Latching topics and the 3dPanel

Hello,

FYI @dbking77. We’re having a problem with the way the 3dPanel keeps data between scrubbing on the timeline and latched topics. The problem is that when we seek forward and back on the timeline, the messages disappear

The problem comes down to the way the seekPlayback function is implemented here. Because all the latched messages in the rosbag.js are found at time 0 and because when you use seekPlayback you go back in time by the SEEK_TIME when you scrub to a particular time, you lose all the latched messages from that time. For us this is particularly frustrating as our maps are latched.

There are 2 ways we were thinking of to solve this issue:

1. We look for latched connections when we run getMessages https://github.com/cruise-automation/webviz/blob/2e7db3aafffec39b541728668c97ce7d83eee007/packages/webviz-core/src/players/RandomAccessPlayer.js#L437 and then just pick up the last message from them regardless of time
2. We implement something that goes through all the topics and gets the last message before this time for that topic.

[janpaul123]

Not yet! But this work is slated really soon.

[cjds]

Was trying to mess with this today and this is where I got till

In the below example, I was trying to use the global variable and a local variable in the node to try to republish the message.

The issues I ran into were:

1. The global variables do not seem editable from inside a node. Once changed they would get reset on the next loop
2. Local variables to the function seem to be reset when the scrubber on the bottom is moved.

As such I think I’m either doing the repub wrong or it isn’t possible with this feature

import { Input, Messages } from "ros";

type Output = {};
type GlobalVariables = {
  id: number;
  localization: Messages.nav_msgs__OccupancyGrid;
};

let x: Messages.nav_msgs__OccupancyGrid;
export const inputs = [
  "/atlas/localization",
  "/controller_costmap_updater_clock"
];
export const output = "/webviz_node/my_new_map";

// Populate 'Input' with a parameter to properly type your inputs, e.g. 'Input<"/your_input_topic">'
const publisher = (
  message:
    | Input<"/localization">
    | Input<"/controller_costmap_updater_clock">,
  globalVars: GlobalVariables
): Messages.nav_msgs__OccupancyGrid | undefined => {
  if (message.topic == "/atlas/localization") {
    log("Resetting message");
    x = message.message;
  }

  if (x !== undefined) {
    log(x.info.resolution);
    return x;
  }
  log("Variable is undefined");
};

export default publisher;