Merge pull request #215 from gwilymk/optimise-font-rendering

Optimise font rendering

agb-image-converter/Cargo.toml

@@ -13,7 +13,7 @@ proc-macro = true
 image = { version = "0.23", default-features = false, features = [ "png", "bmp" ] }
 toml = "0.5"
 serde = { version = "1", features = ["derive"] }
-syn = "1"
+syn = { version = "1", features = ["full"] }
 proc-macro2 = "1"
 quote = "1"
 asefile = "0.3.4"

agb-image-converter/src/font_loader.rs

@@ -33,10 +33,24 @@ pub fn load_font(font_data: &[u8], pixels_per_em: f32) -> TokenStream {
             let width = metrics.width;
             let height = metrics.height;
 
+            let rendered = bitmap
+                .chunks(8)
+                .map(|chunk| {
+                    let mut output = 0u8;
+                    for (i, &value) in chunk.iter().enumerate() {
+                        if value > 100 {
+                            output |= 1 << i;
+                        }
+                    }
+
+                    output
+                })
+                .collect();
+
             LetterData {
                 width,
                 height,
-                rendered: bitmap,
+                rendered,
                 xmin: metrics.xmin,
                 ymin: metrics.ymin,
                 advance_width: metrics.advance_width,
@@ -51,7 +65,7 @@ pub fn load_font(font_data: &[u8], pixels_per_em: f32) -> TokenStream {
             let advance_width = letter_data.advance_width.ceil() as u8;
 
             quote!(
-                agb::display::FontLetter::new(
+                display::FontLetter::new(
                     #width,
                     #height,
                     #data_raw,
@@ -63,6 +77,6 @@ pub fn load_font(font_data: &[u8], pixels_per_em: f32) -> TokenStream {
         });
 
     quote![
-        agb::display::Font::new(&[#(#font),*], #line_height, #ascent)
+        display::Font::new(&[#(#font),*], #line_height, #ascent)
     ]
 }

agb-image-converter/src/lib.rs

@@ -311,6 +311,13 @@ fn palete_tile_data(
     (palette_data, tile_data, assignments)
 }
 
+fn flatten_group(expr: &Expr) -> &Expr {
+    match expr {
+        Expr::Group(group) => &group.expr,
+        _ => expr,
+    }
+}
+
 #[proc_macro]
 pub fn include_font(input: TokenStream) -> TokenStream {
     let parser = Punctuated::<Expr, syn::Token![,]>::parse_separated_nonempty;
@@ -324,7 +331,7 @@ pub fn include_font(input: TokenStream) -> TokenStream {
         panic!("Include_font requires 2 arguments, got {}", all_args.len());
     }
 
-    let filename = match &all_args[0] {
+    let filename = match flatten_group(&all_args[0]) {
         Expr::Lit(ExprLit {
             lit: Lit::Str(str_lit),
             ..
@@ -332,7 +339,7 @@ pub fn include_font(input: TokenStream) -> TokenStream {
         _ => panic!("Expected literal string as first argument to include_font"),
     };
 
-    let font_size = match &all_args[1] {
+    let font_size = match flatten_group(&all_args[1]) {
         Expr::Lit(ExprLit {
             lit: Lit::Float(value),
             ..

agb/src/display/font.rs

@@ -86,33 +86,11 @@ pub struct TextRenderer<'a> {
     bg: &'a mut RegularMap,
     background_colour: u8,
     foreground_colour: u8,
-    tiles: HashMap<(usize, usize), DynamicTile<'a>>,
+    tiles: HashMap<(i32, i32), DynamicTile<'a>>,
 }
 
 impl<'a> Write for TextRenderer<'a> {
     fn write_str(&mut self, text: &str) -> Result<(), Error> {
-        let vram_manager = &mut self.vram_manager;
-        let tiles = &mut self.tiles;
-        let foreground_colour = self.foreground_colour;
-        let background_colour = self.background_colour;
-
-        let mut render_pixel = |x: u16, y: u16| {
-            let tile_x = (x / 8) as usize;
-            let tile_y = (y / 8) as usize;
-            let inner_x = x % 8;
-            let inner_y = y % 8;
-
-            let colour = foreground_colour as u32;
-
-            let index = (inner_x + inner_y * 8) as usize;
-
-            let tile = tiles
-                .entry((tile_x, tile_y))
-                .or_insert_with(|| vram_manager.new_dynamic_tile().fill_with(background_colour));
-
-            tile.tile_data[index / 8] |= colour << ((index % 8) * 4);
-        };
-
         for c in text.chars() {
             if c == '\n' {
                 self.current_y_pos += self.font.line_height;
@@ -122,22 +100,7 @@ impl<'a> Write for TextRenderer<'a> {
 
             let letter = self.font.letter(c);
 
-            let x_start = (self.current_x_pos + letter.xmin as i32).max(0);
-            let y_start =
-                self.current_y_pos + self.font.ascent - letter.height as i32 - letter.ymin as i32;
-
-            for letter_y in 0..(letter.height as i32) {
-                for letter_x in 0..(letter.width as i32) {
-                    let x = x_start + letter_x;
-                    let y = y_start + letter_y;
-
-                    let px = letter.data[(letter_x + letter_y * letter.width as i32) as usize];
-
-                    if px > 100 {
-                        render_pixel(x as u16, y as u16);
-                    }
-                }
-            }
+            self.render_letter(letter);
 
             self.current_x_pos += letter.advance_width as i32;
         }
@@ -146,7 +109,76 @@ impl<'a> Write for TextRenderer<'a> {
     }
 }
 
+fn div_ceil(quotient: i32, divisor: i32) -> i32 {
+    (quotient + divisor - 1) / divisor
+}
+
 impl<'a> TextRenderer<'a> {
+    fn render_letter(&mut self, letter: &FontLetter) {
+        let vram_manager = &mut self.vram_manager;
+        let foreground_colour = self.foreground_colour;
+        let background_colour = self.background_colour;
+
+        let x_start = (self.current_x_pos + letter.xmin as i32).max(0);
+        let y_start =
+            self.current_y_pos + self.font.ascent - letter.height as i32 - letter.ymin as i32;
+
+        let x_tile_start = x_start / 8;
+        let y_tile_start = y_start / 8;
+
+        let letter_offset_x = x_start.rem_euclid(8);
+        let letter_offset_y = y_start.rem_euclid(8);
+
+        let x_tiles = div_ceil(letter.width as i32 + letter_offset_x, 8);
+        let y_tiles = div_ceil(letter.height as i32 + letter_offset_y, 8);
+
+        for letter_y_tile in 0..(y_tiles + 1) {
+            let letter_y_start = 0.max(letter_offset_y - 8 * letter_y_tile) + 8 * letter_y_tile;
+            let letter_y_end =
+                (letter_offset_y + letter.height as i32).min((letter_y_tile + 1) * 8);
+
+            let tile_y = y_tile_start + letter_y_tile;
+
+            for letter_x_tile in 0..(x_tiles + 1) {
+                let letter_x_start = 0.max(letter_offset_x - 8 * letter_x_tile) + 8 * letter_x_tile;
+                let letter_x_end =
+                    (letter_offset_x + letter.width as i32).min((letter_x_tile + 1) * 8);
+
+                let tile_x = x_tile_start + letter_x_tile;
+
+                let mut masks = [0u32; 8];
+                let mut zero = true;
+
+                for letter_y in letter_y_start..letter_y_end {
+                    let y = letter_y - letter_offset_y;
+
+                    for letter_x in letter_x_start..letter_x_end {
+                        let x = letter_x - letter_offset_x;
+                        let pos = x + y * letter.width as i32;
+                        let px_line = letter.data[(pos / 8) as usize];
+                        let px = (px_line >> (pos & 7)) & 1;
+
+                        if px != 0 {
+                            masks[(letter_y & 7) as usize] |=
+                                (foreground_colour as u32) << ((letter_x & 7) * 4);
+                            zero = false;
+                        }
+                    }
+                }
+
+                if !zero {
+                    let tile = self.tiles.entry((tile_x, tile_y)).or_insert_with(|| {
+                        vram_manager.new_dynamic_tile().fill_with(background_colour)
+                    });
+
+                    for (i, tile_data_line) in tile.tile_data.iter_mut().enumerate() {
+                        *tile_data_line |= masks[i];
+                    }
+                }
+            }
+        }
+    }
+
     pub fn commit(mut self) {
         let tiles = core::mem::take(&mut self.tiles);
 
@@ -171,3 +203,48 @@ impl<'a> Drop for TextRenderer<'a> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    const FONT: Font = crate::include_font!("examples/font/yoster.ttf", 12);
+
+    #[test_case]
+    fn font_display(gba: &mut crate::Gba) {
+        let (gfx, mut vram) = gba.display.video.tiled0();
+
+        let mut bg = gfx.background(crate::display::Priority::P0);
+
+        vram.set_background_palette_raw(&[
+            0x0000, 0x0ff0, 0x00ff, 0xf00f, 0xf0f0, 0x0f0f, 0xaaaa, 0x5555, 0x0000, 0x0000, 0x0000,
+            0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
+        ]);
+
+        let background_tile = vram.new_dynamic_tile().fill_with(0);
+
+        for y in 0..20u16 {
+            for x in 0..30u16 {
+                bg.set_tile(
+                    &mut vram,
+                    (x, y).into(),
+                    &background_tile.tile_set(),
+                    TileSetting::from_raw(background_tile.tile_index()),
+                );
+            }
+        }
+
+        vram.remove_dynamic_tile(background_tile);
+
+        let mut writer = FONT.render_text((0u16, 3u16).into(), 1, 2, &mut bg, &mut vram);
+
+        writeln!(&mut writer, "Hello, World!").unwrap();
+        writeln!(&mut writer, "This is a font rendering example").unwrap();
+
+        writer.commit();
+
+        bg.commit();
+        bg.show();
+
+        crate::test_runner::assert_image_output("examples/font/font-test-output.png");
+    }
+}

agb/src/display/object.rs

@@ -961,6 +961,7 @@ mod tests {
 
         let object = gba.display.object.get();
 
+        {
             let mut objects: Vec<_> = alloc::vec![
                 object.object(object.sprite(BOSS.sprite(0))),
                 object.object(object.sprite(EMU.sprite(0))),
@@ -980,4 +981,7 @@ mod tests {
 
             object.commit();
         }
+
+        object.commit();
+    }
 }

agb/src/lib.rs

@@ -112,9 +112,19 @@
 /// ```
 pub use agb_image_converter::include_gfx;
 
+#[doc(hidden)]
 pub use agb_image_converter::include_aseprite_inner;
 
-pub use agb_image_converter::include_font;
+#[doc(hidden)]
+pub use agb_image_converter::include_font as include_font_inner;
+
+#[macro_export]
+macro_rules! include_font {
+    ($font_path: literal, $font_size: literal) => {{
+        use $crate::display;
+        $crate::include_font_inner!($font_path, $font_size)
+    }};
+}
 
 /// This macro declares the entry point to your game written using `agb`.
 ///

mgba-test-runner/src/main.rs

@@ -3,6 +3,7 @@
 mod runner;
 use anyhow::{anyhow, Error};
 use image::io::Reader;
+use image::GenericImage;
 use io::Write;
 use regex::Regex;
 use runner::VideoBuffer;
@@ -135,15 +136,14 @@ fn rgba_to_gba_to_rgba(c: [u8; 4]) -> [u8; 4] {
 
 fn check_image_match(image_path: &str, video_buffer: &VideoBuffer) -> Result<(), Error> {
     let expected_image = Reader::open(image_path)?.decode()?;
-    let expected = expected_image
-        .as_rgba8()
-        .ok_or(anyhow!("cannot convert to rgba8"))?;
+    let expected = expected_image.to_rgba8();
 
     let (buf_dim_x, buf_dim_y) = video_buffer.get_size();
     let (exp_dim_x, exp_dim_y) = expected.dimensions();
     if (buf_dim_x != exp_dim_x) || (buf_dim_y != exp_dim_y) {
         return Err(anyhow!("image sizes do not match"));
     }
+
     for y in 0..buf_dim_y {
         for x in 0..buf_dim_x {
             let video_pixel = video_buffer.get_pixel(x, y);
@@ -151,10 +151,37 @@ fn check_image_match(image_path: &str, video_buffer: &VideoBuffer) -> Result<(),
             let video_pixel = gba_colour_to_rgba(video_pixel);
             let image_pixel = rgba_to_gba_to_rgba(image_pixel.0);
             if image_pixel != video_pixel {
-                return Err(anyhow!("images do not match"));
+                let output_file = write_video_buffer(video_buffer);
+
+                return Err(anyhow!(
+                    "images do not match, actual output written to {}",
+                    output_file
+                ));
             }
         }
     }
 
     Ok(())
 }
+
+fn write_video_buffer(video_buffer: &VideoBuffer) -> String {
+    let (width, height) = video_buffer.get_size();
+    let mut output_image = image::DynamicImage::new_rgba8(width, height);
+
+    for y in 0..height {
+        for x in 0..width {
+            let pixel = video_buffer.get_pixel(x, y);
+            let pixel_as_rgba = gba_colour_to_rgba(pixel);
+
+            output_image.put_pixel(x, y, pixel_as_rgba.into())
+        }
+    }
+
+    let output_folder = std::env::temp_dir();
+    let output_file = "mgba-test-runner-output.png"; // TODO make this random
+
+    let output_file = output_folder.join(output_file);
+    let _ = output_image.save_with_format(&output_file, image::ImageFormat::Png);
+
+    output_file.to_string_lossy().into_owned()
+}