Promit's Ventspace

May 11, 2017

Game Debugging And Tweaking Via MIDI Controller

Filed under: Non-technical — Promit @ 3:34 pm

Today, we’re going to talk about how to configure a MIDI controller to act as a debugging aid for a game – or any software development project.

Why a MIDI controller?


Photo credit: Wikimedia Commons / CC BY-SA 3.0

Why would you want to do this? It’s very common to have a set of internal variables that we want to tweak on the fly, while the game is running, until things are just right. There’s animation, physics, AI, game play and difficulty, graphics, UI, and more. Typically people end up homebrewing a variety of tricks to edit these variables. You might ‘borrow’ a couple keyboard keys and throw an on screen text display in. You might have a developer console command and type in the values. If you really get fancy, you might even have a TCP debug channel that can control things from another UI, maybe even on another computer.

These options all have their pros and cons. Why add MIDI as another option to the mix?

  • It’s really easy and safe to disable for releases. We’re probably not using MIDI for any legitimate user purpose, after all.
  • It doesn’t require any UI, on any screen.
  • Supports platforms like mobile where keystroke debugging can be particularly problematic.
  • It’s quick to get to edit a large range of parameters in tandem.
  • Editing without explicit numerical values avoids the problem of sticking to “convenient” numbers.
  • It’s easy to give this setup to a non-technical person and let them toy around.
  • Tactile editing is just plain fun.

How does a MIDI controller work?

Over the MIDI protocol, naturally. MIDI was standardized in 1983 as a way for musical tools like keyboards, samplers, sequencers, and all sorts of computerized devices to communicate with each other. While in ye olden days the connection was made over a 7 pin DIN cable, many modern controllers have USB interfaces. These are class compliant devices, which means you can simply plug them into a computer and go, without any drivers or mandatory support software.

MIDI itself is a slightly wonky protocol, based strictly around events. There’s a wide range of events, but for our purposes we only really need four: Note On, Note Off, Control Change, and Program Change. Note On/Off are easy – they’re your key down/up equivalents for a MIDI controller. Control Change (CC) represents a value change on an analog control, like a knob or slider. Program Change changes an entire bank or preset.

Note what’s not in there: state. The whole thing is designed to be stateless, which means no state queries either. But many MIDI controllers do have state, in the physical position of their knobs or sliders. That leads us to the dreaded MIDI CC jump. In short, what happens when a value in our software is set to 0 (min) and the user twists a knob is at 127 (max)? The knob will transmit a CC with a value of 126 attached, causing the variable it’s attached to to skyrocket. This desynchronization between software and hardware state can be confusing, inconvenient, and downright problematic.

Choosing a MIDI controller


Photo Credit: Behringer/MUSIC Group

Enter the Behringer X-Touch Mini. For a trivial $60 street at time of writing, take a look at what it gives us:

  • 8 rotary encoders with LED collars for value display
  • Volume slider
  • 24 push buttons (8 push-knob, 16 LED) with configurable behavior (momentary/toggle)
  • Dual control layers, so multiply everything above by two
  • Simple class-compliant USB connectivity

Now back up and read that again. Rotary encoders. LED collars. Get it? Encoders aren’t knobs – they spin freely. The value isn’t based on the position of a potentiometer, but digitally stored and displayed using the LEDs around the outside of each encoder. Same goes for the button states. This is a controller that can not only send CC messages but receive them too, and update its own internal state accordingly. (The volume slider is not digital and will still cause CC jumps.)

Setting up the X-Touch Mini


Photo Credit: Promit Roy / CC BY-SA 3.0

Behringer offers a program called X-Touch Editor which you’ll want to download. Despite the terrible English and oddball UI, It allows you to configure the X-Touch Mini’s behavior and save it persistently onto the controller’s internal memory. You can change the display style of the LEDs (I recommend fan) and change the buttons between momentary (like a keyboard button) and toggle (push on, push again off). It also offers other options for MIDI behavior, but I recommend leaving that stuff where it is. For my purposes, I set the center row of buttons to act as toggles, and left the rest of it alone.

Understanding the MIDI protocol

At this stage it might be helpful to download a program called MIDI-OX. This is a simple utility that lets you send and monitor MIDI messages, which is very useful in understanding exactly what’s happening when you are messing with the controller. Note that MIDI devices are acquired exclusively – X-Touch Edit, MIDI-OX, and your own code will all lock each other out.

The MIDI messages we’ll be using have a simple structure: a four bit message ID, a four bit channel selection, followed by one or two data bytes. The X-Touch Mini is configured to use channel 11 for its controls out of the box. Here are the relevant message IDs:

enum MidiMessageId
    MIDI_NoteOn = 144,
    MIDI_NoteOff = 128,
    MIDI_ControlChange = 176,
    MIDI_ProgramChange = 192,

Channels are 0 based in the protocol, so you’ll add 10 to these values when submitting them. NoteOn and NoteOff are accompanied by a note ID (like a key code) and a velocity (pressure). The key codes go from 0-23 for layer A, representing the buttons left to right and top to bottom. When you switch to layer B, they’ll switch over to 24-47. You’ll receive On and Off to reflect the button state, and you can also send On and Off back to the controller to set Toggle mode buttons on or off. This is really handy when hooked up to internal boolean variables: light on = true, light off = false. We’re not interested in the pressure field, but it does need to be set correctly. The values are 127 for NoteOn and 0 for NoteOff.

ControlChange (CC) will appear any time the knobs are rotated, with the knob ID and the current value as data bytes. The default range is 0-127; I recommend leaving it that way and rescaling it appropriately in software. For layer A, the knob IDs go from 1-8 (yes, they’re one based) and the slider is assigned to 9. On layer B that’ll be 10-17 and 18. You can transmit identical messages back to the controller to set the value on its end, and the LED collar will automatically update to match.

The X-Touch will never send you a ProgramChange (PC) by default. However on the current firmware, it will ignore messages that don’t apply to the currently active layer. You can send it a Program Change to toggle between layer A (0) and B (1), and then send the rest of your data for that layer to sync everything properly. PC only has a single data byte attached, which is the desired program.

Writing the MIDI glue code

Go ahead and grab RtMidi. It’s a nice little open source library, which is really just composed of a single header and source file pair, but supports Windows, Linux, and Mac OSX. (I have an experimental patch for iOS support as well that may go up soon.) I won’t cover how to use the library in detail here, as that’s best left to the samples – the code you need is right on their homepage – but I will give a quick overview.

You’ll need to create two objects: RtMidiIn for receiving data, and RtMidiOut for sending it. Each of these has to be hooked to a “port” – since multiple MIDI devices can be attached, this allows you to select which one you want to communicate with. The easiest thing to do here is just to search the port lists for a string name match.

At this point it’s just a question of signing up for the appropriate callbacks and parsing out their data, and then sending the correct messages back. The last step is to bidirectionally synchronize variables in your code to the MIDI controller. I did it with some template/macro nonsense:

void GameStage::MidiSyncOut()
		_midiOut->Send(MIDI_ProgramChange, 0);
		MidiVars(1, 0, 0, 0);
		_midiOut->Send(MIDI_ProgramChange, 1);
		MidiVars(1, 0, 0, 0);
		_midiOut->Send(MIDI_ProgramChange, 0);

void GameStage::NoteOn(unsigned int channel, unsigned int note, unsigned int velocity)
	MidiVars(0, 0, note, velocity);

void GameStage::NoteOff(unsigned int channel, unsigned int note, unsigned int velocity)
	MidiVars(0, 0, note, velocity);

void GameStage::ControlChange(unsigned int channel, unsigned int control, unsigned int value)
	MidiVars(0, 1, control, value);

template<typename T1, typename T2, typename T3> void MidiVariableOut(const T1& var, T2 min, T3 max, unsigned int knob, MidiOut* midiOut)
	float val = (var - min) / (max - min);
	val = clamp(val, 0.0f, 1.0f);
	unsigned char outval = unsigned char(val * 127);
	midiOut->Send(MIDI_ControlChange + 10, knob, outval);

template<typename T1, typename T2, typename T3> void MidiVariableIn(T1& var, T2 min, T3 max, unsigned int knob, unsigned int controlId, unsigned int noteOrCC, unsigned char value)
	if(noteOrCC && knob == controlId)
		float ratio = value / 127.0f;
		var = T1(min + (max - min) * ratio);

void MidiBoolOut(const bool& var, unsigned int button, MidiOut* midiOut)
		midiOut->Send(MIDI_NoteOn + 10, button, 127);
		midiOut->Send(MIDI_NoteOff + 10, button, 0);

void MidiBoolIn(bool& var, unsigned int button, unsigned int controlId, unsigned int noteOrCC, unsigned char value)
	if(!noteOrCC && button == controlId)
		var = value > 0;

#define MIDIVAR(var, min, max, knob) inout ? MidiVariableOut(var, min, max, knob, _midiOut) : MidiVariableIn(var, min, max, knob, controlId, noteOrCC, value)
#define MIDIBOOL(var, button) inout ? MidiBoolOut(var, button, _midiOut) : MidiBoolIn(var, button, controlId, noteOrCC, value)
void GameStage::MidiVars(unsigned int inout, unsigned int noteOrCC, unsigned int controlId, unsigned int value)

	MIDIVAR(_fogTopColor.x, 0.0f, 1.0f, 1);
	MIDIVAR(_fogTopColor.y, 0.0f, 1.0f, 2);
	MIDIVAR(_fogTopColor.z, 0.0f, 1.0f, 3);
	MIDIVAR(_fogBottomColor.x, 0.0f, 1.0f, 4);
	MIDIVAR(_fogBottomColor.y, 0.0f, 1.0f, 5);
	MIDIVAR(_fogBottomColor.z, 0.0f, 1.0f, 6);
	MIDIVAR(CoCScale, 1.0f, 16.0f, 8);

	MIDIBOOL(RenderEnvironment, 9);
	MIDIBOOL(DepthOfField, 10);

Probably not going to win any awards for that, but it does the trick. MidiVars does double duty as an event responder and a full data uploader. MidiSyncOut just includes the PC messages to make sure both layers are fully updated. Although I haven’t done it here, it would be very easy to data drive this, attach variables to MIDI controls from dev console, etc.

Once everything’s wired up, you have a completely independent physical display of whatever game values you want, ready to tweak and adjust to your heart’s content at a moment’s notice. If any of you have particularly technically minded designers/artists, they’re probably already using MIDI controllers along with independent glue apps that map them to keyboard keys. Why not cut out the middle man and have explicit engine/tool support?

November 5, 2014

Sony A77 Mark II: EVF Lag and Blackout Test

Filed under: Non-technical — Promit @ 4:05 pm

I’m planning to review this camera properly at some point, but for the time being, I wanted to do a simple test of what the parameters of EVF lag and blackout are.

Let’s talk about lag first. What do we mean? The A77 II uses an electronic viewfinder, which means that the viewfinder is a tiny LCD panel, showing a feed of what the imaging sensor currently sees. This view takes camera exposure and white balance into exposure, allowing you to get a feel for what the camera is actually going to record when the shutter fires. However, downloading and processing the sensor data, and then showing it on the LCD, takes time. This shutter firing needs to compensate for this lag; if you hit the shutter at the exact moment an event occurs on screen, the lag is how late you will actually fire the shutter as a result.

How do we test the lag? Well, the A77 II’s rear screen shows exactly the same display as the viewfinder, presumably with very similar lag. So all we have to do is point the camera at an external timer, and photograph both the camera and the timer simultaneously. And so that’s exactly what I did.
Note that I didn’t test whether any particular camera settings affected the results. The settings are pretty close to defaults. “Live View Display” is set to “Setting Effect ON”. These are the values I got, across 6 shots, in millseconds:
32, 16, 17, 34, 17, 33 = 24.8 ms average
I discarded a few values due to illegible screen (mid transition), but you get the picture. The rear LCD, and my monitor, are running at a 60 Hz refresh rate, which means that a new value appears on screen every ~16.67 ms. The lag wobbles between one and two frames, but this is mostly due to the desynchronization of the two screen refresh intervals. It’s not actually possible to measure any finer using this method, unfortunately. However the average value gives us a good ballpark value of effectively 25 ms. Consider that a typical computer LCD screen is already going to be in the 16ms range for lag, and TVs are frequently running in excess of 50ms. This is skirting the bottom of what the fastest humans (pro gamers etc) can detect. Sony’s done a very admirable job of getting the lag under control here.

Next up: EVF blackout. What is it? Running the viewfinder is essentially a continuous video processing job for the camera, using the sensor feed. In order to take a photo, the video feed needs to be stopped, the sensor needs to be blanked, the exposure needs to be taken, the shutter needs to be closed, the image downloaded off the sensor into memory, then the shutter must open again and the video feed must be resumed. The view of the camera goes black during this entire process, which can take quite a long time. To test this, I simply took a video of the camera while clicking off a few shots (1/60 shutter) in single shot mode. Here’s a GIFed version at 20 fps:
By stepping through the video, I can see how long the screen is black. These are the numbers I got, counted in 60 Hz video frames:
17, 16, 16, 17, 16, 16 = 272 ms average
The results here are very consistent; we’ll call it a 0.27 second blackout time. For comparison, Canon claims that the mirror blackout on the Canon 7D is 0.055 seconds, so this represents a substantial difference between the two cameras. It also seems to be somewhat worse than my Panasonic GH4, another EVF based camera, although I haven’t measured it. I think this is an area which Sony needs to do a bit more, and I would love to see a firmware update to try and get this down at least under 200 ms.

It’s worth noting that the camera behaves differently in burst mode, going to the infamous “slideshow” effect. At either 8 or 12 fps settings, the screen shows the shot just taken rather than a live feed. This quantization makes “blackout time” slightly meaningless, but it can present a challenge when tracking with erratically moving subjects.

October 15, 2014

Time Capsule Draft: “Speculating About Xbox Next”

Filed under: Non-technical — Promit @ 11:50 am

I was digging through my Ventspace post drafts, and I found this writeup that I apparently decided not to post. It was written in March of 2012, a full year and a half before the Xbox One arrived in the market. In retrospect, I’m apparently awesome. On the one hand, I wish I’d posted this up at the time, because it’s eerily accurate. On the other hand, the guesses are actually accurate enough that this might have looked to Microsoft like a leak, rather than speculation. Oh well. Here it is for your amusement. I haven’t touched a thing about it.

I’ve been hearing a lot of rumors, though the credibility of any given information is always suspect. I have some supposed info about the specs on the next Xbox, but I’m not drawing on any of that info here. I’m dubious about at least some of the things I heard, and it’s not good to spill that kind of info if you’re trying to maintain a vaguely positive relationship with a company anyway. So what I’m presenting here is strictly speculation based on extrapolation of what we’ve seen in the past and overall industry and Microsoft trends. I’m also assuming that MS is fairly easy to read and that they’re unlikely to come out of left field here.

  • 8 GB shared memory. The original Xbox had 64 MB of shared memory. The Xbox 360 has 512, a jump of 8x. This generation is dragging along a little longer, and memory prices have dropped violently in the last year or so. I would like to see 16 GB actually, but the consoles always screw us on memory and I just don’t think we’ll be that lucky. 4 GB is clearly too low, they’d be insane to ship a console with that now. As for the memory type, we’re probably talking simple (G)DDR3 shared modules. The Xboxes have always been shared memory and there’s no reason for them to change that now. Expect some weird addressing limitations on the GPU side.
  • Windows 8 kernel. All indications are that the WinCE embedded kernel is being retired over the next two years (at least for internal use). There’s a substantial tech investment in Windows 8, and I think we’re going to see the desktop kernel roll out across all three screens. (HINT HINT.) iOS and Android are both running stripped desktop kernels, and the resources in current mobile platforms make WinXP’s minimum hardware requirements look comically low. There is no reason to carry the embedded kernel along any longer. I wouldn’t want to be a CE licensee right now.
  • x86-64, 8×2 threads, out of order CPU. There are three plausible CPU architectures to choose from: x86, ARM, and PowerPC. Remember what I said about the Windows 8 kernel? There’s no Windows 8 PPC build, and we’re not going to see PowerPC again here. ARM is of course a big focus right now, but the design parameters of the current chips simply won’t accommodate a console. They’re not fast enough and that can’t be easily revised. That pretty much leaves us with x86. The only extant in-order x86 architecture is Intel Atom, which sucks. I think they’ll get out of order for free from the existing architectures. As far as the CPU, 8 core is essentially the top of the market right now, and I’m assuming they’ll hyperthread it. They’ll probably steal a core away from the OS, and I wouldn’t be surprised if they disable another core for yield purposes. That means six HT cores, which is a simple doubling of the current Xbox. I have a rumored clock-speed, but have decided not to share. Think lower rather than higher.
  • DirectX 11 GPU — AMD? DX11 class should be blatantly obvious. I have reason to believe that AMD is the supplier, and I did hear a specific arch but I don’t believe it. There’s no word in NVIDIA land about a potential contract, either. No idea if they’re giving the design ownership to MS again or anything like that, all I know is the arrows are all pointed the same way. There are some implications for the CPU here.
  • Wifi N and Gigabit ethernet. This is boring standard consumer networking hardware. No surprises here.
  • Optical drive? — I don’t think they want to have one. I do think they have to have one, though you can definitely expect a stronger push towards digital distribution than ever. There’s no choice but to support Blu-ray at this point. Top tier games simply need the space. I suspect that we’ll see a very large (laptop grade) hard drive included in at least some models. Half terabyte large, with larger sizes later in the lifecycle. That is purely a guess, though.
  • AMD Fusion APU? — I’m going to outlandishly suggest that a Fusion APU could be the heart of this console. With an x86 CPU and a mainstream Radeon core in about the right generation, the existing Fusion product could be retooled for use in a console. Why not? It already has the basic properties you want in a console chip. The big sticking points are performance and heat. It’s easy to solve either one but not both at once, and we all know what happened last time Microsoft pushed the heat envelope too far. If it is Fusion architecture, I would be shocked if they were to actually integrate the CPU and GPU dies.
  • Kinect. — Here’s another outlandish one: Every Xbox Next will include a Kinect (2?), in the box. Kinect has been an enormous winner for Microsoft so far on every single front, and this is where they’re going to draw the battle lines against Nintendo and Sony. Nintendo’s control scheme is now boring to the general public, with the Wii U being introduced to a resounding “meh”. PS Move faded into irrelevance the day it was launched. For the first time in many years, the Xbox is becoming the casual gamers’ console and they’re going to hammer that advantage relentlessly. Microsoft is also pushing use of secondary features (eg microphone) for hardcore games — see Mass Effect 3.
  • $500. Yes, it’s high, although not very high once you adjust for inflation. The Xbox 360 is an extremely capable device, especially for the no-so-serious crowd. It’s also pure profit for Microsoft, and really hitting its stride now as the general public’s long tail console. There’s no need to price its successor aggressively, and the stuff I just described is rather expensive besides. A $600 package option at launch would not be surprising.
  • November 2013. As with the last two Xboxes, it will be launched for the holiday season. Some people were saying it would be announced this year but the more I think about it, the less it makes sense to do so. There’s no way it’s launching this year, and they’re not going to announce it a year and some ahead of time. E3 2013 will probably be the real fun.

There are some problems with the specs I’ve listed so far. AMD doesn’t produce the CPU I described. Not that the rumors match any other known CPU, but Intel is closer. I don’t think one of the Phenom X6 designs is a credible choice. The Xbox 360 CPU didn’t match any existing chips either, so this may not really be a problem. The total package price would have to be quite high with a Kinect 2 included. The Xbox 360 may function as a useful buffer against being priced out of the market.

October 9, 2014

I Am Dolphin – Kinect Prototype

Filed under: Non-technical — Promit @ 5:29 pm

I’d hoped to write up a nice post for this, but unfortunately I haven’t had much time lately. Releasing a game, it turns out, is not at all relaxing. Work doesn’t end when you hit that submit button to Apple.

In the meantime, I happened to put together a video showing a prototype of the game, running off Kinect control. I thought you all might find it interesting, as it’s a somewhat different control than the touch screen. Personally I think it’s the best version of the experience we’ve made, and we’ve had several (touch screen, mouse, PS Move, Leap, etc). Unlike the touch screen version, you get full 3D directional control. We don’t have to infer your motion intention. This makes a big difference in the feeling of total immersion.

September 16, 2014

Game Code Build Times: RAID 0, SSD, or both for the ultimate in speed?

Filed under: Non-technical — Promit @ 7:08 pm

I’ve been in the process of building and testing a new machine using Intel’s new X99 platform. This platform, combined with the new Haswell-E series of CPUs, is the new high end of what Intel is offering in the consumer space. One of the pain points for developers is build time. For our part, we’re building in the general vicinity of 400K LOC of C++ code, some of which is fairly complex — it uses standard library and boost headers, as well as some custom template stuff that is not simple to compile. The worst case is my five year old home machine, an i5-750 compiling to a single magnetic drive, which turns in a six minute full rebuild time. Certainly not the biggest project ever, but a pretty good testbed and real production code.

I wanted to find out what storage system layout would provide the best results. Traditionally game developers used RAID 0 magnetic arrays for development, but large capacity SSDs have now become common and inexpensive enough to entertain seriously for development use. I tested builds on three different volumes:

  • A single Samsung 850 Pro 512 GB (boot)
  • A RAID 0 of two Crucial MX100 512 GB
  • A RAID 0 of three WD Black 4 TB (7200 rpm)

Both RAID setups were blank. The CPU is an i7-5930k hex-core (12 threads) and I’ve got 32 GB of memory on board. Current pricing for all of these storage configurations is broadly similar. Now then, the results. Will the Samsung drive justify its high price tag? Will the massive bandwidth of two striped SSDs scream past the competitors? Can the huge magnetic drives really compete with the pinnacle of solid state technology? Who will win?


They’re all the same.

All three configurations run my test build in roughly 45 seconds, the differences between them being largely negligible. In fact it’s the WD Blacks that posted the fastest time at 42s. The obvious takeaway is that all of these setups are past the threshold where something else is the bottleneck. That something in this case is the CPU, and more specifically the overall hardware thread count. Overclocking the CPU from 3.5 to 4.5 did nothing to help. I’ve heard of some studios outfitting their engineers with dual Xeon setups, and it’s not looking so crazy to do so when employee time is on the line. (The potential downside is that the machine starts to stray significantly from what the game will actually run on.) Given the results, and the sizes of modern game projects, I’d recommend using an inexpensive 500 GB SSD for a boot drive (Crucial MX100, Sandisk Ultra II, 840 EVO), and stocking up on the WD Blacks for data. Case closed.

But… as long as we’re here, why don’t we take a look at what these drives are benchmarking at? The 850 Pro is a monster of a drive. Those striped MX100s might be the real heros though; ATTO shows them flirting with a full gigabyte per second of sequential transfer. Here are the raw CrystalDiskMark numbers for all three:

Samsung 850 Pro:

Sequential Read : 520.557 MB/s
Sequential Write : 489.836 MB/s
Random Read 512KB : 407.993 MB/s
Random Write 512KB : 465.648 MB/s
Random Read 4KB (QD=1) : 24.216 MB/s [ 5912.1 IOPS]
Random Write 4KB (QD=1) : 71.216 MB/s [ 17386.7 IOPS]
Random Read 4KB (QD=32) : 398.378 MB/s [ 97260.3 IOPS]
Random Write 4KB (QD=32) : 331.571 MB/s [ 80950.0 IOPS]

2x Crucial MX100 in RAID 0:

Sequential Read : 898.908 MB/s
Sequential Write : 905.506 MB/s
Random Read 512KB : 695.787 MB/s
Random Write 512KB : 854.666 MB/s
Random Read 4KB (QD=1) : 26.271 MB/s [ 6413.8 IOPS]
Random Write 4KB (QD=1) : 110.554 MB/s [ 26990.8 IOPS]
Random Read 4KB (QD=32) : 430.077 MB/s [104999.3 IOPS]
Random Write 4KB (QD=32) : 413.606 MB/s [100978.0 IOPS]

3x WD Black 4TB in RAID 0:

Sequential Read : 530.522 MB/s
Sequential Write : 494.534 MB/s
Random Read 512KB : 61.752 MB/s
Random Write 512KB : 162.619 MB/s
Random Read 4KB (QD=1) : 0.724 MB/s [ 176.7 IOPS]
Random Write 4KB (QD=1) : 4.461 MB/s [ 1089.1 IOPS]
Random Read 4KB (QD=32) : 5.090 MB/s [ 1242.8 IOPS]
Random Write 4KB (QD=32) : 5.307 MB/s [ 1295.6 IOPS]

I don’t claim that these numbers are reliable or representative. I am only posting them to provide a general sense of the performance characteristics involved in each choice. The SSDs decimate the magnetic drive setup for random ops, though the 512 KB values are respectable. I had expected the 4K random read, for which SSDs are known, to have a significant impact on build time, but that clearly isn’t the case. The WDs are able to dispatch 177 of those per second; despite being 33x slower than the 850 Pro, this is still significantly faster than the compiler can keep up with. Even in the best case scenarios, a C++ compiler won’t be able to clear out more than a couple dozen files a second.

May 14, 2013

A Pixel Is NOT A Little Square

Filed under: Non-technical — Promit @ 12:57 pm
Tags: , , , , ,

It’s good to review the fundamentals sometimes. Written in 1995 and often forgotten: A Pixel Is Not A Little Square.

April 29, 2013

Oddly Elaborate Apple Error Message

Filed under: Non-technical — Promit @ 3:51 pm

I just wanted to share this. Popped up today while initializing an NSDateComponents object.

components:fromDate:toDate:options:]: fromDate cannot be nil
I mean really, what do you think that operation is supposed to mean with a nil fromDate?
An exception has been avoided for now.
A few of these errors are going to be reported with this complaint, then further violations will simply silently do whatever random thing results from the nil.
Here is the backtrace where this occurred this time (some frames may be missing due to compiler optimizations):

So that was unexpected.

April 11, 2013

The Scandalous Yetizen Costume

Filed under: Games,Non-technical — Promit @ 12:18 am
Tags: , , ,

There’s been a lot of chatter on the various blogs and news sites about the IGDA and Yetizen party incident. I’m not going to rehash that. See these articles if you’re not up to date on the whole controversy:
I will comment that I thought that the controversy was a wholly pointless manufactured thing and Brenda Romero’s resignation did not help anybody. That said, I was a little surprised to discover that the scandalous, allegedly inappropriate outfits that created all this trouble aren’t actually shown anywhere, in any of the news about the incident. At all. Not on Joystiq, not on the Gawker owned Kotaku, nowhere. I thought that was strange. Luckily I have photos of the Yetizen models from the previous year, so… here it is. This is the outfit that forced two IGDA members to resign.
Yetizen Outfits
Now you know.

November 14, 2012

The Promise of Motion Control

Filed under: Non-technical — Promit @ 4:16 pm

I saw a blog post on IGN today: 4 reasons why the Nintendo Wii U will fail by Ian Fisch. I won’t comment on the WiiU, because I was one of the people who said the Wii was going to flop and man oh man was I ever off the mark on that one. But I did want to highlight a particular chunk of his post:

When people think of the massive success of the Nintendo Wii, they usually think of middle-aged moms playing Wii Fit, and senior citizens playing Wii Sports bowling at the retirement home. Indeed, the success of the Wii, much like the success of the Nintendo DS was due, in a large part, to casual gamers. We tend to forget that, originally, the excitement for the Wii was at a fever pitch among hardcore gamers. If you were a hardcore gamer then, you might remember sharing Eric Cartman’s excitement over the potential of Wii’s “motion control controls.”

It was hardcore gamers that gave the Wii its terrific launch. For about a year and a half, hardcore gamers were as enthusiastic about the Wii as their out-of-shape mothers soon would be. Of course, once hardcore gamers discovered the severe limitations of the Wii’s motion controls, the system became little more than a dust collector. The Wii U will not get this initial surge of excitement from hardcore gamers. The original Wii tantilized the hardcore set with the (false) promise of a new level of immersion – a step toward virtual reality.

I currently work for the BLAM Lab at Johns Hopkins University, which is part of the Department of Neurology. I helped found a group here called Kata. The Kata Project exists for a lot of reasons, but this idea is really our heart and soul:

In Japanese language, kata (though written as 方) is a frequently-used suffix meaning “way of doing,” with emphasis on the form and order of the process. Other meanings are “training method” and “formal exercise.” The goal of a painter’s practicing, for example, is to merge his consciousness with his brush; the potter’s with his clay; the garden designer’s with the materials of the garden. Once such mastery is achieved, the theory goes, the doing of a thing perfectly is as easy as thinking it.

I’m doing a rich mix of work here, centered around game development not only for medical and scientific research purposes but also commercial production. The key point, though, is that everything we do is centered around the study of biological motion and what it means for games. We’ve got touch, Wii, PS Move, or Kinect, Leap, or whatever else is coming down the pipeline, and I don’t feel that the potential of any of those devices has really been explored properly. The Wii implied something that it turned out not to be, sadly. Motion control itself, combined with game design that really focuses on using it in new and interesting ways, has a very distinct future separate from what we’ve got today. Fruit Ninja is an early expression of it, I think. Of course I believe that we’ll be the ones to crack the code, but no matter how it happens I find it extremely interesting to observe what people are doing with the rich data we can get out of motion control systems. So far Kinect and most iPad games seem to be an expression of how much data we can throw away, instead. That needs to change.

May 26, 2012

New Theme, New Posts Soon, New Happenings

Filed under: Non-technical — Promit @ 12:30 am

I wanted a new coat of paint around here. We’re going to try this one on for size. It may or may not stick, we’ll see. I’m going to try and revive blogging here, as there are a number of things I’ve been meaning to write for many months. Many of those things are about photography, some of them are about games, and not a lot are about SlimDX or SlimTune.

Don’t hold your breath on the Slim* stuff — I just don’t know what is going to happen in the coming months. I’ve decided to pursue a Master’s Degree in Computer Science at my alma mater, Johns Hopkins University. I hate school, but given other events in my life this was an important step to take. It does cut into my time quite severely, so I’m basically stepping out of the consulting business and maintaining a blog during school is daunting to say the least.

I am also working on game development for the Department of Neurology at the Johns Hopkins Hospital. That is an extremely interesting effort which I will attempt to discuss as much as I can, though a lot of it is not and will not be public soon. That’s the nature of the beast, unfortunately. I will say right now that it should be obvious that psychology and neurology play an important role in game design. It turns out that game design plays an important role in psychology and neurology too, and research has only just started to explore the implications of that crossover. There is a lot of potential.

Lastly, I’ve found myself very heavily invested in artistic pursuits, primarily photography. I think it’s important for any game developer (or any entertainment industry professional at all) to nurture their creative/artistic side as much as possible. You don’t have to be good at it, but you can’t neglect it. I picked photography because I’m terrible at drawing, and because I hoped it would clarify a lot of things I’ve never understood in graphics engineering. (It did.) It’s now a pursuit of mine in its own right, and I intend to be writing a lot about it.

Lastly, I want to thank all half dozen people who are actually reading this post. You guys are nuts and I’ve wasted your time, but I promise better things are coming down the pipeline. I am working to finish an epic post detailing the basics of digital color representation. I can almost guarantee you’ll learn something.

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