How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix Flipped Texture Coordinates After Cross-Compiling HLSL to GLSL

Q: What causes flipped texture coordinates after cross-compiling a shader?

HLSL and GLSL disagree on the texture coordinate origin and clip-space Y direction, so a shader ported between them samples or renders vertically mirrored.

Quick answer: Flip the V coordinate (1.0 - v) or invert the clip-space Y at the boundary where the convention changes, doing it once and consistently.

Direct3D's texture origin is top-left and its clip-space Y points down relative to OpenGL's bottom-left and Y-up. Cross-compiling shaders or sharing assets across APIs commonly produces vertically flipped results. Here is how to fix it.

How to fix it

1. Flip the V coordinate

Where the convention differs, sample with uv.y = 1.0 - uv.y so the top-left vs bottom-left origin mismatch is corrected at the source UV.

2. Handle clip-space Y for render targets

When rendering to an offscreen target consumed by the other API, negate clip-space Y in the vertex output so the image is not stored upside down.

3. Fix it in one place

Pick a single canonical convention and convert only at the API boundary; flipping in multiple stages cancels out and produces intermittent, hard-to-trace mirroring.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The errors you never hear about are the ones quietly costing you players. Visibility turns them into a worklist.