[PATCH] Seed random sounds

[Thomas]

Visual Actors now use the same seed for every sound.

Closes #1786.

Before using the random function it uses srand() with the actor id to seed the random function. I also made changes to rand.cpp. Apparently the first value returned by rand() is very dependent on the seed (see ​http://stackoverflow.com/questions/8599238/random-number-generation-in-c-first-number-not-very-random). Most actors were returning the same random value as they have similar seeds. Using modulo instead of dividing uses the least significant bits of the random value, yielding better results.

This is my first patch, so please tell me if I'm doing something wrong.

[Thomas]

Patch

[Stan]

We are currently in feature freeze so this will be for next Alpha version. Please attach patches to older tickets instead of creating new ones :)

Thanks for your patch it will hopefully be reviewed soon after release (in a few weeks) Feel free to take any other tickets.

Please edit this ticket and assign it to you next time you comment :) Feel free to work on any other tickets :)

EDIT : On a quick glance on the patch, if you edit a file you need to make sure the dates are correct : Rand.cpp should be updated to 2015 for now it's 2010

/* Copyright (c) 2010 Wildfire Games
 *

see the programmers section in the wiki ​http://trac.wildfiregames.com/wiki

[Thomas]

I see. Thanks for the info, I'll keep it in mind for next time.

[Thomas]

patch2

[Thomas]

I made a new patch and changed the copyright header.

[Stan]

Thanks for your work :)

[wraitii]

Patch looks fine and seems to work (or at least not to fail). I'm not sure what it changes though? Are sounds more varied? Not sure how to test this.

[historic_bruno]

Replying to wraitii:

Patch looks fine and seems to work (or at least not to fail). I'm not sure what it changes though? Are sounds more varied? Not sure how to test this.

The problem was explained in the other ticket. If you selected a unit, the voice pitch would be different each time. Each unit should have their own constant pitch.

This patch doesn't look like the right solution, it's calling srand() which reseeds the non-simulation RNG for the entire game? That is surely not desirable :) I think what you want to do is use a local rng_t or something like we do for actor variations in CObjectBase::CalculateRandomRemainingSelections.

[elexis]

Backlogging due to lack of progress.

[Thomas]

Do you mean something like this? Unfortunately this code doesn't compile for me, and so far I couldn't figure out why, but the idea should work.

[Stan]

Thanks for keeping working on it: ​http://pastebin.com/zCXm3LmG Here is the build log in case that helps.

[Thomas]

It's been a while, but I thought I'd start again. I think I'm using Boost incorrectly, since most errors occur there.

[echotangoecho]

I'm not sure whether you found it already, but the uni_dist expects a reference, not a pointer. I would change rng_t* rng to rng_t& t. Also, maybe it would be better if we used the C++11 <random> for this? I'm not sure whether this is allowed by our coding conventions though...

[Thomas]

Thanks. The patch is working now.

[wraitii]

Patch applies fine and seems to work following historicbruno's comment above.

I'm not entirely sure we need the complexity of Boost for the random number, but it's simple enough that that's nota big issue here. Bumping to review queue, if nobody sees concern with boost, I think we can commit this.

[elexis]

Moving to the new WIP milestone.

[echotangoecho]

We are already using boost in some parts of the code for random number generation. However, as <random> is supported by all our target compilers, it might be better to use that (which is pretty much equivalent to boost random).

Other than that, the patch looks good to me.

[Stan]

Uploaded the patch, it was ready for committing back then so it should be pretty easy to check.

[Stan]

In 22231:

Seed unit sounds so that their pitch and their gain are always the same for the same unit.
Fixes #3578
Reviewed by: @vladislavbelov

Differential Revision: ​https://code.wildfiregames.com/D1584