Zombox

This week’s work on Zombox was sporadic and mostly behind-the-scenes.

The biggest changes are the following:

-weapons can now damage the environment. Got a hammer? Smash down a wall. Got an axe? Chop down a street light.

-zombie AI and flocking algorithms have been improved. Zombies no longer intersect one another while crowding around the player

-zombie pathfinding has been improved. The A* algorithm now runs in a co-routine so it can process a path over multiple frames, lessening the load on the CPU and allowing for longer paths to be calculated

-objects and enemies can be pushed in the water now. They’ll splash and drown but so can the player so you shouldn’t go too close to the edge!

Here’s a gif showing the splashing in action.

Here’s a gif showing the pathfinding in action.

Here’s a gif showing the environment destruction in action.

This week I had some time to update the weapons and crowd dynamics of Zombox.

There are now different types of zombies…some are smaller/weaker/faster, others are larger/stronger/slower. Some are wearing helmets or protective gear and have more health, others carry simple melee weapons and can deal more damage.

Also, the zombie flocking algorithms have been updated. Zombies now flock around the main player more dynamically, and can be pushed out of the way as you move forward. The zombie physics system has been updated so that certain weapons and attacks can knock zombies back causing them to roll around and knock into nearby scenery.

All weapons have been updated in various ways. Melee weapons will drip drip more blood after hitting a zombie, push the zombies back more and their collision systems are more precise. Firearms do less damage from greater distances, can fling zombies backwards, and sharp projectiles that shoot out of certain firearms (like crossbows and nailguns) will stick into zombies and other hard surfaces. Also, the special taser weapon will electrify zombies, dealing secondary damage over time. Critical hits will cause blue sparks to emanate outwards from the affected zombies, giving subtle visual feedback on the level of damage dealt.

Been working on the inventory system for Zombox.

Here’s how the raw inventory window looks.

Here are the inventory icons for all the weapons and some of the items in Zombox.

The inventory window will have expandable sockets based on the player’s XP level, and that space to the left will show how the player looks with whatever items are equipped.

I’ve put a lot of work into the weapon/item system. I want Zombox to feature hundreds of items that can be found all throughout the environment, each with its own unique stats and/or purpose. I’ve already created the assets for about 75 collectible item types, along with 20 craftable weapon types (yes, Zombox will feature a crafting system). There are also going to be 8 levels of wear-and-tear that each item may exist in…from damaged/broken to clean/new, with a whole bunch of other states in between, as well as a special “super” state that will essentially be the most rare type.

So…100 weapons/items x 8 states = 800 scavengable items…and that’s not yet including armor, clothing, food, etc.

Here is an image showing most of the item assets that I’ve modelled so far. This is just a list of 128×128 renders of the 3d models, which are ready to be loaded into the game engine.

Work on Zombox has been slow lately (due to lots of unforeseen technical problems sneaking up on me), but progress is still being made.

I spent a lot of time optimizing the object pooling system, improving textures, and getting the game to work smoothly on the iPhone 3GS.

Also, I’ve been modifying the procedural city generation system so that different buildings have different features. There are 15 different building types in Zombox, and each building type has its own special properties. For example, the walls of the bank and police station are more difficult to break down, the doors of the gunshop are locked, the church has stained glass windows, etc. This will make exploring the city a more dynamic experience.

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I got some feedback about the size of the UI controls in Zombox, so I went with a sleeker redesign.

Some people suggested I make them semi-transparent but unfortunately transparent shaders cause the iPhone to chug so I’m keeping them opaque.

It’s worthy to note that the web version of Zombox will not have these visible controls at all, since keyboard shortcuts will control the character, rather than clicks on a screen.

These last couple of weeks I’ve been working mainly on detailing the environment.

• Textures have been added to all environment elements
• Buildings now have roofs and unique floors made of various material.
• Damaged walls now get cracked.
• The roads now feature various street signs, parking notices, etc.

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Here’s a video which shows the results of the pathfinding system I’ve implemented. Below I roughly outline the process involved:

I haven’t posted any new developments for Zombox in a couple of weeks because I’ve mainly been doing code re-writes, optimizations and other things to get the game running faster on iOS.

One of the main hiccups in development has been the zombie AI. Until this week, zombies “saw” their environment with raycasts. While I was pooling raycasts and not doing 1 per frame per zombie, raycast performance with 30-40 zombies and many colliders on the iOS was slow. Also, while zombies don’t require an overly complex AI system, the previous I-won’t-chase-it-unless-I-see-it method left them unnecessarily dumb. Not to mention, the AI system couldn’t really be scaled up to include NPCs that need to be able to find targets.

So, I implemented an A* pathfinding system for all AI instead. The main hurdles I encountered while working on this system were:

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The procedural city system now scatters mailboxes, trash bins, construction cones, light poles and traffic lights throughout the city.

These props are randomized per tile, but here’s what they look like if they’re all enabled at once.

Note: the buildings are hidden in this screenshot, as they are generated on the fly based on the position of the character in the world (damage to them persists in the world though). The same is normally true for roads, but I decided to generate them all at once here to see what the explorable world would look like. Note the scale of the character in the bottom right. It’s a pretty big world to explore! (hundreds of blocks and just under 1000 buildings…all generated in less than 1 second).

Click here to open the image!