Heat Signature Q&A With Tom Francis

Tom Francis - Heat Sig

Following on from his reveal of Heat Signature’s key gameplay elements, we talk to Gunpoint creator Tom Francis about his inspirations, aspirations and reservations when it comes to being an Indie Developer totally free to pursue whatever takes his fancy.

First things first, lets talk about Gunpoint. Looking back on it’s development and release, are there any big lessons you’ve taken away from the whole process?

A lot of it went surprisingly smoothly for a first project, but yeah, I learned masses. The biggest lesson that I learned too late with Gunpoint is that hand-crafting levels is not really efficient for me: it takes me ages, and once people have completed them a few times they don’t really have much value. Right now, every other game I have planned or in development involves procedurally generated content.

After the success of Gunpoint and the freedom it’s given you, has it been difficult to focus on making a new game or has the freedom been a catalyst for inspiration and development?

The freedom is fantastic, particularly not having too much time pressure. While I was making Gunpoint I had two jobs, and it was sad to have to miss almost all the cool events going on to get the actual game finished. So after release, I went to pretty much every event I could for the rest of the year. That was fantastic, but pretty soon I started to feel anxious about not having created anything for a few months. So I guess I overcompensated, because then I started working on two games at once.

Where did the inspiration for Heat Signature come from?

A long time ago I was thinking about what a 3D version of Spleunky might look like, and came up with this ridiculously ambitious third-person shooter about jetpacking around space and smashing through the hulls of destructible ships.

Then recently, my friend Graham reminded me of it, and I got thinking about whether it could work in 2D as well. It rather defeats the original idea of making a 3D Spelunky, but now that I know Game Maker inside out, the 2D version suddenly seemed really doable, and potentially really cool.

Heat Signature looks to be a very ambitious project; is there anything about your goals for Heat Signature that are particularly daunting?

The nice thing about it is that because it’s systems-based rather than content-based, the scope is flexible. I could release it tomorrow as a free curiosity if that was as far as I wanted to go with it, or I could work for years adding mechanics and depth and variety and objectives. So it doesn’t feel daunting right now because I feel like I could stop whenever I wanted, and still have something I’d be happy to release.

That said, I just added the ability for ships to blow parts off each other, and immediately hit the problem that if you blow a ship in half, both halves continue to move as one. Figuring out when to split a ship, how many pieces to split it into, and which modules belong to which piece, is probably going to be a tricky but interesting bit of maths.

Do you have a final art style in mind for Heat Signature?

Nope! Once more of the base game is nailed down, I’ll be putting out a call for artists to send in samples of how they might tackle it, and hiring the best. I’m really looking forward to that – we got such a diverse range of possible looks for Gunpoint, I can’t wait to see how different artists tackle both spaceships and their crew.


You’ve stuck with Game Maker for Heat Signature but used Unity with Grappling Hook Game. Why did you want to push into Unity development, and why stick with Game Maker for Heat Signature?

I want to learn Unity partly so I have the option of presenting things in 3D, and partly because the Asset Store is such an amazing concept: you can buy not just art assets but bits of code written by smarter people than you, which lets novice coders like me use features that would otherwise be beyond us. It’s a really radical shift in the way people make games together.

The reason for using Game Maker: Studio for Heat Signature is simpler: I already know how to make it with what I learned from Gunpoint, and I think I can do it pretty quickly. Progress with Unity has been slower than I’d like, so it’s nice to have something I can switch to where I’ll achieve something big every day.

The Unity Asset Store is a real boon for developers regardless of coding/design experience, and it’s something Game Maker lacks. How did you approach learning GML, and is there a particular function or code snippet in GML you’ve come across/created in your projects that you would like to share/discuss?

I learnt Game Maker from the built-in tutorial and a short one by Derek Yu, and then graduated to doing more GML stuff mostly by looking it up in the help. And yeah, there are definitely some useful tricks I’ve learned along the way. Here are two:

1. In Gunpoint I very often needed to change something’s sprite to one that might be a different size, without that thing clipping through a floor or wall they might be near. The code for keeping one particular side of a sprite in the same location is:

OldLeftEdge = bbox_left

sprite_index = NewSprite

x = x – (bbox_left – OldLeftEdge)

I find that impossible to remember, so I wrote a series of scripts like PreserveBase() and RestoreBase() to run before and after each time I changed a sprite.

2. You usually don’t want a moving object to accelerate to its maximum speed instantly, or stop on a dime. Acceleration is easy, but I often struggle with the maths of when and how much something should decelerate to ensure it stops exactly at its destination. In Heat Signature, I finally realized this code gets much simpler and more intuitive if you decide on a DecelerationDistance: how far from its destination it should start to slow down.

Then the main part of the code is just:

if (DistanceToDestination < DecelerationDistance) {
Speed = MaxSpeed * DistanceToDestination / DecelerationDistance

Gunpoint had a wonderful narrative and genuine comedy; how do you intend to approach the narrative/plot in Heat Signature?

Thanks! That’s a good question. Part of my reason for starting the Grappling Hook Game was that I wanted to do something with writing in it again, so I guess that’s my main outlet for that stuff. I won’t try to force a plot or written content into Heat Signature if it doesn’t fit naturally, but I’ll try a few different possibilities before I make that call.

It doesn’t feel like a pre-written ‘main quest’ makes sense for it, so it may be that there are just rare ships or stations that have a unique story, out there to be discovered.

Sudden and often comical deaths seem to be prevalent in the games you like (Spelunky) and make (Gunpoint). Is this conscious design choice on your part, or a natural result of your focus on stealth and combat avoidance?

Haha, I do like to die suddenly. I don’t want to copy any videogame tropes unless I really need them for what I want to make, and I’ve always found hitpoints very abstract and artificial. Being able to take ten gunshots and live just makes me stop believing that those things are gunshots at all, they become weird attrition hoses. With Gunpoint, it was a conscious goal to mirror how vicious and sudden and horrible a gunshot really is, and to make guns feel like scary, nasty things.

In Heat Signature, I want sneaking aboard a hostile ship to feel scary too: you’re somewhere you shouldn’t be, anyone here might catch you, and they’ll kill you if they do. I haven’t settled on exactly how on-board combat will work though, so I don’t know for sure if it’ll always be one-shot kills.

Thanks for taking the time to chat!


Thanks again to Tom for taking the time to chat to us! We’ll be following Heat Signature and his other project Grappling Hook Game so be sure to watch out for more coverage on those and other Tom Francis shenanigans in the future.

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