This adds color support to the output of the console on Windows. Now if
you're using Windows 10 build 1511 or later (I think it's build 1511
anyway; they added more VT sequence support in later versions), you will
see colors by default. This isn't due to Windows helping in any way;
this commit has to specifically enable it with SetConsoleMode() because
by default, Windows won't enable color support unless we enable it. (Or
if it's enabled in the registry, but having to go through the registry
to enable basic shit like that is completely fucking stupid.)
I tested this in my Windows 10 virtual machine and it's completely
working.
Previously, we were using `color_enabled` to mean both that the color
was supported and that it was enabled by the user (which it is enabled
by default). But this logic doesn't work well if the color check
function is called again and ends up enabling color after the user
disabled it. To fix this, just separate the two so the user controls one
`color_supported` variable and the `color_enabled` variable is separate.
Check both of them in order to print color, of course.
This adds the `-console` command-line option (for Win32 only) so the
game can spawn an attached console window which will contain all console
output.
This is to make it easier for people to debug on Windows systems.
Otherwise, the only way to get console output would be to either compile
the application as a console app (i.e. switch the subsystem to console)
- which is undesirable for regular users as this makes it so a console
is always spawned even when unwanted - or launch the game with shell
arguments that make it so output is redirected to a file.
As a result, color checking support is factored out of vlog_init() into
its own function, even though we don't support colors on Windows.
They weren't ever being used, and nobody really ever uses the return
value from the printf family of functions anyway. They return how many
bytes were actually printed, but if it's less than you expected then
there's not much you can really do about them. Also the vlog_* functions
were computing them inaccurately because I only set the return value to
the return value of vprintf when there's other print functions being
called, but regardless there's no reason to have a return value here
anyway.
This started when I saw the warning that GetVersionExW was deprecated,
then looked it up and found StackOverflow answers saying that you should
basically detect the feature directly instead of checking the version,
which makes sense to me. Then I found that I could probably detect color
support by using GetConsoleMode and GetStdHandle. But then I asked
myself what the point was unless you could get color output directly in
the terminal, which it seems like you really can't if your app is a GUI
app. (I have no idea why Windows makes this pointless distinction
between console and GUI apps...)
I tested Command Prompt, PowerShell, Windows Terminal (which is just
PowerShell again), and even Git Bash (MINGW64), but none of them will
ever give the console output of a GUI app such as VVVVVV. The closest I
got is that Git Bash doesn't seem to detach the process, but it will
simply produce no output.
At this point I feel like it's not worth it keeping this code around if
it didn't even work in the first place, so I'm removing it. People can
always enable color by using the -forcecolor command-line argument
anyway.
`-forcecolor` will force color to be on. `-nocolor` will force color to
be off.
And just because I'm a nice person, I've also added British versions of
those flags. As a treat.
This includes the bold as well.
INFO is just default, WARN is yellow, ERROR is red.
We try to automatically detect if the output is a TTY (and thus supports
colors), and don't emit colors if so. Windows 10 supports ANSI color
codes starting with a specific build, but we don't care to emit whatever
garbage Microsoft invented for builds older than that.
