Die Funktion war in meinem Script schon Standardmäßig enthalten, das heißt also du hast diese gelöscht.
stock Float:GetVehicleVelocityX(vehicleid){new Float:velocity_X, Float:velocity_dump_Y, Float:velocity_dump_Z;GetVehicleVelocity(vehicleid, velocity_X, velocity_dump_Y, velocity_dump_Z);velocity_dump_Y = 0.00;velocity_dump_Z = 0.00;return velocity_X;}
stock Float:GetVehicleVelocityY(vehicleid){new Float:velocity_dump_X, Float:velocity_Y, Float:velocity_dump_Z;GetVehicleVelocity(vehicleid, velocity_dump_X, velocity_Y, velocity_dump_Z);velocity_dump_X = 0.00;velocity_dump_Z = 0.00;return velocity_Y;}
stock Float:GetVehicleVelocityZ(vehicleid){new Float:velocity_dump_X, Float:velocity_dump_Y, Float:velocity_Z;GetVehicleVelocity(vehicleid, velocity_dump_X, velocity_dump_Y, velocity_Z);velocity_dump_X = 0.00;velocity_dump_Y = 0.00;return velocity_Z;}
#define GetVehicleSpeed_P(%0) floatmul(floatsqroot(floatadd(floatpower(GetVehicleVelocityX(GetPlayerVehicleID(%0)), 2), floatadd(floatpower(GetVehicleVelocityY(GetPlayerVehicleID(%0)), 2), floatpower(GetVehicleVelocityZ(GetPlayerVehicleID(%0)), 2)))), 200)
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