Fix regression in VGA draw's wrapped line case

[kcgen]

After incorporating vgaonly's features as well as using a 32-bit DAC palette, the draw_linear_line_from_dac_palette's wrapped portion of the function was not updated in the same way as the unwrapped (or "whole-line") approach.

This commit moves the line-writing chunk into a lambda (to avoid code-repetition), which also ensures they all use the same writing logic.

Fixes #2439.

[dreamer]

Tested our QPEG testcase in debug build - works fine. Thanks @kcgen!

[dreamer]

Oh, compilers complain about unused-lambda-capture? Hmm, maybe constexpr variable does not need to be captured in this case?

[kcgen]

Oh, compilers complain about unused-lambda-capture? Hmm, maybe constexpr variable does not need to be captured in this case?

Interesting; yes - looks like it's using the palette_map by value without needing to be explicitly captured. Oh, this is also true for the bytes_per_palette_pixel, which is also a constexpr value.

(updated)

[kcgen]

Oh, compilers complain about unused-lambda-capture? Hmm, maybe constexpr variable does not need to be captured in this case?

Tug-o'-war between compilers :-) clang is happy now, but MSVC is not:

D:\a\dosbox-staging\dosbox-staging\src\hardware\vga_draw.cpp(377,1): error C3493: 'palette_map' cannot be implicitly captured because no default capture mode has been specified [D:\a\dosbox-staging\dosbox-staging\vs\dosbox.vcxproj]

D:\a\dosbox-staging\dosbox-staging\src\hardware\vga_draw.cpp(378,1): error C3493: 'bytes_per_palette_pixel' cannot be implicitly captured because no default capture mode has been specified [D:\a\dosbox-staging\dosbox-staging

[kcgen]

Tried w/ reference and two values:

... = [&target_addr, palette_map, bytes_per_palette_pixel](...)

But now clang is warning again:

../../src/hardware/vga_draw.cpp:372:42: warning: lambda capture 'palette_map' is not required to be captured for this use [-Wunused-lambda-capture]
        auto write_pixels_from = [&target_addr, palette_map, bytes_per_palette_pixel](const uint8_t* vga_line_start,
                                              ~~^~~~~~~~~~~
../../src/hardware/vga_draw.cpp:372:55: warning: lambda capture 'bytes_per_palette_pixel' is not required to be captured for this use [-Wunused-lambda-capture]
        auto write_pixels_from = [&target_addr, palette_map, bytes_per_palette_pixel](const uint8_t* vga_line_start,

Going back to the single reference.

[kcgen]

Investigated the additional clang static analysis issue:

These turned out to be all voodoo-related:

I've added a commit to accommodate them so we can carry on.

Will merge once this is passing CI.

[dreamer]

Investigated the additional clang static analysis issue:

These turned out to be all voodoo-related:

Yeah, this is weird... we already had 12 warnings with voodoo enabled and now it jumped back up…

Good call, let's keep the higher limit for now and limit it by fixing issues in voodoo code.

[kcgen]

the warning bump was my fault in this PR.

I was testing some SIMD acceleration (both SSE and NEON) in the VGA draw function - and forgot to remove that GCC flag from Meson.

This exposed 4 new warnings in libFLAC that I incorrectly believed were there all along.. I've snipped out that Meson SSE flag and we're back to 12 warnings.

[GranMinigun]

MSVC cannot into standards-conforming lambdas by default, I had it spew out a ton of errors on my branch because of that. You can just cherry-pick 1453a5b (or bump to C++20, MSVC will turn on updated parser automatically then) to make everyone happy.

[johnnovak]

@kcgen Just tested this on my end and now QPEG works fine without any crashes! Great quick fix! 🎉