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use anyhow::{anyhow, Context};
use bitvec::{order::Msb0, prelude::BitVec};
use heapless::Vec as SVec;
use image::io::Reader as ImageReader;
use once_cell::unsync::OnceCell;
use proc_macro::TokenStream;
use proc_macro2::TokenStream as TokenStream2;
use quote::{quote, quote_spanned, ToTokens};
use std::{collections::HashMap, mem, path::PathBuf};
use wasm4_common::draw::{BitsPerPixel, DrawIndex, DrawIndices};
mod parse;
type Sprite = wasm4_common::draw::Sprite<Vec<u8>>;
#[proc_macro]
pub fn include_sprites_impl(item: TokenStream) -> TokenStream {
let input = syn::parse_macro_input!(item as parse::Input);
fn implementation(input: parse::Input) -> syn::Result<Output> {
let package_name = input.package.package_name;
let pkg_root = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
let palette = OnceCell::new();
let mut image_paths = HashMap::new();
for item in input.input.consts {
match &item.expr {
parse::Expr::IncludeSprite(include_sprite) => {
if let Some(_) = image_paths.insert(
include_sprite.path.value(),
item.clone().map_expr(|_| include_sprite.clone()),
) {
return Err(syn::Error::new_spanned(
&include_sprite,
"detected image duplication",
));
}
}
parse::Expr::CommonPalette(common_palette) => {
let plt =
SVec::<image::Bgr<u8>, 4>::from_iter(common_palette.colors.iter().map(
|rgb| image::Bgr(rgb.value.to_le_bytes()[..3].try_into().unwrap()),
));
palette
.try_insert((plt, item.clone().map_expr(|_| common_palette.clone())))
.map_err(|_| {
syn::Error::new(
common_palette.name_token.span,
"trying to assign a palette twice",
)
})?;
}
}
}
let (mut palette, palette_item) = palette.into_inner().ok_or_else(|| {
syn::Error::new(
proc_macro2::Span::call_site(),
"no `common_palette!` expresion found",
)
})?;
let sprites =
image_paths
.into_iter()
.map(|(path, item)| {
let span = item.expr.path.span();
(|| -> anyhow::Result<_> {
let fullpath = pkg_root.join(&path);
let img = ImageReader::open(&fullpath)
.with_context(|| format!("could not open {:?} file", &path))?
.decode()
.with_context(|| format!("could not decode {:?} file", &path))?
.into_bgra8();
let mut bpp = BitsPerPixel::One;
let mut indices = SVec::<Option<usize>, 4>::new();
let mut bits = BitVec::<u8, Msb0>::new();
for &p in img.pixels() {
let color = image::Bgr(p.0[..3].try_into().unwrap());
let idx =
match p.0[3] {
0 => None,
255 => Some(
match palette
.iter()
.enumerate()
.find_map(|(i, c)| (*c == color).then(|| i))
{
Some(i) => i,
None => {
let i = palette.len();
palette.push(color).map_err(|c| {
anyhow!("all images combined have more than 4 colors \
(transparent is not counted) \
({:?} and {:?} using indices {:?})", palette, indices, c)
})?;
i
}
},
),
a => anyhow::bail!("got ambiguous alpha value: {}", a),
};
let i = match indices
.iter()
.enumerate()
.find_map(|(n, i)| (*i == idx).then(|| n))
{
Some(i) => i,
None => {
let i = indices.len();
indices.push(idx).map_err(|_| {
anyhow!(
"image have more than 4 colors \
(TRANSPARENT IS COUNTED) \
({:?} and {:?})",
palette,
color
)
})?;
if i == 2 {
bpp = BitsPerPixel::Two;
let old_bits = mem::take(&mut bits);
bits.reserve(old_bits.len() * 2);
bits.extend(old_bits.into_iter().flat_map(|b| [false, b]));
}
i
}
};
match bpp {
BitsPerPixel::One => bits.push(i != 0),
BitsPerPixel::Two => bits.extend([i & 0b10 != 0, i & 0b01 != 0]),
}
}
let indices = DrawIndices::from_array([0, 1, 2, 3].map(|i| {
DrawIndex::new(
indices
.get(i)
.copied()
.flatten()
.map_or(0, |idx| u16::try_from(idx).unwrap() + 1),
)
.unwrap()
}));
bits.set_uninitialized(false);
Ok((
Sprite::from_bytes(
bits.into_vec(),
[img.width(), img.height()],
bpp,
indices,
)
.expect("something's wrong with the image dimentions"),
item,
))
})()
.map_err(|e| syn::Error::new(span, format!("{:#}", e)))
})
.collect::<syn::Result<_>>()?;
palette.resize(4, image::Bgr([0; 3])).unwrap();
let palette = (
palette.into_array().unwrap().map(|bgr| {
wasm4_common::draw::Color(u32::from_le_bytes(
[0, 1, 2, 3].map(|i| bgr.0.get(i).copied().unwrap_or(0)),
))
}),
palette_item,
);
Ok(Output {
package_name,
sprites,
palette,
})
}
implementation(input)
.map_or_else(syn::Error::into_compile_error, ToTokens::into_token_stream)
.into()
}
struct Output {
package_name: syn::Ident,
palette: (
wasm4_common::draw::Palette,
parse::ItemConst<parse::CommonPaletteExpr>,
),
sprites: Vec<(Sprite, parse::ItemConst<parse::IncludeSpriteExpr>)>,
}
impl ToTokens for Output {
fn to_tokens(&self, tokens: &mut TokenStream2) {
let Output {
package_name,
palette: (palette, palette_item),
sprites,
} = self;
{
let parse::ItemConst::<parse::CommonPaletteExpr> {
attrs,
vis,
const_token,
ident,
colon_token,
ty,
eq_token,
expr,
semi_token,
} = palette_item;
let ty = quote_spanned! { ty.spans[0] => #package_name::draw::Palette };
let color_ty = quote! { #package_name::draw::Color };
let palette = palette.map(|c| c.0);
let expr = quote_spanned! { expr.name_token.span => [ #( #color_ty(#palette) ),* ] };
attrs.into_iter().for_each(|attr| attr.to_tokens(tokens));
vis.to_tokens(tokens);
const_token.to_tokens(tokens);
ident.to_tokens(tokens);
colon_token.to_tokens(tokens);
ty.to_tokens(tokens);
eq_token.to_tokens(tokens);
expr.to_tokens(tokens);
semi_token.to_tokens(tokens);
}
let pkg_root = PathBuf::from(std::env::var("CARGO_MANIFEST_DIR").unwrap());
for (sprite, sprite_item) in sprites {
let parse::ItemConst::<parse::IncludeSpriteExpr> {
attrs,
vis,
const_token,
ident,
colon_token,
ty,
eq_token,
expr,
semi_token,
} = sprite_item;
let bytes = sprite.bytes();
let shape = sprite.shape();
let bpp = match sprite.bpp() {
BitsPerPixel::One => quote! { #package_name::draw::BitsPerPixel::One },
BitsPerPixel::Two => quote! { #package_name::draw::BitsPerPixel::Two },
};
let indices = sprite.indices.into_u16();
let byte_len = bytes.len();
let indices_ty = quote! { #package_name::draw::DrawIndices };
let ty = quote_spanned! { ty.spans[0] => #package_name::draw::Sprite<[u8; #byte_len]> };
let path = format!("{}", pkg_root.join(expr.path.value()).display());
let path = quote_spanned!(expr.path.span() => #path);
let expr = quote_spanned! { expr.name_token.span =>
match #package_name::draw::Sprite::from_byte_array(
[ #( #bytes ),* ],
[ #( #shape ),* ],
#bpp,
unsafe { <#indices_ty>::from_u16_unchecked(#indices) },
) {
Some(s) => s,
None => panic!(),
}
};
attrs.into_iter().for_each(|attr| attr.to_tokens(tokens));
vis.to_tokens(tokens);
const_token.to_tokens(tokens);
ident.to_tokens(tokens);
colon_token.to_tokens(tokens);
ty.to_tokens(tokens);
eq_token.to_tokens(tokens);
expr.to_tokens(tokens);
semi_token.to_tokens(tokens);
quote! { const _: &[u8] = include_bytes!(#path); }.to_tokens(tokens);
}
}
}
