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|
pub mod herringbone;
pub mod tileset_loader;
use std::ops::{Add, Mul, Sub};
use glam::IVec2;
use crate::{
config::{CHUNK_SIZE, TILESET_SCALING},
proc_gen::{
herringbone::{split_position, variant_index},
tileset_loader::{Tile, TileOrientation, TilePixelType, Tileset, load_tileset},
},
sim::{cell::Cell, cell_manager::chunk::Chunk, entity::EntityDef},
};
#[inline]
fn lerp<T>(a: T, b: T, t: f32) -> T
where
T: Copy + Add<Output = T> + Sub<Output = T> + Mul<f32, Output = T>,
{
a + (b - a) * t
}
const CHUNK_PIXELS: i32 = CHUNK_SIZE / TILESET_SCALING;
const PIXELS_NEIGHBOURHOOD_SIZE: i32 = CHUNK_PIXELS + 2;
// 2d slice of solidity; chunk + 1 margin
struct BiomeChunkContext {
pixels: [TilePixelType; (PIXELS_NEIGHBOURHOOD_SIZE * PIXELS_NEIGHBOURHOOD_SIZE) as usize],
}
pub struct InterpolatedPixel {
pub interpolated_pixel_indices: [(u8, f32); 4],
pub interpolated_solidity: f32,
}
impl BiomeChunkContext {
fn interpolated_at(&self, local: IVec2, tileset: &Tileset) -> InterpolatedPixel {
// pixel coord centre of cell coord local
let pixel_position = (local.as_vec2() + 0.5) / TILESET_SCALING as f32 + 0.5;
let pixel = pixel_position.floor();
// distance from the current pixel to the centre of the cell
let frac = pixel_position - pixel;
let pixel = pixel.as_ivec2();
let instantaneous_pixel_at = |dx, dy| {
self.pixels[((pixel.x + dx) + (pixel.y + dy) * PIXELS_NEIGHBOURHOOD_SIZE) as usize]
};
let instantaneous_idx_at = |dx, dy| match instantaneous_pixel_at(dx, dy) {
TilePixelType::Void => 0,
TilePixelType::Terrain(_) => 1,
TilePixelType::Custom(i) => i,
};
let instantaneous_solidity_at = |dx, dy| match instantaneous_pixel_at(dx, dy) {
TilePixelType::Void => 0.0,
TilePixelType::Terrain(o) => o,
TilePixelType::Custom(i) => {
tileset.manifest.palette.get(&i).map_or(0.0, |p| p.solidity)
}
};
// linearly interpolate between the solidity of the horizontal cells above and below according to the fractional x component
let s_top = lerp(
instantaneous_solidity_at(0, 0),
instantaneous_solidity_at(1, 0),
frac.x,
);
let s_bottom = lerp(
instantaneous_solidity_at(0, 1),
instantaneous_solidity_at(1, 1),
frac.x,
);
// and then interpolate between those according to the y component
let interpolated_solidity = lerp(s_top, s_bottom, frac.y) - 0.5;
// same for the pixel
// TODO don't allocate per-cell
let mut pixel_indices: Vec<u8> = Vec::new();
let tl = instantaneous_idx_at(0, 0);
if tl != 0 && !pixel_indices.contains(&tl) {
pixel_indices.push(tl);
}
let tr = instantaneous_idx_at(1, 0);
if tr != 0 && !pixel_indices.contains(&tr) {
pixel_indices.push(tr);
}
let bl = instantaneous_idx_at(0, 1);
if bl != 0 && !pixel_indices.contains(&bl) {
pixel_indices.push(bl);
}
let br = instantaneous_idx_at(1, 1);
if br != 0 && !pixel_indices.contains(&br) {
pixel_indices.push(br);
}
let mut interpolated_pixel_indices: [(u8, f32); 4] = [(0, 0.0); 4];
for (i, &p) in pixel_indices.iter().enumerate() {
let i_top = lerp(
if tl == p { 1.0 } else { 0.0 },
if tr == p { 1.0 } else { 0.0 },
frac.x,
);
let i_bottom = lerp(
if bl == p { 1.0 } else { 0.0 },
if br == p { 1.0 } else { 0.0 },
frac.x,
);
let interpolated_strength = lerp(i_top, i_bottom, frac.y);
interpolated_pixel_indices[i] = (p, interpolated_strength);
}
InterpolatedPixel {
interpolated_pixel_indices,
interpolated_solidity,
}
}
}
pub trait Biome {
fn fragment(&self, pixel: InterpolatedPixel, world: IVec2) -> Cell;
fn derive_entities_from_tile(&self, _tile: &Tile) -> Vec<EntityDef> {
Vec::new()
}
}
pub struct TilesetWorldGenerator {
tileset: Tileset,
biome: Box<dyn Biome>,
}
impl TilesetWorldGenerator {
pub fn new(tileset_path: &str, biome: Box<dyn Biome>) -> Self {
TilesetWorldGenerator {
tileset: load_tileset(tileset_path),
biome,
}
}
fn pixel_at(&self, pixel: IVec2) -> TilePixelType {
let (grid, local, orientation) =
split_position(pixel, self.tileset.manifest.dimensions.short as i32);
let tiles = match orientation {
TileOrientation::Horizontal => &self.tileset.horizontal_tiles,
TileOrientation::Vertical => &self.tileset.vertical_tiles,
};
tiles[variant_index(grid, tiles.len())].pixel_at(local)
}
fn get_biome_chunk_context(&self, chunk_position: IVec2) -> BiomeChunkContext {
let origin = chunk_position * CHUNK_PIXELS - 1;
let mut pixels =
[TilePixelType::Void; (PIXELS_NEIGHBOURHOOD_SIZE * PIXELS_NEIGHBOURHOOD_SIZE) as usize];
for y in 0..PIXELS_NEIGHBOURHOOD_SIZE {
for x in 0..PIXELS_NEIGHBOURHOOD_SIZE {
pixels[(x + y * PIXELS_NEIGHBOURHOOD_SIZE) as usize] =
self.pixel_at(origin + IVec2::new(x, y));
}
}
BiomeChunkContext { pixels }
}
pub fn generate_chunk(&self, chunk_position: IVec2) -> Chunk {
let mut chunk = Chunk::void();
let biome_chunk_context = self.get_biome_chunk_context(chunk_position);
let chunk_min = chunk_position * CHUNK_SIZE;
for y in 0..CHUNK_SIZE {
for x in 0..CHUNK_SIZE {
let local = IVec2::new(x, y);
chunk.cells[(x + y * CHUNK_SIZE) as usize] = self.biome.fragment(
biome_chunk_context.interpolated_at(local, &self.tileset),
chunk_min + local,
);
}
}
chunk.sleeping = false;
chunk.mark_collider_dirty(0);
chunk
}
}
|
