int numbers[5] = { 1, 2, 3, 4, 5 };
for (int i = 0; i < 5; i++) {
    std::cout << "Number " << i << ": " << *(numbers+i) << std::endl;
}

This will print out all the numbers of the array. And just to mention it – this is equivalent to:

int numbers[5] = { 1, 2, 3, 4, 5 };
for (int i = 0; i < 5; i++) {
    std::cout << "Number " << i << ": " << numbers[i] << std::endl;
}

It turns out that the array-operator [] performs the pointer arithmetic and the dereferencing under the hood and simply "looks nicer".

While this example may look straight-forward to you, how about the next one?

int* a = new int(33554432);
int** b = &a;

**b++;   // 1) changes the value of a?
**(b++); // 2) changes the value of a?
*(*b++); // 3) changes the value of a?
*(*b)++; // 4) changes the value of a?
(**b)++; // 5) changes the value of a?

Okay, why would somebody do something like that? Well, a very common practice is to use pointers to pointers in methods to let the caller decide where to store the calculated data of the method. Don't ask me why this pattern has become so popular... Probably they just didn't know better some years ago (or they wanted to make sure nobody will get their jobs later ).

Anyways what's the solution to the example above? Which statement actually changes the value of a? Let's look at the statements one-by-one:

The statements 1, 2 and 3 do not change the value of a but they change the location b points to! Statements 1, 2 and 3 are equivalent which is a result of how C++ binds the operators. In these cases the pointer location gets incremented by 8 bits, but this number depends on the size of a pointer (32bit / 64bit machine). If we are unlucky we end up pointing to somewhere ... let's say not pointing to a anymore! So you do not want to use that arithmetic at all!

Statement 4 increments the pointer of a, meaning the address variable a points to, but not actually the value of a. You can use this arithmetic if a was an array and you need to iterate of the array that was given by the address b. This is a very useful case even though I would recommend you do not to fool other people by reading these lines of code! You could simply hand in a copy of the reference pointing to the array instead, which makes it much more easier to read!

Statement 5 finally changes the value of a and if a was an array of ints it would change the value of the first element of the array.

As you can see pointers can easily confuse the readers of your code (and you are also a reader of your own code!). I don't say that you should not use them to tweak up your programs but I advice you to take care of your pointers. Better think twice before using pointers in such ways...

To understand them, we have to look at the header and implementation files separately. Let’s start with the base (abstract) class header file:

class AbstractBaseClass {
public:
    AbstractBaseClass();
    ~AbstractBaseClass();

    virtual void printMe();
    virtual int getNumber() = 0;
};

The important thing here is that you will have to declare the abstract methods as virtual and assign them a 0 (Null Pointer). The class itself does not have any special declarations itself. So in the example above we have one abstract function (getNumber()) which makes our class to be abstract!

Within the implementation file you leave out all virtual functions that were assigned the null pointer (0):

AbstractBaseClass::AbstractBaseClass() {}
AbstractBaseClass::~AbstractBaseClass() {}
void AbstractBaseClass::printMe() {
    std::cout < < "My number is: " << getNumber() << std::endl;
}

Now, let’s take a look into the header file of an inherited class:

class ConcreteClass : public AbstractBaseClass {
public:
    ConcreteClass();
    ~ConcreteClass();

    virtual int getNumber();
};

It is important to know that you will have to redeclare the function without assigning the null pointer within the header file! Otherwise the compiler will throw an exception whenever you try to instantiate a object of the concrete type!

The implementation file is straight-forward:

ConcreteClass::ConcreteClass() {}
ConcreteClass::~ConcreteClass() {}
int ConcreteClass::getNumber() {
    return 1;
}

To use you concrete class you will have to create it using its own constructor. If you simply want to work with the interface (the abstract base class) then you will have to cast the newly created instance before assigning it to a pointer variable:

AbstractBaseClass* ref = (AbstractBaseClass*) new ConcreteClass();

PS: Keep in mind that polymorphism in C++ only works with pointer variables!

I wanted to use my iPhone compatible headset with my MacBook Pro (mid 2010) but had to experience a big echo effect. The headset makes use of the two channels by using one for the microphone and both for the playback. Therefore, you record all you are listening to which results in an echo.

iChat, Skype and co. are filtering this echo automatically, but unfortunately the teamspeak client (3.0.0_36beta for MacOSX) does not. But you can help yourself until they are fixing the problem by installing the Soundflower Application. This will help you to configure new virtual sound devices that you can configure yourself. The next section of this article will show how to configure two sound devices to use with iPhone compatible headsets.

1. Installing Soundflower

The installation of Soundflower is straigh forward and does not need any explaination. Just download and install the way you are used to install software on your Mac.

2. Start Soundflower / Configure new virtual sound devices

In order to configure new virtual sound devices you need to start the Soundflowerbed application that is shipped with the Soundflower installation package and will be installation to your Applications folder. So open Spotlight, type “Soundflowerbed” and start it.

After starting you will find a small flower icon in your toolbar. Left-click it and select “Audio Setup…” from the context menu. In the new dialog click the “plus” icon to create a new virtual device and name it “Headset Input”. After that click on the “Headset Input” device and activate the checkbox for the internal microphone on the right side (see figure 1).

Create a new virtual sound device and activate the checkbox for the internal microphone.

Now we are almost done but we have only created a virtual device for the internal input. So here comes the trick: Open the extended configuration of the “Headset Input” device by clicking the small arrow icon in front of the name of the device. This will open the subconfiguration in which you click on “Internal Microphone”. Now use the slider for the first channel to mute it, i.e. set the value of channel 1 to zero (see figure 2). Do not use the mute checkbox as this will mute the whole input (don’t know why). Now we are finally done.

Mute the first channel of the new virtual sound device to remove echo effects when using e.g. the teamspeak client.

3. Start teamspeak and use the new device for input

Go back to teamspeak and set the new virtual device as your input device and everything will work as exspected. Enjoy.

And the very nice follow-up e-mail I got contained this radar picture:

Although the title is English the actual thesis is written in German (sorry about that). Interested readers may want to have a look at the work: Bachelor Thesis: Rendering Octree managed Voxel Volumes.

Technical specification

1. Processor: ARM 9
2. Screen: 96×18 OLED Display
3. Camera: High speed infrared camera (over 70 images/sec)
4. 2GB NAND (over 200h recording time) (depends on audio quality)
5. Battery: 300 mAh rechargeable lithium (unfortunately NON-removable)
6. Embedded microphone: Mono recording
7. Headset microphone: 3-D recording, binaural or stereo recording
8. Playback: Embedded speaker or audio jack (2.5mm)
9. USB mobile charging cradle
10. Size: 15.5cm length, 1.5cm width
11. Weight: 36g

More details can be viewed on the Livescribe website at: http://www.livescribe.com/smartpen/techspecs.html

The first steps

The Smartpen comes with a software “Livescribe Desktop” for Microsoft Windows and Apple’s Mac OS. I installed both, the Windows version within a VMWare image and the Mac OS version native.

After the setup i plugged in the pen and the first thing happened a messages pop up telling me there is a newer software version for the Smartpen. Very cool! I clicked update and it… well the update failed on Mac OS! There is no progress bar and no indicator if the update is still running. After 1h I stopped it and tried to restart the procedure. This failed on Mac OS and the stick didn’t work with voice recording. I booted up the Windows again and tried the flash update from there and i worked fine! For me it seems that the Mac OS version of Livescribe Desktop is still in development and not yet final.

Finally the update was successful and I progressed with the first example sheet from Livescribe. This sheet is a little how-to guide showing the functionality of the pen. This is very straight forward. Nicely done!

After that I started writing my first own sheet and tried the MyScript for Livescribe. This is a OCR for handwriting and it is extreme exact! I was surprised by the results of the OCR. It internally works with a dictionary and matches all words with it. Therefore it is necessary to install the dictionary of the language you are writing in. You can add any language at any time after the installation.

I am very happy with this investigation. I will try to give a short summery in pros and contras:

Pros

• Based on Java technology
• Intelligent system
• Links voice to the written text
• Voice replay by clicking on the text
• Easily transfers notes to PC/Mac
• Note management, use of different notebooks (1-8)
• Notebooks can be printed with postscript ready laser printer
• Battery time is great

Contra

• Notebooks are expensive
• Mac software seems to be a beta release
• Flash Update fails on Mac
• A native Mac software would be great

Hints

If you do not have a PostScript ready printer you can download the notebooks 1-4 as PDF files. Have a look at the Livescribe forum. There is an topic with download links for the PDF and PS files.

Step-by-step guide

Installation of MacTeX

This is a real straight forward process. Go to http://www.tug.org/mactex and download the latest release of MacTeX. Run the installer and you are done. Cool, isn’t it?

Installation of eclipse

Umm, no, I will not give any attention to that point here.
Simply point your browser to: http://www.eclipse.org/downloads/packages/. This is as easy as installtion MacTeX, so you won’t have any troubles here…

Installation of TeXlipse

After adding the eclipse update site for TeXlipse (http://texlipse.sourceforge.net) I started the automatic installer. It took some time to get all the dependencies resolved, but the tricky part was the configuration of the plugin after the recommended restart. If you need a step-by-step guide for this, please go to http://texlipse.sourceforge.net/manual/installation.html where you will find a in-detail description about the installation process.

Configuration of TeXlipse

Now the very tricky part. After eclipse has restarted open the configuration (CMD+,) and open the section about Texlipse. You will need to change the Builder and Viewer Settings.

Builder Settings

The plugin will manage the settings for you if you enter a valid binary path to all latex tools. Installing MacTeX will put them into the following folder: /usr/local/texlive/2008/bin/universal-darwin. The first time I configured the settings didn’t become active. I had to manually browse to /Library/TeX/Distributions/TeXLive-2008.texdist/Contents/Programs/i386.
After that press the apply button and the configuration will search for the tools in this path and when it finds it, save their path regardless.

Viewer Settings

I wanted the preview to open up in the preview. There are two advantages for that: First the preview is a very small program without wasting lots of resources on the system. Second whenever you save a file in eclipse the builder will recompile the pdf and by reactivating the preview it automatically refreshes the content and stays at the page you where viewing before. To configure this open the Viewer Settings section and click on acroread. Use the button Up until it is the first entry. Click on the button Edit and enter “/usr/bin/open” as the viewer command. Keep “%file” as the viewer arguments and the default system viewer will be started to show the pdf (this is the preview in my case). You may also want to configure the preview exclusive (if it isn’t your default viewer). Then simple change the viewer arguments to “-a /Applications/Preview.app %file” and you’re done.

Done

Now you’re done. Enjoy using TeXlipse on your Mac.

Besides this, the game has no limitations, so you will have all the joy and fun with this version, too.

Download

ScrapMetalRacer Single Player Only Setup ZIP archive file

MD5: c35b50777a5bc083e0ccd9787a7948f0
SHA1: c0dac9f1f2f1bdbcb7956a7a3defd7805961560d
SHA512:
2e0ec0df3bd87388ebe91013140fac49
97b95b8f37b9c25bb0b962803c248d8
6354901d10fa9536a2df7a0853dfa3f2f
342b934b585973e1ff7926f97607a8d3

Screenshots

• Welcome Screen
• Vehicle Selection
• Track Selection
• Gameplay 01
• Gameplay 02
• Gameplay 03
• Gameplay 04
• Gameplay 05
• Gameplay 06
• Gameplay 07
• Gameplay 08
• Gameplay 09
• Gameplay 10
• Gameplay 11

The controls

Keyboard

Arrows: Acceleration (up), break (down) and stearing (left/right)
ESC: Pause (single player only), options menu and exit race
F11: Toggle BlinnPhong / DeferredShading
F12: Change scenario

Gamepad

Left thumb stick: stearing (left/right)
Right throttle: Acceleration
Left throttle: Break

Features

Here is a full list of the features:

• 4 racers
• 9 tracks
• 11 scenarios
• keyboard/gamepad controls
• minimap deactivatable
• toggle fullscreen
• 2 lighting modes: BlinnPhong & DeferredShading
• Normal Mapping
• Normal Mode (draws the colorized normal vectors)
• Filter effects: Blackwhite, Sepia, Negative
• Additional properties for BlinnPhong lighting:
  • Fillmode: solid or wireframe
  • MotionBlur effect
  • Bloom effect
• Additional properties for Deferred Shading:
  • Shadow Mapping

We wish you a lot of fun while playing and hope you enjoy the game!

Stefan & Kai-Marian

PS: Please leave us a comment or criticism on the comment area of this post. We will need your input to advance the game. Thank you!

We are currently testing the release and if you want to help us testing, feel free to download and install the first version of the racer. There are still some limitations that we are about to fix in the meantime, e.g. the screen resolution cannot be changed from 1024×768.

Download

(updated February, 16th 2010)
ScrapMetalRacer Setup ZIP archive file

MD5: 1fb7fcbb823fdfcc2bcbfd0cc9daa196
SHA1: 7e28370757aeea9410958a1108d452ac24c12d9d
SHA512:
6325e1e1aab3c33d804a20557870462e
91e1b3169775314303f1182482977e5e
673a22ce6b01572aab45462c63bf4e78b
e1989dd9ef7b821ed9039efd38ba0df

Microsoft XNA Game Studio 3.1

From Microsoft’s XNA website
(necessary in order to run the game)

Screenshots

• Welcome Screen
• Vehicle Selection
• Track Selection
• Gameplay 01
• Gameplay 02
• Gameplay 03
• Gameplay 04
• Gameplay 05
• Gameplay 06
• Gameplay 07
• Gameplay 08
• Gameplay 09
• Gameplay 10
• Gameplay 11

The controls

Keyboard

Arrows: Acceleration (up), break (down) and stearing (left/right)
ESC: Pause (single player only), options menu and exit race
F11: Toggle BlinnPhong / DeferredShading
F12: Change scenario

Gamepad

Left thumb stick: stearing (left/right)
Right throttle: Acceleration
Left throttle: Break

Features

Here is a full list of the features:

• 4 racers
• 9 tracks
• 11 scenarios
• keyboard/gamepad controls
• minimap deactivatable
• toggle fullscreen
• 2 lighting modes: BlinnPhong & DeferredShading
• Normal Mapping
• Normal Mode (draws the colorized normal vectors)
• Filter effects: Blackwhite, Sepia, Negative
• Additional properties for BlinnPhong lighting:
  • Fillmode: solid or wireframe
  • MotionBlur effect
  • Bloom effect
• Additional properties for Deferred Shading:
  • Shadow Mapping

We wish you a lot of fun while playing and hope you enjoy the game!

Stefan & Kai-Marian

PS: Please leave us a comment or criticism on the comment area of this post. We will need your input to advance the game. Thank you!

Welcome in 20.10!

So I searched the web and finally came to the website http://www.dreamspark.com. As a student you can log in with your Windows Live! account and get verified. You are then allowed to receive a trial code that will give you a trial membership for the XNA Creators Club… very cool!

So here are the steps to request your own trial membership:

1. Create a Windows Live! account, if you don’t have one.
2. Go to the website http://www.dreamspark.com
3. Click on the XNA Game Studio Link
4. Sign in with your Windows Live! account
5. Get verified: Select your university and click on continue. This step depends on the university you are matriculated to, so I cannot go in detail here. Please follow the screen information.
6. Very IMPORTANT: Click on the button “GET KEY” on the download page and copy your trial code
7. Now you can switch to http://creators.xna.com
8. Login with your Windows Live! account
9. Step forward to http://creators.xna.com/en-US/membership
10. Search for the link “Signup for your premium membership” and click it (see step 4 on the website)
11. Select the option “Code einlösen” or “Submit code” in English and continue.
12. Enter your trial code from step 6 and go on.
13. You have a one year free XNA Creators Club Trial Membership right now. See your profile at http://creators.xna.com for your membership state and have fun.

Additional I made some screenshot which you can view in the gallery below.

Hope this helps! Enjoy your trial membership.

After some hours of work I had the model done. Feeling fine I tried to put a texture on the model. All of a sudden a cold shower ran down my neck. The texture mapping was very strange and I had to remap all the UV coordinates for the whole model. Hours later I finished like this:

As this is my first blender model I lay back and feel fine now, but I think there is still a lot of work until it looks as pretty as it does in the movies… Maybe next time.

You can download the animation and have a quick lock in my work. At this place, special thanks to JHT for the great Planetary Pixel Emporium where I found all the textures!

Here is the download:
Solar System Animation Setup

You can control the animation by the following mouse / keyboard actions:

• F5-F8: Change the subdivisions of the planet model
• F12: Reset the scene
• Tabulator: Switch camera view to the next planet
• Numbers 0-9: Directly select a planet
  • 0: Sun (shows the whole scene)
  • 1: Mercury
  • 2: Venus
  • 3: Earth
  • 4: Mars
  • 5: Jupiter
  • 6: Saturn
  • 7: Uranus
  • 8: Neptune
  • 9: Pluto
• By holding the left mouse button down you can turn the camera around.

Have fun with it and let me know if you like it or if you have any ideas for improvements.

Actually I am missing a Point Light in XNA, because it would be better to have the sun as the one-and-only light source in the scene, at least more realistic. Maybe somebody has some input for me.

Blockout3D is a 3D variant of the famous Tetris game. Well, you will find thousands of this throughout the web, but I really love my own implementation the most. Surprise…

You can download Blockout3D Setup and start playing. Have fun!

Lighting Program with lights and reflections

You can configure a lot of things in this application, but I love the “San Francisco Mode” the most. It shows up a picture of the shore around the Golden Gate Bridge, which I took when I was in SFO this year. Great place! Beside this, you can switch on and off the four lights, that can be placed somewhere in the room by using the right and middle mouse key (or scroll wheel). The camera position can be moved by using the left mouse key. Colors and other configs like the shininess factor can be controled by using the functional keys… For more details, please open the application, there is a little help within.

If anybody is interested in some codes, please let me know, then I will post it at this place.

Feel free to download the Lighting Application and enjoy it.

Come join the Night of Science at the new university campus Riedberg in Frankfurt, Germany.

To see a full list of the speakers and detail information, please visit the Night of Science Website.

See you on Friday night

The third program I have just finished on my C# study is a little XNA program, which renders a given 3D-model with a texture. You can define the camera position and you can rotate the world. I also developped four models with can be switched via shortcut, so you can only see one model a time. There are some more shortcuts available:

• F1: Show 1. model
• F2: Show 2. model
• F3: Show 3. model
• F4: Show 4. model
• F5: Delete one horizontal division
• F6: Add one horizontal division
• F7: Delete one vertical division
• F8: Add one horizontal division
• F12: Reset the configuration
• Arrow-Keys: Move the camera position (X/Y)
• NUM+ and NUM-: Move the camera position (Z)
• SHIFT-Keys: Accelerate the movement and divisions by 10
• Left-Mouse-Down: Rotation the view
• Right-Mouse-Key: Change the fill mode

The models I implemented are:

1. Rectangle with TriangleList
2. Rectangle with TriangleStrip
3. Tube
4. Torus

Okay, the first two are not really 3D-models, but it was the starting point that I had to start with and they are really cool, aren’t they? All models must be dividable, that means, you can dynamically change the number of subdivision in X/Y direction. After the rectangles I started to build a tube and after the tube I finally worked out on a torus. To implement the torus I worked with the formular given on Wikipedia and iterated over two times PI.

I cannot give you too much details here, because other student may work on their programs for that and I don’t want them to simple copy my results. But if you are interested on these implementations just let me know and I will give more detail later on.

If you would like to test the application, feel free to download the BasicModels installer right here.

Have fun!

No it is not! As long as we all trust in the words of Larry Ellison, who spoke about the great effort Oracle has made out of Java and that they will not stop the work on the community. Well, we have to wait, how things will go on, but the Java One will not be the same…

Java One 2009 opening session

The show must go on and so did the conference. I visited very cool sessions, mostly about JavaFX and how things are developing. So I joined the BOF of the JavaFX Designer MeetUp and the sessions held by Richard Bair and Jasper Potts. I like your stuff, keep on rolling! I also went to the session about animations, renamed “Animation rocks”, by Chet Haase and Romain Guy. Awesome session, again, after the one you two guys held at the Devoxx 2008!

Overall scoring: This Java One, even if it is not as big as it used to be the years before (that’s what alumni said) – I really enjoyed my time here at San Francisco. Thanks to all!

San Francisco and the Golden Gate Bridge at sunset