commit that adds pre-multiplied to images, also changes alpha for colored container?

[cybersoulK]

f893ad1

The first image is before the commit, second is after the commit.
The elements are colored_box and colored_box_container

[LPGhatguy]

Interesting! This should be an easy fix and probably impacts our game too.

[msparkles]

@LPGhatguy we're noticing in #179 that the coloured texts are already premul'd (at least as far as we can tell)

We also found a really bad performance issue in the alpha premultiplication.

We're committing a fix for those because it heavily affects coloured texts, it takes like 5s to write 3 coloured text characters on release right now, Oops!

[msparkles]

P.S. We ran a profiler on yakui example to see that premul'd alpha really is taking too long. It's all on .round()

[LPGhatguy]

@msparkles Those changes seem useful even outside of cosmic text. If the conversion that removes round is the same, I'd take that in a separate PR.

I wonder where the best place to handle the premultiplication in the pipeline is.

[msparkles]

Should we cherry-pick them into a separate branch?

[LPGhatguy]

Did this end up fixed as part of the cosmic text PR?

[cybersoulK]

I haven't updated winit since 0.30. is there a way i could test?
using yakui rev = "ec96d2461374bb84042790c7474c6b16321d488f"

[cybersoulK]

I put some effort into upgrading.
Unfortunately, it doesn't seem like branch main has fixed the issue.

Additionally several colored box layouts and buttons seem to have gotten broken after this commit:
7205a74

[cybersoulK]

I determine the color like so
colored_box_container(Color::rgba(20, 20, 50, 100))

The pipeline uses pre multiplied alpha.

yakui/crates/yakui-wgpu/src/lib.rs

Line 465 in a16421c

blend: Some(wgpu::BlendState::PREMULTIPLIED_ALPHA_BLENDING),

So i guess colored box needs to be premultiplied by yakui somewhere before the rendering.

[cybersoulK]

A quick fork and change PREMULTIPLIED_ALPHA_BLENDING to ALPHA_BLENDING, and even removing
let texture = premultiply_alpha(texture); hasn't reverted to the initial color. 🤷‍♂️

[LPGhatguy]

Super odd, this is something to look into. I imagine it's affecting our game as well but not to the same extent.

[cybersoulK]

I just went back to review the commit and found a silly error. doing A/B testing the colors look the same with this fix.