fixed point delta time ?

[SeleDreams]

I am working on a game engine for very low end devices like the DS. I wanted to use flecs, but I noticed that if i redefine ecs_ftime_t as an int, the engine will freeze on a call to ecs_progress.
floating point operations are a no-go for this kind of platform.
Is there a way to completely skip the deltatime aspect of flecs ? I just want to use it for ecs. I already manage myself the delta aspect of my engine. I tried passing manual values such as 1 but it doesn't seem to do much.

[copygirl]

Relevant issue: #1166

The issue you described should've been fixed already, but perhaps there was a regression? Worth making sure you are on a recent flecs version. You also do not have to use delta_time yourself, just call ecs_progress at determined intervals and treat each step as progressing by one frame. Or use a component / static value to keep track of delta time and time since world start or similar. If a workaround works for you.

[SeleDreams]

I have my own deltatime used by my engine, that's how it calls ecs_progress every frame at 60fps.
i've set ecs_ftime_t as int and I called ecs_progress as
ecs_progress(p_scene->world, 1);
however ecs_progress after a single frame never returns.

I noticed that if i set a breakpoint and continue through each frame, it will actually work, but if i just play it normally at 60 fps it will freeze after 1 or 2 frames.
there must be some timing management code going on, but i don't want it

[SeleDreams]

I found a fix.
After the initialization of the world, I had to add the line ecs_measure_frame_time(p_scene->world,false); to disable the time management of flecs. after that it didn't freeze anymore

[copygirl]

That might've been enabled by the REST addon? I wonder if it's necessary for statistics to work.

Worth creating an issue for. This code might be the culprit?

flecs/src/world.c

Lines 1843 to 1866 in dd39321

	if ((world->flags & EcsWorldMeasureFrameTime) ||
	(ECS_EQZERO(user_delta_time)))
	{
	ecs_time_t t = world->frame_start_time;
	do {
	if (world->frame_start_time.nanosec || world->frame_start_time.sec){
	delta_time = flecs_insert_sleep(world, &t);
	} else {
	ecs_time_measure(&t);
	if (ECS_NEQZERO(world->info.target_fps)) {
	delta_time = (ecs_ftime_t)1.0 / world->info.target_fps;
	} else {
	/* Best guess */
	delta_time = (ecs_ftime_t)1.0 / (ecs_ftime_t)60.0;
	if (ECS_EQZERO(delta_time)) {
	delta_time = user_delta_time;
	break;
	}
	}
	}
	/* Keep trying while delta_time is zero */
	} while (ECS_EQZERO(delta_time));

[SeleDreams]

that's at least around here that it stayed stuck before