taisei/src/global.c
Andrei Alexeyev 180f9e3856
Emscripten compatibility (#161)
* Major refactoring of the main loop(s) and control flow (WIP)

run_at_fps() is gone 🦀

Instead of nested blocking event loops, there is now an eventloop API
that manages an explicit stack of scenes. This makes Taisei a lot more
portable to async environments where spinning a loop forever without
yielding control simply is not an option, and that is the entire point
of this change.

A prime example of such an environment is the Web (via emscripten).
Taisei was able to run there through a terrible hack: inserting
emscripten_sleep calls into the loop, which would yield to the browser.
This has several major drawbacks: first of all, every function that
could possibly call emscripten_sleep must be compiled into a special
kind of bytecode, which then has to be interpreted at runtime, *much*
slower than JITed WebAssembly. And that includes *everything* down the
call stack, too! For more information, see
https://emscripten.org/docs/porting/emterpreter.html

Even though that method worked well enough for experimenting, despite
suboptimal performance, there is another obvious drawback:
emscripten_sleep is implemented via setTimeout(), which can be very
imprecise and is generally not reliable for fluid animation. Browsers
actually have an API specifically for that use case:
window.requestAnimationFrame(), but Taisei's original blocking control
flow style is simply not compatible with it. Emscripten exposes this API
with its emscripten_set_main_loop(), which the eventloop backend now
uses on that platform.

Unfortunately, C is still C, with no fancy closures or coroutines.
With blocking calls into menu/scene loops gone, the control flow is
reimplemented via so-called (pun intended) "call chains". That is
basically an euphemism for callback hell. With manual memory management
and zero type-safety. Not that the menu system wasn't shitty enough
already. I'll just keep telling myself that this is all temporary and
will be replaced with scripts in v1.4.

* improve build system for emscripten + various fixes

* squish menu bugs

* improve emscripten event loop; disable EMULATE_FUNCTION_POINTER_CASTS

Note that stock freetype does not work without
EMULATE_FUNCTION_POINTER_CASTS; use a patched version from the
"emscripten" branch here:

    https://github.com/taisei-project/freetype2/tree/emscripten

* Enable -Wcast-function-type

Calling functions through incompatible pointers is nasal demons and
doesn't work in WASM.

* webgl: workaround a crash on some browsers

* emscripten improvements:

    * Persist state (config, progress, replays, ...) in local IndexDB
    * Simpler HTML shell (temporary)
    * Enable more optimizations

* fix build if validate_glsl=false

* emscripten: improve asset packaging, with local cache

Note that even though there are rules to build audio bundles, audio
does *not* work yet. It looks like SDL2_mixer can not work without
threads, which is a problem. Yet another reason to write an OpenAL
backend - emscripten supports that natively.

* emscripten: customize the html shell

* emscripten: force "show log" checkbox unchecked initially

* emscripten: remove quit shortcut from main menu (since there's no quit)

* emscripten: log area fixes

* emscripten/webgl: workaround for fullscreen viewport issue

* emscripten: implement frameskip

* emscripter: improve framerate limiter

* align List to at least 8 bytes (shut up warnings)

* fix non-emscripten builds

* improve fullscreen handling, mainly for emscripten

* Workaround to make audio work in chromium

emscripten-core/emscripten#6511

* emscripten: better vsync handling; enable vsync & disable fxaa by default
2019-03-09 21:32:32 +02:00

63 lines
1.6 KiB
C

/*
* This software is licensed under the terms of the MIT-License
* See COPYING for further information.
* ---
* Copyright (c) 2011-2019, Lukas Weber <laochailan@web.de>.
* Copyright (c) 2012-2019, Andrei Alexeyev <akari@alienslab.net>.
*/
#include "taisei.h"
#include "global.h"
Global global;
void init_global(CLIAction *cli) {
memset(&global, 0, sizeof(global));
tsrand_init(&global.rand_game, time(0));
tsrand_init(&global.rand_visual, time(0));
tsrand_switch(&global.rand_visual);
memset(&global.replay, 0, sizeof(Replay));
global.replaymode = REPLAY_RECORD;
global.frameskip = cli->frameskip;
if(cli->type == CLI_VerifyReplay) {
global.is_headless = true;
global.is_replay_verification = true;
global.frameskip = 1;
} else if(global.frameskip) {
log_warn("FPS limiter disabled. Gotta go fast! (frameskip = %i)", global.frameskip);
}
fpscounter_reset(&global.fps.logic);
fpscounter_reset(&global.fps.render);
fpscounter_reset(&global.fps.busy);
}
// Inputdevice-agnostic method of checking whether a game control is pressed.
// ALWAYS use this instead of SDL_GetKeyState if you need it.
// XXX: Move this somewhere?
bool gamekeypressed(KeyIndex key) {
return SDL_GetKeyboardState(NULL)[config_get_int(KEYIDX_TO_CFGIDX(key))] || gamepad_game_key_pressed(key);
}
static SDL_atomic_t quitting;
void taisei_quit(void) {
if(SDL_AtomicCAS(&quitting, 0, 1)) {
log_info("Exit requested");
}
}
bool taisei_quit_requested(void) {
return SDL_AtomicGet(&quitting);
}
void taisei_commit_persistent_data(void) {
config_save();
progress_save();
vfs_sync(VFS_SYNC_STORE, NO_CALLCHAIN);
}