tiger_lib/rivers.rs
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//! Special validator for the `rivers.png` file.
//!
//! The `rivers.png` file has detailed requirements for its image format and the layout of every pixel.
use std::fs::File;
use std::ops::{RangeInclusive, RangeToInclusive};
use std::path::{Path, PathBuf};
use anyhow::{bail, Result};
use png::{ColorType, Decoder};
use crate::everything::Everything;
use crate::fileset::{FileEntry, FileHandler};
use crate::helpers::{TigerHashMap, TigerHashSet};
use crate::parse::ParserMemory;
use crate::report::{err, warn, will_maybe_log, ErrorKey};
/// The `rivers.png` has an indexed palette where the colors don't matter, only the index values
/// used in the pixels matter. Pixels that are not among the values defined here are ignored when
/// the game processes the `rivers.png`.
struct RiverPixels {}
impl RiverPixels {
/// Normal rivers of various widths (usually blue through greenish).
/// They are still all one pixel wide in the `rivers.png`; this just controls how they are painted on the map.
/// River pixels must be adjacent to each other horizontally or vertically; together they form river segments.
const NORMAL: RangeInclusive<u8> = (RiverPixels::FIRST_NORMAL..=RiverPixels::LAST_NORMAL);
const FIRST_NORMAL: u8 = 3;
const LAST_NORMAL: u8 = 15;
/// "specials" are the starting and ending pixels of river segments
const SPECIAL: RangeToInclusive<u8> = (..=RiverPixels::LAST_SPECIAL);
const LAST_SPECIAL: u8 = 2;
/// A pixel at the start of a river segment (usually green)
const SOURCE: u8 = 0;
/// A pixel that joins one river segment into another (usually red)
const TRIBUTARY: u8 = 1;
/// A pixel that is used where a river splits off from another (usually yellow)
const SPLIT: u8 = 2;
/// Noncoding pixels
const FIRST_IGNORE: u8 = 16;
}
#[derive(Clone, Debug, Default)]
pub struct Rivers {
/// for error reporting
entry: Option<FileEntry>,
width: u32,
height: u32,
color_type: Option<ColorType>,
palette: Option<Vec<u8>>,
pixels: Vec<u8>,
}
impl Rivers {
pub fn load_png(&mut self, fullpath: &Path) -> Result<()> {
let decoder = Decoder::new(File::open(fullpath)?);
let mut reader = decoder.read_info()?;
let info = reader.info();
self.width = info.width;
self.height = info.height;
self.color_type = Some(info.color_type);
if let Some(palette) = info.palette.clone() {
self.palette = Some(palette.into_owned());
}
self.pixels = vec![0; reader.output_buffer_size()];
let frame_info = reader.next_frame(&mut self.pixels)?;
if frame_info.width != self.width
|| frame_info.height != self.height
|| frame_info.color_type != self.color_type.unwrap()
{
bail!("PNG frame did not match image info");
}
Ok(())
}
fn river_neighbors(&self, x: u32, y: u32, output: &mut Vec<(u32, u32)>) {
output.clear();
if x > 0 && RiverPixels::NORMAL.contains(&self.pixel(x - 1, y)) {
output.push((x - 1, y));
}
if y > 0 && RiverPixels::NORMAL.contains(&self.pixel(x, y - 1)) {
output.push((x, y - 1));
}
if x + 1 < self.width && RiverPixels::NORMAL.contains(&self.pixel(x + 1, y)) {
output.push((x + 1, y));
}
if y + 1 < self.height && RiverPixels::NORMAL.contains(&self.pixel(x, y + 1)) {
output.push((x, y + 1));
}
}
fn special_neighbors(&self, c: (u32, u32)) -> Vec<(u32, u32)> {
let (x, y) = c;
let mut vec = Vec::new();
if x > 0 && RiverPixels::SPECIAL.contains(&self.pixel(x - 1, y)) {
vec.push((x - 1, y));
}
if y > 0 && RiverPixels::SPECIAL.contains(&self.pixel(x, y - 1)) {
vec.push((x, y - 1));
}
if x + 1 < self.width && RiverPixels::SPECIAL.contains(&self.pixel(x + 1, y)) {
vec.push((x + 1, y));
}
if y + 1 < self.height && RiverPixels::SPECIAL.contains(&self.pixel(x, y + 1)) {
vec.push((x, y + 1));
}
vec
}
fn pixel(&self, x: u32, y: u32) -> u8 {
let idx = (x + self.width * y) as usize;
self.pixels[idx]
}
fn validate_segments(
&self,
river_segments: TigerHashMap<(u32, u32), (u32, u32)>,
mut specials: TigerHashMap<(u32, u32), bool>,
) {
let mut seen = TigerHashSet::default();
for (start, end) in river_segments {
if seen.contains(&start) {
continue;
}
seen.insert(end);
if start == end {
// Single-pixel segment
let special_neighbors = self.special_neighbors(start);
if special_neighbors.len() > 1 {
let msg = format!(
"({}, {}) river pixel connects two special pixels",
start.0, start.1
);
warn(ErrorKey::Rivers).msg(msg).loc(self.entry.as_ref().unwrap()).push();
} else if special_neighbors.is_empty() {
let msg = format!("({}, {}) orphan river pixel", start.0, start.1);
warn(ErrorKey::Rivers).msg(msg).loc(self.entry.as_ref().unwrap()).push();
} else {
let s = special_neighbors[0];
if specials[&s] {
let msg =
format!("({}, {}) pixel terminates multiple river segments", s.0, s.1);
warn(ErrorKey::Rivers).msg(msg).loc(self.entry.as_ref().unwrap()).push();
} else {
specials.insert(s, true);
}
}
} else {
let mut special_neighbors = self.special_neighbors(start);
special_neighbors.append(&mut self.special_neighbors(end));
if special_neighbors.is_empty() {
let msg = format!(
"({}, {}) - ({}, {}) orphan river segment",
start.0, start.1, end.0, end.1
);
warn(ErrorKey::Rivers).msg(msg).loc(self.entry.as_ref().unwrap()).push();
} else if special_neighbors.len() > 1 {
let msg = format!(
"({}, {}) - ({}, {}) river segment has two terminators",
start.0, start.1, end.0, end.1
);
warn(ErrorKey::Rivers).msg(msg).loc(self.entry.as_ref().unwrap()).push();
} else {
let s = special_neighbors[0];
if specials[&s] {
let msg =
format!("({}, {}) pixel terminates multiple river segments", s.0, s.1);
warn(ErrorKey::Rivers).msg(msg).loc(self.entry.as_ref().unwrap()).push();
} else {
specials.insert(s, true);
}
}
}
}
}
pub fn validate(&self, _data: &Everything) {
// TODO: check image width and height against world defines
if self.color_type != Some(ColorType::Indexed) {
let msg = "rivers.png should be in indexed color format (with 8-bit palette)";
err(ErrorKey::ImageFormat).msg(msg).loc(self.entry.as_ref().unwrap()).push();
return;
}
if self.palette.is_none() {
let msg = "rivers.png must have an 8-bit palette";
err(ErrorKey::ImageFormat).msg(msg).loc(self.entry.as_ref().unwrap()).push();
return;
}
// Early exit before expensive loop, if errors won't be logged anyway
if !will_maybe_log(self.entry.as_ref().unwrap(), ErrorKey::Rivers) {
return;
}
// Maps each endpoint of a segment to the other endpoint.
// Single-pixel segments map that coordinate to itself.
// The river pixels that connect the endpoints are not remembered.
let mut river_segments: TigerHashMap<(u32, u32), (u32, u32)> = TigerHashMap::default();
// Maps the coordinates of special pixels (sources, sinks, and splits)
// to a boolean that says whether the pixel terminates a segment.
let mut specials = TigerHashMap::default();
// A working vec, holding the list of river-pixel neighbors of the current pixel.
// It is declared here to avoid the overhead of creating and destroying the Vec in every
// iteration.
let mut river_neighbors = Vec::new();
let mut bad_problem = false;
// TODO: multi-thread this
for x in 0..self.width {
for y in 0..self.height {
match self.pixel(x, y) {
RiverPixels::SOURCE => {
self.river_neighbors(x, y, &mut river_neighbors);
if river_neighbors.len() == 1 {
specials.insert((x, y), false);
} else {
let msg =
format!("({x}, {y}) river source (green) not at source of a river");
warn(ErrorKey::Rivers)
.msg(msg)
.loc(self.entry.as_ref().unwrap())
.push();
bad_problem = true;
}
}
RiverPixels::TRIBUTARY => {
self.river_neighbors(x, y, &mut river_neighbors);
if river_neighbors.len() >= 2 {
specials.insert((x, y), false);
} else {
let msg = format!(
"({x}, {y}) river tributary (red) not joining another river",
);
warn(ErrorKey::Rivers)
.msg(msg)
.loc(self.entry.as_ref().unwrap())
.push();
bad_problem = true;
}
}
RiverPixels::SPLIT => {
self.river_neighbors(x, y, &mut river_neighbors);
if river_neighbors.len() >= 2 {
specials.insert((x, y), false);
} else {
let msg = format!(
"({x}, {y}) river split (yellow) not splitting off from a river",
);
warn(ErrorKey::Rivers)
.msg(msg)
.loc(self.entry.as_ref().unwrap())
.push();
bad_problem = true;
}
}
RiverPixels::FIRST_NORMAL..=RiverPixels::LAST_NORMAL => {
self.river_neighbors(x, y, &mut river_neighbors);
if river_neighbors.len() <= 2 {
let mut found = false;
for &coords in &river_neighbors {
if let Some(&other_end) = river_segments.get(&coords) {
found = true;
if let Some(&third_end) = river_segments.get(&(x, y)) {
// This can only happen if we're on the second iteration.
// It means the pixel borders two segments, and joins them.
// First make sure it's not a single segment in a loop
// though.
if third_end == (x, y) {
let msg = format!("({x}, {y}) river forms a loop");
warn(ErrorKey::Rivers)
.msg(msg)
.loc(self.entry.as_ref().unwrap())
.push();
bad_problem = true;
} else {
river_segments.insert(other_end, third_end);
river_segments.insert(third_end, other_end);
river_segments.remove(&(x, y));
river_segments.remove(&coords);
}
} else {
// Extend the neighboring segment to include this pixel.
river_segments.insert((x, y), other_end);
river_segments.insert(other_end, (x, y));
river_segments.remove(&coords);
}
}
}
if !found {
// Start a new single-pixel segment.
river_segments.insert((x, y), (x, y));
}
} else {
let msg = format!(
"({x}, {y}) river pixel has {} neighbors",
river_neighbors.len()
);
warn(ErrorKey::Rivers)
.msg(msg)
.loc(self.entry.as_ref().unwrap())
.push();
bad_problem = true;
}
}
RiverPixels::FIRST_IGNORE.. => (),
}
}
}
if !bad_problem {
self.validate_segments(river_segments, specials);
}
}
}
impl FileHandler<()> for Rivers {
fn subpath(&self) -> PathBuf {
PathBuf::from("map_data/rivers.png")
}
fn load_file(&self, _entry: &FileEntry, _parser: &ParserMemory) -> Option<()> {
Some(())
}
fn handle_file(&mut self, entry: &FileEntry, _loaded: ()) {
self.entry = Some(entry.clone());
if let Err(e) = self.load_png(entry.fullpath()) {
err(ErrorKey::ReadError)
.msg("could not read image")
.info(format!("{e:#}"))
.loc(entry)
.push();
}
}
}