js
//方向検知-先頭車型
function getCollideTrain(entity){
    var world = entity.field_70170_p;
    var aabb = entity.field_70121_D.func_72314_b(0, 2, 0);
    var train = null;
    world.func_72839_b(entity, aabb).forEach(
        function(collideEntity){
            if(collideEntity instanceof EntityTrainBase) train = collideEntity.getFormation().get(0).train;
            if(collideEntity instanceof EntityBogie) train = collideEntity.getTrain().getFormation().get(0).train;
        }
    );
    if(!train) return null;
    var motionX = train.field_70169_q - train.field_70165_t;
    var motionY = train.field_70167_r - train.field_70163_u;
    var motionZ = train.field_70166_s - train.field_70161_v;
    var motionVec = new Vec3(motionX, motionY, motionZ);
    if (motionVec.length() === 0) {
        var fotmation = entity.getFormation();
        var isDirInvert = fotmation ? Boolean(fotmation.getEntry(entity).dir) : false;
        var speed = isDirInvert ? -entity.getSpeed() : entity.getSpeed();
        var trainYaw = entity.field_70177_z + 180;
        motionVec = new Vec3(0, 0, speed);
        motionVec = motionVec.rotateAroundY(trainYaw);
    }
    var trainYaw = Math.floor(motionVec.getYaw() + 360) % 360;
    var signalYaw = Math.floor(entity.field_70177_z + 360) % 360;
    var negativeSignalYaw = signalYaw >= 5 ? signalYaw - 5 : signalYaw - 5 + 360;
    var positiveSignalYaw = signalYaw <= 355 ? signalYaw + 5 : signalYaw + 5 - 360;
    if (signalYaw > 5 && signalYaw < 355) {
        if (negativeSignalYaw <= trainYaw && trainYaw <= positiveSignalYaw) {
            return train.getFormation().get(0).train;;
        }
    }
    else {
        if (negativeSignalYaw <= trainYaw || trainYaw <= positiveSignalYaw) {
            return train.getFormation().get(0).train;;
        }
    }
    return null;
}