crates/console/prometeu-drivers/src/gfx.rs

@@ -79,6 +79,21 @@ pub struct Gfx {
 
 const GLYPH_UNKNOWN: [u8; 5] = [0x7, 0x7, 0x7, 0x7, 0x7];
 
+struct RenderTarget<'a> {
+    back: &'a mut [u16],
+    screen_w: usize,
+    screen_h: usize,
+}
+
+#[derive(Clone, Copy)]
+struct CachedTileDraw<'a> {
+    x: i32,
+    y: i32,
+    entry: CachedTileEntry,
+    bank: &'a GlyphBank,
+    tile_size: prometeu_hal::glyph_bank::TileSize,
+}
+
 #[inline]
 fn glyph_for_char(c: char) -> &'static [u8; 5] {
     match c.to_ascii_uppercase() {
@@ -629,6 +644,7 @@ impl Gfx {
         request: &LayerCopyRequest,
         glyph_banks: &dyn GlyphBankPoolAccess,
     ) {
+        let mut target = RenderTarget { back, screen_w, screen_h };
         let layer_cache = &cache.layers[request.layer_index];
         if !layer_cache.valid {
             return;
@@ -657,52 +673,43 @@ impl Gfx {
                 }
 
                 Self::draw_cached_tile_pixels(
-                    back,
-                    screen_w,
-                    screen_h,
-                    screen_tile_x,
-                    screen_tile_y,
+                    &mut target,
+                    CachedTileDraw {
+                        x: screen_tile_x,
+                        y: screen_tile_y,
                         entry,
-                    &bank,
-                    request.tile_size,
+                        bank: &bank,
+                        tile_size: request.tile_size,
+                    },
                 );
             }
         }
     }
 
-    fn draw_cached_tile_pixels(
-        back: &mut [u16],
-        screen_w: usize,
-        screen_h: usize,
-        x: i32,
-        y: i32,
-        entry: CachedTileEntry,
-        bank: &GlyphBank,
-        tile_size: prometeu_hal::glyph_bank::TileSize,
-    ) {
-        let size = tile_size as usize;
+    fn draw_cached_tile_pixels(target: &mut RenderTarget<'_>, tile: CachedTileDraw<'_>) {
+        let size = tile.tile_size as usize;
 
         for local_y in 0..size {
-            let world_y = y + local_y as i32;
-            if world_y < 0 || world_y >= screen_h as i32 {
+            let world_y = tile.y + local_y as i32;
+            if world_y < 0 || world_y >= target.screen_h as i32 {
                 continue;
             }
 
             for local_x in 0..size {
-                let world_x = x + local_x as i32;
-                if world_x < 0 || world_x >= screen_w as i32 {
+                let world_x = tile.x + local_x as i32;
+                if world_x < 0 || world_x >= target.screen_w as i32 {
                     continue;
                 }
 
-                let fetch_x = if entry.flip_x() { size - 1 - local_x } else { local_x };
-                let fetch_y = if entry.flip_y() { size - 1 - local_y } else { local_y };
-                let px_index = bank.get_pixel_index(entry.glyph_id, fetch_x, fetch_y);
+                let fetch_x = if tile.entry.flip_x() { size - 1 - local_x } else { local_x };
+                let fetch_y = if tile.entry.flip_y() { size - 1 - local_y } else { local_y };
+                let px_index = tile.bank.get_pixel_index(tile.entry.glyph_id, fetch_x, fetch_y);
                 if px_index == 0 {
                     continue;
                 }
 
-                let color = bank.resolve_color(entry.palette_id, px_index);
-                back[world_y as usize * screen_w + world_x as usize] = color.raw();
+                let color = tile.bank.resolve_color(tile.entry.palette_id, px_index);
+                target.back[world_y as usize * target.screen_w + world_x as usize] = color.raw();
             }
         }
     }

crates/console/prometeu-hal/src/scene_viewport_cache.rs

@@ -325,6 +325,34 @@ mod tests {
         assert_eq!(cache.layers[0].ring_origin(), (1, 1));
     }
 
+    #[test]
+    fn layer_cache_wraps_ring_origin_for_negative_and_large_movements() {
+        let scene = make_scene();
+        let mut cache = SceneViewportCache::new(&scene, 3, 3);
+
+        cache.move_layer_window_by(0, -1, -4);
+        assert_eq!(cache.layers[0].logical_origin(), (-1, -4));
+        assert_eq!(cache.layers[0].ring_origin(), (2, 2));
+
+        cache.move_layer_window_by(0, 7, 8);
+        assert_eq!(cache.layers[0].logical_origin(), (6, 4));
+        assert_eq!(cache.layers[0].ring_origin(), (0, 1));
+    }
+
+    #[test]
+    fn move_window_to_matches_incremental_ring_movement() {
+        let scene = make_scene();
+        let mut direct = SceneViewportCache::new(&scene, 4, 4);
+        let mut incremental = SceneViewportCache::new(&scene, 4, 4);
+
+        direct.move_layer_window_to(0, 9, -6);
+        incremental.move_layer_window_by(0, 5, -2);
+        incremental.move_layer_window_by(0, 4, -4);
+
+        assert_eq!(direct.layers[0].logical_origin(), incremental.layers[0].logical_origin());
+        assert_eq!(direct.layers[0].ring_origin(), incremental.layers[0].ring_origin());
+    }
+
     #[test]
     fn cache_entry_fields_are_derived_from_scene_tiles() {
         let scene = make_scene();
@@ -415,6 +443,113 @@ mod tests {
         assert_eq!(cache.layers[3].entry(3, 3).glyph_id, 415);
     }
 
+    #[test]
+    fn refresh_after_wrapped_window_move_materializes_new_logical_tiles() {
+        let scene = make_scene();
+        let mut cache = SceneViewportCache::new(&scene, 3, 3);
+
+        cache.refresh_layer_all(&scene, 0);
+        cache.move_layer_window_to(0, 1, 2);
+        cache.refresh_layer_all(&scene, 0);
+
+        assert_eq!(cache.layers[0].logical_origin(), (1, 2));
+        assert_eq!(cache.layers[0].ring_origin(), (1, 2));
+        assert_eq!(cache.layers[0].entry(0, 0).glyph_id, 109);
+        assert_eq!(cache.layers[0].entry(1, 0).glyph_id, 110);
+        assert_eq!(cache.layers[0].entry(2, 0).glyph_id, 111);
+        assert_eq!(cache.layers[0].entry(0, 1).glyph_id, 113);
+        assert_eq!(cache.layers[0].entry(2, 1).glyph_id, 115);
+        assert_eq!(cache.layers[0].entry(0, 2), CachedTileEntry::default());
+    }
+
+    #[test]
+    fn partial_refresh_uses_wrapped_physical_slots_after_window_move() {
+        let scene = make_scene();
+        let mut cache = SceneViewportCache::new(&scene, 3, 3);
+
+        cache.move_layer_window_to(0, 1, 0);
+        cache.refresh_layer_column(&scene, 0, 0);
+
+        assert_eq!(cache.layers[0].ring_origin(), (1, 0));
+        assert_eq!(cache.layers[0].entry(0, 0).glyph_id, 101);
+        assert_eq!(cache.layers[0].entry(0, 1).glyph_id, 105);
+        assert_eq!(cache.layers[0].entry(0, 2).glyph_id, 109);
+        assert_eq!(cache.layers[0].entry(1, 0), CachedTileEntry::default());
+        assert_eq!(cache.layers[0].entry(2, 0), CachedTileEntry::default());
+    }
+
+    #[test]
+    fn out_of_bounds_logical_origins_materialize_default_entries_after_wrap() {
+        let scene = make_scene();
+        let mut cache = SceneViewportCache::new(&scene, 2, 2);
+
+        cache.move_layer_window_to(0, -2, 3);
+        cache.refresh_layer_all(&scene, 0);
+
+        for y in 0..2 {
+            for x in 0..2 {
+                assert_eq!(cache.layers[0].entry(x, y), CachedTileEntry::default());
+            }
+        }
+    }
+
+    #[test]
+    fn ringbuffer_preserves_logical_tile_mapping_across_long_mixed_movements() {
+        let scene = make_scene();
+        let mut cache = SceneViewportCache::new(&scene, 3, 3);
+        let motions = [
+            (1, 0),
+            (0, 1),
+            (2, 2),
+            (-1, 0),
+            (0, -2),
+            (4, 1),
+            (-3, 3),
+            (5, -4),
+            (-6, 2),
+            (3, -3),
+            (7, 7),
+            (-8, -5),
+        ];
+
+        for &(dx, dy) in &motions {
+            cache.move_layer_window_by(0, dx, dy);
+            cache.refresh_layer_all(&scene, 0);
+
+            let (origin_x, origin_y) = cache.layers[0].logical_origin();
+            for cache_y in 0..cache.height() {
+                for cache_x in 0..cache.width() {
+                    let expected_scene_x = origin_x + cache_x as i32;
+                    let expected_scene_y = origin_y + cache_y as i32;
+
+                    let expected = if expected_scene_x < 0
+                        || expected_scene_y < 0
+                        || expected_scene_x as usize >= scene.layers[0].tilemap.width
+                        || expected_scene_y as usize >= scene.layers[0].tilemap.height
+                    {
+                        CachedTileEntry::default()
+                    } else {
+                        let tile_x = expected_scene_x as usize;
+                        let tile_y = expected_scene_y as usize;
+                        let tile = scene.layers[0].tilemap.tiles
+                            [tile_y * scene.layers[0].tilemap.width + tile_x];
+                        CachedTileEntry::from_tile(&scene.layers[0], tile)
+                    };
+
+                    assert_eq!(
+                        cache.layers[0].entry(cache_x, cache_y),
+                        expected,
+                        "mismatch at logical origin ({}, {}), cache ({}, {})",
+                        origin_x,
+                        origin_y,
+                        cache_x,
+                        cache_y
+                    );
+                }
+            }
+        }
+    }
+
     #[test]
     fn materialization_populates_all_four_layers() {
         let scene = make_scene();