Continuing the old theme…

CAN I HAS MOIRE SHADOWS?

I just changed my job title to say “Code Chef“. I like it, and it represents my current understanding of programming pretty well. I cook code. That’s my job.

Some N years ago I would have liked a title with “Architect” or “Analyst” or something like that. I would have called myself “developer” instead of “programmer” because hey, a developer thinks up things, whereas a programmer is a mere “code monkey”. More on code monkeys below.

But wait! Back then I also believed that knowing and using Design Patterns is essential for a programmer! In one place when I was interviewing new hires, design pattern knowledge was something I would look for… how stupid! Nowadays my view of patterns is more along the lines of “yeah, whatever”. I don’t exactly think of them as things from hell, but they could have caused more harm than good already.

Back to job titles. Code monkey is actually the key employee. A software product is largely defined by the code, heck, it is code. Sure, it also has the user interface, the fancy icons, the documentation, the website, the support, the roadmap and whatnot, but the code is the product, whereas everything else is more or less addons (possibly excluding UI… UI also defines the product).

Code design? Design patterns? Who cares about that.

It’s the final result that matters. Futurist programming for the win.

On the other hand, Memento Observer is probably very cool.

Said by Jonathan Czeck of Graveck:

What kind of filtering does Resize() function use? Nearest-neighbor, bilinear, bicubic, biawesome?

Since then “biawesome” became a local meme at work. Biawesome is awesome on steroids.

After wasting nearly two days on some really funky animation import crash, I checked in a code change with this log message:

Fix FBX animation import crash once more. When exported symbols are not listed for a dylib, it seems to link back to calling executable (?!), making them share function impls with the same name. And because Keyframe is actually different in editor vs ImportFBX, this is wrong. Apparently this is OS X Leopard only, or something. Argh.

The code change in question was just telling the compiler “here’s the list of the functions that are exported from this dynamic library”. The list was already there, just the compiler was never told about existence of it.

The bug manifested itself as a crash when importing animations. But it would not happen when importer was run from a small unit test application. There were no memory corruptions happening, it was not running out of memory, yet the code was crashing with access violation, usually because STL’s vector was returning it’s wrong size (but the actual data of the vector was correct; it was just returning bogus size). And it was doing that only on OS X Leopard, and not on OS X Tiger. Huh?

Turns out what did happen - and I’m not sure if that’s a bug in OS X or a feature - is that the calling application did contain a class called Keyframe. And the shared library (where the crash was happening) also contained a class called Keyframe. But those classes were slightly different; first was 20 bytes in size, and second one was 16 bytes.

Now, somehow when the shared library was calling vector<Keyframe>::size(), the function from the calling application was used. I have no idea at all how or why this was happening, but it sure was! I could see from tracing the assembly code, that it was doing difference of two pointers, and then doing something that for sure was not division by 16.

What was the code doing? Turns out it was calculating division by 20 in a cunning way:

mov  edx,esi   # edx = end()
sub  edx,eax   # edx -= begin()
mov  eax,edx   # eax = edx
sar  eax,0x2   # eax >>= 2
imul eax,eax,0xcccccccd # eax *= 0xcccccccd

In other words, the compiler was replacing division by constant (as used in vector’s size()) by a shift and multiplication with a magic number. You can read more about the technique here or here.

But of course the code above only works if the number was actually divisible by 20; otherwise it returns totally wrong result. This is perfectly fine for computing the difference in two pointers to structures of known size… Except that inside the shared library the Keyframe structures are 16 bytes, and not 20!

So yeah. Watch out for peculiarities of dynamic linking on your platform.

ShiftShader 2.0, a pure software renderer with a Direct3D 9 interface, just got released. I tried it on rendering unit tests and some benchmark tests we have for Unity.

In short, I’m impressed.

It runs rendering tests almost correctly; the only minor bugs seem to be somewhere in attenuation of fixed function vertex lights. Everything else, including shaders, shadows, render to texture works without any problems.

Performance wise, of course it’s dozens to hundreds times slower than a real graphics card, but hey. I also tested with Intel 965 (aka GMA X3000) integrated graphics for comparison. All this on Intel Core2 Quad (Q6600), 3 GB RAM, Windows XP SP2.

• Avert Fate demo: Radeon HD 3850 about 300 FPS, SwiftShader about 5 FPS (about 15 FPS if per-pixel lighting is turned off), Intel 965 about 22 FPS (about 50 FPS if per-pixel lighting is turned off).
• Scene with lots of objects and lots of shadow-casting lights: Radeon HD 3850 about 76 FPS, SwiftShader 2.5 FPS, Intel - shadows not supported, duh.
• High detail terrain with lots of vegetation and four cameras rendering it simultaneously: Radeon HD 3850 about 68 FPS, SwiftShader about 3 FPS, Intel 965 about 12 FPS.

Ok, so SwiftShader loses on performance to Intel 965, but the difference is only “a couple of times”, and not in order of magnitude or so. Pretty good I’d say.

As if the world was not a bad enough place - I put up a new blog about Random Stuff. It’s in Lithuanian and is mostly about that “life” stuff; no triangles there.

Here it is: aras-p.info/blogas

Seriously, what are they up to? Intel acquires Offset Software, a game development studio that is doing a game and an engine. Wait, I was thinking the game and tech are for PC and Xbox360? What would Intel do with that?

Not so long ago, some well known graphics guys went to work for Intel. A while ago Intel acquired Neoptica…

Signs of Larrabee coming? Intel starting to take GPUs seriously? Something else?

I decided to make a very small game with Unity. Coincidentally, Danc of Lost Garden fame just announced a small game design challenge called “Play With Your Peas“. It comes with a set of cute graphics and a ready-to-be-implemented game design. What more could I want?

So it’s a small very small 2D game without any next-gen bells and whistles. It can probably be done casually on the side, by allocating an hour here and there. We’ll see how it goes. Hey, I never actually done any game in Unity, I only make or break some underlying parts…

Of course, first I start with no game, just imported graphics. Hey look, I can do sprites!

Then cook up some base things: define the game grid, throw in some basic user interface on the right hand side, and make it actually do something. This wasn’t so hard; that already gets me an almost working level building functionality. It does not have fancy block building delay or block deletion yet; that will come later.

Next come basic physics. Danc’s design calls for simple arcade-like physics (things moving at constant speeds, bouncing off at equal angles, and so on), but in Unity I have a fully fledged physics engine just waiting to be used. Let’s use that.

The design has sloped ramp pieces, which are hard to approximate using any primitive colliders, so instead I’ll use convex mesh colliders for them. Now, on this machine I only have Blender, which I totally don’t know how to use; and I was too lazy to go to PC and use 3ds Max there. What a coder does? Of course, just type in the mesh file in ASCII FBX format. Excerpt:

; scaled 2x in Z, by 0.85 in Y
Vertices: -0.5,-0.425,-1.0, 0.5,-0.425,-1.0, -0.5,-0.425,1.0, 0.5,-0.425,1.0, -0.5,0.425,-1.0, -0.5,0.425,1.0
PolygonVertexIndex: 0,1,-3,2,1,-4,1,0,-5,2,3,-6,0,2,-5,2,5,-5,3,1,-5,5,3,-5

It’s a left ramp mesh! So much for fancy asset auto-importing functionality, when you don’t know how to use those 3D apps :)

After a while I’ve got peas being controlled by physics, colliding with level and so on. Physics is very bad for productivity, as I ended up just playing around with pea-stacks!

So far there’s no game yet… Next up: implement some AI for the peas, so they can wander around, climb the walls, fall down and bounce around. I guess that will be more work and less playing around… We’ll see.

So I decided to check out Crysis myself. A demo for a non-gamer like me would be perfect, I thought.

It’s probably three frames per second. In the menu!

I did not see the game itself yet, got bored while waiting for the after-menu-but-before-game intro movie to end (it’s not skippable, and it also ran at about three FPS). This is after watching half a dozen obligatory before-menu intro movies at 3 FPS with stuttering sound (”nvidia,vidia,vidia,vidia… the way it’s meant,meant,meant,meant…” - TWIMTBP).

All of this on a half-decent PC, I think - Intel Core 2 Quad, 4GB RAM, Radeon 3850, Windows XP, latest drivers, none of extra stuff running; the PC is able to run other 3D stuff just fine. I’m sure the developers and EA’s testing labs have tested everything extensively, but sometimes something completely random apparently can make things be oh so slow. Oh well. Get back to work.

This is just too cool: Off-Road Velociraptor Safari game. Read that again. Who says game industry is all about sequels and safe licenses?

You drive a jeep with a spiky ball, and your goal is to chase down raptors and send them to the future, presumably to end world hunger. Or you can do stunts. And you the driver are a raptor, only you wear a hat and a monocle.

Just go and play it already: raptorsafari.com. It’s free.

Or watch a trailer if you want to miss all the real fun, or read a press release. Of course it’s made in Unity, in two months from start to finish.

To me, this is a perfect example of focus. Basically there are three things - 1) vehicle, 2) raptors, 3) physics mayhem - and that almost describes a game. Yes, there are crates and stunts and achievements and online leaderboards, but that’s just additional stuff on top of the core game.

Sounds like a good plan for making game prototypes:

1. Think up a game idea and describe it in one concise sentence. The idea may be totally crazy, like in this case. I guess an idea like Velociraptor Safari would not fly in a pitch at any publisher, but that does not matter at this point.
2. Get a small team of smart people. In Flashbang’s case, it seems they were 4 to 7 person team.
3. Choose a game engine/toolset that will allow you to make your game fast. *cough cough*
4. Do it!

All the above requires is a small smart team and groceries/rent for a couple of months.

Your original idea may be totally crazy, but with the actual working prototype at hand it might just work. Looks like Velociraptor Safari really clicked something on the internets (see Kotaku, JayIsGames, Destructoid, TIGSource, AtomicGamer, …).