Add support for transparent sprites

agb-image-converter/src/colour.rs

@@ -3,15 +3,20 @@ pub struct Colour {
     pub r: u8,
     pub g: u8,
     pub b: u8,
+    pub a: u8,
 }
 
 impl Colour {
-    pub fn from_rgb(r: u8, g: u8, b: u8) -> Self {
-        Colour { r, g, b }
+    pub fn from_rgb(r: u8, g: u8, b: u8, a: u8) -> Self {
+        Colour { r, g, b, a }
     }
 
     pub fn to_rgb15(self) -> u16 {
         let (r, g, b) = (self.r as u16, self.g as u16, self.b as u16);
         ((r >> 3) & 31) | (((g >> 3) & 31) << 5) | (((b >> 3) & 31) << 10)
     }
+
+    pub fn is_transparent(self) -> bool {
+        self.a != 255
+    }
 }

agb-image-converter/src/config.rs

@@ -76,7 +76,7 @@ impl Image for ImageV1 {
             let g = u8::from_str_radix(&colour[2..4], 16).unwrap();
             let b = u8::from_str_radix(&colour[4..6], 16).unwrap();
 
-            return Some(Colour::from_rgb(r, g, b));
+            return Some(Colour::from_rgb(r, g, b, 255));
         }
 
         None

agb-image-converter/src/image_loader.rs

@@ -25,7 +25,7 @@ impl Image {
         let mut colour_data = Vec::with_capacity(width * height);
 
         for (_, _, pixel) in img.pixels() {
-            colour_data.push(Colour::from_rgb(pixel[0], pixel[1], pixel[2]));
+            colour_data.push(Colour::from_rgb(pixel[0], pixel[1], pixel[2], pixel[3]));
         }
 
         Image {

agb-image-converter/src/lib.rs

@@ -94,7 +94,9 @@ pub fn include_aseprite_inner(input: TokenStream) -> TokenStream {
         Err(e) => return e.to_compile_error().into(),
     };
 
-    let mut optimiser = palette16::Palette16Optimiser::new();
+    let transparent_colour = Colour::from_rgb(255, 0, 255, 0);
+
+    let mut optimiser = palette16::Palette16Optimiser::new(Some(transparent_colour));
     let mut images = Vec::new();
     let mut tags = Vec::new();
 
@@ -116,12 +118,17 @@ pub fn include_aseprite_inner(input: TokenStream) -> TokenStream {
             assert!(width == frame.height() && width.is_power_of_two() && width <= 32);
 
             let image = Image::load_from_dyn_image(frame);
-            add_to_optimiser(&mut optimiser, &image, width as usize);
+            add_to_optimiser(
+                &mut optimiser,
+                &image,
+                width as usize,
+                Some(transparent_colour),
+            );
             images.push(image);
         }
     }
 
-    let optimised_results = optimiser.optimise_palettes(None);
+    let optimised_results = optimiser.optimise_palettes();
 
     let (palette_data, tile_data, assignments) = palete_tile_data(&optimised_results, &images);
 
@@ -212,8 +219,8 @@ fn convert_image(
         panic!("Image size not a multiple of tile size");
     }
 
-    let optimiser = optimiser_for_image(&image, tile_size);
-    let optimisation_results = optimiser.optimise_palettes(settings.transparent_colour());
+    let optimiser = optimiser_for_image(&image, tile_size, settings.transparent_colour());
+    let optimisation_results = optimiser.optimise_palettes();
 
     rust_generator::generate_code(
         variable_name,
@@ -225,9 +232,13 @@ fn convert_image(
     )
 }
 
-fn optimiser_for_image(image: &Image, tile_size: usize) -> palette16::Palette16Optimiser {
-    let mut palette_optimiser = palette16::Palette16Optimiser::new();
-    add_to_optimiser(&mut palette_optimiser, image, tile_size);
+fn optimiser_for_image(
+    image: &Image,
+    tile_size: usize,
+    transparent_colour: Option<Colour>,
+) -> palette16::Palette16Optimiser {
+    let mut palette_optimiser = palette16::Palette16Optimiser::new(transparent_colour);
+    add_to_optimiser(&mut palette_optimiser, image, tile_size, transparent_colour);
     palette_optimiser
 }
 
@@ -235,6 +246,7 @@ fn add_to_optimiser(
     palette_optimiser: &mut palette16::Palette16Optimiser,
     image: &Image,
     tile_size: usize,
+    transparent_colour: Option<Colour>,
 ) {
     let tiles_x = image.width / tile_size;
     let tiles_y = image.height / tile_size;
@@ -247,7 +259,10 @@ fn add_to_optimiser(
                 for i in 0..tile_size {
                     let colour = image.colour(x * tile_size + i, y * tile_size + j);
 
-                    palette.add_colour(colour);
+                    palette.add_colour(match (colour.is_transparent(), transparent_colour) {
+                        (true, Some(transparent_colour)) => transparent_colour,
+                        _ => colour,
+                    });
                 }
             }
 
@@ -292,7 +307,9 @@ fn palete_tile_data(
                         for j in inner_y * 8..inner_y * 8 + 8 {
                             for i in inner_x * 8..inner_x * 8 + 8 {
                                 let colour = image.colour(x * tile_size + i, y * tile_size + j);
-                                tile_data.push(palette.colour_index(colour));
+                                tile_data.push(
+                                    palette.colour_index(colour, optimiser.transparent_colour),
+                                );
                             }
                         }
                     }

agb-image-converter/src/palette16.rs

@@ -27,11 +27,22 @@ impl Palette16 {
         self.colours.push(colour);
         true
     }
-    pub fn colour_index(&self, colour: Colour) -> u8 {
+
+    pub fn colour_index(&self, colour: Colour, transparent_colour: Option<Colour>) -> u8 {
+        let colour_to_search = match (transparent_colour, colour.is_transparent()) {
+            (Some(transparent_colour), true) => transparent_colour,
+            _ => colour,
+        };
+
         self.colours
             .iter()
-            .position(|c| *c == colour)
-            .expect("Can't get a colour index without it existing") as u8
+            .position(|c| *c == colour_to_search)
+            .unwrap_or_else(|| {
+                panic!(
+                    "Can't get a colour index without it existing, looking for {:?}, got {:?}",
+                    colour, self.colours
+                )
+            }) as u8
     }
 
     fn union_length(&self, other: &Palette16) -> usize {
@@ -62,19 +73,22 @@ impl IntoIterator for Palette16 {
 pub(crate) struct Palette16Optimiser {
     palettes: Vec<Palette16>,
     colours: Vec<Colour>,
+    transparent_colour: Option<Colour>,
 }
 
 #[derive(Debug)]
 pub(crate) struct Palette16OptimisationResults {
     pub optimised_palettes: Vec<Palette16>,
     pub assignments: Vec<usize>,
+    pub transparent_colour: Option<Colour>,
 }
 
 impl Palette16Optimiser {
-    pub fn new() -> Self {
+    pub fn new(transparent_colour: Option<Colour>) -> Self {
         Palette16Optimiser {
             palettes: vec![],
             colours: Vec::new(),
+            transparent_colour,
         }
     }
 
@@ -94,10 +108,7 @@ impl Palette16Optimiser {
         }
     }
 
-    pub fn optimise_palettes(
-        &self,
-        transparent_colour: Option<Colour>,
-    ) -> Palette16OptimisationResults {
+    pub fn optimise_palettes(&self) -> Palette16OptimisationResults {
         let mut assignments = vec![0; self.palettes.len()];
         let mut optimised_palettes = vec![];
 
@@ -108,7 +119,7 @@ impl Palette16Optimiser {
             .collect::<HashSet<Palette16>>();
 
         while !unsatisfied_palettes.is_empty() {
-            let palette = self.find_maximal_palette_for(&unsatisfied_palettes, transparent_colour);
+            let palette = self.find_maximal_palette_for(&unsatisfied_palettes);
 
             for test_palette in unsatisfied_palettes.clone() {
                 if test_palette.is_satisfied_by(&palette) {
@@ -132,17 +143,14 @@ impl Palette16Optimiser {
         Palette16OptimisationResults {
             optimised_palettes,
             assignments,
+            transparent_colour: self.transparent_colour,
         }
     }
 
-    fn find_maximal_palette_for(
-        &self,
-        unsatisfied_palettes: &HashSet<Palette16>,
-        transparent_colour: Option<Colour>,
-    ) -> Palette16 {
+    fn find_maximal_palette_for(&self, unsatisfied_palettes: &HashSet<Palette16>) -> Palette16 {
         let mut palette = Palette16::new();
 
-        if let Some(transparent_colour) = transparent_colour {
+        if let Some(transparent_colour) = self.transparent_colour {
             palette.add_colour(transparent_colour);
         }
 

agb-image-converter/src/rust_generator.rs

@@ -51,7 +51,8 @@ pub(crate) fn generate_code(
                     for j in inner_y * 8..inner_y * 8 + 8 {
                         for i in inner_x * 8..inner_x * 8 + 8 {
                             let colour = image.colour(x * tile_size + i, y * tile_size + j);
-                            tile_data.push(palette.colour_index(colour));
+                            tile_data
+                                .push(palette.colour_index(colour, results.transparent_colour));
                         }
                     }
                 }