I took the wolf out some weeks ago because it kept wandering into shot when I was taking my videos. Now the game has moved along to the point where I want to add wolves (and other mobs) back in. As I mentioned back in my introductory post (almost exactly a month ago), moving creatures will be a big part of the game, especially the robotic automatons that I want to you to be able to create and use to defend yourself with. To achieve that I want to enable different combinations of behaviours to be bolted together. For built-in animals like wolves these behaviours will be fixed but for the constructed automatons the player will be able to tweak them in all kinds of ways.

The classic text in this area is Craig Reynolds’ 1999 paper Steering Behaviours For Autonomous Characters which outlines algorithms for several basic steering patterns:

• Seek and Flee
• Pursue and Evade
• Wander
• Arrival
• Path following
• Collision avoidance
• Flocking (subdivided into Separation, Cohesion and Alignment)

These can be combined to produce some quite realistic behaviours. In my implementation I give each mob type a list of MobBehaviours, each of which looks like this:

type MobBehaviour struct {
    behaviour   uint8
    targetType  uint8
    targetRange uint8
    targetAngle uint8
    weight      uint8
    sunlight    uint8
    last        bool
}

The behaviour field specifies what kind of behaviour pattern to use such as Persue or Wander. targetType, targetRange and targetAngle specify a particular type of thing that will trigger this behaviour if it comes within range and field of view. The weight field enables a particular behaviour to be more dominant than others when triggered. sunlight gives a range of valid light levels for the behaviour (so mobs could sleep at night or hunt at dusk). last simply indicates that no other behaviours should be triggered if this one has been.

I’ve used this to reimplement the Wolf in the game and added random spawning of wolf packs as you move around. The results are quite fun. Their natural behaviour is to wander around as a pack. During the day they will only attack if you get really close to them but at night they will pursue you from a much longer distance. I’ve tried to capture this in these videos but it’s quite hard because I’m constantly thinking about how to get the best shot for the video while trying to keep out of the way of the wolves. Also, I’m rapidly turning the camera and the player which looks jerky on the video. When you’re playing it’s veyr immersive but watching on a video is harder. The wolves are represented by the open squares moving around the landscape. When I recorded these last night I hadn’t implmented upward movement for mobs so they tended to get stuck in depressions in the ground. Since filming them I added auto jumping up blocks and now they can chase you a long way!

The first is the addition of machines into the game and the first appearance of Amberfell itself. Amberfell is found distributed across the world as orange/yellow pools that seep up from the depths. They are implemented as a column of unbreakable blocks that extend from the bottom of the map to the surface. I experimented with adding blackened/burnt grass around them but wasn’t happy with the results. I may revisit that idea later. The “fell” in Amberfell is an adjective.

The first new machine is an Amberfell Pump. You place this onto an Amberfell Source block and it will slowly pump up Amberfell from the depths. Slowly is the operative word here. When you switch to using the “hand” action (no icon in the picker yet!) you can click on the pump to inspect it. This brings up the reworked inventory screen. The pump has its own section in the middle. When I have some decent skins to apply, I envisage this being styled nicely as a working pump.

If you wait long enough you’ll see some Amberfell appear in the pump’s slot. You can see in this screenshot that the pump says it’s unpowered. You can power it by placing a Steam Generator block next to it and adding some coal to the generator. That really gets the pump working and in a short time you’ll have five units of Amberfell collected which you then have to take out.  You then need to tuen to your Amberfell Condenser to refine the liquid amberfell into something more valuable: Amberfell Crystals. I imagine the condenser as a distillation apparatus made from glass and heated underneath. It needs Amberfell and firewood to work and consumes them to produce hard earned crystals. The crystals score you points in the game but also will have other uses. What I haven’t worked out yet is all the crafting steps to create these items.

You can see all of this in action in this video. As part of implementing these features I redeveloped the entire mouse interaction metaphor in the inventory screen. You click on items to pick them up and then click where you want to place them. Holding shift acts on the entire stack of items at once and using control reverses the a take into a drop and vice versa. This was actually quite complex to implement because when you have some item selected clicking on the same slot again picks up whereas clicking on a different slot drops the item. The code is horrendous but works, so I’ll need to come back to it and make it nice too.

You can also see in the video the first outing of the Carpenter’s Bench and how it can be used to craft planks and wooden walls.

• Tom Papworth separates the ceremonial from the legal in a letter to a constituent about same-sex marriage: ” I hope that we can one day move to a system whereby individuals are free to define their union, celebrate it and – where appropriate – have it blessed in whatever manner they chose.” Why stop at couples? Shouldn’t we allow any form of free and voluntary association and enable recognition of inheritance rights and pooling of incomes for larger groups?
• On the other hand, self-styled libertarian, Rand Paul, reveals that his notion of individual freedom only applies to people that share his views. At a recent gathering he said about Obama’s support for gay marriage: “Call me cynical, but I wasn’t sure his views on marriage could get any gayer.”
• A new study suggests genetic factors are less likely to influence economic status than some recent papers have suggested. The thought that some people may be genetically predisposed to poverty is an uncomfortable one so this is welcome news.
• More than half of Greek police officers voted for the neo-Nazi Golden Dawn party in recent elections. My prediction is the next round of elections will be even more polarising.
• The School Food Trust finds that “89 out of 100 academies were selling at least one of the snack foods high in sugar, salt or fat that were outlawed by Labour to rid schools of products that were bad for children and damaging their concentration”.  I have a lot of issues with this. Firstly if parents don’t like that policy then they won’t apply to that school and the school will need to change its policy if it wants to survive – its a point of differentiation for schools. Secondly, these academies are going to be testing the presumption that junk food affects performance (vs the potentially more likely outcome that happy kids will perform better) and if they see grades dropping then they’ll be scrambling to make changes including around food. Finally, there’s an underlying problem with studies like this that are funded by single-issue organisations. The purpose of the School Fund Trust is to perpetuate the food standards brought in a few years ago, not to give an objective opinion on the diet of kids in schools, so their view is rather partisan. Also, it’s worth pointing out that they don’t appear to receive any funding from the public, so they have no evidence as to whether they have public support for their views or not. The fake charities site (I hate that name – this is clearly not a fake charity and its insulting to say so) says they are funded with £7.5M from the government and the remaining £1.2M from lottery grants.

Along the left are slots for the items you are currently carrying. I’ve taken the decision that it’ll be a lot more playable if your inventory shows everything you’ve picked up in one place rather than trying to be physically accurate and only allowing a limited number of items. That means you can carry 999 dirt blocks comfortably along with your 999 log walls.

The middle section is the handheld crafting area. There will be other crafting areas later on when you’ve built a workshop and the tools to go in it. Simply click on an item in your inventory to place it in the components section of the crafting area. Any items you can make with the selected components are shown in the product section of the crafting area. Simply click on them to add them to your inventory. Currently there are only three recipes in the game: tree trunks can be turned into log walls, log slabs or firewood. You’re going to end up with a lot of firewood because when you break up a placed log wall or slab they turn into firewood automatically!

Here’s the video showing this in action:

You can also control+click on an item in your inventory to add it to the “picker” at the bottom right. This represents the things you have easily to hand and when playing you can quickly switch them with the mouse or by pressing the 4,5,6,7,8 keys. The three other slots in the picker (no icons so you have to guess what I mean) are “interact/activate”, “break/dig” and “weapon”.

A plain landscape at default zoom and window size now shows FPS of 40-45, compared with the 30 I was getting before. You can see I’m only drawing 13512 vertices and dropping 84440 that were off screen or rear facing. As i rotate the number of vertices on screen changes because of the trees. Then  zoom out which brings even more vertices on screen with a corresponding drop in FPS. When I zoom right in, the number of drawn vertices drops under 2000 and the FPS shoots up to 60 (rate limited by the vsync on my GPU). Lastly I zoom right out and expand the view range to include more blocks onscreen. The FPS drops down to about 10, drawing about 140K vertices and dropping another 228K. Good results, and still room for improvement as I optimise the code even more.

There are other implementations available for Go, but none as standalone packages.

I use noise to generate the height of the terrain with further noise functions to generate soil depth, rock formations and tree distribution. Here’s a couple of screenshots of the result:

It’s important to scale the noise just the right amount otherwise you get very dramatic landscapes. These might be ok for a first person game but they’re really hard to navigate in isometric views:

The best thing about the new landscapes is that Amberfell suddenly becomes very explorable. I find myself wandering around looking for interesting landscapes and hidden corners. Hopefully I’m really going to be able to enhance this effect with some of the surface features I want to add such as ruins to explore. A lovely sky would be great too.

Here’s a video of me exploring a little. I’m zoomed in to show off the landscape but I don’t think it’s particularly playable at that zoom level.