Balancing the human artificial intelligence has been one of the harder parts of development. The difficulty stems from trying to make the AI do things that seem “logical” to the player. For example, consider the two possible desirable actions “harvest food” and “eat food”. We need to determine which action takes priority. If someone is hungry, the logical action would be to see if there’s any food around and eat it. OK, simple. We set the desire to eat to be higher than the desire to harvest food.

What if there isn’t anything to eat lying around? Since the desire to eat is higher, they will continually try to eat and never try to harvest food first. The player thinks, “What a stupid AI”. The logical action would be to harvest food first, and then eat the food. OK, then let’s switch it around so we set the person’s desire to harvest food to be higher than the desire to eat food.

Now what if the player creates 50 “harvest food” tasks on 50 different plants? Remember, the tribe member’s desire to harvest food is set higher than their desire to eat food. The AI thought process will be: hungry -> harvest food -> harvest food -> … -> harvest food -> STARVING -> harvest food -> harvest food -> starved to death. They will continue harvesting until they either finish all the harvest tasks or starve to death, despite being surrounded by plenty of recently harvested food. Once again the player thinks, “What a stupid AI”.

One way to work around this is having a variable desire to eat that fluctuates depending on current conditions. Firstly, add a check for food’s existence before trying to eat food. If there is nothing to eat, then set the desire to eat to be zero, no matter how hungry the person. That way the person will carry out any harvest tasks first. Secondly, if something to eat exists, make the person’s desire to eat higher the hungrier they become. With these extra rules, let’s see how the AI behaves in the above scenario with 50 harvest tasks.

The AI thought process will be: hungry -> look for food -> find no food -> harvest food -> harvest food -> … -> harvest food -> STARVING -> look for food -> find food -> eat food. This thought process requires more calculations, but it makes the tribe member appear smarter to the player.

Now add in desires for drinking, sleeping, staying warm, fighting, fleeing, finding missing equipment, crafting and building to this equation. It’s pretty easy to end up with an AI that doesn’t always do the “logical” thing if the desires aren’t carefully balanced. Even worse is an AI whose desire fluctuates every few milliseconds, causing it to flip-flop between two different actions but not making any progress on either one. If you’ve ever seen an AI in a game move their units backward and forward over and over again, you’ll know what I mean.

I’m constantly testing and tweaking the human AI in Tribe Of Pok to balance desires (and stop them burning themselves, like in the above gif). It can be time-consuming, but I think it’s worth the effort. It’s great to see your Pokians on screen running around acting the way you would expect.

Firstly, there are some new ways I’ll be communicating to the community. You can now follow me on Twitter via @ParsleyPWG for more regular updates on what I’m working on. I’ll also be posting a weekly work log on the website blog. Remember, you can also sign up to be notified when new Early Access versions are available.

Combat mode

Combat Mode was something I put in a while ago, and took out when it became too confusing. When entering Combat Mode, the tribe members stop what they are doing and wait for the player to give orders. Several improvements have been made to the point where I’m happy to put it back in the game.

It works much like in an RTS game now, left-click drag to select and right-click to give move or attack orders. If someone is under attack, you can enter Combat Mode and send other tribe members to help them fight. Much more intuitive than in the previous iteration.

Prosperity

Once a tribe’s food and water needs were met, I didn’t feel there was a strong enough force driving the gameplay forward. While testing the game, I got to a point where everyone was happy and thought to myself, “ok… now what?” Something was needed to tie everything together. There had to be a goal the player could aim for in addition to survival. So I did some thinking and came up with a single measure to handle all this – prosperity.

Prosperity is a measure of how well your tribe is doing. Currently it is affected by factors such as the size of your tribe, amount of food available, the value of items and severity of diseases. In general, the value of items will only count if they’re located within your “circle of influence”. The circle of influence is an area around the tribe that can grow or shrink. I implemented it a while ago as a way to prevent roaming animals from constantly wandering into the player’s campsite and starting fights. I wasn’t sure whether to display this influence area or leave it as a bit of a mystery, but with the introduction of prosperity, the effect needs to be made clear. The influence area can be expanded by building additional fire poles, which need to be occasionally maintained by adding animal fat to them.

The intention is to have prosperity fluctuate as the fortunes of your tribe change. I have some ideas to build on this mechanic in terms of progression and unlocking advanced crafts. It needs a bit more work though before I say any more.

This update will be about ways I’ve been improving the UI for a better player experience. Below you can see the new look for the UI.

Alerts system – to give a bit more direction to the player, I have added an alerts system. It’s similar to the one used in the Europa Universalis series, and a great way to inform the player about issues that need attention. When a certain trigger is activated, a little popup will appear at the top of the screen with some information. Examples of issues that will trigger an alert include lack of available food and water, being under attack and lack of a camp fire. Once these needs are taken care of, the alert should disappear. Hovering over the image also gives a description of the problem.

More immediate feedback – the player will receive immediate feedback when trying to perform an illegal action. I noticed players tended to start clicking random buttons and hexes when nothing in the game was reacting to them, so now a tool tip immediately pops up informing the player what went wrong. This should lead to less frustration.

Minimap – The minimap is more useful after some improvements. It now shows buildings, people and animals wandering around. You can also click on it to zoom the view to that location.