From 8e548c8c54fca6c33d2dd466a9f30c94e14535f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Elena=20Torr=C3=B3?= <elenatorro@gmail.com>
Date: Tue, 23 Jun 2026 10:25:45 +0200
Subject: [PATCH] :bug: Fix blank tiles and atlas crash on render-wasm zoom/pan
 (#10367)

* :bug: Fix missing tiles on page switch and pan/zoom end

* :bug: Fix blank tiles and atlas crash on render-wasm zoom/pan
---
 render-wasm/src/main.rs            |  6 ++++--
 render-wasm/src/render/surfaces.rs | 14 ++++++--------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/render-wasm/src/main.rs b/render-wasm/src/main.rs
index 2f7503d181..bcdd9bf28a 100644
--- a/render-wasm/src/main.rs
+++ b/render-wasm/src/main.rs
@@ -107,13 +107,14 @@ pub extern "C" fn set_canvas_background(raw_color: u32) -> Result<()> {
 #[wasm_error]
 pub extern "C" fn render(timestamp: i32, flags: u8) -> Result<FrameType> {
     with_state!(state, {
+        let render_state = get_render_state();
         state.rebuild_touched_tiles();
         // Drain the throttled modifier-tile invalidation accumulated
         // since the previous rAF. set_modifiers skips this work during
         // interactive_transform; we do it once here, with the current
         // modifier set, so the cost is paid once per rAF rather than
         // once per pointer move.
-        if get_render_state().options.is_interactive_transform() {
+        if render_state.options.is_interactive_transform() {
             // Collect into an owned Vec to release the immutable borrow on
             // `state.shapes` before the mutable `rebuild_modifier_tiles` call.
             let ids = state.shapes.modifier_ids().to_vec();
@@ -121,7 +122,8 @@ pub extern "C" fn render(timestamp: i32, flags: u8) -> Result<FrameType> {
                 state.rebuild_modifier_tiles(&ids)?;
             }
         }
-        let frame_type = if flags & RenderFlag::Partial as u8 == RenderFlag::Partial as u8 {
+        let is_partial = flags & RenderFlag::Partial as u8 == RenderFlag::Partial as u8;
+        let frame_type = if is_partial && !render_state.preserve_target_during_render {
             state
                 .continue_render_loop(timestamp)
                 .map_err(|_| Error::RecoverableError("Error rendering".to_string()))?
diff --git a/render-wasm/src/render/surfaces.rs b/render-wasm/src/render/surfaces.rs
index 28210c6517..dc39595e96 100644
--- a/render-wasm/src/render/surfaces.rs
+++ b/render-wasm/src/render/surfaces.rs
@@ -1631,15 +1631,13 @@ impl TileTextureCache {
     }
 
     pub fn add(&mut self, tile_viewbox: &TileViewbox, tile: &Tile) -> TileAtlasTextureRef {
-        if self.grid.len() > TEXTURES_CACHE_CAPACITY {
-            // First we try to remove the obsolete tiles.
-            self.gc();
-        }
+        // Evict against the real slot count (`provider.length`), not the
+        // hardcoded capacity — otherwise the guard never fires and the atlas
+        // fills up until `allocate()` has no slot left.
+        let capacity = self.provider.length.min(TEXTURES_CACHE_CAPACITY);
 
-        // If we still have a texture capacity problem, then
-        // we try to remove all of those tiles that aren't
-        // visible.
-        if self.grid.len() > TEXTURES_CACHE_CAPACITY {
+        if self.grid.len() >= capacity {
+            self.gc();
             self.gc_non_visible(tile_viewbox);
         }