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-rw-r--r--src/util/numeric.h83
1 files changed, 41 insertions, 42 deletions
diff --git a/src/util/numeric.h b/src/util/numeric.h
index 7fc3d2167..42d9a87a9 100644
--- a/src/util/numeric.h
+++ b/src/util/numeric.h
@@ -184,57 +184,56 @@ inline void sortBoxVerticies(v3s16 &p1, v3s16 &p2) {
}
-/*
- See test.cpp for example cases.
- wraps degrees to the range of -360...360
- NOTE: Wrapping to 0...360 is not used because pitch needs negative values.
-*/
-inline float wrapDegrees(float f)
+/** Returns \p f wrapped to the range [-360, 360]
+ *
+ * See test.cpp for example cases.
+ *
+ * \note This is also used in cases where degrees wrapped to the range [0, 360]
+ * is innapropriate (e.g. pitch needs negative values)
+ *
+ * \internal functionally equivalent -- although precision may vary slightly --
+ * to fmodf((f), 360.0f) however empirical tests indicate that this approach is
+ * faster.
+ */
+inline float modulo360f(float f)
{
- // Take examples of f=10, f=720.5, f=-0.5, f=-360.5
- // This results in
- // 10, 720, -1, -361
- int i = floor(f);
- // 0, 2, 0, -1
- int l = i / 360;
- // NOTE: This would be used for wrapping to 0...360
- // 0, 2, -1, -2
- /*if(i < 0)
- l -= 1;*/
- // 0, 720, 0, -360
- int k = l * 360;
- // 10, 0.5, -0.5, -0.5
- f -= float(k);
- return f;
+ int sign;
+ int whole;
+ float fraction;
+
+ if (f < 0) {
+ f = -f;
+ sign = -1;
+ } else {
+ sign = 1;
+ }
+
+ whole = f;
+
+ fraction = f - whole;
+ whole %= 360;
+
+ return sign * (whole + fraction);
}
-/* Wrap to 0...360 */
+
+/** Returns \p f wrapped to the range [0, 360]
+ */
inline float wrapDegrees_0_360(float f)
{
- // Take examples of f=10, f=720.5, f=-0.5, f=-360.5
- // This results in
- // 10, 720, -1, -361
- int i = floor(f);
- // 0, 2, 0, -1
- int l = i / 360;
- // Wrap to 0...360
- // 0, 2, -1, -2
- if(i < 0)
- l -= 1;
- // 0, 720, 0, -360
- int k = l * 360;
- // 10, 0.5, -0.5, -0.5
- f -= float(k);
- return f;
+ float value = modulo360f(f);
+ return value < 0 ? value + 360 : value;
}
-/* Wrap to -180...180 */
+
+/** Returns \p f wrapped to the range [-180, 180]
+ */
inline float wrapDegrees_180(float f)
{
- f += 180;
- f = wrapDegrees_0_360(f);
- f -= 180;
- return f;
+ float value = modulo360f(f + 180);
+ if (value < 0)
+ value += 360;
+ return value - 180;
}
/*