update

frontend/src/tiles.rs

@@ -0,0 +1,102 @@
+//! Tile visibility and data fetching utilities
+
+use wasm_bindgen::JsCast;
+use crate::camera::Camera;
+
+/// Fetch tile data with caching
+pub async fn fetch_cached(url: &str) -> Option<Vec<u8>> {
+    let window = web_sys::window()?;
+    let caches = window.caches().ok()?;
+    let cache_name = "map-data-v5-sand";
+    let cache = wasm_bindgen_futures::JsFuture::from(caches.open(cache_name)).await.ok()?;
+    let cache: web_sys::Cache = cache.dyn_into().ok()?;
+
+    let request = web_sys::Request::new_with_str(url).ok()?;
+    let match_promise = cache.match_with_request(&request);
+    let match_val = wasm_bindgen_futures::JsFuture::from(match_promise).await.ok()?;
+
+    if !match_val.is_undefined() {
+        let response: web_sys::Response = match_val.dyn_into().ok()?;
+        let buffer_promise = response.array_buffer().ok()?;
+        let buffer = wasm_bindgen_futures::JsFuture::from(buffer_promise).await.ok()?;
+        let array = js_sys::Uint8Array::new(&buffer);
+        return Some(array.to_vec());
+    }
+
+    // Network fetch
+    let response_val = wasm_bindgen_futures::JsFuture::from(window.fetch_with_request(&request)).await.ok()?;
+    let response: web_sys::Response = response_val.dyn_into().ok()?;
+    
+    // Clone response for cache
+    let response_clone = response.clone().ok()?;
+    let put_promise = cache.put_with_request(&request, &response_clone);
+    wasm_bindgen_futures::JsFuture::from(put_promise).await.ok()?;
+
+    let buffer_promise = response.array_buffer().ok()?;
+    let buffer = wasm_bindgen_futures::JsFuture::from(buffer_promise).await.ok()?;
+    let array = js_sys::Uint8Array::new(&buffer);
+    Some(array.to_vec())
+}
+
+/// Get visible tiles based on current camera position
+pub fn get_visible_tiles(camera: &Camera) -> Vec<(i32, i32, i32)> {
+    // Select zoom level based on camera zoom
+    // Zoom 6: World/Country view
+    // Zoom 9: Region view
+    // Zoom 12: City view
+    // Zoom 14: Street view
+    let z = if camera.zoom < 100.0 {
+        2
+    } else if camera.zoom < 500.0 {
+        4
+    } else if camera.zoom < 2000.0 {
+        6
+    } else if camera.zoom < 5000.0 {
+        9
+    } else if camera.zoom < 10000.0 {
+        12
+    } else {
+        14
+    };
+    let n = 2.0f64.powi(z);
+    
+    let half_width = 1.0 * camera.aspect / camera.zoom;
+    let half_height = 1.0 / camera.zoom;
+    
+    let min_x = (camera.x - half_width).max(0.0) as f64;
+    let max_x = (camera.x + half_width).min(1.0) as f64;
+    let min_y = (camera.y - half_height).max(0.0) as f64;
+    let max_y = (camera.y + half_height).min(1.0) as f64;
+    
+    let min_tile_x = (min_x * n).floor() as i32;
+    let max_tile_x = (max_x * n).floor() as i32;
+    let min_tile_y = (min_y * n).floor() as i32;
+    let max_tile_y = (max_y * n).floor() as i32;
+    
+    let mut tiles = Vec::new();
+    for x in min_tile_x..=max_tile_x {
+        for y in min_tile_y..=max_tile_y {
+            tiles.push((z, x, y));
+        }
+    }
+    tiles
+}
+
+/// Get parent tile for the tile retention hierarchy
+pub fn get_parent_tile(z: i32, x: i32, y: i32) -> Option<(i32, i32, i32)> {
+    // Hierarchy: 14 -> 12 -> 9 -> 6 -> 2
+    let parent_z = match z {
+        14 => 12,
+        12 => 9,
+        9 => 6,
+        6 => 4,
+        4 => 2,
+        _ => return None,
+    };
+    
+    // Calculate scale difference
+    let diff = z - parent_z;
+    let factor = 2i32.pow(diff as u32);
+    
+    Some((parent_z, x / factor, y / factor))
+}