From 4d07126fcc72920b56b2c31fb4eaf88a6b653f20 Mon Sep 17 00:00:00 2001
From: bnewbold <bryan@octopart.com>
Date: Sun, 29 Jan 2012 03:13:05 -0500
Subject: code backup

---
 src/sprite_test/util.pde | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 src/sprite_test/util.pde

(limited to 'src/sprite_test/util.pde')

diff --git a/src/sprite_test/util.pde b/src/sprite_test/util.pde
new file mode 100644
index 0000000..7fbf70d
--- /dev/null
+++ b/src/sprite_test/util.pde
@@ -0,0 +1,33 @@
+int atxy(int x, int y)
+{
+  return (y << 6) + x;
+}
+
+// ----------------------------------------------------------------------
+//     qrand: quick random numbers
+// ----------------------------------------------------------------------
+
+static uint16_t lfsr = 1;
+
+static void qrandSeed(int seed)
+{
+  if (seed) {
+    lfsr = seed;
+  } else {
+    lfsr = 0x947;
+  }
+}
+
+static byte qrand1()    // a random bit
+{
+  lfsr = (lfsr >> 1) ^ (-(lfsr & 1) & 0xb400);
+  return lfsr & 1;
+}
+
+static byte qrand(byte n) // n random bits
+{
+  byte r = 0;
+  while (n--)
+    r = (r << 1) | qrand1();
+  return r;
+}
-- 
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