Holiday switch in the debug menu; darker wood for the treasury chests

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/render3d.rs

@@ -1255,6 +1255,7 @@ pub struct R3d {
     target: Option<(RenderTarget, u32, u32)>, // low resolution render target
     lava: Vec<f32>,                           // lava light per tile (see lava_field)
     chunks_hd: bool,                          // the chunks were built with the high-res atlas
+    chunks_holiday: u8,                       // ... and with this holiday's decorations
 }
 
 // The 3D resolution setting refers to a window 1080 device pixels high: smaller windows use a
@@ -1305,7 +1306,7 @@ fn chunk_sig(map: &Map, cx: i32, cz: i32) -> u64 {
 
 impl R3d {
     pub fn new() -> R3d {
-        R3d { lit: lit_material(), glow: glow_material(), opaque: opaque_material(), chunks: Vec::new(), ncx: 0, ncz: 0, outlines: true, wall_sub: 3, max_lights: MAX_LIGHTS, pixel_rows: crate::settings::PIXEL_ART_ROWS as u32, target: None, lava: Vec::new(), chunks_hd: false }
+        R3d { lit: lit_material(), glow: glow_material(), opaque: opaque_material(), chunks: Vec::new(), ncx: 0, ncz: 0, outlines: true, wall_sub: 3, max_lights: MAX_LIGHTS, pixel_rows: crate::settings::PIXEL_ART_ROWS as u32, target: None, lava: Vec::new(), chunks_hd: false, chunks_holiday: 0 }
     }
 
     // Changing the wall detail rebuilds all chunks
@@ -1345,10 +1346,13 @@ impl R3d {
                 ch.sig = 0;
             }
         }
-        // the graphics style changed: the chunks are built again with the other atlas
+        // the graphics style or the holiday changed: the chunks are built again (other atlas,
+        // other decorations)
         let hd = self.pixel_rows >= crate::settings::HIGH_RES_ROWS as u32;
-        if hd != self.chunks_hd {
+        let holiday = crate::holiday::current();
+        if hd != self.chunks_hd || holiday != self.chunks_holiday {
             self.chunks_hd = hd;
+            self.chunks_holiday = holiday;
             for ch in self.chunks.iter_mut() {
                 ch.sig = 0;
             }