DirectX and OpenGL Textures do not match in y coordinate

[sebastian.vesenmayer]

Hello,

we do have issues when creating a Texture Object the y coordinates don't match between opengl and directx. The used textures are upside down in this case.

This bug can be seen in 2.11 and 2.13, maybe older versions too.

Is there any quick fix?

Thanks

texture_swap_reproducer.zip

[silent]

Hi Sebastian,

That's because DX and GL have different coordinate systems. You need to check Render::isFlipped() flag and flip your textures to match the desired results.

Thanks!

[sebastian.vesenmayer]

How can I flip a Texture object? Is there a method or do I need to manually change pixeld data?

Do I need to flip the Texture object every time after rendering to it?

Should this not be API independently?

[silent]

The easiest way to do this is write a custom shader that will flip the incoming texture and call it after each renderTexture(). Do you need any help with this?

We can't automatically do this because we don't really know when and how this texture will be used after (will it be assigned to an object or directly displayed on screen as in your scenario).

Thanks!

[sebastian.vesenmayer]

We are using this in 2 ways right now. For displaying directly and postprocessing it in a shader.

I did already the workarround for displaying directly, by swapping the texture coordinates of a plane, but I think using the uv_transform would be a better solution.

The second use case is in a compute shader, so I may duplicate this code and change it for directx then.

[silent]

Swapping UVs is also fine. Didn't think about it :)