gemini_engine/primitives/
triangle.rs

1use crate::core::{CanDraw, ColChar, Vec2D};
2
3use super::Line;
4
5/// A triangle primitive which implements [`CanDraw`], and so can be drawn to [Canvas](crate::core::Canvas)es
6pub struct Triangle {
7    /// The 3 corners of the triangle
8    pub corners: [Vec2D; 3],
9    /// The [`ColChar`] used to fill the triangle
10    pub fill_char: ColChar,
11}
12
13impl Triangle {
14    /// Create a new `Triangle` from three separate positions and a `ColChar`
15    #[must_use]
16    pub const fn new(pos0: Vec2D, pos1: Vec2D, pos2: Vec2D, fill_char: ColChar) -> Self {
17        Self::with_array([pos0, pos1, pos2], fill_char)
18    }
19
20    /// Create a new `Triangle` from an array of `Vec2D`s and a `ColChar`
21    #[must_use]
22    pub const fn with_array(corners: [Vec2D; 3], fill_char: ColChar) -> Self {
23        Self { corners, fill_char }
24    }
25}
26
27impl CanDraw for Triangle {
28    fn draw_to(&self, canvas: &mut impl crate::core::Canvas) {
29        let mut corners = self.corners;
30        corners.sort_unstable_by_key(|k| k.y);
31        let (x0, y0) = corners[0].into();
32        let (x1, y1) = corners[1].into();
33        let (x2, y2) = corners[2].into();
34
35        let mut x01 = super::interpolate(y0, x0, y1, x1);
36        let x12 = super::interpolate(y1, x1, y2, x2);
37        let x02 = super::interpolate(y0, x0, y2, x2);
38
39        // Concat the two shorter sides
40        x01.pop();
41        let x01_12 = [x01, x12].concat();
42
43        let m = (x01_12.len() as f64 / 2.0).floor() as usize;
44        let (x_left, x_right) = if x02[m] < x01_12[m] {
45            (x02, x01_12)
46        } else {
47            (x01_12, x02)
48        };
49
50        for (i, y) in (y0..y2).enumerate() {
51            for x in x_left[i]..x_right[i] {
52                canvas.plot(Vec2D::new(x, y), self.fill_char);
53            }
54        }
55
56        // Outline (will probably remove later)
57        Line::new(corners[0], corners[1], self.fill_char).draw_to(canvas);
58        Line::new(corners[1], corners[2], self.fill_char).draw_to(canvas);
59        Line::new(corners[2], corners[0], self.fill_char).draw_to(canvas);
60    }
61}
gemini_engine/primitives/triangle.rs

gemini_engine/primitives/
triangle.rs
