tawasuyu/llimphi

1//! Demo headless de M6 (primera rebanada): **world-gen procedural + atmósfera**.
2//!
3//! Genera un paisaje voxel grande por ruido fractal ([`llimphi_3d::terrain`]) y
4//! lo ray-marchea con **cielo gradiente + niebla por distancia** ([`Atmosphere`])
5//! — lo que hace legible el borde lejano de un mundo grande (sin niebla, el
6//! horizonte del terreno se ve como un muro recortado). Imprime además el ahorro
7//! de memoria del brick pool sparse: un mundo es casi todo aire, así que el pool
8//! ocupa una fracción del grid denso.
9//!
10//! `cargo run -p llimphi-3d --example terrain_demo --release -- [dim_xz] [seed]`
11//! → escribe /tmp/m6_terrain_{a,b,c}.png (tres ángulos de órbita).
12
13use std::fs::File;
14use std::io::BufWriter;
15
16use llimphi_3d::glam::Vec3;
17use llimphi_3d::{Atmosphere, Camera3d, VoxelRenderer};
18use llimphi_hal::{wgpu, Hal};
19use llimphi_voxel::terrain;
20use llimphi_raster::peniko::Color;
21use llimphi_raster::{vello, Renderer};
22
23const W: u32 = 960;
24const H: u32 = 540;
25const FMT: wgpu::TextureFormat = wgpu::TextureFormat::Rgba8Unorm;
26
27fn main() {
28    let dim_xz: u32 = std::env::args().nth(1).and_then(|s| s.parse().ok()).unwrap_or(192);
29    let seed: u32 = std::env::args().nth(2).and_then(|s| s.parse().ok()).unwrap_or(1337);
30    let dy: u32 = (dim_xz * 4 / 10).max(48); // mundo "ancho y bajo": continente, no torre.
31    let dim = [dim_xz, dy, dim_xz];
32
33    let hal = pollster::block_on(Hal::new(None)).expect("hal");
34    let mut renderer = Renderer::new(&hal).expect("renderer");
35
36    let grid = terrain(dim, seed);
37    let mut vr = VoxelRenderer::new(&hal.device, &hal.queue, FMT, &grid);
38    let (used, total) = vr.brick_usage();
39    let (pool, dense) = vr.memory_bytes();
40    eprintln!(
41        "terreno {}×{}×{} (seed {seed}) — brick pool {used}/{total} bricks ({:.1}%) → {} KiB vs denso {} KiB ({:.1}× menos)",
42        dim[0], dim[1], dim[2],
43        used as f32 / total as f32 * 100.0,
44        pool / 1024,
45        dense / 1024,
46        dense as f32 / pool.max(1) as f32,
47    );
48
49    // Atmósfera diurna: sol bajo (luz rasante = relieve marcado), niebla suave
50    // escalada al tamaño del mundo (lo lejano desvanece, lo cercano queda nítido).
51    vr.sun_dir = [0.55, 0.55, 0.35];
52    vr.atmosphere = Atmosphere {
53        sky_zenith: [64, 118, 196],
54        sky_horizon: [200, 216, 234],
55        fog_density: 0.5 / dim_xz as f32,
56    };
57
58    let inter = hal.device.create_texture(&wgpu::TextureDescriptor {
59        label: Some("inter"),
60        size: wgpu::Extent3d { width: W, height: H, depth_or_array_layers: 1 },
61        mip_level_count: 1,
62        sample_count: 1,
63        dimension: wgpu::TextureDimension::D2,
64        format: FMT,
65        usage: wgpu::TextureUsages::STORAGE_BINDING
66            | wgpu::TextureUsages::TEXTURE_BINDING
67            | wgpu::TextureUsages::RENDER_ATTACHMENT
68            | wgpu::TextureUsages::COPY_SRC,
69        view_formats: &[],
70    });
71    let inter_view = inter.create_view(&wgpu::TextureViewDescriptor::default());
72
73    let d = dim_xz as f32;
74    for (tag, yaw) in [("a", 35.0_f32), ("b", 120.0), ("c", 230.0)] {
75        // (1) Fondo vello (lo tapa la atmósfera del pase voxel, pero dejamos el
76        //     mismo orden que el runtime: [vello base] → [GPU 3D]).
77        let base = vello::Scene::new();
78        renderer
79            .render_to_view(&hal, &base, &inter_view, W, H, Color::from_rgba8(0, 0, 0, 255))
80            .expect("render base");
81
82        // (2) Pase voxel. Órbita mirando un poco por encima del centro para que
83        //     entre cielo en cuadro; pitch bajo = vista de paisaje.
84        let camera = Camera3d::orbit(
85            Vec3::new(0.0, dy as f32 * 0.12, 0.0),
86            yaw.to_radians(),
87            22_f32.to_radians(),
88            d * 1.45,
89        );
90        let mut enc = hal
91            .device
92            .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: Some("voxel-pass") });
93        vr.render(&hal.device, &hal.queue, &mut enc, &inter_view, (W, H), &camera);
94        hal.queue.submit(std::iter::once(enc.finish()));
95        let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
96
97        let out = format!("/tmp/m6_terrain_{tag}.png");
98        write_png(&hal, &inter, &out);
99        eprintln!("escrito {out} ({W}x{H}, yaw={yaw}°)");
100    }
101}
102
103fn write_png(hal: &Hal, target: &wgpu::Texture, path: &str) {
104    let unpadded = (W * 4) as usize;
105    let align = wgpu::COPY_BYTES_PER_ROW_ALIGNMENT as usize;
106    let padded = unpadded.div_ceil(align) * align;
107    let buf = hal.device.create_buffer(&wgpu::BufferDescriptor {
108        label: Some("readback"),
109        size: (padded * H as usize) as u64,
110        usage: wgpu::BufferUsages::MAP_READ | wgpu::BufferUsages::COPY_DST,
111        mapped_at_creation: false,
112    });
113    let mut enc = hal
114        .device
115        .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
116    enc.copy_texture_to_buffer(
117        wgpu::TexelCopyTextureInfo {
118            texture: target,
119            mip_level: 0,
120            origin: wgpu::Origin3d::ZERO,
121            aspect: wgpu::TextureAspect::All,
122        },
123        wgpu::TexelCopyBufferInfo {
124            buffer: &buf,
125            layout: wgpu::TexelCopyBufferLayout {
126                offset: 0,
127                bytes_per_row: Some(padded as u32),
128                rows_per_image: Some(H),
129            },
130        },
131        wgpu::Extent3d { width: W, height: H, depth_or_array_layers: 1 },
132    );
133    hal.queue.submit(std::iter::once(enc.finish()));
134    let slice = buf.slice(..);
135    let (tx, rx) = std::sync::mpsc::channel();
136    slice.map_async(wgpu::MapMode::Read, move |r| {
137        let _ = tx.send(r);
138    });
139    let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
140    rx.recv().unwrap().unwrap();
141    let data = slice.get_mapped_range();
142    let mut pixels = Vec::with_capacity((W * H * 4) as usize);
143    for row in 0..H as usize {
144        let s = row * padded;
145        pixels.extend_from_slice(&data[s..s + unpadded]);
146    }
147    drop(data);
148    buf.unmap();
149    let file = File::create(path).expect("png");
150    let mut enc = png::Encoder::new(BufWriter::new(file), W, H);
151    enc.set_color(png::ColorType::Rgba);
152    enc.set_depth(png::BitDepth::Eight);
153    let mut w = enc.write_header().unwrap();
154    w.write_image_data(&pixels).unwrap();
155}