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
84
85
86
87
88
89
90
91
92
93
94
95
96
/// You can use the `fps_gameloop!` macro to avoid writing a lot of boilerplate code. Take this block of code from a program written using the `gemini-engine` crate, for example:
/// ```no_run
/// # use gemini_engine::{core::{ColChar, Vec2D}, view::View, mesh3d::{Mesh3D, Transform3D}, view3d::Viewport, gameloop};
/// # use std::time::Instant;
/// # let mut view = View::new(0, 0, ColChar::BACKGROUND);
/// # let mut viewport = Viewport::new(Transform3D::default(), 0.0, Vec2D::ZERO);
/// viewport.objects.push(Mesh3D::default_cube());
/// let FPS = 30.0;
///
/// let mut frame_skip = false;
/// loop {
/// let now = Instant::now();
///
/// // Logic
/// let cube_transform = &mut viewport.objects[0].transform;
/// *cube_transform = cube_transform
/// .mul_mat4(&Transform3D::from_rotation_y(-0.05));
///
/// // Rendering
/// if !frame_skip {
/// view.clear();
/// view.draw(&viewport);
/// view.display_render().unwrap();
/// }
///
/// let elapsed = now.elapsed();
/// frame_skip = gameloop::sleep_fps(FPS, Some(elapsed));
/// }
/// ```
/// There's a lot of boilerplate code here. That's where this macro comes in. Here is the same block of code, rewritten with `fps_gameloop!`:
/// ```no_run
/// # use gemini_engine::{core::{ColChar, Vec2D}, view::View, view3d::{Viewport, DisplayMode}, mesh3d::{Mesh3D, Transform3D}};
/// # use main_loop_root::fps_gameloop;
/// # let mut view = View::new(0, 0, ColChar::BACKGROUND);
/// # let mut viewport = Viewport::new(Transform3D::default(), 0.0, Vec2D::ZERO);
/// viewport.objects.push(Mesh3D::default_cube());
/// let FPS = 30.0;
///
/// fps_gameloop!(
/// {
/// let cube_transform = &mut viewport.objects[0].transform;
/// *cube_transform = cube_transform
/// .mul_mat4(&Transform3D::from_rotation_y(-0.05));
/// },
/// {
/// view.clear();
/// view.draw(&viewport);
/// view.display_render().unwrap();
/// },
/// FPS
/// );
/// ```
/// The code is now a lot less cluttered. This macro accepts three fragments (and an optional fourth fragment):
/// - A logic block fragment for code that should run every single frame
/// - A render block fragment for code related to displaying to the terminal (all plots, draws and renders). This will not run if the previous frame took too long
/// - An `f32` fragment representing the desired frames per second.
/// - Optionally, a function of type `Fn(`[`Duration`](std::time::Duration)`, bool)`. The passed duration will be the time taken to render everything, and the passed `bool` indicates whether the last frame was skipped or not. It can be used to, say, print debug info. Here's an example:
/// ```no_run
/// # use main_loop_utils::fps_gameloop;
/// # use std::time::Duration;
/// fps_gameloop!(
/// // -- other fields --
/// # {}, {}, 0.0,
/// |elapsed: Duration, frame_skip: bool| {
/// println!(
/// "Elapsed: {:.2?}µs | Frame skip: {}",
/// elapsed.as_micros(),
/// frame_skip
/// );
/// }
/// );