform& WidgetToScreen = AllottedGeometry.GetAccumulatedRenderTransform(); const FSlateRenderTransform Transform = FCogImguiHelper::RoundTranslation(displayPosition.Concatenate(WidgetToScreen));

[arnaud-jamin]

Thanks a lot for the research! Don't hesitate to make a pull request!

Sorry I didn't reply sooner, was too busy.

[JailbreakPapa]

This appears to be addressed by replacing the texture loading code in FCogImguiContext::BuildFont.

It's also notable that the texture format is not PF_R8G8B8A8, it is 4 bytes per pixel, not 8.

`FontAtlasTexture = UTexture2D::CreateTransient(TextureWidth, TextureHeight); FontAtlasTexture->UpdateResource();

auto SrcDataCleanup = [](uint8* Data) { delete[] Data; };

FUpdateTextureRegion2D* TextureRegion = new FUpdateTextureRegion2D(0, 0, 0, 0, TextureWidth, TextureHeight);
auto DataCleanup = [SrcDataCleanup](uint8* Data, const FUpdateTextureRegion2D* UpdateRegion)
{
	delete UpdateRegion;
};
FontAtlasTexture->UpdateTextureRegions(0, 1u, TextureRegion, BytesPerPixel * TextureWidth, BytesPerPixel, TextureDataRaw, DataCleanup);`

As a separate issue, Cog rendered on console is very small as opposed to PC. I adapted SCogImguiWidget::OnPaint's calculation of Transform to match what imGui's Unreal integration does. The original code only accounts for transform and not scale.

FSlateRenderTransform displayPosition(DrawData.DisplayPos); const FSlateRenderTransform& WidgetToScreen = AllottedGeometry.GetAccumulatedRenderTransform(); const FSlateRenderTransform Transform = FCogImguiHelper::RoundTranslation(displayPosition.Concatenate(WidgetToScreen));

Thanks for these fixes! we just started using cog and were wondering why fonts were messing up.

[sergi-gonzalez]

hI @JailbreakPapa @arnaud-jamin

We were using your solution but we had random crashes when updating the font texture.
The problem is that TextureDataRaw could be already deleted when the render command is processed.
In order to fix this problem, the simplest solution is to call FlushRenderingCommands() after UpdateTextureRegions to guarantee that TextureDataRaw is still alive when the render command is processed.

Hope it helps

[arnaud-jamin]

If you want to do a pull request don't hesitate.
I'm not able to test on consoles.

[sdugloudYBG]

For anyone reading this thread, the main issue (font corruption on consoles) has been fixed on July 2025, within the pull request #58: 4e27ec6.

For the second issue mentioned (small rendering of Cog on Console), the proposed fix doesn't work. It will scale up the whole rendering area, making it bigger than the actual screen space. Imgui is bigger yes, but a good chunk of it is not visible (right and bottom parts).
The solution I've found is to apply a "widget/viewport scale" in addition to the user DPI scale on both font and style, using the actual MainWidget geometry scale.

bool FCogImguiContext::BeginFrame(float InDeltaTime)
{
    [...]
    if (MainWidget != nullptr)
    {
        IO.DisplaySize = FCogImguiHelper::ToImVec2(MainWidget->GetTickSpaceGeometry().GetAbsoluteSize());
        // FIX+
        float mainViewportScale = MainWidget->GetTickSpaceGeometry().GetAccumulatedLayoutTransform().GetScale();
        if (mainViewportScale != ViewportScale)
        {
            ViewportScale = mainViewportScale;
            bRefreshDPIScale = true; // Force refresh font and scaling
        }
        // FIX-
    }
    [...]
    if (bRefreshDPIScale)
    {
        bRefreshDPIScale = false;

        BuildFont();

        ImGuiStyle NewStyle = ImGuiStyle();
        ImGui::GetStyle() = MoveTemp(NewStyle);
        ImGui::GetStyle().ScaleAllSizes(ViewportScale * DpiScale); // FIX+ Add ViewportScale
    }

I will stress-test this before doing a pull request.