siplot 0.4.1

silx-style scientific plotting for egui, rendered with wgpu
Documentation 
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
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144

//! Headless render check for the plot3d P1.3 textured-image pipeline
//! (`render::gpu_scene3d` image layers + `scene3d_image.wgsl`): a 2×2 colour
//! checkerboard placed as a quad in the z=0 plane should project, quadrant by
//! quadrant, to the expected screen colours.
//!
//! The image data is row-major (row 0 first); UV `v=0` is at the origin corner
//! (world y=0), so row 0 lands at the *bottom* of the screen and row 1 at the
//! top (screen y is flipped). With the camera centred on the image:
//!
//! - bottom-left  = (row0, col0) = red
//! - bottom-right = (row0, col1) = green
//! - top-left     = (row1, col0) = blue
//! - top-right    = (row1, col1) = white
//!
//! Asserting the four quadrants proves texture upload, UV mapping, the world-rect
//! quad, and the MVP projection are all correct.

use egui_kittest::Harness;
use egui_kittest::wgpu::{WgpuTestRenderer, create_render_state, default_wgpu_setup};
use siplot::egui::{self, Color32};
use siplot::egui_wgpu::RenderState;
use siplot::{
    Camera, ImageInterpolation, Scene3dGeometry, Scene3dImageLayer, Vec3, install_scene3d,
    paint_scene3d, set_scene3d,
};
use std::cell::RefCell;
use std::rc::Rc;

const SCENE_ID: u64 = 0;
const WIN: f32 = 300.0;

/// Premultiplied-linear RGBA8 for an opaque colour (the layer's pixel format).
fn px(c: Color32) -> [u8; 4] {
    let [r, g, b, a] = egui::Rgba::from(c).to_array();
    [
        (r * 255.0).round() as u8,
        (g * 255.0).round() as u8,
        (b * 255.0).round() as u8,
        (a * 255.0).round() as u8,
    ]
}

struct App {
    camera: Camera,
    last_rect: Option<egui::Rect>,
}

impl App {
    fn new(rs: &RenderState) -> Self {
        install_scene3d(rs);

        // 2×2 image: row0 = [red, green], row1 = [blue, white].
        let mut pixels = Vec::new();
        for c in [Color32::RED, Color32::GREEN, Color32::BLUE, Color32::WHITE] {
            pixels.extend_from_slice(&px(c));
        }
        let mut g = Scene3dGeometry::new();
        g.add_image_layer(Scene3dImageLayer {
            pixels,
            width: 2,
            height: 2,
            origin: [0.0, 0.0, 0.0],
            scale: [1.0, 1.0], // spans world [0,2]×[0,2]
            interpolation: ImageInterpolation::Nearest,
        });
        set_scene3d(rs, SCENE_ID, &g);

        // Camera centred on the image centre (1,1,0), looking down −z.
        let camera = Camera::new(
            30.0,
            0.1,
            100.0,
            (1.0, 1.0),
            Vec3::new(1.0, 1.0, 5.0),
            Vec3::new(0.0, 0.0, -1.0),
            Vec3::new(0.0, 1.0, 0.0),
        );
        Self {
            camera,
            last_rect: None,
        }
    }

    fn ui(&mut self, ui: &mut egui::Ui) {
        let (rect, _resp) = ui.allocate_exact_size(ui.available_size(), egui::Sense::hover());
        paint_scene3d(ui, rect, SCENE_ID, &self.camera, Color32::BLACK);
        self.last_rect = Some(rect);
    }
}

#[test]
fn scene3d_image_quad_projects_its_texels() {
    let rs = create_render_state(default_wgpu_setup());
    let app = Rc::new(RefCell::new(App::new(&rs)));
    let renderer = WgpuTestRenderer::from_render_state(rs);

    let app_ui = app.clone();
    let mut harness = Harness::builder()
        .with_size(egui::vec2(WIN, WIN))
        .with_pixels_per_point(1.0)
        .renderer(renderer)
        .build_ui(move |ui| app_ui.borrow_mut().ui(ui));

    harness.step();
    let rect = app.borrow().last_rect.expect("scene rect captured");

    let image = harness.render().expect("headless wgpu render");
    let (iw, ih) = (image.width() as usize, image.height() as usize);
    let raw = image.as_raw();

    let at = |fx: f32, fy: f32| -> (u8, u8, u8) {
        let x = ((rect.min.x + fx * rect.width()).round() as usize).min(iw - 1);
        let y = ((rect.min.y + fy * rect.height()).round() as usize).min(ih - 1);
        let i = (y * iw + x) * 4;
        (raw[i], raw[i + 1], raw[i + 2])
    };

    // Corners (outside the image quad): the black offscreen clear.
    for (fx, fy) in [(0.03, 0.03), (0.97, 0.97)] {
        let (r, g, b) = at(fx, fy);
        assert!(r < 40 && g < 40 && b < 40, "corner should be black clear");
    }

    // Quadrant centres (image spans the central ~75% of the square rect).
    let red = at(0.313, 0.687);
    let green = at(0.687, 0.687);
    let blue = at(0.313, 0.313);
    let white = at(0.687, 0.313);

    let dominant = |(r, g, b): (u8, u8, u8), ch: usize| {
        let v = [r, g, b];
        v[ch] > 200 && v[(ch + 1) % 3] < 70 && v[(ch + 2) % 3] < 70
    };
    assert!(dominant(red, 0), "bottom-left should be red; got {red:?}");
    assert!(
        dominant(green, 1),
        "bottom-right should be green; got {green:?}"
    );
    assert!(dominant(blue, 2), "top-left should be blue; got {blue:?}");
    assert!(
        white.0 > 200 && white.1 > 200 && white.2 > 200,
        "top-right should be white; got {white:?}"
    );
}