1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
|
#include <simloop.h>
#include <assert.h>
static simloop_time_t ddt_from_fps(int fps) {
static constexpr double NANOSECONDS = 1e9;
return (fps == 0) ? 0 : (simloop_time_t)(NANOSECONDS / (double)fps);
}
Simloop simloop_make(const SimloopArgs* args) {
assert(args);
assert(args->update_fps > 0);
return (Simloop){
.frame = 0,
.update =
(SimloopTimeline){
.ddt = ddt_from_fps(args->update_fps),
.time = 0,
},
.render =
(SimloopTimeline){
.ddt = ddt_from_fps(args->max_render_fps),
.time = 0,
},
.first_iter = true,
.updates_since_last_render = false,
};
}
static bool step_update(const Simloop* sim, SimloopTimeline* timeline) {
assert(sim);
assert(timeline);
assert(timeline->ddt > 0);
const simloop_time_t dt = sim->clock - timeline->time;
const bool should_step = dt >= timeline->ddt;
timeline->time += should_step ? timeline->ddt : 0;
return should_step;
}
static bool step_render(const Simloop* sim, SimloopTimeline* timeline) {
assert(sim);
assert(timeline);
bool render = false;
if (timeline->ddt > 0) {
render = step_update(sim, timeline);
} else {
timeline->time = sim->clock;
render = true;
}
return render;
}
void simloop_update(Simloop* sim, simloop_time_t dt, SimloopOut* out) {
assert(sim);
assert(out);
sim->clock += dt;
// Simulation update.
const bool updated = step_update(sim, &sim->update);
sim->updates_since_last_render = sim->updates_since_last_render || updated;
// Simulation render.
const bool rendered =
(sim->updates_since_last_render && step_render(sim, &sim->render)) ||
(sim->first_iter); // Trigger an initial render on the first frame.
sim->updates_since_last_render =
sim->updates_since_last_render && !out->should_render;
// Loop state update.
sim->frame += (updated ? 1 : 0);
sim->first_iter = false;
out->frame = sim->frame;
out->render_elapsed = sim->render.time;
out->update_elapsed = sim->update.time;
out->update_dt = sim->update.ddt;
out->should_update = updated;
out->should_render = rendered;
}
|
