[Image Removed]
On machines with AMD graphics cards, HLOD exhibits this strange green or black coloring. HLOD uses SVT. After frame capture analysis, the issue was finally traced to UV overflow during VT sampling, which caused sampling from an incorrect position on the Physical Texture, resulting in wrong color samples. This rendering issue does not occur on NVIDIA cards and has a high reproduction rate on AMD cards.
[Image Removed]
As shown in the figure, the Color and PBR maps in SVT are stored on the same BC1 Physical Space. Therefore, when UV coordinates are incorrect, it is easy to sample tiles from the green PBR channel by mistake.
[Image Removed]
The PageTable in the problematic frame capture looks a bit odd, but I’m not certain if there is an actual issue with it.
[Image Removed]
The value of VirtualTexture_PageTable should not exceed 20 bits, but the values of both erroneous page tables have exceeded 20 bits.One of the pagetable values obtained is 0xA3630000.
[Attachment Removed]
Hello,
Thank you for reaching out.
I’ve been assigned this issue, and we will be looking into it for you.
Can you please send us a minimal test project that demonstrates this, and include screenshots of the issue from that test project?
The guide for test projects:
[Content removed]
[Attachment Removed]
Hello, I’m having some trouble with TestProject, our game project is very huge, and test project could not replay the fault.
RenderDoc always crash when replay in AMD. I can provide a PIX frame capture. Hope this helps. The issue seems to start as early as when we locate the PageTable. I’d like to ask if Epic has any historical records of this issue on AMD hardware.
[Attachment Removed]
Hello,
The Pix capture is failing to replay on our machine.
Can you please try updating to the latest driver version?
To avoid the crashes with RenderDoc, please try disabling “Reply->Use API Validation on replay” in RenderDoc’s settings.
If this does not work, can you please create a GPU Dump for us using the console command: “dumpgpu”?
For captures, please ensure that “r.RHISetGPUCaptureOptions” is set to 1. This will turn on draw events.
[Attachment Removed]