TogglePlayerControllable(playerid, 0);

public OnPlayerKeyStateChange ( playerid, newkeys, oldkeys )
{
    if ( PRESSED ( KEY_FIRE ) )
    {
        if ( GetPlayerWeapon ( playerid ) != 0 )
        {
            foreach(Player, i)
            {
                if ( IsPlayerAimingAtPlayer( playerid, i ) )
                {
                    if ( i != playerid )
                    {
                        new Float:pHP;
                        GetPlayerHealth ( playerid, pHP);
                        if ( pHP < 50.0 )
                        {
                            //Apply animation.
                            TogglePlayerControllable ( i, 0 );
                        }
                    }
                }
            }
        }
    }
    return 1;
}

Float:DistanceCameraTargetToLocation(Float:CamX, Float:CamY, Float:CamZ, Float:ObjX, Float:ObjY, Float:ObjZ, Float:FrX, Float:FrY, Float:FrZ) {

    new Float:TGTDistance;

    TGTDistance = floatsqroot((CamX - ObjX) * (CamX - ObjX) + (CamY - ObjY) * (CamY - ObjY) + (CamZ - ObjZ) * (CamZ - ObjZ));

    new Float:tmpX, Float:tmpY, Float:tmpZ;

    tmpX = FrX * TGTDistance + CamX;
    tmpY = FrY * TGTDistance + CamY;
    tmpZ = FrZ * TGTDistance + CamZ;

    return floatsqroot((tmpX - ObjX) * (tmpX - ObjX) + (tmpY - ObjY) * (tmpY - ObjY) + (tmpZ - ObjZ) * (tmpZ - ObjZ));
}

stock Float:GetPointAngleToPoint(Float:x2, Float:y2, Float:X, Float:Y)
{

    new Float:DX, Float:DY;
    new Float:angle;

    DX = floatabs(floatsub(x2,X));
    DY = floatabs(floatsub(y2,Y));

    if (DY == 0.0 || DX == 0.0)
    {
        if(DY == 0 && DX > 0) angle = 0.0;
        else if(DY == 0 && DX < 0) angle = 180.0;
        else if(DY > 0 && DX == 0) angle = 90.0;
        else if(DY < 0 && DX == 0) angle = 270.0;
        else if(DY == 0 && DX == 0) angle = 0.0;
    }
    else
    {
        angle = atan(DX/DY);
        if(X > x2 && Y <= y2) angle += 90.0;
        else if(X <= x2 && Y < y2) angle = floatsub(90.0, angle);
        else if(X < x2 && Y >= y2) angle -= 90.0;
        else if(X >= x2 && Y > y2) angle = floatsub(270.0, angle);
    }
    return floatadd(angle, 90.0);
}

stock GetXYInFrontOfPoint(&Float:x, &Float:y, Float:angle, Float:distance)
{
    x += (distance * floatsin(-angle, degrees));
    y += (distance * floatcos(-angle, degrees));
}

stock IsPlayerAimingAt(playerid, Float:x, Float:y, Float:z, Float:radius)
{
    new Float:camera_x,Float:camera_y,Float:camera_z,Float:vector_x,Float:vector_y,Float:vector_z;
    GetPlayerCameraPos(playerid, camera_x, camera_y, camera_z);
    GetPlayerCameraFrontVector(playerid, vector_x, vector_y, vector_z);

    new Float:vertical, Float:horizontal;

    switch (GetPlayerWeapon(playerid)) {
       case 34,35,36: {
       if (DistanceCameraTargetToLocation(camera_x, camera_y, camera_z, x, y, z, vector_x, vector_y, vector_z) < radius) return true;
       return false;
       }
       case 30,31: {vertical = 4.0; horizontal = -1.6;}
       case 33: {vertical = 2.7; horizontal = -1.0;}
       default: {vertical = 6.0; horizontal = -2.2;}
    }

    new Float:angle = GetPointAngleToPoint(0, 0, floatsqroot(vector_x*vector_x+vector_y*vector_y), vector_z) - 270.0;
    new Float:resize_x, Float:resize_y, Float:resize_z = floatsin(angle+vertical, degrees);
    GetXYInFrontOfPoint(resize_x, resize_y, GetPointAngleToPoint(0, 0, vector_x, vector_y)+horizontal, floatcos(angle+vertical, degrees));

    if (DistanceCameraTargetToLocation(camera_x, camera_y, camera_z, x, y, z, resize_x, resize_y, resize_z) < radius) return true;
    return false;
}

stock IsPlayerAimingAtPlayer(playerid, targetplayerid)
{
    new Float:x, Float:y, Float:z;
    GetPlayerPos(targetplayerid, x, y, z);
    return IsPlayerAimingAt(playerid, x, y, z, 1.1);
}