VK_KHR_Maintenance1 inverted viewport support (for OpenGL scene compat)

[nolankramer]

Just wondering - what's a good way to implement flipping the viewport (for compatibility with OpenGL scenes/gl-style rendering).

From what I understand, it would require making the viewport height negative and moving the y down by the height, and also setting winding order to CW (and then offscreen rendering must be compensated for).

As detailed here: https://www.saschawillems.de/blog/2019/03/29/flipping-the-vulkan-viewport/

Curious if there's an easy way to implement this with VSG? From what I can tell there's quite a few places that would need to either be subclassed (vsg::RenderGraph) or worked around (vsg::WindowResizeHandler behavior).

[robertosfield]

Why would want to do this?

[nolankramer]

Some people might like to render with OpenGL scene compatibility as a backend... personally I worked around this by just flipping UVs on import/export since the asset world seems to be stuck in OpenGL land

[nolankramer]

I did find it WAS possible to do this, but yeah - I had to do all those subclassing and change vsg::WindowResizeHandler, and adding VSG_DECLSPEC to vsg::State

[nolankramer]

It wasn't worth the effort. Entire day wasted