There's a bit to unpack here, but I'll ask that you please read this post and my motivation before giving a verdict. At the moment I'm just opening this thread for debate: If the idea isn't shot down as absurd and we agree it's possible to consider, I may proceed with a bug tracker entry otherwise forget I said anything. Also this post does NOT imply we have developers willing to work on it, if no one in the team considers it an effort worth investing time in I'm not going to beg. It would be a major change that takes time to test, so even if it does happen it would likely be next year at earliest (TDM 2.11 or later). Lastly this is intended solely as an OPTION... as the person suggesting it I don't believe it should ever be enabled by default due to how it would alter the gameplay, only offered as an extra component for players who want the mechanic. That being said, the idea occurred to me yesterday and I've been excited thinking about how it could work, it actually kept me up last night and I'm getting this off my chest to hear some feedback so I can fall asleep more easily tonight
Let's get into it. The idea is partly inspired from some horror games I watched Youtubers play a while back. They had a mechanic where the engine accessed the player's microphone to read the volume: If you made too much noise, monsters would hear you and come after you. The player had to stay silent else they'd be in trouble.
Last night it clicked with me how perfectly this mechanic would fit into TDM with our AI and gameplay. Imagine if any noise you made IRL risked alerting nearby guards... whereas oppositely you could use your voice to distract them to your location and move past. I'll discuss both uses below, first let's go into some technical aspects.
This would obviously require engine changes: The engine needs to learn how to access the default microphone device from the sound system, enough translate the volume into a to 0 - 1 float. The game reads this volume at an interval balanced between accuracy and performance (eg: 0.5 seconds). Based on the loudness it captures that call, the same signal emitted by sound sources to alert AI is propagated from the player's view origin. The effect tapers off with distance in a fashion similar to s_mindistance (full effect below this radius) and s_maxdistance (fully ignored beyond that radius), reasonable defaults might be min 4 / max 16 measuring with the radius of a speaker in DarkRadiant. Multiplied with that distance and the AI's acuity factor, the mic volume determines the alert level being generated. The ranges I'm suggesting for this would be:
0% to 20%: Ignored, doesn't generate any alert. Ambient noise and insignificant sounds are usually in this range for all microphones.
20% to 40%: Can go up to the 1st alert level, makes the AI mumble and say "did I hear something" but move on and ignore you.
40% to 60%: Can produce 2nd alert level in guards, making them stop in place to look around.
60% to 80%: 3rd alert level allowed, guards realize something is up and start searching the area.
80% to 100%: Loud enough to make your presence in the area known, 4th alert level is possible making guards draw their weapon and dare you to come out.
100%: So loud that your exact location is clear to the guard as if you bumped into them, 5th alert level activates and the AI proceeds to attack you.
So what is the point of this? Some would see it as an annoyance and the player sabotaging themselves, though just like selecting a higher difficulty level it's a controlled form of making your run more interesting. I for one am in it for the immersion and ingenuity: It would offer a new way to integrate the player into the world, using hardware almost every player has: A headset with a microphone, a mic on their desk, even one in their webcam. This has been done in small games but never attempted in a full stealth game for my knowledge, TDM could be among the first project of this genre to use the idea which would be an extra selling point to make it more interesting and appealing.
The first aspect is fear of being heard. Imagine you really are the player in a typical FM, hiding in the shadows as guards are walking past or running around looking for you. The last thing you want to do in such a circumstance is make any noise: You'd be careful about your breathing, and god forbid you need to cough or sneeze. This mechanic would emulate just that: Players have to be aware of their breath as an enemy walks past them... if for any reason you feel like sneezing or coughing, you better hold off or the guards will become alert in-game. To me this sounds super neat... I can already imagine playing TDM with the added fear and adrenaline
The second part is how this can be used to attract guards in a controlled way. Jumping in place works but it's hard to make guards come and investigate, with this you'd do it using your voice. The fun here is learning how loud to speak to get the desired alert level: If you whisper to the guards they won't hear you and just walk past, but if you scream too loudly they'll know where you are and attack you on sight! You'll want to say something like "hey" at just the right volume to make them investigate.
As a bonus to end the idea, why not introduce this for friendly AI too as a fun detail? You know how some FM's have pubs the player can enter where the maid and party-goers won't attack you; Whenever the player says something in their mic, friendlies and neutrals look at you and use the generic response bark! Imagine how much fun we'll have taking breaks from the objective to say all kinds of stupid things in the mic and each time someone responds with a "hello there" or "you said it" or "yeah yeah"