Currently the houses only grow if all their basic needs are met, and construction materials are supplied. With the next iteration, each housing tier will have different needs that don't overlap.
In addition to that, I want to revamp the decision if a house can grow or not. Currently all basic needs must be supplied. This can become increasingly difficult and frustrating as higher tiers need additional types of food, and one of them usually runs low.
To do that, we'll explore changing the current binary decision (yes or no) to a percentage chance (0% to 100%). Construction materials and water are still required as before.
The percentage chance is made up of 2 factors:
- Food (generates a score of 0 to 100)
- Public transportation (adds a bonus score of 0 to 25)
All numbers in this discussion are subject to change.
Food
Thew new score of 0 to 100 is calculated by taking all required foods into account, and yielding fast city growth if the city is well supplied, and slow growth if the city is not well supplied. You will however not be stuck anymore if you lack one of many food types.
Here's the formula that we're going to explore more below: ((S1/D1 + S2/D2 + ... + Sn/Dn) / n)²
S stands for supply, D for demand, and n is the number of required food types for that housing tier.
The result of this formula is capped at 100%.
Let's start with a simple example: The simple houses. They demand apples and don't need public transportation. If we supply 100/100 apples, then they will grow in each growth cycle. With more simple houses the demand for apples will go up, and eventually drops below 100%. If we then supply 200/400 apples, we calculate the new score as ((200/400) / 1)² = 0.5² = 0.25. That means at 50% supplied, there's a 25% chance for growth. If 20% are supplied, then the chance drops to 4%.
When the simple houses upgrade to residential houses, they develop new demands. Instead of apples, they now required meat, bread, milk bottles, and fish filets. If all are supplied at 100%, then the residential houses can grow in each cycle. But what happens if there's a lack of supply? Let's assume that meat is supplied at 100/200, bread is supplied at 20/80, milk bottles are supplied at 150/150, and fish filets are supplied at 170/170. When we plug those numbers into the formula above we get ((100/200+20/80+150/150+170/170)/4)² = ((0.5+0.25+1+1)/4)² = (2.75/4)² = 0.6875² = 0.47265625. The residential houses now have a 47.3% chance to grow.
Highrise houses currently can't upgrade to a higher tier, so we'll ignore them for now.
As the population grows, the demands go up, and therefore your chance for growth continually goes down, unless you continue to increase the supply.
Public Transportation
Currently public transportation only gives you currency. I'd like to change that so that it also helps you with city growth. I've been pondering if it's better to integrate this factor into the formula above, but for now we'll just keep it separate.
The general idea of this factor is that citizens want to travel, and if you help them do that they're happier. We'll take a couple shortcuts with the implementation though. One shortcut is that we'll count passengers that arrived in a given city (i.e. tourism instead of public transportation), and that we hardcode the maximum at 100 instead of making it relative to the city size. That can be done later, but I have not idea what a good factor is yet. Feel free to suggest something below!
The public transport score goes from 0 to 100 and is calculated by taking the number of arrived passengers, dividing them by 100 (or a city size related number in the future). Since food is much more important than travelling (and a city should not grow if there's no food but only transportation), we only add 25% of the public transportation score to the overall score. If e.g. 40 passengers arrived in the last cycle, and the food based growth is 47.3%, then the total score calculates as (47.3% + (40 / 100 / 4)) = 47.3% + 40% / 4 = 47.3% + 10% = 57.3%.
This means that you can boost the city growth a bit further with public transport to make up for gaps in your supply chains.
Additional Factors
The next iteration won't include more factors so that we can test a relatively simple model.
In the future however we may consider additional or more advanced factors as construction noise, water shortages, and pollution.
Feedback
Let me know what you think here or on our Discord.
