tawasuyu/llimphi

1//! Demo headless de M0: un cubo 3D con depth test, compuesto sobre un fondo
2//! vello — el mismo orden que aplica el runtime de Llimphi para
3//! `View::gpu_paint_with` (`[vello base] → [GPU 3D]`).
4//!
5//! No abre ventana: compone sobre una textura intermedia `Rgba8Unorm` (misma
6//! mecánica que el frame real) y vuelca a PNG.
7//!
8//! `cargo run -p llimphi-3d --example cubo_demo --release -- [out.png] [yaw_deg]`
9
10use std::fs::File;
11use std::io::BufWriter;
12
13use llimphi_3d::glam::Vec3;
14use llimphi_3d::{Camera3d, Renderer3d};
15use llimphi_hal::{wgpu, Hal};
16use llimphi_raster::peniko::Color;
17use llimphi_raster::{vello, Renderer};
18
19const W: u32 = 720;
20const H: u32 = 480;
21const FMT: wgpu::TextureFormat = wgpu::TextureFormat::Rgba8Unorm;
22
23fn main() {
24    let out = std::env::args()
25        .nth(1)
26        .unwrap_or_else(|| "cubo_demo.png".to_string());
27    let yaw_deg: f32 = std::env::args()
28        .nth(2)
29        .and_then(|s| s.parse().ok())
30        .unwrap_or(35.0);
31
32    let hal = pollster::block_on(Hal::new(None)).expect("hal");
33    let mut renderer = Renderer::new(&hal).expect("renderer");
34    let mut r3d = Renderer3d::new(&hal.device, FMT);
35
36    let inter = hal.device.create_texture(&wgpu::TextureDescriptor {
37        label: Some("inter"),
38        size: wgpu::Extent3d {
39            width: W,
40            height: H,
41            depth_or_array_layers: 1,
42        },
43        mip_level_count: 1,
44        sample_count: 1,
45        dimension: wgpu::TextureDimension::D2,
46        format: FMT,
47        usage: wgpu::TextureUsages::STORAGE_BINDING
48            | wgpu::TextureUsages::TEXTURE_BINDING
49            | wgpu::TextureUsages::RENDER_ATTACHMENT
50            | wgpu::TextureUsages::COPY_SRC,
51        view_formats: &[],
52    });
53    let inter_view = inter.create_view(&wgpu::TextureViewDescriptor::default());
54
55    // (1) Fondo vello: limpia la intermedia a un azul oscuro (render_to_view
56    //     escribe todos los pixels con base_color).
57    let base = vello::Scene::new();
58    renderer
59        .render_to_view(
60            &hal,
61            &base,
62            &inter_view,
63            W,
64            H,
65            Color::from_rgba8(18, 22, 32, 255),
66        )
67        .expect("render base");
68
69    // (2) Pase 3D: cubo orbitado, depth test propio, LoadOp::Load sobre el fondo.
70    let camera = Camera3d::orbit(
71        Vec3::ZERO,
72        yaw_deg.to_radians(),
73        25_f32.to_radians(),
74        4.0,
75    );
76    let mut enc = hal
77        .device
78        .create_command_encoder(&wgpu::CommandEncoderDescriptor {
79            label: Some("3d-pass"),
80        });
81    r3d.render(&hal.device, &hal.queue, &mut enc, &inter_view, (W, H), &camera);
82    hal.queue.submit(std::iter::once(enc.finish()));
83    let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
84
85    write_png(&hal, &inter, &out);
86    eprintln!("cubo_demo: escrito {out} ({W}x{H}, yaw={yaw_deg}°)");
87}
88
89fn write_png(hal: &Hal, target: &wgpu::Texture, path: &str) {
90    let unpadded = (W * 4) as usize;
91    let align = wgpu::COPY_BYTES_PER_ROW_ALIGNMENT as usize;
92    let padded = unpadded.div_ceil(align) * align;
93    let buf = hal.device.create_buffer(&wgpu::BufferDescriptor {
94        label: Some("readback"),
95        size: (padded * H as usize) as u64,
96        usage: wgpu::BufferUsages::MAP_READ | wgpu::BufferUsages::COPY_DST,
97        mapped_at_creation: false,
98    });
99    let mut enc = hal
100        .device
101        .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
102    enc.copy_texture_to_buffer(
103        wgpu::TexelCopyTextureInfo {
104            texture: target,
105            mip_level: 0,
106            origin: wgpu::Origin3d::ZERO,
107            aspect: wgpu::TextureAspect::All,
108        },
109        wgpu::TexelCopyBufferInfo {
110            buffer: &buf,
111            layout: wgpu::TexelCopyBufferLayout {
112                offset: 0,
113                bytes_per_row: Some(padded as u32),
114                rows_per_image: Some(H),
115            },
116        },
117        wgpu::Extent3d {
118            width: W,
119            height: H,
120            depth_or_array_layers: 1,
121        },
122    );
123    hal.queue.submit(std::iter::once(enc.finish()));
124    let slice = buf.slice(..);
125    let (tx, rx) = std::sync::mpsc::channel();
126    slice.map_async(wgpu::MapMode::Read, move |r| {
127        let _ = tx.send(r);
128    });
129    let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
130    rx.recv().unwrap().unwrap();
131    let data = slice.get_mapped_range();
132    let mut pixels = Vec::with_capacity((W * H * 4) as usize);
133    for row in 0..H as usize {
134        let s = row * padded;
135        pixels.extend_from_slice(&data[s..s + unpadded]);
136    }
137    drop(data);
138    buf.unmap();
139    let file = File::create(path).expect("png");
140    let mut enc = png::Encoder::new(BufWriter::new(file), W, H);
141    enc.set_color(png::ColorType::Rgba);
142    enc.set_depth(png::BitDepth::Eight);
143    let mut w = enc.write_header().unwrap();
144    w.write_image_data(&pixels).unwrap();
145}