Working game!


Hello hello!

Finally a game from the most time consuming student of contrechoc!

First a bit history, information about the things that pushed me in the directions of this little piece of art.
</sarcasm> (people who don’t know me: place these tags random in the rest of the text, you can’t go wrong)
Initially I had the idea to create a nice ‘framework’ , so you could easily make buttons in C. Just like in java or php. Make a button, put some text on it, adding a handler etc. But that was not going to happen, I found out after several weeks of time consuming research, cheers! It was too difficult for someone like me, who didn’t know anything about C yet

Contrechoc allready told me several times it was better if I made a simple game first, before I would drown myself in complicated pointer structures. I heard him but didn’t listen! So the first deadline for this class was a miss. I had to make a game in the retry.

So I decided to make a simple game with the information and basic functionality I had for the framework: some buttons on the screen, one of those pressed would take you to the next level! A hole in the market as we’d say here in the Netherlands.

Not only buttons should be visible, that’s not really a game. So I displayed the level and a timer on the screen, a lot more competitive. So after some trash buttons you press the ‘end-boss’-button of each level, proceed to the next level, repeat this like twenty times and set a new world record.
Then I decided to add sounds to this, something like drum sounds, so you press buttons like a crazy, and each ‘level’ you make a new popsong. So it’s not only competitive, but also a lot of fun. Or you just play for fun and make music, with five! different sounds.

This all could be programmed in under three hours, I made it in … I fell asleep while counting.

What took me so long?
Well the most ‘simple’ things were driving me crazy.
For example the case where I was adding the counter. It wouldn’t work for days, until master Contrechoc tested my app on the nds, and found out the emulator (wich we use to develop) doesn’t support time… awesome! I needed stuff like that too, and arranged a dstt card to get my code running on my little sister’s nds.
The last days I was trying to print the time taken in decimals on the screen, tried for days to print a double with “iprintf(…%.2f…)”. Found several working examples on the internet where they did what I wanted:  “printf(…%.2f….)”. Didn’t worked on my pc nor ds! why didn’t I just copy and paste the working code? why did I have to found out with Contrechoc that I missed the “i” as in “iprintf” in my code? Well it doesn’t matter anymore, I can’t ctrl+z my spent time anyway.
These were only two examples of some ‘easy’ to make functionality. Imagine me struggling with more ‘complicated’ C issues.

Because this was allready so time consuming for me, and especially contrechoc, the to-do-list (or wishlist) is kinda long for such a small game:
– Save the best time with name of competitor
– Make an exit program function, so I can’t be sued by addicted gamers
– Really make a good button framework (as initially planned)
– More buttons and sounds
– In-game configuring of levels, button sizes, number of buttons
– Best feature imho: switch buttons to the top screen while you have to press on the toucharea!
– Choose the sounds to use with the buttons
– Make it impossible to play the game while dragging like a crazy over the screen, so you have to ‘tap’ each button. You have to release after you tried a button. Anyway i can make a lot money with selling new touchscreens muhahaha.
– And etc.

[Edited download link on 08/03/2010]
Click here to get your own copy for free.

I decided to release the .nds file too, because there can be problems when you try to compile your own with my code. This can be caused due a difference in mine and your version of devkitpro.
Get the nds file here.

NDS Framework (in C)


Earlier I was planning a release 2 weeks ago on Sunday… But I really needed much more time, yesterday I finally got it working: my NDS Framework.

Since the whole blog is to give people more info about NDS programming and making it easier to program, I could just make a game like everyone does, but I’ve chosen to create something useful for almost everything you want to create on your NDS: A framework.

My framework works using a parent child concept (just like HTML) in order to position elements quickly to there positions. This way you can easily create a button on the right bottom side of your screen without calculating with pixels, it’s all done by the program!

Taken the above example: “You want to create a button on the right bottom side of the screen”, you will first have to create a screen to render on:

// Create a screen (width, height, backgroundimage (can be NULL))
struct CElement *screen1 = CElementCreateScreen(256, 192, backgroundimage);

// Since I don't have a button element yet, we will draw a squire
// It has the properties (RenderOn, leftOffset, topOffset, width, height)
CElementCreateSquire(screen, -1,-1,100,50);

If the leftOffset will be lower than 0, it will render it on the other side of the screen (the right side), the same counts for the topOffset. The width and height are 100px by 50px.

Another example can be found over here: where you can see it can also automatically scale (like: width = 100%) all sorts of elements by giving it a width of 0 or a height of 0. A negative width or height will create a rightOffset, so if you want to position something with a border of 5 px, you can do this:

CElementCreateRectangle(screen, 5,5,-5,-5);

I’ve created a screen, what’s next? Well now the program has to calculate the real width, height, offsetLeft and offsetRight of the element. It’s done using the same meganism that DOM is using, by looking to the parent of the element. This is because all elements are positioned relatively to their parents, for example, you’ve created a container (= a special element that can hold multiple elements) on the bottom right of the screen. If you will draw a Squire, it will be drawn on the bottom right section (so relatively to the container where it’s in). To calculate all this, you only have to call the next line:


Ok, so now you’ve got a screen holding elements, but you want to render it on one of the two screens of the NDS, this is what you will do to get that working:

CElementDraw(screen1, video_buffer1);
CElementDraw(screen1, video_buffer4);

It will now render my virtual screen to both screens of the NDS. This way you can make multiple screens and load them in memory, and when you need them, you only have to execute CElementDraw(screen_settings, video_buffer4); to get it working!

Is there more?

Well since a framework is never done, and I am limited to time, I included the following things in this framework:

  • The auto calculation of elements (biggest part of the code)
  • A lookup element to see on what element is pushed using CElementAt(screen1, x, y)
  • An element to draw a triangle
  • An element to draw a rectangle
  • An element to draw a line
  • An element to draw a circle
  • A List “class” to create dynamic arrays
  • A function to remove a bunch of elements (so if you want to delete screen1, you can just: CElementRemove(screen1) and it will remove all other elements with it! And release there pointers 😉 )
  • A draw function to create a AntiAliassed line using the Xiaolin Wu algorithm (echter deze kijkt ook echt naar de achtergrond om de anti aliassing kleur te genereren)
  • A draw function to create a Circle (not anti aliassed, since it costs 1000 lines of code to get that working)
  • An element that can contain multiple elements
  • An element that lets you devide a screen in to multiple sections (sortof a table)

Things like text elements aren’t implemented, but you can easy implement a Element by looking to my code. The only thing you really have to create is a function to draw it on your screen.


	// Create a virtual screen
	struct CElement *screen1 = CElementCreateScreen(256, 192);
	// Create a container fill it to the whole screen (width: 0, height: 0)
	struct CElement *container = CElementCreateContainer(screen1, 0, 0, 0, 0);
	// Split the screen in two sections vertically (and add it to the container)
	struct CElement *splitterY = CElementCreateSplitterY(container, 0, 0, 0, 0, 2);
	// Split the screen in three sections horizontally (and add them to the above splitter)
	struct CElement *splitterX1 = CElementCreateSplitterX(splitterY, 0, 0, 0, 0, 3);
	struct CElement *splitterX2 = CElementCreateSplitterX(splitterY, 0, 0, 0, 0, 3);
	// Add some elements to it:
	CElementCreateRectangle(splitterX1, 0,0,0,0);
	CElementCreateTriangle(splitterX1, 0,0,0,0);
	CElementCreateRectangle(splitterX1, 0,0,0,0);
	CElementCreateRectangle(splitterX2, 0,0,0,0);
	CElementCreateCircle(splitterX2, 0,0,0,0);
	struct CElement *rect= CElementCreateRectangle(splitterX2, 0,0,0,0);
	// Set properties & draw
	CElementDraw(screen1, video_buffer1);
	CElementDraw(screen1, video_buffer4);

	splashImage(video_buffer4, (u32 *)iepro_fun_img_bin);
	CElementDraw(screen1, video_buffer4);


  • Updated CDraw.h/.c + CDrawElement.h/.c; renamed Squire to Rectangle (since it is a rectangle, and squire isn’t spelled correctly
  • Added negative left / top to become the right offset like posted above


The download package will have 2 folders, C and C_NDS, the C is to easily debug (without using NDS related code), if compiled you can see exactly what it is doing. The C_NDS is the same package + NDS related code to create a NDS rom.

[ Download ]

Anti-aliased line Alpha



here you can see my “game” (which isn’t really a game) from my project. As you can see images are missing but I didn’t had time to do this. Therefor a little preview of a line with and without anti-aliasing. The algoritm I used for anti-aliasing is Xiaolin Wu’s line algorithm. For the “normal” line I used the Bresenham line’s algorithm. Source code can be found here. I hope you can see the difference 😉

Eclipse on windows using ARM9 toolchain


The following images contain some info about the settings for eclipse for the nds on windows XP. All settings can be found in the project settings.

Print debug info on top screen


If you want to easily print debug info with iprintf on the top screen of your nds, copy and paste the following code right above where you want to begin debugging:

PrintConsole topScreen;
consoleInit(&topScreen, 3,BgType_Text4bpp, BgSize_T_256x256, 31, 0, true, true);
iprintf(“\n\n\tHello DS dev’rs\n”);

First post, findings, end result!


Hello, my name is Herman van der Meulen.

Started with no C and NDS knowledge a few weeks ago, I have now built a simple game!

I will try to write the events in this one post in chronological order:

Learning C

Installing (on Mac OS X)

Game concept



Read the rest of this entry »

Project: Anti-aliasing lines on pictures


Hi there,

I’m going to make anti-aliasing lines on pictures. I start with making anti-aliasing lines for a background with only 1 color. After I’m succesful on doing this, I’m going to try to apply this to a picture as background. This will be a bit challenging because I have to work with transparency but that’s fun! The final step of my project is to make some buttons for changing the background image.

Rob de Rijk