Merge pull request #211 from gwilymk/avoid-overwriting-text-on-line-above

Avoid overwriting text on line above

agb/examples/text_render.rs

@@ -42,6 +42,8 @@ fn main(mut gba: agb::Gba) -> ! {
     writeln!(&mut writer, "Hello, World!").unwrap();
     writeln!(&mut writer, "This is a font rendering example").unwrap();
 
+    writer.commit();
+
     bg.commit();
     bg.show();
 

agb/src/display/font.rs

@@ -3,7 +3,7 @@ use core::fmt::{Error, Write};
 use crate::fixnum::Vector2D;
 use crate::hash_map::HashMap;
 
-use super::tiled::{RegularMap, TileSetting, VRamManager};
+use super::tiled::{DynamicTile, RegularMap, TileSetting, VRamManager};
 
 pub struct FontLetter {
     width: u8,
@@ -72,6 +72,7 @@ impl Font {
             bg,
             background_colour,
             foreground_colour,
+            tiles: Default::default(),
         }
     }
 }
@@ -85,13 +86,13 @@ pub struct TextRenderer<'a> {
     bg: &'a mut RegularMap,
     background_colour: u8,
     foreground_colour: u8,
+    tiles: HashMap<(usize, usize), DynamicTile<'a>>,
 }
 
 impl<'a> Write for TextRenderer<'a> {
     fn write_str(&mut self, text: &str) -> Result<(), Error> {
-        let mut tiles = HashMap::new();
-
         let vram_manager = &mut self.vram_manager;
+        let tiles = &mut self.tiles;
         let foreground_colour = self.foreground_colour;
         let background_colour = self.background_colour;
 
@@ -141,6 +142,14 @@ impl<'a> Write for TextRenderer<'a> {
             self.current_x_pos += letter.advance_width as i32;
         }
 
+        Ok(())
+    }
+}
+
+impl<'a> TextRenderer<'a> {
+    pub fn commit(mut self) {
+        let tiles = core::mem::take(&mut self.tiles);
+
         for ((x, y), tile) in tiles.into_iter() {
             self.bg.set_tile(
                 self.vram_manager,
@@ -150,7 +159,15 @@ impl<'a> Write for TextRenderer<'a> {
             );
             self.vram_manager.remove_dynamic_tile(tile);
         }
-
-        Ok(())
+    }
+}
+
+impl<'a> Drop for TextRenderer<'a> {
+    fn drop(&mut self) {
+        let tiles = core::mem::take(&mut self.tiles);
+
+        for (_, tile) in tiles.into_iter() {
+            self.vram_manager.remove_dynamic_tile(tile);
+        }
     }
 }