From 1ac442a213ce910baa022506cfeee6277095b8ec Mon Sep 17 00:00:00 2001
From: Rafael Barreto <baarreth@hotmail.com>
Date: Sat, 24 Jul 2010 22:03:52 +0000
Subject: [PATCH] more anticheats compatibility, using fast sqrt (100% faster
 than sqrtf)

git-svn-id: svn://svn.code.sf.net/p/actiongame/code/trunk/ac@5456 e016b1c5-ed68-44aa-a2f7-31cac88cffde
---
 source/src/geom.h         | 29 +++++++++++++++++++++++++++++
 source/src/server.cpp     |  2 +-
 source/src/serverchecks.h |  4 ++--
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/source/src/geom.h b/source/src/geom.h
index 2b694373..873d8b44 100644
--- a/source/src/geom.h
+++ b/source/src/geom.h
@@ -1,3 +1,28 @@
+// Fast Inverse Sqrt
+// http://www.gamedev.net/community/forums/topic.asp?topic_id=139956
+// http://www.lomont.org/Math/Papers/2003/InvSqrt.pdf
+// http://www.mceniry.net/papers/Fast%20Inverse%20Square%20Root.pdf
+// http://en.wikipedia.org/wiki/Fast_inverse_square_root
+
+inline float fInvSqrt (float x)
+{
+    union
+    {
+        int d;
+        float f;
+    } u;
+
+    u.f = x;
+    u.d = 0x5f3759df - (u.d >> 1);
+//     return u.f; // ultra-fast, about 3.5% of error
+    return 0.5f * u.f * ( 3.00175f - x * u.f * u.f ); // about 0.1% of error
+}
+
+inline float fSqrt (float x)
+{
+    return x * fInvSqrt(x);
+}
+
 struct vec
 {
     union
@@ -34,12 +59,16 @@ struct vec
     float magnitude() const { return sqrtf(squaredlen()); }
     vec &normalize() { div(magnitude()); return *this; }
 
+    float fmag() const { return fSqrt(squaredlen()); }
+
     float dist(const vec &e) const { vec t; return dist(e, t); }
     float dist(const vec &e, vec &t) const { t = *this; t.sub(e); return t.magnitude(); }
 
     float distxy(const vec &e) const { float dx = e.x - x, dy = e.y - y; return sqrtf(dx*dx + dy*dy); }
     float magnitudexy() const { return sqrtf(x*x + y*y); }
 
+    float fmagxy() const { return fSqrt(x*x + y*y); }
+
     bool reject(const vec &o, float max) const { return x>o.x+max || x<o.x-max || y>o.y+max || y<o.y-max; }
 
     vec &cross(const vec &a, const vec &b) { x = a.y*b.z-a.z*b.y; y = a.z*b.x-a.x*b.z; z = a.x*b.y-a.y*b.x; return *this; }
diff --git a/source/src/server.cpp b/source/src/server.cpp
index c424fdfb..f4bff6cb 100644
--- a/source/src/server.cpp
+++ b/source/src/server.cpp
@@ -1354,7 +1354,7 @@ void checkitemspawns(int diff)
 
 void serverdamage(client *target, client *actor, int damage, int gun, bool gib, const vec &hitpush = vec(0, 0, 0))
 {
-    if (!m_demo && !m_coop && !validdamage(target, actor, gun, gib)) return;
+    if (!m_demo && !m_coop && !validdamage(target, actor, damage, gun, gib)) return;
     clientstate &ts = target->state;
     ts.dodamage(damage);
     actor->state.damage += damage != 1000 ? damage : 0;
diff --git a/source/src/serverchecks.h b/source/src/serverchecks.h
index 3a2b1448..08bbc2c9 100644
--- a/source/src/serverchecks.h
+++ b/source/src/serverchecks.h
@@ -596,10 +596,10 @@ inline void checkshoot (int & cn, gameevent & shot, int & hits)
     return;
 }
 
-bool validdamage (client *&target, client *&actor, int &gun, bool &gib)
+bool validdamage (client *&target, client *&actor, int &damage, int &gun, bool &gib)
 {
 #ifdef ACAC
-    if (!d_engine(target, actor, gun, gib)) return false;
+    if (!d_engine(target, actor, damage, gun, gib)) return false;
 #endif
     return true;
 }