+/*
+// LordHavoc: quaternion math, untested, don't know if these are correct,
+// need to add conversion to/from matrices
+// LordHavoc: later note: the matrix faq is useful: http://skal.planet-d.net/demo/matrixfaq.htm
+// LordHavoc: these are probably very wrong and I'm not sure I care, not used by anything
+
+// returns length of quaternion
+#define qlen(a) ((float) sqrt((a)[0]*(a)[0]+(a)[1]*(a)[1]+(a)[2]*(a)[2]+(a)[3]*(a)[3]))
+// returns squared length of quaternion
+#define qlen2(a) ((a)[0]*(a)[0]+(a)[1]*(a)[1]+(a)[2]*(a)[2]+(a)[3]*(a)[3])
+// makes a quaternion from x, y, z, and a rotation angle (in degrees)
+#define QuatMake(x,y,z,r,c)\
+{\
+if (r == 0)\
+{\
+(c)[0]=(float) ((x) * (1.0f / 0.0f));\
+(c)[1]=(float) ((y) * (1.0f / 0.0f));\
+(c)[2]=(float) ((z) * (1.0f / 0.0f));\
+(c)[3]=(float) 1.0f;\
+}\
+else\
+{\
+float r2 = (r) * 0.5 * (M_PI / 180);\
+float r2is = 1.0f / sin(r2);\
+(c)[0]=(float) ((x)/r2is);\
+(c)[1]=(float) ((y)/r2is);\
+(c)[2]=(float) ((z)/r2is);\
+(c)[3]=(float) (cos(r2));\
+}\
+}
+// makes a quaternion from a vector and a rotation angle (in degrees)
+#define QuatFromVec(a,r,c) QuatMake((a)[0],(a)[1],(a)[2],(r))
+// copies a quaternion
+#define QuatCopy(a,c) {(c)[0]=(a)[0];(c)[1]=(a)[1];(c)[2]=(a)[2];(c)[3]=(a)[3];}
+#define QuatSubtract(a,b,c) {(c)[0]=(a)[0]-(b)[0];(c)[1]=(a)[1]-(b)[1];(c)[2]=(a)[2]-(b)[2];(c)[3]=(a)[3]-(b)[3];}
+#define QuatAdd(a,b,c) {(c)[0]=(a)[0]+(b)[0];(c)[1]=(a)[1]+(b)[1];(c)[2]=(a)[2]+(b)[2];(c)[3]=(a)[3]+(b)[3];}
+#define QuatScale(a,b,c) {(c)[0]=(a)[0]*b;(c)[1]=(a)[1]*b;(c)[2]=(a)[2]*b;(c)[3]=(a)[3]*b;}
+// FIXME: this is wrong, do some more research on quaternions
+//#define QuatMultiply(a,b,c) {(c)[0]=(a)[0]*(b)[0];(c)[1]=(a)[1]*(b)[1];(c)[2]=(a)[2]*(b)[2];(c)[3]=(a)[3]*(b)[3];}
+// FIXME: this is wrong, do some more research on quaternions
+//#define QuatMultiplyAdd(a,b,d,c) {(c)[0]=(a)[0]*(b)[0]+d[0];(c)[1]=(a)[1]*(b)[1]+d[1];(c)[2]=(a)[2]*(b)[2]+d[2];(c)[3]=(a)[3]*(b)[3]+d[3];}
+#define qdist(a,b) ((float) sqrt(((b)[0]-(a)[0])*((b)[0]-(a)[0])+((b)[1]-(a)[1])*((b)[1]-(a)[1])+((b)[2]-(a)[2])*((b)[2]-(a)[2])+((b)[3]-(a)[3])*((b)[3]-(a)[3])))
+#define qdist2(a,b) (((b)[0]-(a)[0])*((b)[0]-(a)[0])+((b)[1]-(a)[1])*((b)[1]-(a)[1])+((b)[2]-(a)[2])*((b)[2]-(a)[2])+((b)[3]-(a)[3])*((b)[3]-(a)[3]))
+*/