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        god_rays: 0.0,
57    };
58
59    let inter = hal.device.create_texture(&wgpu::TextureDescriptor {
60        label: Some("inter"),
61        size: wgpu::Extent3d { width: W, height: H, depth_or_array_layers: 1 },
62        mip_level_count: 1,
63        sample_count: 1,
64        dimension: wgpu::TextureDimension::D2,
65        format: FMT,
66        usage: wgpu::TextureUsages::STORAGE_BINDING
67            | wgpu::TextureUsages::TEXTURE_BINDING
68            | wgpu::TextureUsages::RENDER_ATTACHMENT
69            | wgpu::TextureUsages::COPY_SRC,
70        view_formats: &[],
71    });
72    let inter_view = inter.create_view(&wgpu::TextureViewDescriptor::default());
73
74    let d = dim_xz as f32;
75    for (tag, yaw) in [("a", 35.0_f32), ("b", 120.0), ("c", 230.0)] {
76        // (1) Fondo vello (lo tapa la atmósfera del pase voxel, pero dejamos el
77        //     mismo orden que el runtime: [vello base] → [GPU 3D]).
78        let base = vello::Scene::new();
79        renderer
80            .render_to_view(&hal, &base, &inter_view, W, H, Color::from_rgba8(0, 0, 0, 255))
81            .expect("render base");
82
83        // (2) Pase voxel. Órbita mirando un poco por encima del centro para que
84        //     entre cielo en cuadro; pitch bajo = vista de paisaje.
85        let camera = Camera3d::orbit(
86            Vec3::new(0.0, dy as f32 * 0.12, 0.0),
87            yaw.to_radians(),
88            22_f32.to_radians(),
89            d * 1.45,
90        );
91        let mut enc = hal
92            .device
93            .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: Some("voxel-pass") });
94        vr.render(&hal.device, &hal.queue, &mut enc, &inter_view, (W, H), &camera);
95        hal.queue.submit(std::iter::once(enc.finish()));
96        let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
97
98        let out = format!("/tmp/m6_terrain_{tag}.png");
99        write_png(&hal, &inter, &out);
100        eprintln!("escrito {out} ({W}x{H}, yaw={yaw}°)");
101    }
102}
103
104fn write_png(hal: &Hal, target: &wgpu::Texture, path: &str) {
105    let unpadded = (W * 4) as usize;
106    let align = wgpu::COPY_BYTES_PER_ROW_ALIGNMENT as usize;
107    let padded = unpadded.div_ceil(align) * align;
108    let buf = hal.device.create_buffer(&wgpu::BufferDescriptor {
109        label: Some("readback"),
110        size: (padded * H as usize) as u64,
111        usage: wgpu::BufferUsages::MAP_READ | wgpu::BufferUsages::COPY_DST,
112        mapped_at_creation: false,
113    });
114    let mut enc = hal
115        .device
116        .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
117    enc.copy_texture_to_buffer(
118        wgpu::TexelCopyTextureInfo {
119            texture: target,
120            mip_level: 0,
121            origin: wgpu::Origin3d::ZERO,
122            aspect: wgpu::TextureAspect::All,
123        },
124        wgpu::TexelCopyBufferInfo {
125            buffer: &buf,
126            layout: wgpu::TexelCopyBufferLayout {
127                offset: 0,
128                bytes_per_row: Some(padded as u32),
129                rows_per_image: Some(H),
130            },
131        },
132        wgpu::Extent3d { width: W, height: H, depth_or_array_layers: 1 },
133    );
134    hal.queue.submit(std::iter::once(enc.finish()));
135    let slice = buf.slice(..);
136    let (tx, rx) = std::sync::mpsc::channel();
137    slice.map_async(wgpu::MapMode::Read, move |r| {
138        let _ = tx.send(r);
139    });
140    let _ = hal.device.poll(wgpu::PollType::wait_indefinitely());
141    rx.recv().unwrap().unwrap();
142    let data = slice.get_mapped_range();
143    let mut pixels = Vec::with_capacity((W * H * 4) as usize);
144    for row in 0..H as usize {
145        let s = row * padded;
146        pixels.extend_from_slice(&data[s..s + unpadded]);
147    }
148    drop(data);
149    buf.unmap();
150    let file = File::create(path).expect("png");
151    let mut enc = png::Encoder::new(BufWriter::new(file), W, H);
152    enc.set_color(png::ColorType::Rgba);
153    enc.set_depth(png::BitDepth::Eight);
154    let mut w = enc.write_header().unwrap();
155    w.write_image_data(&pixels).unwrap();
156}