Fixing color order for RGB10A2 on vulkan.

[mtytel]

Not sure why this was flipped but this fixes RGB10A2 frame buffer colors on vulkan.

[bkaradzic]

What is wrong with it?

[mtytel]

Hmm, ok that example is correct.
But if I change the RGBA32F frame buffers in the 38-bloom example to RGB10A2 format. R and B are flipped.
RGBA32F:

RGB10A2:

[mtytel]

OK, now this change seems to make both work.

[mtytel]

@bwrsandman Sorry for the ping but I saw you've touched this format/swizzle code before. You mind taking a look?
It looks like the color was only flipped when creating a framebuffer and not a texture and this change makes both work.

[bwrsandman]

I can have a look over the weekend.
What's missing from the 47-pixel format example to repro the bug?

[mtytel]

Thanks!
The bug is when creating frame buffers with createFrameBuffer and 47-pixelformats uses createTexture2D so it works fine there.

To reproduce the bug change this line

bgfx/examples/38-bloom/bloom.cpp

Line 398 in b927871

, bgfx::TextureFormat::RGBA32F

to use RGB10A2 instead and the colors will change like above (flipping R and B)