Looking to trace out at 45 degrees off the players center...

[Whistler]

HL is based on Quake1, and RTCW is based on Quake3 so that's why they are similar and Quake1, Quake2, Quake3, RTCW are all in C instead of C++.

"because our MAKE_VECTORS is actually a macro that calls AngleVectors()..."
it doesn't call AngleVectors() but g_engfuncs.pfnMakeVectors() although they are actually the same thing

[sfx1999]

Pierre haven't you looked at Quake code yet? Please note that HL is based off Quake I and not Quake II. Also, make sure it is the QuakeWorld server code (unless you want client stuff).

In Quake I's mathlib.h:

/*
 Copyright (C) 1996-1997 Id Software, Inc.
 
 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU General Public License
 as published by the Free Software Foundation; either version 2
 of the License, or (at your option) any later version.
 
 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 
 See the GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
 */
 // mathlib.h
 
 typedef float vec_t;
 typedef vec_t vec3_t[3];
 typedef vec_t vec5_t[5];
 
 typedef	int	fixed4_t;
 typedef	int	fixed8_t;
 typedef	int	fixed16_t;
 
 #ifndef M_PI
 #define M_PI		3.14159265358979323846	// matches value in gcc v2 math.h
 #endif
 
 struct mplane_s;
 
 extern vec3_t vec3_origin;
 extern	int nanmask;
 
 #define	IS_NAN(x) (((*(int *)&x)&nanmask)==nanmask)
 
 #define DotProduct(x,y) (x[0]*y[0]+x[1]*y[1]+x[2]*y[2])
 #define VectorSubtract(a,b,c) {c[0]=a[0]-b[0];c[1]=a[1]-b[1];c[2]=a[2]-b[2];}
 #define VectorAdd(a,b,c) {c[0]=a[0]+b[0];c[1]=a[1]+b[1];c[2]=a[2]+b[2];}
 #define VectorCopy(a,b) {b[0]=a[0];b[1]=a[1];b[2]=a[2];}
 
 void VectorMA (vec3_t veca, float scale, vec3_t vecb, vec3_t vecc);
 
 vec_t _DotProduct (vec3_t v1, vec3_t v2);
 void _VectorSubtract (vec3_t veca, vec3_t vecb, vec3_t out);
 void _VectorAdd (vec3_t veca, vec3_t vecb, vec3_t out);
 void _VectorCopy (vec3_t in, vec3_t out);
 
 int VectorCompare (vec3_t v1, vec3_t v2);
 vec_t Length (vec3_t v);
 void CrossProduct (vec3_t v1, vec3_t v2, vec3_t cross);
 float VectorNormalize (vec3_t v);		// returns vector length
 void VectorInverse (vec3_t v);
 void VectorScale (vec3_t in, vec_t scale, vec3_t out);
 int Q_log2(int val);
 
 void R_ConcatRotations (float in1[3][3], float in2[3][3], float out[3][3]);
 void R_ConcatTransforms (float in1[3][4], float in2[3][4], float out[3][4]);
 
 void FloorDivMod (double numer, double denom, int *quotient,
 		int *rem);
 fixed16_t Invert24To16(fixed16_t val);
 fixed16_t Mul16_30(fixed16_t multiplier, fixed16_t multiplicand);
 int GreatestCommonDivisor (int i1, int i2);
 
 void AngleVectors (vec3_t angles, vec3_t forward, vec3_t right, vec3_t up);
 int BoxOnPlaneSide (vec3_t emins, vec3_t emaxs, struct mplane_s *plane);
 float	anglemod(float a);
 
 void RotatePointAroundVector( vec3_t dst, const vec3_t dir, const vec3_t point, float degrees );
 
 
 #define BOX_ON_PLANE_SIDE(emins, emaxs, p)	\
 	(((p)->type < 3)?    		    		\
 	(	    		    		    		\
 		((p)->dist <= (emins)[(p)->type])?	\
 		    1		    		    		\
 		:    		    		    		\
 		(    		    		    		\
 			((p)->dist >= (emaxs)[(p)->type])?\
 		    	2	    		    		\
 		    :		    		    		\
 		    	3	    		    		\
 		)    		    		    		\
 	)	    		    		    		\
 	:	    		    		    		\
 		BoxOnPlaneSide( (emins), (emaxs), (p)))

[sfx1999]

Make sure that you can change that angle!!!

When your bots zoom in with a rifle, it WILL change their FOV. If you don't the bots will be able to see anything as if they were not zoomed in.

[Whistler]

well, here's some more implementions of HL engine functions. Some of them are "crazily" optimized
I also inlined all of them to make them faster

inline float UTIL_AngleMod(float a)
{
   // this function adds or substracts 360 enough times needed to the given angle in
   // order to set it into the range [0, 360) and returns the resulting angle. Letting
   // the engine have a hand on angles that are outside these bounds may cause the
   // game to freeze by screwing up the engine math code.

   return (360.0 / 65536) * ((int)(a * (65536.0 / 360.0)) & 65535);
}

inline float AngleNormalize(float angle)
{
   // this function adds or substracts 360 enough times needed to the given angle in
   // order to set it into the range [-180, 180) and returns the resulting angle. Letting
   // the engine have a hand on angles that are outside these bounds may cause the game
   // to freeze by screwing up the engine math code.

   return (360.0 / 65536) * ((int)((angle + 180) * (65536.0 / 360.0)) & 65535) - 180;
}

inline void ClampAngles(Vector &vecAngles)
{
   vecAngles.x = AngleNormalize(vecAngles.x);
   vecAngles.y = AngleNormalize(vecAngles.y);
   vecAngles.z = 0;
}

void
#ifndef __BORLANDC__
inline
#endif
SinCos( float rad, float *flSin, float *flCos )
{
#ifdef __linux__
   register double __cosr, __sinr;
   __asm __volatile__ ("fsincos" : "=t" (__cosr), "=u" (__sinr) : "0" (rad));
   *flSin = __sinr;
   *flCos = __cosr;
#else
#if !defined(__BORLANDC__) && !defined(_MSC_VER)
   *flSin = sinf(rad);
   *flCos = cosf(rad);
#else
   __asm
   {
      fld DWORD PTR[rad]
      fsincos
      mov edx, DWORD PTR[flCos]
      mov eax, DWORD PTR[flSin]
      fstp DWORD PTR[edx]
      fstp DWORD PTR[eax]
   }
#endif
#endif
}

inline float UTIL_AngleDiff( float destAngle, float srcAngle )
{
   return AngleNormalize(destAngle - srcAngle);
}

inline float UTIL_VecToYaw( const Vector &vec )
{
   // the purpose of this function is to convert a spatial location determined by the vector
   // passed in into an absolute Y angle (yaw) from the origin of the world.

   if (vec.x == 0 && vec.y == 0)
      return 0;
   else
      return atan2(vec.y, vec.x) * (180 / M_PI);
}

inline Vector UTIL_VecToAngles( const Vector &vec )
{
   // the purpose of this function is to convert a spatial location determined by the vector
   // passed in into absolute angles from the origin of the world.

   float yaw, pitch;

   if (vec.x == 0 && vec.y == 0)
   {
      yaw = 0;
      pitch = (vec.z > 0) ? 90 : 270;
   }
   else
   {
      yaw = atan2(vec.y, vec.x) * (180 / M_PI);
      pitch = atan2(vec.z, vec.Length2D()) * (180 / M_PI);
   }

   return Vector(pitch, yaw, 0);
}

inline void UTIL_MakeVectors( const Vector &vecAngles )
{
   float sp = 0, cp = 0, sy = 0, cy = 0, sr = 0, cr = 0;
   float angle = vecAngles.x * (M_PI / 180);
   SinCos(angle, &sp, &cp);
   angle = vecAngles.y * (M_PI / 180);
   SinCos(angle, &sy, &cy);
   angle = vecAngles.z * (M_PI / 180);
   SinCos(angle, &sr, &cr);

   gpGlobals->v_forward.x = cp * cy;
   gpGlobals->v_forward.y = cp * sy;
   gpGlobals->v_forward.z = -sp;
   gpGlobals->v_right.x = -sr * sp * cy + cr * sy;
   gpGlobals->v_right.y = -sr * sp * sy - cr * cy;
   gpGlobals->v_right.z = -sr * cp;
   gpGlobals->v_up.x = cr * sp * cy + sr * sy;
   gpGlobals->v_up.y = cr * sp * sy - sr * cy;
   gpGlobals->v_up.z = cr * cp;
}

[sfx1999]

Hey look Quake I's mathlib.h is extremely similar to Half-life's mathlib.h.

[Pierre-Marie Baty]

@Whistler: somehow these comments remind me of something, but I cant remember what ? I can swear I've seen them earlier......
the style looks like the comments I was making in the first RACC preview.....

[Whistler]

Yes, that is your comments. Besides, I have changed "-180/+180" to "[-180, 180)".