sample-code: Have fun with random number generators

sample-code/rand.cl

@@ -0,0 +1,37 @@
+//! Pseudo-random number generation using a LFSR algorithm
+
+static state: u64 = 0xdeadbeefdeadbeef;
+
+pub fn seed(seed: u64) {
+    state = seed;
+}
+
+pub fn lfsr_next() {
+    state ^= state >> 7;
+    state ^= state << 9;
+    state ^= state >> 13;
+}
+
+/// Returns a pseudorandom byte
+pub fn rand() -> u8 {
+    for _ in 0..8 {
+        lfsr_next()
+    }
+    state & 0xff
+}
+
+// Prints a maze out of diagonal box drawing characters, ['╲', '╱']
+fn mazel(width: u64, height: u64) {
+    let walls = ['\u{2571}', '\u{2572}'];
+    rand_rect(width, height, walls)
+}
+
+// Prints a rectangle with the provided walls
+fn rand_rect(width: u64, height: u64, walls: [char; 2]) {
+    for _ in 0..height {
+        for _ in 0..width {
+            print(walls[rand() % 2])
+        }
+        println()
+    }
+}