This patch optimizes the loop used to limit the framerate in 30-FPS-only
mode so that it uses SDL_Delay() instead of an accumulator. This means
that the game will take up less CPU power in 30-FPS-only mode. This also
means that the game loop code has been simplified, so there's only two
while-loops, and only two places where game.over30mode is checked, thus
leading to easier-to-understand logic.
Using an accumulator here would essentially mean busywaiting until the
34 millisecond timer was up. (The following is just what leo60228 told
me.) Busywaiting is bad because it's inefficient. The operating system
assumes that if you're busywaiting, you're performing a complex
calculation and handles your process accordingly. And this is why
sleeping was invented, so you could busywait without taking up
unnecessary CPU time.
There's a bug where playtesting from Ved doesn't properly play the music
of the level, due to no fault with Ved.
This was because the music was being faded out by
scriptclass::startgamemode() case 23 after main() called music.play().
To fix this, just call music.play() when all the other variables are
being set in Game::customloadquick().
The problem we're running into is entirely contained in the Screen - we need to
either decouple graphics context init from Screen::init or we need to take out
the screenbuffer interaction from loadstats (which I'm more in favor of since we
can just pull the config values and pass them to Screen::init later).
Now that you have a mini menu in MAPMODE, it's a bit annoying to have to
deal with the slowed-down timestep when pressing left/right/ACTION
inside it. Especially since going to an options menu restores the
timestep back to normal (because it's in TITLEMODE). Also removed it
from TELEPORTERMODE for consistency.
The Alt+Enter Glitch is a funny glitch where if you press any toggle
fullscreen keybind during a cutscene, Viridian will stop moving (if
they're being moved by a walk()) and ACTION will start being held down
for them. Meaning in most cases you can interrupt a walk and flip at the
same time.
This can obviously break cutscenes if a casual just wants to toggle
fullscreen, so I'm fixing it. But it will be unfixed in glitchrunner
mode in case you want to glitch out custom levels (I know I do).
More information on the Alt+Enter Glitch is available here:
https://gitgud.io/infoteddy/vvvvvv-knowledge/blob/master/bugs/bugs.md#the-altenter-glitch
(The page is a bit outdated, some bugs have been fixed in 2.3 already.)
This patch is very kludge-y, but at least it fixes a semi-noticeable
visual issue in custom levels that use internal scripts to spawn
entities when loading a room.
Basically, the problem here is that when the game checks for script
boxes and sets newscript, newscript has already been processed for that
frame, and when the game does load a script, script.run() has already
been processed for that frame.
That issue can be fixed, but it turns out that due to my over-30-FPS
game loop changes, there's now ANOTHER visible frame of delay between
room load and entity creation, because the render function gets called
in between the script being loaded at the end of gamelogic() and the
script actually getting run.
So... I have to temporary move script.run() to the end of gamelogic()
(in map.twoframedelayfix()), and make sure it doesn't get run next
frame, because double-evaluations are bad. To do that, I have to
introduce the kludge variable script.dontrunnextframe, which does
exactly as it says.
And with all that work, the two-frame (now three-frame) delay is fixed.
In my previous PR, I wrongly assumed that I could just replace the `i`
handling code of those options with an `i++;` at the beginning, and thus
I could put all blocks' `i++;` into ARG_INNER(). Well I was wrong,
because the code was written the original way for a reason, namely that
we still need `i` to point to the -playx/y/rx/ry/gc/music argv so we can
re-compare which argument led us into this code block.
Just to be helpful if someone has a failing FILESYSTEM_init(), but
doesn't know that's their issue and keeps wondering why VVVVVV just
exits with code 1.
The command-line argument parsing code has a lot of copy-paste. This
copy-paste would get even worse if I added safety checks to make sure
you couldn't index argv out-of-bounds by having an argument like
`-renderer` without having anything after it, i.e. you'd be doing the
command `./VVVVVV -renderer`.
Previously, only the playtest arguments (apart from the recently-added
`playassets`) had this safety check, but the message it printed whenever
the safety check failed was always "-playing option requires one
argument" regardless of whatever argument actually failed to be parsed.
So I fixed it so that all arguments actually output the correct
corresponding failed argument instead.
Also, `strcmp(argv[i], <name>) == 0` is really kind of noisy, even if
you understand what it does perfectly well.
So I refactored it with a bunch of macros. ARG() just does the strcmp()
char* comparison, and ARG_INNER() does the safety check and returns 1,
along with printing a message, if the safety check fails.
This is used if you're loading a level file from STDIN. The game needs
to know the actual level assets directory you're referring to, since
when it gets the level from STDIN, it doesn't know the actual filename
of the level.
Fixes#309.
Ugh, this is terrible and stupid and I hate myself for it.
Anyway, since the SDL2 VSync hint only applies when the renderer is
created, we have to re-create the renderer whenever VSync is toggled.
However, this also means we need to re-create m_screenTexture as well,
AND call ResizeScreen() after that or else the letterbox/integer modes
won't be applied.
Unfortunately, this means that in main(), gameScreen.init() will create
a renderer only to be destroyed later by graphics.processVsync().
There's not much we can do about this. Fixing this would require putting
graphics.processVsync() before gameScreen.init(). However, in order to
know whether the user has VSync set, we would have to call
game.loadstats() first, but wait, we can't, because game.loadstats()
mutates gameScreen! Gahhhhhh!!!!
@leo60228 suggested to fix that problem (
https://github.com/TerryCavanagh/VVVVVV/pull/220#issuecomment-624217939
) by adding NULL checks to game.loadstats() and then calling it twice,
but then you're trading wastefully creating a renderer only to be
destroyed, for wastefully opening and parsing unlock.vvv twice instead
of once. In either case, you're doing something twice and wasting work.
Otherwise a NO_CUSTOM_LEVELS build would fail. Also I got rid of the
'graphics.flipmode = false;' in the fixed loop because I don't think it
does anything.
This is needed for the next step. I want to put all the loop stuff in
their own functions so the code isn't one huge blob, but to do that I'll
need to make 'time' a global variable, but I can't do that because
actually 'time' is already a function, apparently, and you're only
allowed to shadow variables when already inside a function.
This is to make sure no lerping occurs in 30-FPS mode, otherwise things
might look weird. A good case that this fixes is how entities look in a
double-gotoroom (they should be completely frozen in 30-FPS mode).
There is now an option in "graphic options" named "toggle fps", which
toggles whether the game visually runs at 1000/34 FPS or over 1000/34
FPS. It is off by default.
I've had to put the entire game loop in yet another set of braces, I'll
indent it next commit.
This is because otherwise, on my Linux system at least, the game will
take up a lot of CPU that it doesn't really need to (I only have a 60hz
monitor).
On Windows, it looks like Windows already enforces V-sync for
applications anyway, unless they have exclusive fullscreen control.
Linux doesn't enforce V-sync on apps and lets them take up as much CPU
as they want, so I'm putting this here to limit the framerate.
The game is already actually 30 FPS anyway, the nice smooth FPS is just
visual. V-sync won't introduce any more "input lag" than already exists.
As much as it looks cool to have a slowly-scrolling background on the
title screen, it's quite annoying that slowmode applying on the title
screen mean that your keypresses are less responsive.
To fix this, I draw another row/column of incoming textures. But of
course, I have to extend the size of the towerbuffer, otherwise the
incoming textures will just be gone.
This has to be done in order to fix rendering when on a conveyor or
moving platform and actively moving with or against it. Pretty sure this
shouldn't break anything, oldxp/oldyp is mostly visual after all (and by
the time it's used for gravity line collision checking,
updateentitylogic() would've already gotten around to it anyway).
Incidentally, this also fixes a jitter that would occur if you were
moving at the time you died or collected a trinket or custom crewmate,
due to the game temporarily freezing and either doing deathsequence or
completestop.
Otherwise the screen will shake too fast for my liking.
Also I'm planning to add an FPS limiting option later (because right
now, un-capping the FPS is pretty wasteful and eats up lots of
resources, especially since I have only a 60hz monitor), and it'd feel
weird if screen shaking updated every delta timestep.
I've added a function Graphics::lerp() which simply interpolates between
two values given a certain alpha value. It's just like drawing a
straight line between two points.
Also, Graphics now has an `alpha` attribute, and it is set on every
deltatime update to be used in linear interpolation.
Ok, and this is where the fun starts.
In an ideal world, this would be the end of this patch. However, of
course, there are many, MANY places in the game that update
fixed-timestep timers DIRECTLY inside the render function, which is not
ideal because it means those timers go super fast.
I'll have to fix those later.
Ok, NOW indent it. I didn't indent it previously because the diffs are
annoying to read if there's an indent that doesn't otherwise change
anything (and even now it's pretty annoying to read).
Alright, this is the start of the over-30-FPS patch!
First things first, we'll need to make it possible to have a separate
deltatime loop outside of the fixed timestep loop. And for that, we
can't be using SDL_Delay(), as SDL_Delay() (as you might imagine) blocks
the whole program.
Instead we'll be using this thing called an accumulator. It looks at how
long the previous poll took (the raw deltatime), and lets timesteps pass
accordingly.
On a side note, I've had to split the `time` and `timePrev` declaration
each onto their own separate line, otherwise there's undefined behavior
from `time` not being initialized.
I use `accumulator = fmodf(...)` instead of `accumulator -=
timesteplimit` because otherwise it'll fast-forward if it's behind,
which is a jarring thing to see.
Also in preparation for what's going to come down the over-30-FPS road,
I've also added `deltatime` and `alpha`. `deltatime` is going to be used
if the game is in slowdown mode, and `alpha` is going to be used for
linear interpolation of animations.
By the way, what was the main game loop previously (and is now the new
timestep loop) is now in an extra set of curly braces, but I haven't
indented it yet to reduce the noise in this commit.
A few months ago, I added ghosts to the VVVVVV: Community Edition editor. I was told recently I should think
about upstreaming it, and with Terry saying go ahead I finally ported them into VVVVVV. There's one slight
difference however--you can choose whether you have them or not in the editor's settings menu. They're off by
default, and this is saved to the save file.
Anyway, when you're playtesting, the game saves the players position, color, room coordinates and sprite every 3
frames. The max is 100, where if it tries to add more, the oldest one gets removed.
When you exit playtesting, the saved positions appear one at a time, and you can use the Z key to speed it up.
[Here's a video of them in action.](https://o.lol-sa.me/4H21zCv.mp4)
