Software renderer off-by-one errors

[unknownbrackets]

The software renderer has several off by one errors, I'm not sure if they're in UV handling or drawing.

Here's one example from Wild Arms XF (alternating between GLES and softgpu - you can see where the triangles aren't matching up or something):

Here's another from Hexyz Force intro (the texture is actually 512x32, slices):

-[Unknown]

[thedax]

Possibly related: FF4's text boxes and some backgrounds/sprites tend to "bounce around" by one pixel or so in GLES mode, when HW transform is on, like the first gif you posted.

[unknownbrackets]

Well, this is only regarding the software renderer, not GLES. I believe GLES is mostly correct here - there's a separate bug for that (and it's actually affected by the vertex cache too iirc.)

-[Unknown]

[thedax]

I know it's for software, I was just seeing if there was a possible connection in how both handle these things.

[unknownbrackets]

The examples I have are all nearest, and if bilinear is forced on, it doesn't happen. This is likely just missing a half-pixel offset (per @hrydgard), which makes sense.

-[Unknown]

[unknownbrackets]

So, it's got a formula like this for the logo:

s = (0.85937500 * 1.0 * 180224 + 0.62109375 * 1.0 * 7168 + 0.62109375 * 1.0 * 62464) / 249856.0;

The result is meant to come to 0.79296875 (406/512), but instead comes to 0.79296869 due to loss of precision.

The other screen has more issues than just the face (text too.) Forcing linear fixes them too but also breaks some other things.

I tried adding small portions but I couldn't find anything that made sense and didn't break anything else...

-[Unknown]

[unknownbrackets]

Reopening this - still a rounding issue in throughmode. It's because the w values as floats are too inaccurate.

Easily seen in Crisis Core.

-[Unknown]

[unknownbrackets]

This was fixed more correctly in #9673. I'm still not sure it's perfect, but the Crisis Core and other cases are now working right.

-[Unknown]