1 files changed, 102 insertions, 0 deletions

diff --git a/src/texture.rs b/src/texture.rs
new file mode 100644
index 0000000..bdbb15c
--- /dev/null
+++ b/src/texture.rs
@@ -0,0 +1,102 @@
+use rand::Rng;
+
+pub const TEX_SIZE: usize = 64;
+
+/// Deterministic hash for coherent procedural noise.
+fn hash(x: u32, y: u32, seed: u64) -> u64 {
+    let mut h = (x as u64).wrapping_mul(0x9e3779b9);
+    h = h.wrapping_add((y as u64).wrapping_mul(0x517cc1b727220a95));
+    h = h.wrapping_add(seed);
+    h = (h ^ (h >> 33)).wrapping_mul(0xc6a4a7935bd1e995);
+    h = (h ^ (h >> 29)).wrapping_mul(0x5bd1e995);
+    h
+}
+
+/// Brown cracked wall texture — 64×64, brick pattern with mortar lines and fissures.
+pub fn generate_wall_texture(rng: &mut impl Rng) -> Vec<u32> {
+    let seed = rng.gen::<u64>();
+    let mut tex = vec![0u32; TEX_SIZE * TEX_SIZE];
+
+    for y in 0..TEX_SIZE {
+        for x in 0..TEX_SIZE {
+            let h = hash(x as u32, y as u32, seed);
+
+            let r = 105u8.wrapping_add((h % 50) as u8);
+            let g = 55u8.wrapping_add(((h >> 8) % 35) as u8);
+            let b = 22u8.wrapping_add(((h >> 16) % 25) as u8);
+
+            // Brick mortar every 16 pixels
+            let mortar = y % 16 == 0 || y % 16 == 15;
+
+            let (r, g, b) = if mortar {
+                (42, 20, 8)
+            } else {
+                let crack_hash = hash(x.wrapping_add(1000) as u32, y as u32, seed);
+                let crack_val = (crack_hash % 100) as u8;
+                if crack_val < 8 {
+                    // dark crack
+                    let factor = 0.30 + (crack_val as f64 / 8.0) * 0.25;
+                    (
+                        (r as f64 * factor) as u8,
+                        (g as f64 * factor) as u8,
+                        (b as f64 * factor) as u8,
+                    )
+                } else if crack_val < 14 {
+                    // light crack highlight
+                    (
+                        (r.saturating_add(25)).min(255),
+                        (g.saturating_add(18)).min(255),
+                        (b.saturating_add(10)).min(255),
+                    )
+                } else {
+                    (r, g, b)
+                }
+            };
+
+            tex[y * TEX_SIZE + x] =
+                0xFF00_0000 | ((r as u32) << 16) | ((g as u32) << 8) | (b as u32);
+        }
+    }
+    tex
+}
+
+/// Gray stone-tile floor — 64×64, checkerboard with grout and subtle colour tint.
+pub fn generate_floor_texture(rng: &mut impl Rng) -> Vec<u32> {
+    let seed = rng.gen::<u64>();
+    let mut tex = vec![0u32; TEX_SIZE * TEX_SIZE];
+
+    for y in 0..TEX_SIZE {
+        for x in 0..TEX_SIZE {
+            let h = hash(x as u32, y as u32, seed);
+            let h2 = hash(x.wrapping_add(2000) as u32, y.wrapping_add(2000) as u32, seed);
+
+            let tile_x = x / 16;
+            let tile_y = y / 16;
+            let is_light_tile = (tile_x + tile_y) % 2 == 0;
+
+            let local_x = x % 16;
+            let local_y = y % 16;
+            let is_grout = local_x == 0 || local_y == 0;
+
+            let base_gray: u8 = if is_light_tile { 115 } else { 95 };
+            let noise = (h % 15) as u8;
+
+            let tint_r = (h2 % 8) as i16 - 4i16;
+            let tint_b = ((h2 >> 8) % 8) as i16 - 4i16;
+
+            let gray = if is_grout {
+                base_gray.saturating_sub(30).saturating_add(noise / 3)
+            } else {
+                base_gray.saturating_add(noise / 2)
+            };
+
+            let r = (gray as i16 + tint_r).clamp(0, 255) as u8;
+            let g = gray;
+            let b = (gray as i16 + tint_b).clamp(0, 255) as u8;
+
+            tex[y * TEX_SIZE + x] =
+                0xFF00_0000 | ((r as u32) << 16) | ((g as u32) << 8) | (b as u32);
+        }
+    }
+    tex
+}