I didn't make it. Found it somewhere.
Code:
bool:IsBackstab(const attacker, const victim) {
new Float: vec1[3];
new Float: vec2[3];
velocity_by_aim(attacker, 1, vec1);
new Float:invlen = xs_rsqrt(vec1[0] * vec1[0] + vec1[1] * vec1[1]);
vec1[0] *= invlen;
vec1[1] *= invlen;
pev(victim, pev_angles, vec2);
angle_vector(vec2, ANGLEVECTOR_FORWARD, vec2);
return vec1[0] * vec2[0] + vec1[1] * vec2[1] > 0.8 ? true : false;
}
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