From 3b6480c5b0c968ad9f5a7cfb7ca494989be03629 Mon Sep 17 00:00:00 2001
From: Craig Robbins <kde.psych@gmail.com>
Date: Mon, 23 Feb 2015 16:25:14 +1000
Subject: [PATCH] Fix wrapDegrees family of functions
wrapDegrees() (renamed to modulo360f)
wrapDegrees_0_360
wrapDegrees_180
Minor errors were present in previous versions; see issue #2328
---
src/network/packethandlers/server.cpp | 4 +-
src/test.cpp | 44 +++++++++++---
src/util/numeric.h | 83 +++++++++++++--------------
3 files changed, 80 insertions(+), 51 deletions(-)
diff --git a/src/network/packethandlers/server.cpp b/src/network/packethandlers/server.cpp
index feb8d66be..137327e0b 100644
--- a/src/network/packethandlers/server.cpp
+++ b/src/network/packethandlers/server.cpp
@@ -543,8 +543,8 @@ void Server::handleCommand_PlayerPos(NetworkPacket* pkt)
v3f position((f32)ps.X / 100.0, (f32)ps.Y / 100.0, (f32)ps.Z / 100.0);
v3f speed((f32)ss.X / 100.0, (f32)ss.Y / 100.0, (f32)ss.Z / 100.0);
- pitch = wrapDegrees(pitch);
- yaw = wrapDegrees(yaw);
+ pitch = modulo360f(pitch);
+ yaw = modulo360f(yaw);
Player *player = m_env->getPlayer(pkt->getPeerId());
if (player == NULL) {
diff --git a/src/test.cpp b/src/test.cpp
index 3b7c75c6e..350cab127 100644
--- a/src/test.cpp
+++ b/src/test.cpp
@@ -147,15 +147,45 @@ struct TestBase
struct TestUtilities: public TestBase
{
+ inline float ref_WrapDegrees180(float f)
+ {
+ // This is a slower alternative to the wrapDegrees_180() function;
+ // used as a reference for testing
+ float value = fmodf(f + 180, 360);
+ if (value < 0)
+ value += 360;
+ return value - 180;
+ }
+
+ inline float ref_WrapDegrees_0_360(float f)
+ {
+ // This is a slower alternative to the wrapDegrees_0_360() function;
+ // used as a reference for testing
+ float value = fmodf(f, 360);
+ if (value < 0)
+ value += 360;
+ return value < 0 ? value + 360 : value;
+ }
+
+
void Run()
{
- /*infostream<<"wrapDegrees(100.0) = "<<wrapDegrees(100.0)<<std::endl;
- infostream<<"wrapDegrees(720.5) = "<<wrapDegrees(720.5)<<std::endl;
- infostream<<"wrapDegrees(-0.5) = "<<wrapDegrees(-0.5)<<std::endl;*/
- UASSERT(fabs(wrapDegrees(100.0) - 100.0) < 0.001);
- UASSERT(fabs(wrapDegrees(720.5) - 0.5) < 0.001);
- UASSERT(fabs(wrapDegrees(-0.5) - (-0.5)) < 0.001);
- UASSERT(fabs(wrapDegrees(-365.5) - (-5.5)) < 0.001);
+ UASSERT(fabs(modulo360f(100.0) - 100.0) < 0.001);
+ UASSERT(fabs(modulo360f(720.5) - 0.5) < 0.001);
+ UASSERT(fabs(modulo360f(-0.5) - (-0.5)) < 0.001);
+ UASSERT(fabs(modulo360f(-365.5) - (-5.5)) < 0.001);
+
+ for (float f = -720; f <= -360; f += 0.25) {
+ UASSERT(fabs(modulo360f(f) - modulo360f(f + 360)) < 0.001);
+ }
+
+ for (float f = -1440; f <= 1440; f += 0.25) {
+ UASSERT(fabs(modulo360f(f) - fmodf(f, 360)) < 0.001);
+ UASSERT(fabs(wrapDegrees_180(f) - ref_WrapDegrees180(f)) < 0.001);
+ UASSERT(fabs(wrapDegrees_0_360(f) - ref_WrapDegrees_0_360(f)) < 0.001);
+ UASSERT(wrapDegrees_0_360(fabs(wrapDegrees_180(f) - wrapDegrees_0_360(f))) < 0.001);
+ }
+
UASSERT(lowercase("Foo bAR") == "foo bar");
UASSERT(trim("\n \t\r Foo bAR \r\n\t\t ") == "Foo bAR");
UASSERT(trim("\n \t\r \r\n\t\t ") == "");
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;
}
/*
--
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