DrawableNoise taking up too much memory

[Merudo]

Describe the bug
There has been multiple reports of MapTool using up much more memory since 1.5.7

Reverting commits in batches, I think I've isolated the problem to the DrawableNoise feature (commit 2275f6f).

Each ZoneRenderer stores up a DrawableNoise object, which takes up a lot memory. @Phergus estimated that each noise mask is around 28MB.

To Reproduce
Steps to reproduce the behavior:

1. Load a campaign with multiple maps.
2. Record how much memory it is using.
3. Modify the source code of ZoneRenderer, so that the line

private final DrawableNoise noise = new DrawableNoise();

is replaced by

private final DrawableNoise noise = null;

4. Run and load the same campaign.
5. Record how much memory it is using. In my case, it went from 250mb to 100mb.

Expected behavior
Users shouldn't have to pay hundred of mbs in memory if the feature isn't active.

I suggest that noise variable be only constructed once the user activates the noise feature.

MapTool Info

• Version: 1.5.7+
• Install: New

Desktop (please complete the following information):

• OS: Windows
• Version: 10

[Phergus]

Probably should have the /tn on and off commands add/remove the drawable noise from the ZoneRenderer.

[sentry-io]

Sentry issue: MAPTOOL-2NT

[Phergus]

Closing.