minedmap: add mipmapping

src/bin/minedmap/main.rs

@@ -1,5 +1,6 @@
 mod common;
 mod region_processor;
+mod tile_mipmapper;
 mod tile_renderer;
 
 use std::path::PathBuf;
@@ -9,6 +10,7 @@ use clap::Parser;
 
 use common::Config;
 use region_processor::RegionProcessor;
+use tile_mipmapper::TileMipmapper;
 use tile_renderer::TileRenderer;
 
 #[derive(Debug, Parser)]
@@ -25,6 +27,7 @@ fn main() -> Result<()> {
 
 	let regions = RegionProcessor::new(&config).run()?;
 	TileRenderer::new(&config).run(regions.iter().copied())?;
+	TileMipmapper::new(&config).run(regions)?;
 
 	Ok(())
 }

src/bin/minedmap/tile_mipmapper.rs

@@ -0,0 +1,125 @@
+use std::collections::BTreeSet;
+
+use anyhow::{Context, Result};
+
+use minedmap::{io::fs, types::*};
+
+use super::common::*;
+
+pub struct TileMipmapper<'a> {
+	config: &'a Config,
+}
+
+impl<'a> TileMipmapper<'a> {
+	pub fn new(config: &'a Config) -> Self {
+		TileMipmapper { config }
+	}
+
+	fn done(tiles: &BTreeSet<TileCoords>) -> bool {
+		tiles
+			.into_iter()
+			.all(|TileCoords { x, z }| (-1..=0).contains(x) && (-1..=0).contains(z))
+	}
+
+	fn map_coords(tiles: &BTreeSet<TileCoords>) -> BTreeSet<TileCoords> {
+		let mut ret = BTreeSet::new();
+
+		for coords in tiles {
+			ret.insert(TileCoords {
+				x: coords.x >> 1,
+				z: coords.z >> 1,
+			});
+		}
+
+		ret
+	}
+
+	fn render_mipmap<P: image::PixelWithColorType>(
+		&self,
+		kind: TileKind,
+		level: usize,
+		coords: TileCoords,
+		prev: &BTreeSet<TileCoords>,
+	) -> Result<()>
+	where
+		[P::Subpixel]: image::EncodableLayout,
+		image::ImageBuffer<P, Vec<P::Subpixel>>: Into<image::DynamicImage>,
+	{
+		const N: u32 = (BLOCKS_PER_CHUNK * CHUNKS_PER_REGION) as u32;
+
+		let output_path = self.config.tile_path(kind, level, coords);
+
+		println!(
+			"Rendering mipmap tile {}",
+			output_path
+				.strip_prefix(&self.config.output_dir)
+				.expect("tile path must be in output directory")
+				.display(),
+		);
+
+		let mut image: image::DynamicImage =
+			image::ImageBuffer::<P, Vec<P::Subpixel>>::new(N, N).into();
+
+		for (dx, dz) in [(0, 0), (0, 1), (1, 0), (1, 1)] {
+			let source_coords = TileCoords {
+				x: 2 * coords.x + dx,
+				z: 2 * coords.z + dz,
+			};
+			if !prev.contains(&source_coords) {
+				continue;
+			}
+
+			let source_path = self.config.tile_path(kind, level - 1, source_coords);
+			let source = match image::open(&source_path) {
+				Ok(source) => source,
+				Err(err) => {
+					eprintln!(
+						"Failed to read source image {}: {}",
+						source_path.display(),
+						err,
+					);
+					continue;
+				}
+			};
+			let resized = source.resize(N / 2, N / 2, image::imageops::FilterType::Triangle);
+			image::imageops::overlay(
+				&mut image,
+				&resized,
+				dx as i64 * (N / 2) as i64,
+				dz as i64 * (N / 2) as i64,
+			);
+		}
+
+		fs::create_with_tmpfile(&output_path, |file| {
+			image
+				.write_to(file, image::ImageFormat::Png)
+				.context("Failed to save image")
+		})
+	}
+
+	pub fn run(self, tiles: BTreeSet<TileCoords>) -> Result<Vec<BTreeSet<TileCoords>>> {
+		let mut tile_stack = vec![tiles];
+
+		loop {
+			let level = tile_stack.len();
+			let prev = &tile_stack[level - 1];
+			if Self::done(prev) {
+				break;
+			}
+
+			fs::create_dir_all(&self.config.tile_dir(TileKind::Map, level))?;
+			fs::create_dir_all(&self.config.tile_dir(TileKind::Lightmap, level))?;
+
+			let next = Self::map_coords(prev);
+
+			for &coords in &next {
+				self.render_mipmap::<image::Rgba<u8>>(TileKind::Map, level, coords, prev)?;
+				self.render_mipmap::<image::LumaA<u8>>(TileKind::Lightmap, level, coords, prev)?;
+			}
+
+			tile_stack.push(next);
+		}
+
+		Ok(tile_stack)
+	}
+}