Posts Tagged XNA

Species 0.6.1 Release Date

The code’s finally in a stable enough state that I feel justified in announcing a release date. So here goes nothing…

Species 0.6.1 will be released on the 1st February.

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This update includes a lot of the cleanup and polish elements originally planned for 0.7.0. A lot of the changes are background

improvements to the underlying code, but that’s not to say you won’t see some changes to the game itself…

Stability Improvements

A variety of major 0.6.0 bugs have been addressed, most notably:

  • several fatal crashes have been fixed (‘System.OutOfMemoryException’, ‘CladeDiagram.CollideBranches’, ‘UIManager.Paused_Export_Update’),
  • the method for addressing problems when the game is minimised or graphics card is lost has been improved,
  • built-in troubleshooting for some start-up problems (running from the zip file, running from Program Files, running on computer with unsupported graphics card) has been added

(Of course, it’s entirely likely we’ve added our own set of new errors to replace them, so don’t get too comfortable)

Aesthetic Adjustments

Quite a few visual improvements:

  • Procedural texturing: creatures now have different top, side and underbelly textures, giving them a more distinct appearance and more recognisable body covers.
  • Custom textures: beaks, claws, teeth and mouths now have their own (appropriately horrifying) textures, blended into the triplanar texturing.
  • Fur: Fuzzy wuzzy was a bear, fuzzy wuzzy had no hair, but the creature’s in Species do now. And they find bear meat tasty.
  • Water reflections: They only reflect the skybox, but they significantly improve the appearance of the game nonetheless.

Plus a number of subtler ones, like adjusted tree shaders, a better wasteland texture and we got rid of that weird blue shading on trees when you pause the game.

Content Additions

It’s not been all about code and shaders: we’ve also overhauled the content in some of the less-developed area’s of the game.

  • Body coverings: fur, feathers, scales and skins. Also octopus suckers, toad warts and Quasars forearms (ewwww…), but we’re probably better off not mentioning those.
  • Leg shapes: from 6 to 20, meaning a much greater variety of knees.
  • Heads: a number of additions (and of course, the existing heads had to be adjusted to provide beak and mouth textures and fur polygons).

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Recent Development Work

I’ve been creating Things That Should Not Be. Alright alright, I’ve actually just been modelling limbs, but the Things That Should Not Be are a direct side effect.

Ignore the graphical errors, such is the nature of the development version. I’m much more comfortable creating things when surrounded by unfathomable hideousness and strange transparency artifacts. It’s like Linus’ security blanket, except for me it’s non-euclidian geometry and broken texturing artifacts.

Or possibly I just have a tendency to break things and put off fixing them because coding is more fun than content creation. Irrelevant.

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In addition to monstrous abominations of tentacled science, I’ve also been breaking and then fixing and then breaking again (repeat as required) a few other things.

I created a dedicated HighlightTint object for managing colour coding and status flashes on a per-creature basis. Different highlight causes now have priorities, and lower priority causes can’t override higher priority ones. This should fix those display issues with creature’s not showing that they’d been spliced or attacked because of the grazing or feeding cycles. Not the highest priority bug fix, but it came free with the code cleanup and I’ve always been a sucker for bargains (that’s a total lie, I don’t buy anything unless I’ve thought about it and decided it’s useful and practic- YOU CAN BUY QUADROTERS FOR ONLY $50?! GIMME!).

 

Let’s see… I also glared silently at the QuadTerrain generation algorithm until it surrendered to my will and reduced world-loading times by about 30%.

 

And I fixed a difficult problem that had been plaguing me for weeks, ever since I modularised the SpeciesList, which is that the species count wasn’t going down when creatures died. Found out it was caused by a typo adding Creatures to the Species twice. Easy fix.

 

And the Body Part Voting Competition has reached Round 7. It features a choice of heads from Avialae, which is objectively and indisputably the best-est clade. And once again, the choice I voted for is doing miserably.

 

Toucan Beak
Cockatoo Crest
Hawk Head
Hummingbird Probiscus-beak

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Torso Height

I’ve been playing with the torso height system.

As I’ve mentioned before, the creature’s are drawn from the torso outwards with their limbs ‘hanging’ off them, like a jellyfish or an octopus or the incomprehensibly alien True Form of our current Prime Minister [“He knows! Get him!”]. In order to give the impression of standing on their legs, the creatures in Species need to calculate a vertical offset called “torsoHeight” before they draw.

The previous system for establishing this offset was fairly simple: every frame, check each limb against the ground, and if none of them touch, reduce the torsoheight. Inversely, if the limbs are underground, push torsoheight upwards.

This dynamic system led to torsoHeight becoming one of the most abused values in the game: I’ve used it for gravity, anti-burrowing measures, the ‘bouncing’ when they’re attacked, etc. Unfortunately, this sort of abuse leads to emergent behavior, and not the good sort: this is the reason creatures float up out of the ground when they’re born, why they can fly when continually attacked by multiple attackers, and why they drop down onto their torso when the LOD stops drawing their limbs.

And more importantly, it’s why I haven’t been able to use torsoHeight for selection pressures. When two identical creatures can have different values based on Level Of Detail, using it would introduce strange artificial pressures based on where the camera was and what it was focusing on.

So for 0.7.0, torsoHeight is being replaced by a non-dynamic version: it will be calculated once at birth based on the creature’s skeleton, doubled when they grow to adulthood, and not updated again until they die, vanish and are recycled. I’ve broken it out into 3 components: ShoulderToCoG, ShoulderToAnkle and Tipheight.

Witness my magnificent artistry!

Witness my magnificent artistry!

It never as simple as it looks, of course: needed a bit of trigonomtery for ShoulderToCOG (why didn’t anyone tell me trig would be useful in school?), a few world-space transforms for converting bone matrices back into world co-ordinates, and I needed to find a way to test each component seperately because I tend to go through a lot of trial and error with this sort of thing.

But after a few hiccups with floating/burrowing creatures it’s finally starting to work out (though there’s still a few oddball cases that cause floaters), and eliminating those emergent properties I mentioned above makes things look quite a bit neater. Especially noticable is that creature’s no longer drift up out of the ground as you approach them, which makes it more apparent that the stuff popping in was there, but just not displayed before. It’s just polish, but it gives the game a slightly more professional feel.

And better yet, since torsoHeight is determined at birth now, I have a good solid foundation to work from and I can start considering what other parameters it’s going to affect… [insert maniacal laughter]

Qu.

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Out Of Memory Exceptions

I learned something today: Out of Memory errors are not actually caused by being out of memory! What a silly I am for expecting error messages to make sense.

So, for everyone preparing to set your RAM on fire, stomp on it and throw it out the window before burying it in a deep dark hole and pouring concrete on top: don’t bother! You RAM is fine. Assuming you haven’t already set it on fire. If you have, your RAM is not fine. And you might want to put that out.

No if you’re out of RAM you’ll get performance issues caused by ‘thrashing’ (when a computer starts relying on the Hard Drive instead of RAM), but you won’t get Out Of Memory exceptions. So, what causes OoM exceptions?

32-bit Windows causes OoM exceptions.

Screw 32-bit Windows.

See, when Microsoft says “you are out of memory”, they actually mean “you are out of consecutive address space”.

You now have several options (it’s like a game!):
– For a “proper” explanation, go read the article I read that taught me all this: http://blogs.msdn.com/b/ericlippert/archive/2009/06/08/out-of-memory-does-not-refer-to-physical-memory.aspx
– For an “improper” explanation, go ahead and use your imagination (I’m sure it’s way more kinky than anything I can come up with).
– For an “incredibly-simplified and probably-wrong” explanation, continue reading…

When an object like a Creature or a Tree is assigned, it gets put in memory and Windows assigns it an address. And by ‘put in memory’, I don’t mean RAM. Forget RAM. RAM is a glorified performance optimisation. The memory we’re talking about here is your hard drive. And as you’re probably aware, your hard drive is huge. You’re not in any danger of running out of that unless you’ve packed the drive to it’s very limit.

Okay, so you’re not in danger of running out of Hard Drive space, and lack of RAM doesn’t cause exceptions, just performance issues. So the next place to look is at that address the object was assigned by Windows when it was put in memory.

This address is where windows get’s it’s 32/64 bit designation. The absurd oversimplification I’m about to make will likely make any computer-science types reading this swallow their hats, but it’s basically a number stating that object X can be found Y bits into the memory stream.

Always be prepared!

The cause of Out Of Memory exceptions is that “Y-bits into the memory stream”. See, even though the process has the entire hard drive to work with, a 32-bit address format can only store addresses up to ~4GB (and half of that is reserved by the operating system for other things). This is why 32-bit editions of Windows can’t make use of more than 2GB ram: the 32-bit format doesn’t have enough address space to map more than 2GB.

Okay, but surely that’s basically the same as a 2GB memory limit for the purposes of Out Of Memory exceptions?

Nope. See, to assign and map a new object, there needs to be an empty “hole” in address space for it to go into. If there isn’t a hole large enough, an Out Of Memory exception will be thrown. (finally!)

I’ll explain via metaphor. Imagine putting three baskets into your car, then filling in the area in between them with smaller items. Then you realise that you need a large esky instead, so you take out the baskets and try to put the esky in. Even though the three baskets combined took up more space than the esky, and even though they’ve been removed, the esky still won’t fit because the smaller infill items are blocking it.

That’s the problem with address space: if you fragment it with smaller items in between the big ones, the next time you need to allocate something big it’ll throw an Out Of Memory exception, even if you freed up the big ones and have plenty of cumulative space to use. *That* is what is causing the memory issues in Species.

I’m sure a decent Computer Science course would have covered all this but I’m self taught, so I get to learn by the slightly more direct route of sticking my hand in the fire and finding out what happens.

OH GOD IT BURNS! WHY WOULD YOU LET ME DO THAT?

So, on to the usual question: how do we fix this?

Well, the obvious solution is “compile to 64-bit.” A 64-bit address space can map about 4 billion times as much memory (no, literally), so chances are we wouldn’t be seeing fragmentation errors any time soon. Of course, it also means people using 32-bit windows wouldn’t be able to play the game.

I’d rather solve the error at the source and retain backwards compatibility, but “solve” is a relative term. Memory fragmentation on a 32 bit machine isn’t something that can be stopped. But it can be significantly reduced, and I’d prefer to do that for the sake of memory management *before* dropping the metaphorical world-killer asteroid that is a 64-bit compilation.

The “World Killing Asteroid” compile-time option is only included in the December 21 service-release of Visual Studio 2012.

So, on to the source. What, ultimately, causes memory errors in Species?

I’d done memory profiling in the past, but I hadn’t properly understood what it was telling me until now. They indicated I had two main memory draws: grass vertices, and tree instances. But these two memory hogs always appeared in different graphs: tree instances would appear in allocation, grass vertices in snapshots.

With what I know now, this makes sense. Grass vertices are created when the terrain is built, and held from then on out. This means that the grasses memory cost at any moment in time is huge: after all, it’s storing the position of every potential billboard vertex on the map. Imagine the map completely covered in the dense savanna grass: that’s what the grass memory cost is.

But relative to the hard drive, or even the RAM, it’s not that big: I think somewhere around the 200MB mark? Can’t remember exactly, but regardless, it’s also generally a static cost. The grass grabs up all that memory when the terrain is built and doesn’t release it until the terrain is destroyed. You might be able to force an OoM exception by repeatedly loading/generating worlds, and fragmenting the memory that way. Fixing it isn’t urgent, but probably worth doing: need to ensure the memory is allocated at startup, rather than on terrain-build.

The second cost is the Tree Instances array. This one confused me because it was barely noticable on the moment-to-moment memory, but was invariably a massive cost in terms of amount allocated. This was because the Tree Instances array was designed to grow organically with the vegetation: if the number of trees grew too large for the array, it would allocate a new array with an extra 500 slots for trees and copy the data to that (well okay it actually uses Array.Resize(), but that’s what Array.Resize() does internally).

Of course, frequently allocating a massive new tree array is a great method for fragmenting your address space, which is why large (>2) worlds were invariably hitting an OoM exception during the vegetation generation at startup. Since I didn’t realise this was a problem, the amount allocated in the memory profiler didn’t mean anything to me.

I’ve already applied a few simple optimisations to this method, which makes generating size-3 worlds possible again, but fixing it will be another matter entirely. Ultimately, the vegetation should probably be capped to a set level, but this is tricky because the array is fed directly into the graphics card when drawing the trees. This means that those 500 “excess” trees still incur a GPU cost, even though they’re invisible. In a size 3 world, this cost is enough to cap FPS to 12, even when there are no creatures.

To fix this one I’m going to need to adapt the InstancedModel DrawInstances() method to take the total number of trees as a parameter, and feed that to an overload of the DynamicVertexBuffer. This should allow me to submit the entire oversized array, but then lower the number of instances that are actually drawn each frame.

(Edit) Well that was surprisingly easy. A heap of address space is now set aside for trees, but only the actual trees themselves are sent to the graphics card. Assuming XNA isn’t doing something horrible with them beneath the hood, that should take care of most of the OoM exceptions in the game. Stability improvements ahoy!

Cheers,
Qu

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GRASS GRASS GRASS GRASS

GRASS GRASS GRASS GRASS GRASS GRASS

There’s not too much to say about the obvious mechanisms of the 0.5.0 in-game grass: it uses the billboard system which I explained a while back. I could mention the other technical details: it only draws a few, nearby, vegetation nodes, grazing affects the length of the entire node, it fades out at a distance because there’s way too much of it to draw it across the entire map… okay, done that, now what?

Well, seeing as how talking about implementation is boring, I guess we might as well talk about the design aspects.

The moment I decided on grazing as a feature for 0.5.0, I knew I’d have to represent it somehow. The grass itself, though, wasn’t originally meant to be that representation. Indeed, I’m still not entirely convinced that grass is the best representation for it: rendering grass has limitations that make it less than ideal.

But…

Uh…

Hmmm…

Okay, I’m in the middle of typing up this post and I’m beginning to realise that the height of the billboard grass really isn’t the best way to represent grazable material. That’s what I get for blogging about a feature I’m in the middle of coding. Oh the joys of an evolving project.

Okay, new approach: I’m going to use this post as an opportunity to get my thoughts in order before I go off and play with the code a bit more.

The plan (prior to about about 30 seconds ago) was to include a grazables container or bucket within each square of terrain. This container would contain all the energy that creatures could graze from, and how ‘full’ it was would determine how long the grass in that square was. Fertility loss due to grazing would occur when the bucket was empty and had to ‘buy’ more energy to regrow.

Documenting my design decisions. I am a professional and I act like a professional.

The big pro to this approach is that grass height shows you at a glance how much grazable energy the local area has. Unfortunately, there’s also a lot of cons:

– all grazable scatter-material grows like grass and is edible, regardless of what it actually looks like. This includes pebbles on rocky terrain, shells on the beach, salt in a salt plain, and lava rocks in lava.
– grass in an area is all the same height. Since an ‘area’ is an exact square of roughly 10m x 10m, this would be especially noticable at borders where grass on one side is short and grass on the other is long.
– fertility loss is applied on an area-scale, not on a local one. A creature eating at the very corner of an area will affect the fertility of ground 14.1421m away (+/- 10m, anyway. Oh who am I kidding, I have no idea how big the vegetation squares are), while not affecting the ground just behind it.
– Grass is invisible at a distance, so you can’t see the direct effects of grazing from far away.

Yes, the rocks are edible. Why wouldn’t the rocks be edible? Stop being so carbon-based in your thinking.

Now, all of these are things that can be dealt with to eliminate or reduce their effect: scattering a squares vegetation a bit beyond it’s border would blur the straight line between squares, by applying fertility loss on a macro level makes it less apparent that it’s related to overall area and not to the actions of individual creatures.

But what if we could deal with all of these problems just by changing the way ‘grazable energy’ is stored? This is the idea I’ve just had:

Eliminate the energy buckets in terrain squares, and effectively remove all terrain-based control over grazable energy. Grass no longer has any limit: creatures can just keep grazing and grazing within their biome… until the biome changes.

OH-EM-GEE I’M SO FRIKKIN PROFESSIONAL YOU GUISE!!! LIKE TOTALLY!!!!!

With this system, a creature emits a ‘death aura’ while grazing, gradually reducing the fertility in a small area directly underneath themselves. Eventually, the biome under them degrades. This introduces a direct correlation between fertility and energy: a creature absorbs fertility from the ground and gains energy in exchange.

Do vegetarians usually suck dry the very soul of the planet? Oh no wait that’s vegans. Ba-dum tchch! (teasing vegans. I’m so original)

Since grazables are no longer dependant on area but on biome, we’ll be able to introduce a variety of biome dependant statistics (starting with a simple isGrazable boolean) as a central function of the simulation, rather than as something tacked on afterwards as was originally planned.

A conventient bonus is the fact that the ‘death aura’ code already exists, in the form of biome stabilisation from trees. The only difference is that where tree’s stabilise the habitat they’re best suited for (with the exception of some unbalanced pioneering species which make the simulation more dynamic by stabilising towards biomes they can’t survive in), grazing creatures stabilise the habitat towards arid, desert biomes, and then have to move on to find more grass.

Of course, I’ll have to rework some of the code for this: the ‘buckets’ system already exists in the development version. But that’s the nature of prototyping.

[The following day]

Welp, that’s done. This actually makes the environment feel a lot more ‘directed’, since you can now pinpoint the source of every fertility change: it’s either grazing creatures, trees or water. I might have to add a few more fertility-change sources, just to make it less predictable.

Ultimately, this change leaves the grass itself as little more than an aesthetic item. Oh well: the system’s in place now, it’s useful in defining the presence and quantity of grazable material in each biome, and when even the placeholder art looks good, you know you’re doing something right..

GRASS GRASS GRASS GRASS GRASS GRASS

Cheers,
Qu

He doesn’t mean it about the vegans. We actually think vegans are pretty awesome: it must take a lot of willpower and strength of conviction.

Please don’t kill us with your psychic vegan powers.

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Biome Map

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Multi-texturing and Biomes

One of the priorities for 0.5.0 (the environmental update) has been to overhaul the multi-texturing system.

In 0.4.1 the best the engine could do was 4 textures (desert, grass, forests and cliffs), and those textures were placed at world-start, never changing. The end result was a very static map, very boring environment: basic tree loss/growth was the entire extent of environmental dynamics.

All this changes in 0.5.0. The design plan calls for a dynamic, responsive environment, and by crikey that’s what we’re going to have. (Crikey is Australian for… something. I dunno. Honestly I don’t even know what the word means, but it’s a stipulation of citizenship that we all say it at least once a week)

The first thing to add is more biomes. Desert/grass/forest works well as a basic, semi-tropical biome set, but what about colder biomes? Or warmer ones? Or wetter ones or drier ones? My current biome map concept has more than 20 different biomes drawn on a temperature/fertility map, including some hilariously extreme ones

If you can’t survive in a lava lake you’re simply not trying hard enough.

But that many biomes means a whole different approach to multi-texturing… or at least, I thought it did. This was when development started to go bad…

In 0.4.1 I used a multitexturing method called ‘texture splatting’. Imagine you’re painting the ground texture on a blank canvas. What texture splatting does is gives you a ‘stencil’ for each texture: so you can paint forest through the red stencil, grass through the green stencil and desert through the blue one, and by the time you’ve used all the stencils you’ve painted the entire terrain. All these stencils are nicely wrapped up into a single texture, called the blend texture.

Unfortunately, this only works for a limited number of textures per draw call: you can’t load more than a set limit of textures onto the GPU without it having a fit. So in order to render an unlimited number of textures, I’d need to change how I was approaching it.

My first attempt at a replacement system was sort of like an extremely complicated colouring book, where each grid square is numbered 1,2,3,4,etc and our hypothetical artist fills in the grid with grass/desert/forest from a colour key. Since we can include as many numbers as we like in the key, we can have as many biomes as we want.

Quick! Chop down a tree with your fists!

Once that’s done, our artist is faced with a problem: (s)he has to blur these colours together smoothly without pixilation or sharp edges. And since it’s going to be animated, a simple linear interpolation just isn’t going to cut it.

As it turns out, this is HARD. My own approach was to sample the biome-legend multiple times to give each pixel *four* biomes, each with a weighting value, which I then folded into the same channel as the key
(effectively, I designated the first digit of the channel as the key, and the remaining digits as the weight).

Honestly, the most surprising thing about this ridiculously complicated strategy is that it worked… mostly.

The grid is meant to be there.

But “works in general”, doesn’t mean “works well enough to use”. On closer inspection, the system produced artifacts all over the terrain. (not a typo: graphical glitches are “artefacts”, ancient relics are “artifacts”. I read that somewhere and internalised it, so it must be true) I actually got it working perfectly wherever 2 biomes met, but that was the limit: at any intersection with more than 2 it produced hard edges and odd colours, and the moment it was animated these artefacts started jumping about and generally making themselves easy to spot.

How many artefacts can you count?

So I ended up scrapping the idea entirely, and starting over with a new strategy, one requiring less math and more art.

This new strategy was much simpler: we go back to using the ‘stencil painting’ system, but this time once we’re done painting with the first 4 stencils (biomes), we put a new, transparent canvas over the existing canvas and keep on painting on that with a new set of stencils. Rinse and repeat.

This method turned out to have it’s own set of pitfalls, chief among them, alpha-blending and redrawing the entire terrain multiple times, with different textures each time. For an item which takes up as much of the screen as the terrain, this is a large graphics cost, and in a GPU-bound game probably would have spelled the end of this strategy. But Species is CPU-bound: it has GPU cycles to spare. So full-steam ahead.

“Everlasting pure darkness” will not be a biome in the full game. (Unless someone mods it in).

The artefacts of this method also turned out to be quite different to the ones I faced with the other method. The other method loved to produce singular, localised artefacts: hard edges and biome colours where they shouldn’t be. This method’s artefacts usually affected the entire terrain. I’d say two in particular are worthy of noting here, mainly because I haven’t actually managed to fix them: double rendered polygons and biome-set edges.

Biome-set edges were where one transparent layer tried to fade out into another. I never had any trouble with the inter-set blending, but proper alpha blending is a temperamental thing. In this case, because the biome colour fades out at the same time as the opacity does, the end result was a faded-but-noticeable black ‘border’ between different blend-sets.

Oh so that’s what wars are fought over.

I managed to ‘fill-in’ the majority of these borders by extending the colour to the very edge, but there is still a faint one around the first draw pass. Thankfully it’s subtle, and dealing with it had some odd side effects, so I’m going to leave that one alone. It’s not hugely noticeable.

Double-rendered polygons, on the other hand, are a problem.

It’s zombie-triangle apocalypse! Only trigonometry geeks will survive.

This isn’t actually a problem with the rendering method: it’s a problem with the QuadTerrain itself, which I didn’t know about until the rendering method made it visible. See, when the terrain is completely opaque, rendering a polygon twice has no effect. The colour from both renderings is the same, so it’s an invisible artefact. But when you render a *transparent* object, like, say… one of the 4-biome passes of the terrain… *then* it becomes quite visible, as you can see above.

But fixing it means re-familiarising myself with the QuadTerrain class, which I haven’t touched in quite some time. I’ve already made a little progress, eliminating about half of the artefacts above with one fix. Hopefully the next fix will get the rest, but I doubt it: bugs like this are often inversely exponential. You might be able to fix the majority of them easily, but there are always one or two subtle, extremely well hidden ones that you have next-to-no chance of ever finding.

Oh well, best I can do is to make sure I get most of them.

Currently, I have 23 biomes defined as rough shapes on a temperature/fertility axis. This includes ‘extreme’ biomes, like lava and salt-plains, and a number of underwater biomes that will only be found… err, underwater. (Fertility will at least partly be determined by height: everything below the water plain will be water).

So far everything is coming together as planned. Biomes are done, 3d trees are done (I’ll do a proper post on them later), I’m midway through tying the two together, and soon the nanozombies will be unleashed on the unsuspecting… oh wait wrong blog. You didn’t hear that.

Qu

“Other stipulations of Australian citizenship include:

– Must defend vegemite no matter personal opinion of taste. (sticky salty gunk)
– Must be willing to throw foreign tourists in front of a croc to save yourself. (Or was that the other way around?)
– Must know how to defend against drop-bears (trick question: there is no way to defend against drop bears)”

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Meatpiling

Who wants an insight into the debugging process? Nobody? Well you’re getting one anyway.

‘Meatpiling’ was a survival strategy, caused by a bug which was fixed in hotfix 3, where hundreds of giant carnivorous blobs would converge in a small location and survive by eating each other. The name comes from the gigantic corpses that served as the food source for the entire mass. It was a horrific conglomeration of living and dead biomass: the pinnacle of evolution!

Which can only be defeated by a ragtag group of Very Attractive Scientists and a firetruck full of Product Placement!

Logically, this shouldn’t be possible. Carnivores can’t get energy without eating herbivores, who in turn can’t get energy without eating plants, but The Mass was almost entirely carnivorous, and stationary. There was no way should have been able to feed itself, yet it was such a viable survival strategy that almost every simulation seemed to converge on this end result. The logical conclusion was that there was a bug in there somewhere.

And thus began the bug finding endeavour, a heroic tale heroism and courage, uniting the world and saving the- no okay it was long and boring.

I started by studying the creatures. In addition to being giant fat carnivores with an energy capacity that would rival a medium sized star, they were social and amorous, and had a very high attack damage.

“Aha!” I thought, excited and slightly aroused by the prospect of solving the bug simply by looking at it, “Clearly The Cause Of This Problem Is Attack Damage! Onward, To Victory And Pie!”

My assumption was that when a creature attacked and killed another creature, the corpse was accidentally gaining energy. The logic behind this is simple: when a creature attacks another creature, any health lost is converted to biomass (meat).

Attack Damage = 100
Health Before Attack = 10 Biomass Before Attack = 0
Health After Attack = -90 Biomass After Attack = 100

Since hP is no longer used when a creature is dead, the resultant corpse has 90 more energy than the original creature.

I checked the code for attack damage, and sure enough it was subtracting the full amount of attack damage, without regard to how much was left. So I fixed this by subtracting/adding whichever was smaller of Attack Damage and Total Health, dislocated my shoulder trying to pat myself on the back, and loaded up the simulation just to make sure it was fixed.

Guess what happened next?

WHY U NO DISSAPPEAR???

After a bit more research, I determined that not only was Attack Damage not the problem, it was never a problem in the first place. You see, when a creature dies, any remaining health and energy is dumped into biomass. So the negative 90 health in the above example was being added to the positive 100 biomass, resulting in a correct value of 10 biomass. My actions hadn’t actually made any difference.

This still left me with a problem: if it wasn’t attack damage, what was it? Where was all the extra delicious meat energy coming from?

I adopted a new approach, one I’ve used in the past. I have a function called “RecalculateGlobalEnergy”, that generates the Mega joule statistic next to the ‘environment’ by adding together all the creatures health, energy, biomass and all the tree, corpse and ground energy. By peppering the game code with this function, turning off photosynthesis, and watching for when the energy content increases, I can spot exactly when positive energy leaks like this one occur (negative energy leaks are harder to find, but are also less dangerous: you can’t make a survival strategy out of losing energy).

This should have worked. It really should have. Unfortunately, things are never that simple.

See, floating point digits can store 7 unique digits. This can be expanded to store numbers with more digits, but you lose precision at the lowest level to rounding errors.

The environment The Mass lived in had an energy content with 8 digits.

This meant that, due to rounding errors, the lower end of the energy content number would jump up and down by a few units, resulting in loads and loads of false-positive increases. Separating the genuine increases from the false ones was more difficult than it should have been.

I experimented briefly with reducing the number by only looking at meat energy, and turning off eating plants entirely. Unfortunately, the number was still more than 7 digits.

So I adopted yet another new approach: reduce the energy content the nasty way. I already had a genocide button (“K”, for anyone wondering), and I went and added some new functionality to clear the corpses (“L”).

For anyone keeping count: by this stage the game runs at less than 1 fps due to recalculating the Global Energy dozens of times each frame, hits a breakpoint a couple of times per frame in debug mode, the creatures can no longer eat or interact with plants, and I was holding down K and L to make them die and erase their corpses from existence.

I managed to get the energy content down to 7 digits and save the map, then I reactivated debug mode. The game barely-ran for quite some time, before hitting the breakpoint with a positive increase of more than 400 energy. Got you.

(And yes, I’m aware I could have filtered out the false positives by only looking for larger increases, but I didn’t know at the time how large an individual increase would be. For all I knew, the false positives were the increases)

The end result: it had nothing to do with carnivory, energy content or attack damage. The energy increase happened during reproduction. When a mated/non-virgin creature reproduced, I’d forgotten to subtract energy from the parent when giving it to the child. Effectively, mated creatures could give birth for free.

The meatpile was an orgy.

I didn’t want to google for an appropriate image, so here’s a creature looking unimpressed.

The worst thing about this particular comedy of errors? If I’d paid closer attention at the start, I could have worked it out myself. Amorousness, the behavioural tendency that makes creatures decide to mate, was extremely high in every creature in the pile. I mistakenly assumed it was a side effect of being in such close proximity to each other, not the reason they were converging.

So quite often, that’s what Species is for me. A comedy of frustrating, painful errors that, at the end, results in a nothing more than a slightly more accurate, slightly more interesting, simulation of evolution.

And you know something? It’s totally worth it.
Qu.

“There are things in this world: dark, terrible things, that should never be googled.”

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Species 0.4.1

… is Released!

Heeeellllooo…

Download the game here: Species ALRE Official Website

From the Development Thread:

Developments

Gene Splicing
Radiation Gun
Highlight Colour Filters (basic implementation)
Ultra Time Acceleration (deactives rendering, runs at the maximum speed the computer can handle)
Q/E to make the camera Rise/Fall. (It’s like maaagic)
Head animation and movement. (To make them look like they’re actually thinking. Makes them seem a lot less brain-dead)
Eye animation and movement. (as above)
Animated Cloud Plane.
Tree’s waving in the breeze. (These two should make the Time Accelleration actually feel like Time Accelleration, as opposed to simply putting all the creatures on meth)
Better Looking Corpse/Meat Models (Steaks! Delicious bloody raw steaks! How can they resist evolving into carnivores now?)
Fake Shadows
Basic Ambient Noises (placeholder sounds: check back for a hotfix for them later this week)
Export Creature function
Import Creature function
Mutation Map – Feature Model
Mutation Map – Feature Texture
Mutation Map – Body Covering
Mutation Map – Colour Pattern
Update the Mod Maker to acknowledge new Mutation Maps.
Mark Perception Target. (Head animation already made the creatures a bit easier to read: showing the player what the selected creature is targeting should improve that even more)
Remake the Eyes (Eyestalks and eyelids and light sensing pits!)
Remake the Eye textures (Lenses and Compound Eyes!)
Autorestart option for Mass Extinction (in the Options Menu)

Fixes

Creatures not wandering even though they say they are. (LIIIIIEES!)
Creatures spinning endlessly in circles around tree’s. (Clearly they’re attempting to rob the planet of it’s rotational momentum. They must be stopped)
Game crashes at some point when you set the population cap to 2000.
Autosave closing any open UI tabs. (My bad guys, I should have fixed that one before release)
Creature’s heads rotating into their own bodies (mostly fixed, still happens occasionally though)
Creatures looking in the wrong direction in the Creature Details Panel.
Fake shadows visible through cliffs.
Fake shadows not orienting to ground properly.
Remove Creature Thumbnails. (currently they’re being taken at birth for every creature on the map, which costs performance. It would be better to take one solely for whichever creature is currently selected)
Deforest the area outside the border
Automatically detect if the player’s graphics card can’t handle Pixel Shader 3.0 and/or > 2048×2048 textures
Deal with all of the AI problems that Mark Perception Target made painfully obvious
Bind the Up, Down, Left and Right keys as secondary movement controls for people who don’t have qwerty keyboards.
Option to save as BMP files, for systems that don’t support saving to PNG (assuming that’s what’s causing the loss-of-terrain problems some people are reporting)
Check Biomass Bar for possible Memory Leak (No way to test it, but I have made sure it won’t try to draw more than 150 scale sprites)

Report any bugs here. (or leave a comment below)
Discuss the release here.
Make suggestions for 0.5.0 here.

You think you know me? You know nothing.

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I am not making an MMORPG, But…

Okay, first things first.

Species Alpha 0.4.1 comes out in a week, on Sunday 15th July.

Check the still-ongoing development thread for info on what it contains: over here I’m just going to say “gene splicing and head animation” and leave it at that.

Now on with the show…

I was originally going to keep this planned feature a secret, since I’ve never done anything like it before, but Skylimit preempted me in the comments by simultaniously coming up with a fairly similar idea. I would call that memetic convergent evolution if I was trying to be thematically pretentious, but since I’m still trying to maintain the illusion that I don’t think I’m smarter than everybody else I won’t.

Anyway, the feature is, quite simply, Online Multiplayer.

Now before I go any further, I want to draw everyone’s attention to a particular archetype/stereotype. On many games programming forums, there will be a few new threads with a title like “help me make my game”, or “my game idea” or something equally vague. They will often be the first post by this particular user, (and in many cases the last) and will consist of something like this:

“i have a game idea for a great game I want to make its an MMORPG and wil make lots of mony but I don’t know how to program what do i do plz help”*

And it is always, always, an MMO. I don’t know why, and I’m not even going to try to guess.

I mention this archetype so that I can say: this is not me. I know my limitations, and a genuine MMO is fairly well beyond them. What I’m suggesting for Species is not so much a way to play the game with other people as a way to expand the creatures world by connecting one border of your map to theirs and allowing creatures to wander fom yours to theirs, thus ‘combining’ your CPU power.

It’s at this point that I get excited, because this grid of connected worlds utterly demolishes the biggest restriction we have on the game: performance. Suddenly, the world of Species can be as close to infinite as makes no difference. We go from petrie dish to planet in one hit! And with some sort of multiplayer map view, you could see how the descendants of creatures from your world are doing other worlds, and in the overworld in general.

My plan is to connect the borders directly: essentially making it so that, to the creatures, there are no borders at all. There won’t be any ‘migration’ routine or any decision on the creatures part to go to the next world over: they’ll just cross the edge in the course of their usual wandering and appear in your neighbours world. I like this idea because it means you’re not just connecting standalone worlds and allowing them to pass creatures to each other: you’re actually expanding a single, gigantic world.

And then my excitement starts to die down as I consider the problems this poses.

On the immediate, border-to-border scale we’ve got time accelleration. Imagine a world running at 10x connected to a world running at 1x. Things turn into an episode of Dr Who at the border.

This problem isn’t too bad, though, compared to others. What about players connecting and disconnecting? This is the equivilent of huge chunks of terrain, and all the creatures and vegetation in them, appearing and disappearing with no warning.

So far we’ve come up with four solutions, none of them ideal:

Static. This mode ensures the player can keep their world and their position in the overworld, no matter what.
– – When a player disconnects their world ‘freezes’: creatures can no longer pass into, out of, or through their world.
– – The advantage is that the overworld as a whole remains static across multiple sessions: perfect for small, organised simulations, where you can turn all machines in the network on at the same time.
– – The disadvantage, obviously, is that entire chunks of the map can vanish and become impassable if someone shuts the game off.

Dynamic Player. This mode sacrifices player persistance to enable a large, semi-static overworld.
– – When a player disconnects, another player on the network (someone at the ‘edge’ of the overworld) or an incoming player automatically loads and begins simulating their world.
– – The advantage here is that a large, disorganised network can still run a relatively controlled and scientific simulation.
– – The disadvantage is that you as the player won’t be able to call any particular world or species your own.

Dynamic Overworld. This mode keeps player persistance and prevents impassable grid squares by turning the overworld into a constantly-shifting and changing environment.
– – When a player disconnects, someone else on the network (probably a neighbour) has their entire map picked up and moved into the vacant spot. (this may initiate a cascading shuffle, since someone else may now have to occupy their spot)
– – The advantage is obvious: the player gets to keep their map across multiple sessions and also connect to a large, disorganised network.
– – The disadvantage is the effects mobile terrain. A particularly lucky map could move halfway across the overworld, seeding it’s creatures into other maps the whole way.

Virtual Overworld: This mode treats the overworld not as a 2d grid of terrain, but as a web of connected nodes.
– – When a player disconnects, rather than their neighbours being physically shuffled about, only the links are re-arranged, with the nodes being pulled into position by a web-physics simulation similar to what the Mod Manager has.
– – The advantage’s are similar to the Dynamic Overworld option, with the overworld being less mobile: rather than shuffling world bits about, the borders will just grab onto each other and tie the web tighter together. And when they re-connect, they can return to the same spot and connect to the same neighbours.
– – The disadvantage is that it can’t be represented as a ‘planet’ of contiguous terrain anymore. If you’re having trouble visualising what I mean: which square is connected to the north-east corner of square 8 in the far-right diagram above?) As a result, rather than zooming out to some sort of impressive satellite view showing mountains and forests and rivers, we’d need to display the web of connected nodes.

The other problem is that some of this conflicts with other idea’s we’d had. We had considered building the AI facility/science lab that will serve as the player avatar into the crater walls. This neatly solves the problem of the buildings and nursary taking up space and getting in the road of the wild creatures, means I don’t have to implement per-creature collision for them which is a performance bonus, and it looks cool. Unfortionately, if the overworld is meant to be contiguous, the crater has to go (at least in multiplayer), which means we’re back to the original, relatively boring idea of dumping the science base in the middle of the map.

Actually, even if it’s not contiguous, we’ll still need to ‘connect’ the map to it’s neighbours somehow so that there’s at least an explanation for where the disappearing creatures at the border are going. I’m pretty sure the blind legless slugblobs aren’t quite capable of scaling the crater walls.

I’m actually in need some suggestions here: this is all very much long term stuff (we haven’t even worked out the design style for the science base yet: all I’ve got in my notes is “somewhere between jurassic park, NASA, and a volkswagon-factory”), but it’s presenting some interesting design challenges. How do we reconcile the need for an open overworld with the need for overworld stability? Where do we put the AI complex and nursary? How many roads can a man walk down?

Any ideas?
Qu

*footnote: In the interests of keeping this post constructive and not just laughing hysterically at the n00bs: if the archetype above sounds like you (minus the lack of grammar), here’s a few suggestions:

a) Start small. You’ll learn a lot faster making a 2D game or a mod for another game, and you’ll screw up your large project less in the long run because you’ll make all the beginner mistakes in the small project, rather than in the large.

b) What programs you should be using depends on how keen you are and how much prior experience you have. If you’ve never programmed before in your life, try making a simple Pong clone in Macromedia Flash or Game Maker, or better yet in Visual Studio’s Windows Forms Designer (that will also introduce you to Visual Studio, which will help later). You can do it in an afternoon (there’s loads of online tutorials around), and it will at least give you a very basic idea of what is involved. If that goes well, grab a copy of Vistual Studio and decide what programming language you want to learn. I like C#, but really, the similarities are more important than the differences. If you can program in one language, you can learn to program in most of them.

c) If you’re already a programmer, or you’ve done (b) and decided this programming stuff doesn’t seem too hard, you’ve got a few options: use/mod an existing game engine (if you’re making an FPS, you might as well start with the Crysis world editor or the Unreal Engine), download a genre-independant game engine (I’ve heard good things about Unity), or download a framework like XNA or even just native DirectX and build your own engine. Which way you go depends on how keen you are: if you want complete freedom and are willing to pay for it with increased time and effort, go straight for XNA or DirectX. If you’re happy to be somewhat restricted, but get your game out months in advance, go for a pre-existing engine.

d) Don’t try to make games on your own for the money. The AAA industry is already doing that, and they’ve got rediculous budgets to throw at it, so competing with them is useless: if you want a part of that action you’ll have to go sell your soul to join them. And if you want to make loads of money from the indie crowd, ala Minecraft, you're not going to get away with pandering to what you think they want, because they want originality (which is a nice way of saying they don't have the slightest clue what they want until they see it. Seriously, imagine pitching the Minecraft concept to anyone prior to the game being made). If you're going to sell to the indie crowd, then you need to be making games because you want to make games, not for any other reason.

“We will of course be laughing hysterically at the n00bs anyway in an attempt to crush their naive enthusiasm under wave upon wave of sadistic cynicism.”

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