fix tile rendering

src/processor/gpu.rs

@@ -330,6 +330,7 @@ impl CPU {
             palette,
             scroll_x,
             scroll_y,
+            true,
         );
     }
 
@@ -345,6 +346,7 @@ impl CPU {
                 palette,
                 pos_x,
                 pos_y,
+                false,
             )
         }
     }
@@ -429,28 +431,39 @@ impl CPU {
         tilemap: &TilemapArea,
         tiledata: &TiledataArea,
         palette: Palette,
-        _offset_x: u8,
+        offset_x: u8,
         offset_y: u8,
+        wrap: bool,
     ) {
-        let tile_line = (scanline as usize) + (offset_y as usize);
+        let tile_line_y = scanline.wrapping_add(offset_y);
-        let tilemap_row = tile_line / 8;
+        if (scanline as usize + offset_y as usize) % 0xFF > 0 && !wrap {
-        let tile_px = (tile_line) % 8;
+            return;
-        let tiledata_offset = tile_px * 2;
+        }
-        let row_addr = ((tilemap_row * 32) % 0x400) as u16;
+        let tilemap_row = tile_line_y / 8;
-        for x in 0..32_u16 {
+        let tile_px_y = (tile_line_y) % 8;
-            let tile_addr = tiledata.get_addr(self.memory.get(tilemap.get_addr(row_addr + x)))
+        let tiledata_offset = tile_px_y * 2;
-                + tiledata_offset as u16;
+        let row_addr = ((tilemap_row as usize * 32) % 0x400) as u16;
+        for x in 0..WIDTH {
+            let tile_line_x = (x as u8).wrapping_add(offset_x);
+            if ((x + offset_x as usize) / 0xFF) > 0 && !wrap {
+                continue;
+            }
+
+            let tilemap_column = (tile_line_x / 8) as u16;
+
+            let tile_px_x = (tile_line_x % 8) as u8;
+            let tile_addr = tiledata.get_addr(
+                self.memory
+                    .get(tilemap.get_addr(row_addr + (tilemap_column))),
+            ) + tiledata_offset as u16;
+
             let lsbs = self.memory.get(tile_addr);
             let msbs = self.memory.get(tile_addr + 1);
-            for px_x in 0..8 {
+            let lsb = get_bit(lsbs, 7 - tile_px_x);
-                let lsb = get_bit(lsbs, 7 - px_x);
+            let msb = get_bit(msbs, 7 - tile_px_x);
-                let msb = get_bit(msbs, 7 - px_x);
             let colour = bits_to_mapped_colour(lsb, msb, palette);
-                let x_coord = ((x * 8) + (px_x as u16)) as usize;
+
-                if x_coord < WIDTH {
+            self.gpu.buffer[(scanline as usize * WIDTH) + x] = colour.to_rgb();
-                    self.gpu.buffer[(scanline as usize * WIDTH) + x_coord] = colour.to_rgb();
-                }
-            }
         }
     }