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author | Jesse Buhagiar <jooster669@gmail.com> | 2021-08-20 21:19:42 +1000 |
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committer | Ali Mohammad Pur <Ali.mpfard@gmail.com> | 2021-08-21 13:48:59 +0430 |
commit | 0152f1924b9330e00c027c8b0cc0e7cab22a89f0 (patch) | |
tree | f29e7678583fa7beb1d93ea6290ff76793e5ff43 /Ports/libatomic_ops | |
parent | 2fe5f1528fc134ced8c8f2e0a5d5ec3b9f2a44f4 (diff) | |
download | serenity-0152f1924b9330e00c027c8b0cc0e7cab22a89f0.zip |
LibGL: Use integer comparison for GL_EQUAL and GL_NOTEQUAL
This is an interesting quirk that occurs due to us using the x87 FPU
when Serenity is compiled for the i386 target. When we calculate our
depth value to be stored in the buffer, it is an 80-bit x87
floating point number, however, when stored into the DepthBuffer,
this is truncated to 32 bits. This 38 bit loss of precision means
that when x87 `FCOMP` is eventually used here the comparison fails.
This could be solved by using a `long double` for the depth buffer,
however this would take up significantly more space and is completely
overkill for a depth buffer. As such, comparing the first 32-bits of
this depth value is "good enough" that if we get a hit on it being
equal, we can pretty much guarantee that it's actually equal.
Diffstat (limited to 'Ports/libatomic_ops')
0 files changed, 0 insertions, 0 deletions