NAN if dt is high in headset_simulator

[nensanders]

lovr/src/modules/headset/headset_simulator.c

Line 468 in 26d17fc

vec3_lerp(state.velocity, velocity, 1.f - expf(-MOVESMOOTH * state.dt));

When restarting on a simulated headset platform the dt can become so high that this line produces a NAN, which breaks rendering further down the line.

I would suggest clamping it at the start of the function.

[bjornbytes]

Ah, I had already fixed this in #727, but it hasn't been merged yet. This was actually caused by a negative dt resulting from forgetting to reset the timing variables properly. I applied the fix to the stable/dev branches. Thanks!