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
/// Configuration for an orientation axes widget.
///
/// Renders XYZ axis arrows in a corner of the viewport.
/// The axes rotate with the camera to show the current viewing orientation.
/// Position and size are in normalized device coordinates [0, 1].
#[derive(Debug, Clone)]
pub struct AxesWidget {
/// Position of the widget center in NDC [0, 1] (bottom-left origin).
pub position: [f32; 2],
/// Size (radius) in NDC units.
pub size: f32,
/// Whether to show axis labels (X, Y, Z).
pub show_labels: bool,
/// Whether the widget is enabled.
pub enabled: bool,
}
impl Default for AxesWidget {
fn default() -> Self {
Self {
position: [0.1, 0.1],
size: 0.07,
show_labels: true,
enabled: true,
}
}
}
impl AxesWidget {
pub fn new() -> Self {
Self::default()
}
/// Compute the 2D projected axis endpoints for the given view matrix.
///
/// Returns `[(tip_x, tip_y, [r,g,b], label)]` for X, Y, Z axes.
/// Coordinates are in NDC [0, 1].
pub fn projected_axes(&self, view_matrix: &[[f64; 4]; 4]) -> Vec<([f32; 2], [f32; 3], char)> {
let axes = [
([1.0, 0.0, 0.0f64], [1.0f32, 0.2, 0.2], 'X'),
([0.0, 1.0, 0.0f64], [0.2, 1.0, 0.2], 'Y'),
([0.0, 0.0, 1.0f64], [0.3, 0.3, 1.0], 'Z'),
];
let mut result = Vec::with_capacity(3);
for (dir, color, label) in &axes {
// Transform direction by the rotational part of the view matrix (upper 3x3)
let tx = view_matrix[0][0] * dir[0] + view_matrix[1][0] * dir[1] + view_matrix[2][0] * dir[2];
let ty = view_matrix[0][1] * dir[0] + view_matrix[1][1] * dir[1] + view_matrix[2][1] * dir[2];
// Project to 2D: x goes right, y goes up
let tip_x = self.position[0] + tx as f32 * self.size;
let tip_y = self.position[1] + ty as f32 * self.size;
result.push(([tip_x, tip_y], *color, *label));
}
result
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn default_axes_widget() {
let w = AxesWidget::default();
assert!(w.enabled);
assert!(w.show_labels);
}
#[test]
fn projected_axes_identity() {
let w = AxesWidget::default();
// Identity view matrix
let view = [
[1.0, 0.0, 0.0, 0.0],
[0.0, 1.0, 0.0, 0.0],
[0.0, 0.0, 1.0, 0.0],
[0.0, 0.0, 0.0, 1.0],
];
let axes = w.projected_axes(&view);
assert_eq!(axes.len(), 3);
// X axis tip should be to the right of center
assert!(axes[0].0[0] > w.position[0]);
// Y axis tip should be above center
assert!(axes[1].0[1] > w.position[1]);
}
}