Holidays: Christmas and Easter beside Halloween, two weeks before to a few days after; decorations in the dungeon and around the title

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

src/gfx.rs

@@ -94,6 +94,9 @@ pub const I_CATAPULT: u32 = 210; // catapult tool
 pub const T_SNOW: u32 = 211; // 4 variants: snow on the land above ground (winter)
 pub const T_PUMPKIN: u32 = 215; // a carved pumpkin (Halloween)
 pub const T_MOSS: u32 = 216; // 4 variants: mushroom grove ground, moss with glowing spores
+pub const T_GIFT: u32 = 220; // a wrapped present (Christmas)
+pub const T_FIR: u32 = 221; // fir needles with baubles (Christmas)
+pub const T_EGG: u32 = 222; // 2 variants: a painted egg (Easter)
 
 pub struct Gfx {
     pub atlas: Texture2D,
@@ -1256,6 +1259,38 @@ fn gen_atlas() -> Image {
             Some(c(240, 128, 30))
         }
     });
+    // Christmas: a present in red paper with a golden ribbon, fir needles with baubles
+    cv.cell(T_GIFT, |x, y| {
+        if x == 7 || x == 8 || y == 7 || y == 8 {
+            Some(c(250, 210, 80))
+        } else if (x + y) % 5 == 0 {
+            Some(c(200, 30, 40))
+        } else {
+            Some(c(176, 24, 34))
+        }
+    });
+    cv.cell(T_FIR, |x, y| {
+        let r = hash(x, y, 470);
+        if r % 29 == 0 {
+            Some([c(240, 60, 60), c(250, 210, 80), c(90, 160, 255)][(r / 29 % 3) as usize])
+        } else if (x + 2 * y) % 5 == 0 {
+            Some(c(20, 70, 40))
+        } else {
+            Some(shade((34, 104, 56), (rnd(x, y, 471) * 16.0) as i32 - 8))
+        }
+    });
+    // Easter: painted eggs, stripes and zigzags in spring colours
+    for v in 0..2u32 {
+        cv.cell(T_EGG + v, |x, y| {
+            let cols = if v == 0 { [c(140, 200, 250), c(250, 230, 120), c(255, 255, 255)] } else { [c(250, 160, 200), c(150, 220, 140), c(255, 250, 230)] };
+            let zig = (y + (x % 4 - 2).abs()) % 8;
+            Some(match zig {
+                0 | 1 => cols[1],
+                4 => cols[2],
+                _ => cols[0],
+            })
+        });
+    }
     // grass above ground
     for v in 0..4u32 {
         cv.cell(T_GRASS + v, |x, y| {