Diff: math_extra.cpp

Revision:

0:cf4396614a79

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/math_extra.cpp	Fri Nov 03 18:48:48 2017 +0000
@@ -0,0 +1,29 @@
+#include "math_extra.h"
+#include <stdint.h>
+
+int in_range(int x, int lower, int upper)
+{
+    return (x > lower && x < upper);
+}
+
+float clamp(float x, float limit)
+{
+    x = (x > limit) ? limit : x;
+    x = (x < -limit) ? -limit : x;
+    return x;
+}
+
+int sgn(float x)
+{
+    return (x > 0.0) - (x < 0.0);
+}
+
+float coin_flip()
+{
+    // Compute psuedorandom numbers! Don't worry about how this works.
+    // If you really must know, search for "Linear-feedback shift register"
+    static uint16_t rand = 0xA1B2;
+    uint16_t bit = ((rand >> 0) ^ (rand >> 2) ^ (rand >> 3) ^ (rand >> 5) ) & 1;
+    rand = (rand >> 1) | (bit << 15);
+    return (rand & 1) ? 1.0 : -1.0;
+}
\ No newline at end of file