Promit's Ventspace

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:

http://www.joystiq.com/2013/03/28/igda-party-features-dancers-prompts-controversy-resignations/

http://www.joystiq.com/2013/04/09/igda-defines-new-rules-for-future-industry-parties-after-gdc-mi/

http://yetizen.com/2013/03/30/official-statement-by-the-yetizen-ceo-on-the-yetizen-igda-gdc-party/2/

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.

April 2, 2013

A Glimpse of What I’m Working On

Filed under: Graphics — Promit @ 12:32 am

I’ve decided to focus a little less on complaining and a little more on the actual work I do. Here’s a teaser:
Monitor array
I had a substantial amount of help with the over-water environmental rendering (not pictured) from a friend of mine, Nauful Shaikh. See his site for some great graphics work.

This wall of monitors was graciously made available to us by the Computer Science department for a presentation to the President of the University as well as a healthy mix of department chairs from Neuroscience, Neurology, Brain Sciences Institute, Computer Science, and Electrical/Computer Engineering at Johns Hopkins. I’m driving it at 60fps off a single 7970 in Eyefinity 6. It was supposed to be Crossfire but somebody’s driver is broken *cough cough* so I had to gut the render pipeline somewhat. Total resolution is 5760×2160 plus some margins for bezel compensation. The actual app is Kinect and PS Move enabled, and maybe I can share more about it this summer. The focus is a dolphin which we’ve developed with significant help and guidance from the National Aquarium in Baltimore, who let us work directly with their dolphins to better understand the animals, how they move and think, etc.

We’re planning to launch an iPad version this year on the iTunes App Store, and create a large scale interactive installation version for aquariums, hospitals, museums and similar at 4K resolution in stereoscopic 3D.

January 31, 2013

Follow-up on DirectX/XNA

Filed under: Graphics,SlimDX — Promit @ 5:45 pm

Received today, and hopefully the “you can quote me” part means this is an exception to NDA because it’s important:

The message said “DirectX is no longer evolving as a technology.” That is definitely not true in any way, shape or form. Microsoft is actively investing in DirectX as the unified graphics foundation for our key platforms, including Xbox 360, Windows Phone and Windows. DirectX is evolving and will continue to evolve. For instance, right now we’re investing in some very cool graphics code authorizing [sic] technology in Visual Studio. We have absolutely no intention of stopping innovation with DirectX, and you can quote me on that. :)

My intent was not to start a firestorm of questioning on DirectX’s future viability, and I said up-front that I felt that communication was poorly worded with regards to intent. My frustrations were also apparently poorly worded. Since I accidentally launched this, let’s clear up a few things.

Number One: In the absolute (and implausible) worst case scenario that MS really scales back their Direct3D support to a minimum, that situation is still better than OpenGL. The Direct3D system is a technically superior piece of technology, and support for working with it is still better than OpenGL whether you’re a hobbyist or a pro. I cannot emphasize this point enough, so for the love of god stop bringing up OpenGL. It’s a badly designed API and has been since I started doing this in 2000.
Number Two: A new picture is coming into focus that shifts a lot of the DirectX SDK’s burden onto VS. This hasn’t been made previously clear to us on the MVP side. As I’ve begun to explore the tools already inside VS 2012, I like what I’m seeing. It’ll take some time to see how it all plays out, but in a very real way having Direct3D integrated into core VS development is a serious promotion.
Number Three: There’s more content in today’s email regarding XNA which I don’t care to share, thanks to a stern NDA reminder. (Ironically, when MS finally gives us what they should be saying to the public all along, I can’t share it.) But this is very much a case of “put up or shut up” and defending XNA’s status as a serious technology seems patently ridiculous to me right now. The community, whether it’s my work or someone else’s, has stepped in to integrate .NET and DirectX for many wonderful use cases. But there are things we can’t do (like Xbox) and it’s clear that matters to a lot of people. It’s not clear that it matters to Microsoft.

That said, I am not walking back my actual complaints about how DirectX and XNA are being handled. I like the work that’s been done in integrating VS and DirectX, which is arguably many years overdue. That doesn’t make everything else okay. The fact that we’re having this discussion, the fact that my dashed off blog post exploded on Twitter, the fact that clarification had to be written up behind the scenes — this is a problem. Which brings me at long last to the actual point I was trying to make yesterday:

As developers, we need Microsoft to communicate clearly with us, in public. As MVPs we were asked to act as community representatives, to guide everyone interested in the tech and have an open line on future development. Apparently that means we get half-hearted vague emails from time to time that dodges our serious questions and casts further doubts about the status of the technology and teams, all covered by an NDA agreement. And then, shockingly enough, people get the wrong idea. We’re sitting on the outside, trying to play this stupid guessing game of “which Microsoft technology is alive?” XNA doesn’t support DirectX 10+ or Windows 8, but it’s still a “supported product”, as if that means anything in the real world. Windows XP is still a “supported product” too.

It shouldn’t take a leaked email to force a straight answer.

January 30, 2013

DirectX/XNA Phase Out Continues

Filed under: Graphics,SlimDX — Promit @ 12:50 pm


Please read the follow up post.

This email was sent out to DirectX/XNA MVPs today:

The XNA/DirectX expertise was created to recognize community leaders who focused on XNA Game Studio and/or DirectX development. Presently the XNA Game Studio is not in active development and DirectX is no longer evolving as a technology. Given the status within each technology, further value and engagement cannot be offered to the MVP community. As a result, effective April 1, 2014 XNA/DirectX will be fully retired from the MVP Award Program.

There’s actually a fair bit of information packed in there, and I think some of it is poorly worded. The most stunning part of it was this: “DirectX is no longer evolving as a technology.” That is a phrase I did not expect to hear from Microsoft. Before going to “the sky is falling” proclamations, I don’t think this is a death sentence for DirectX, per se. It conveys two things. Number one, DirectX outside of Direct3D is completely dead. I hope this is not a shock to you. Number two, it’s a reminder that Direct3D has been absorbed into Windows core, and thus is no more a “technology” than GDI or Winsock.

Like I said, poorly worded.

There are a few other things packed in there. XNA Game Studio is finished. That situation has been obvious for years now, so it also should not really come as a surprise either. And finally the critical point for me: our “MVP” role as community representatives and assistants is appreciated but no longer necessary. On this point, the writing has been on the wall for some time and so I should not be surprised. But I am. Maybe dismayed is a better word.

As I’ve said previously, I don’t feel that the way DirectX has been handled in recent years has been a positive thing. A number of technical decisions were made that were unfortunate, and then a number of business and marketing type decisions were made that compounded the problem. Many of the technologies (DirectInput, DirectSound, DirectShow) have splayed into a mess of intersecting fragments intended to replace them. The amount of developer support for Direct3D from Microsoft has been unsatisfactory, and anecdotal reports of internal team status have not been promising. Somebody told me a year or two back that the HLSL compiler team was one person. That’s not something you want to hear, true or not. Worst of all, though, was the communication. That’s the part that bugs me.

When you are in charge of a platform, whatever that platform may be, developers invest in your platform tech. That’s time and money spent, and opportunity costs lost elsewhere. This is an expected aspect of software development. As developers and managers, we want as much information as possible in order to make the best short and long term decisions on what to invest in. We don’t want to rewrite our systems from scratch every few years. We don’t want to fall behind competitors due to platform limitations. Navigating these pitfalls is crucial to survival for us. Microsoft has a vested interest in some level of non-disclosure and secrecy about what they’re doing. All companies do. I understand that. But some back and forth is necessary in order for the relationship to be productive.

Look at XNA — there have been a variety of questions surrounding it for years, about the extent to which the technology and its associated marketplace were going to be taken seriously and forward into the future. It is clear at this juncture that there was no future and the tech was being phased out. Direct3D 10 was launched in late 2006, a bit over six years ago, yet XNA was apparently never going to be brought along with the major improvements in DWM and Direct3D. How long was it known internally at Microsoft that XNA was a dead-end? How many people would’ve passed over XNA if MS had admitted circa 2008 (or even 2010, when 4.0 was released) that there was no future for the tech? The official response, of course, was always something vague and generic: “XNA is a supported technology.” That means nothing in Microsoft world, because “it will continue to work in its current state for a while” is not a viable way for developers to stay current with their competition.

Just to be clear, I don’t attribute any of this fumbling to malice or bad faith. There’s a lot of evidence that this type of behavior is merely a delayed reflection of internal forces at Microsoft which are wreaking havoc on the company’s ability to compete in any space. But the simple ground truth is that we’re entering an era where Windows’ domination is openly in question, and a lot of us have the flexibility and inclination to choose between a range of platforms, whether those platforms are personal computers, game consoles, or mobile devices. Microsoft’s offer in that world is lock-in to Windows, in exchange for powerful integrated platforms like .NET which are far more capable than their competitors (eg Java, which is just pathetic). That was an excellent trade-off for many years. Looking back now, though? The Windows tech hegemony is a graveyard. XNA. Silverlight. WPF. DirectX. Managed C++. C++/CLI. Managed DirectX. Visual Basic. So when you guys come knocking and ask us to commit to Metro — sorry, the Windows 8 User Experience — and its associated tech?

You’ll understand if I am not in a hurry to start coding for your newest framework.

Before things get out of hand: No, you should not switch to OpenGL. I get to use it professionally every day and it sucks. Direct3D 11 with the Win8 SDK is a perfectly viable choice, much more so than OpenGL for high end development. None of the contents of my frequent complaints should imply in any way that OpenGL is a good thing.

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.

October 9, 2012

Gamma FAQ

Filed under: Graphics — Promit @ 5:22 pm

I am working on Part 2 of my Digital Color posts, but it won’t be ready for a while yet. The goal of that post is to talk all about luminance, brightness, gamma, and the various other attributes and properties of how light a color is, rather than what shade it is.

In the meantime, please accept my apology and consider reading this page I found: the Gamma FAQ by Charles Poynton.

October 8, 2012

C++-JSON Serialization

Filed under: Software Engineering — Promit @ 2:40 pm

I’ve decided to share some code today, just because I’m such a nice guy. Those of you who enjoy the more perverse ways to apply C++ tricks will enjoy this. Those who prefer simpler, more primitive approaches (that’s not a bad thing) may not appreciate this creation as much. What I’ve got here is a utility class that makes it fairly straightforward to serialize C++ objects to and from JSON using the generally decent JsonCpp library. Hierarchies are properly saved and loaded with no real effort. It works well for us, and probably has plenty of limitations too. Maybe some of you out there will find it useful. It seems to be difficult to find decent serialization code that isn’t also somehow awful to use.

This lives in a single file, but the bad news is it takes boost dependencies in order to get type traits. I think everything I’m using from boost is added to C++ core as of TR1, but I haven’t checked. It also depends on JsonCpp, but changing it over to use other JSON, XML, binary, etc libraries shouldn’t be terribly difficult. I don’t know how this compares to other serialization libraries, but boost::serialization sounded like a train-wreck so I wrote my own.

Let’s cover usage first. Generally speaking, you’ll simply add a member function to a structure that declares the members to be serialized (free functions are allowed too). Each declaration is a string name for the value, and the variable to be serialized under that value. There’s a few macros to combine those via preprocessor. Values can also be read-only or write-only serialized. The serializer is able to traverse vectors and structures, and will produce nicely structured JSON. Here’s a sample:

void Serialize(Vector3D& vec, JsonSerializer& s)
{
	//each Vector3D is written as an array
	s.Serialize(0, vec.x);
	s.Serialize(1, vec.y);
	s.Serialize(2, vec.z);
}

struct PathSave {

	bool LeftWall;
	bool RightWall;
	float LeftWallHeight;
	float RightWallHeight;

	vector<Vector3D>	c_Center,
				c_Left,
				c_Right;

	vector<int> hitPillarSingle_type;
	vector<struct PCC> hitPillarSingle_pcc;
	vector<Vector3D> hitPillarSingle_hh;

	int pathPointDensity;
	int pillarNum;
	
	void Serialize(JsonSerializer& s)
	{
		s.SerializeNVP(LeftWall);
		s.SerializeNVP(RightWall);
		s.SerializeNVP(LeftWallHeight);
		s.SerializeNVP(RightWallHeight);
		
		s.Serialize("Center", c_Center);
		s.Serialize("Left", c_Left);
		s.Serialize("Right", c_Right);
		
		s.SerializeNVP(hitPillarSingle_pcc);
		s.SerializeNVP(hitPillarSingle_hh);
		s.SerializeNVP(hitPillarSingle_type);
		
		s.WriteOnly(NVP(pathPointDensity));
		s.ReadOnly(NVP(pillarNum));
	}
};

void SaveToFile(PathSave& path)
{
	JsonSerializer s(true);
	path.Serialize(s);
	std::string styled = s.JsonValue.toStyledString();
	printf("Saved data:\n%s\n", styled.c_str());
}

bool LoadFromFile(const char* filename, PathSave& path)
{
	std::string levelJson;
	bool result = PlatformHelp::ReadDocument(filename, levelJson);
	if(!result)
		return false;

	JsonSerializer s(false);
	Json::Reader jsonReader;
	bool parse = jsonReader.parse(levelJson, s.JsonValue);
	if(!parse)
		return false;
	
	path.Serialize(s);
	return true;
}

And that will generally produce something that looks like this:

{
    "LeftWall" : true,
    "LeftWallHeight" : 4.50,
    "RightWall" : true,
    "RightWallHeight" : 4.50,
    "Center" : [
    [ 0.05266714096069336, 0.0, -15.13085746765137 ],
    [ 0.1941599696874619, 0.0, 1.553306341171265 ],
    [ 0.5984783172607422, 0.0, 50.54330444335938 ]
    ],
    "Left" : [
    [ -10.44694328308105, 0.0, -15.04044914245605 ],
    [ -15.55506420135498, 0.0, 1.709598302841187 ],
    [ -8.466680526733398, 2.896430828513985e-07, 42.68054962158203 ]
    ],
    "Right" : [
    [ 10.55227851867676, 0.0, -15.22126579284668 ],
    [ 15.94338321685791, 0.0, 1.397014379501343 ],
    [ 9.663637161254883, -1.829234150818593e-07, 58.40605926513672 ]
    ],
    "hitPillarSingle_hh" : null,
    "hitPillarSingle_pcc" : null,
    "hitPillarSingle_type" : null,
    "pathPointDensity" : 24,
    "pillarNum" : 0,
}

Now I happen to think that’s fairly tidy, as far as C++ serialization goes. Symmetry is maintained between read and write steps, and there’s very little in the way of syntax magic. I do have a few macros in there (the stuff that says NVP), but they’re optional and I find that they clean things up. Now shield your eyes, because here is the actual implementation.

/*
 * Copyright (c) 2011-2012 Promit Roy
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#ifndef JSONSERIALIZER_H
#define JSONSERIALIZER_H

#include <json/json.hpp>
#include <boost/utility.hpp>
#include <boost/type_traits.hpp>
#include <string>

class JsonSerializer
{
private:
	//SFINAE garbage to detect whether a type has a Serialize member
	typedef char SerializeNotFound;
	struct SerializeFound { char x[2]; };
	struct SerializeFoundStatic { char x[3]; };
	
	template<typename T, void (T::*)(JsonSerializer&)>
	struct SerializeTester { };
	template<typename T, void(*)(JsonSerializer&)>
	struct SerializeTesterStatic { };
	template<typename T>
	static SerializeFound SerializeTest(SerializeTester<T, &T::Serialize>*);
	template<typename T>
	static SerializeFoundStatic SerializeTest(SerializeTesterStatic<T, &T::Serialize>*);
	template<typename T>
	static SerializeNotFound SerializeTest(...);
	
	template<typename T>
	struct HasSerialize
	{
		static const bool value = sizeof(SerializeTest<T>(0)) == sizeof(SerializeFound);
	};
	
	//Serialize using a free function defined for the type (default fallback)
	template<typename TValue>
	void SerializeImpl(TValue& value,
						typename boost::disable_if<HasSerialize<TValue> >::type* dummy = 0)
	{
		//prototype for the serialize free function, so we will get a link error if it's missing
		//this way we don't need a header with all the serialize functions for misc types (eg math)
		void Serialize(TValue&, JsonSerializer&);
		
		Serialize(value, *this);
	}

	//Serialize using a member function Serialize(JsonSerializer&)
	template<typename TValue>
	void SerializeImpl(TValue& value, typename boost::enable_if<HasSerialize<TValue> >::type* dummy = 0)
	{
		value.Serialize(*this);
	}
	
public:
	JsonSerializer(bool isWriter)
	: IsWriter(isWriter)
	{ }
	
	template<typename TKey, typename TValue>
	void Serialize(TKey key, TValue& value, typename boost::enable_if<boost::is_class<TValue> >::type* dummy = 0)
	{
		JsonSerializer subVal(IsWriter);
		if(!IsWriter)
			subVal.JsonValue = JsonValue[key];
		
		subVal.SerializeImpl(value);
		
		if(IsWriter)
			JsonValue[key] = subVal.JsonValue;
	}
		
	//Serialize a string value
	template<typename TKey>
	void Serialize(TKey key, std::string& value)
	{
		if(IsWriter)
			Write(key, value);
		else
			Read(key, value);
	}
	
	//Serialize a non class type directly using JsonCpp
	template<typename TKey, typename TValue>
	void Serialize(TKey key, TValue& value, typename boost::enable_if<boost::is_fundamental<TValue> >::type* dummy = 0)
	{
		if(IsWriter)
			Write(key, value);
		else
			Read(key, value);
	}
	
	//Serialize an enum type to JsonCpp 
	template<typename TKey, typename TEnum>
	void Serialize(TKey key, TEnum& value, typename boost::enable_if<boost::is_enum<TEnum> >::type* dummy = 0)
	{
		int ival = (int) value;
		if(IsWriter)
		{
			Write(key, ival);
		}
		else
		{
			Read(key, ival);
			value = (TEnum) ival;
		}
	}
	
	//Serialize only when writing (saving), useful for r-values
	template<typename TKey, typename TValue>
	void WriteOnly(TKey key, TValue value, typename boost::enable_if<boost::is_fundamental<TValue> >::type* dummy = 0)
	{
		if(IsWriter)
			Write(key, value);
	}
	
	//Serialize a series of items by start and end iterators
	template<typename TKey, typename TItor>
	void WriteOnly(TKey key, TItor first, TItor last)
	{
		if(!IsWriter)
			return;
		
		JsonSerializer subVal(IsWriter);
		int index = 0;
		for(TItor it = first; it != last; ++it)
		{
			subVal.Serialize(index, *it);
			++index;
		}
		JsonValue[key] = subVal.JsonValue;
	}
	
	template<typename TKey, typename TValue>
	void ReadOnly(TKey key, TValue& value, typename boost::enable_if<boost::is_fundamental<TValue> >::type* dummy = 0)
	{
		if(!IsWriter)
			Read(key, value);
	}

	template<typename TValue>
	void ReadOnly(std::vector<TValue>& vec)
	{
		if(IsWriter)
			return;
		if(!JsonValue.isArray())
			return;
		
		vec.clear();
		vec.reserve(vec.size() + JsonValue.size());
		for(int i = 0; i < JsonValue.size(); ++i)
		{
			TValue val;
			Serialize(i, val);
			vec.push_back(val);
		}
	}
	
	template<typename TKey, typename TValue>
	void Serialize(TKey key, std::vector<TValue>& vec)
	{
		if(IsWriter)
		{
			WriteOnly(key, vec.begin(), vec.end());
		}
		else
		{
			JsonSerializer subVal(IsWriter);
			subVal.JsonValue = JsonValue[key];
			subVal.ReadOnly(vec);
		}
	}
	
	//Append a Json::Value directly
	template<typename TKey>
	void WriteOnly(TKey key, const Json::Value& value)
	{
		Write(key, value);
	}
	
	//Forward a pointer
	template<typename TKey, typename TValue>
	void Serialize(TKey key, TValue* value, typename boost::disable_if<boost::is_fundamental<TValue> >::type* dummy = 0)
	{
		Serialize(key, *value);
	}
	
	template<typename TKey, typename TValue>
	void WriteOnly(TKey key, TValue* value, typename boost::disable_if<boost::is_fundamental<TValue> >::type* dummy = 0)
	{
		Serialize(key, *value);
	}
	
	template<typename TKey, typename TValue>
	void ReadOnly(TKey key, TValue* value, typename boost::disable_if<boost::is_fundamental<TValue> >::type* dummy = 0)
	{
		ReadOnly(key, *value);
	}
	
	//Shorthand operator to serialize
	template<typename TKey, typename TValue>
	void operator()(TKey key, TValue& value)
	{
		Serialize(key, value);
	}
	
	Json::Value JsonValue;
	bool IsWriter;
	
private:
	template<typename TKey, typename TValue>
	void Write(TKey key, TValue value)
	{
		JsonValue[key] = value;
	}
				  
	template<typename TKey, typename TValue>
	void Read(TKey key, TValue& value, typename boost::enable_if<boost::is_arithmetic<TValue> >::type* dummy = 0)
	{
		int ival = JsonValue[key].asInt();
		value = (TValue) ival;
	}
	
	template<typename TKey>
	void Read(TKey key, bool& value)
	{
		value = JsonValue[key].asBool();
	}
	
	template<typename TKey>
	void Read(TKey key, int& value)
	{
		value = JsonValue[key].asInt();
	}
	
	template<typename TKey>
	void Read(TKey key, unsigned int& value)
	{
		value = JsonValue[key].asUInt();
	}
	
	template<typename TKey>
	void Read(TKey key, float& value)
	{
		value = JsonValue[key].asFloat();
	}
	
	template<typename TKey>
	void Read(TKey key, double& value)
	{
		value = JsonValue[key].asDouble();
	}
	
	template<typename TKey>
	void Read(TKey key, std::string& value)
	{
		value = JsonValue[key].asString();
	}
};

//"name value pair", derived from boost::serialization terminology
#define NVP(name) #name, name
#define SerializeNVP(name) Serialize(NVP(name))

#endif

Now that’s not so bad, is it? A bit under three hundred lines of type traits and template games and we’re ready to get on with our lives. A lot of the code is just fussing about what type it’s being applied to and drilling down to the correct read or write function. The SFINAE based block at the top of the class is used to locate the correct Serialize function for any given type, which can be an instance member function, static member function, or free function.

There is your free C++ to JSON serializer utility class for the day, complete with ultra permissive license. Enjoy.

September 11, 2012

Cinematic Color

Filed under: Graphics,Photography — Promit @ 3:32 pm
Tags: , ,

I chose not to go to SIGGRAPH 2012, and I’m starting to wish I had. Via Julien Guertault, I found the course on Cinematic Color.

I’ve mentioned this in the past: I believe that as a graphics programmer, a thorough understanding of photography and cinematography through the entire production pipeline is necessary. Apparently I am not alone in this regard. Interesting corollary: should cinematographers understand computer graphics? Hmm.

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