Thread: Typedef Structs inside Typdef structs

Hello, I'm currently making a game, called rubik cube, however, this is more a syntax question than it is about the game properly.

I have defined the following structure, and can«t find out how to initialize the whole structure.

Code:

// each square of the little cubes in the rubik cube
typedefstruct quadr
{
        char collor;
        char axys;
} quad;

// Cubes in the rubik cube
typedefstruct squareR
{
        quad q[6];
        char axys;
        // Check if its side is valid, eg. If it shows on the rubik cube
        int valid;
} square;

// Rubik cube
typedefstruct cubeR
{
        square q[3][3][3];
} cube;

I was thinking of doing something like this:

Code:

void startup()
{
int x,y,z,w;
        for(x=0;x<3;x++)
        {
                for(y=0;y<3;y++)
                {
                        for(z=0;z<3;z++)
                        {
                                for(w=0;w<6;w++)
                                {
                                        //initialization goes here
                                }
                        }
                }
        }
}

The hard part i find by now, is making the initialization...

The axys variable has to do to which side the cube(s) are turning to, so that i can show the correct collors.
The collors at the beggining, will be filled probably with numbers from 0 to 5, or something like that.

I would also appreciate some feedback on the way I'm trying to make the game, and know if I'm proceeding correctly.

Thank you,

Oh, yes, sorry, the typedef struct thing happened when I coppied it from my source.

Anyway, yes, that does make sense.

I'm having problem initializing the variables. Thats the biggest problem. Seen some things, but just don't how to proceede in filling the cube to the initial state. By initial state I mean, each side has it's color like if it was solved.

It seems to me that you have too many pieces of data:

If I understand correctly: quad is a single face of one of the small squares. square is 6 of these: a small cube. Finally cube is 27 of the small squares. Right? That makes 162 coloured sides.... which is many more than a rubik's cube actually has. I think the confusion is that you're treating it as though some sides of the small cubes can be hidden. I don't think this is the case: I think they're always all visible.

I would probably just represent the cube as 6 sides of 9 colours. Moves have to update all appropriate sides.

That's just my thoughts though....

For initialisation with your current code... I think it'd go something like:

Code:

cube c;

int x,y,z,w,s;
for(x=0;x<3;x++)
{
	for(y=0;y<3;y++)
	{
		for(z=0;z<3;z++)
		{
			for (s = 0; s <= 6; s++)
			{
				c.q[x][y][z].q[s].collor = s;
			}
		}
	}
}

To visualise what this does I think you need to number the sides, e.g. say that the sides facing you are number '0'. Then this loop will colour *every* side of every little cube facing you with colour '0'. Including the ones in the middle that will never be seen.

Originally Posted by gremory

Hello, I'm currently making a game, called rubik cube, however, this is more a syntax question than it is about the game properly.

I have defined the following structure, and can«t find out how to initialize the whole structure.

In my experience, when you design a data structure that complex --especially for a realitively simple task--
you're probably not thinking the problem through far enough to find a simpler way to do it.

Thankyou. I will explain then.

I picked up a paper, drew and made everything look logic, and then tried to define the structure of what i made in the paper.

So, First I thought about it this way.

A cube has 27 cubes in it, that "would" have the same colors as the main cube if it was solved.
So I would make an array[3][3][3].

Therefor this structure:

Code:

// Rubik cube
typedef struct cubeR
{
        square q[3][3][3];
}cube;

Then I thought that if you are viewing the cube from a 3d perspective. You can imagine that it has two sides facing the X axis, two facing the Y axis, and two facing the Z axis. Therefor making the 6 sides of the cube.

And why did I use that variable. Because, when filling the smaller cubes with colors, there are squares that dont face the outside of the cube. So at this point, I would pick up your sugestion and use the enum you sugested me.
Instead of having little cubes with 6 squares with collors that dont even face the outside of the cube, I would probably use your sugestion. That is why I used the structure bellow. With the quad vector[6] (six sides of each little square).

Code:

// Cubes in the rubik cube
typedef struct squareR
{
        quad q[6];
char axys;
// Check if its side is valid, eg. If it shows on the rubik cube
int valid;
}square;

I'm hopping you're understanding what I'm writting here.

Then, For each of those little squares, on each of the 27 cubes, of the rubik cube, I had this:

Code:

// each square of the little cubes in the rubik cube
typedef struct quadr
{
        char collor;
char axys;
} quad;

So once again, we have the axys variable. And why do I have an axys before and after. So that I can compare this axys variable to the main cube axys variable and see of they are the same, if they were the same, it would mean that they would be showing, and that way, they would be "valid".


This is like the first part. My second part has another couple of structures defining the way you visually see it.

Thankyou once again.

Originally Posted by CommonTater

In my experience, when you design a data structure that complex --especially for a realitively simple task--
you're probably not thinking the problem through far enough to find a simpler way to do it.

I think you might be right...

It would be the most "correct" (in the context of real life) to have all faces documented:

Code:

struct basic_cube {
    u8 faces[6]; 

#define RED 0x1
#define YELLOW 0x2
#define GREEN 0x4
#define BLUE 0x8
#define WHITE 0x10

};

struct rubix {
    struct basic_cube rubix_cube[3][3][3]; /* no need for triple pointer, as the size is static */
    /* any other data you'll need to pass, goes here */
}; 

/* to init */

struct rubix *init_cube(void)
{
    struct rubix *tmp;
    tmp = malloc (sizeof(struct rubix)); /* bad practice, this is just proof-of-concept -.- */

    /* your for loops and everything else goes here */

    return tmp;
}

The problem is that while it only takes up 162 bytes in memory (after padding, assuming no __packed__), the for loops will take a lot of processor power. The best solution is to split it off into threads:

Code:

void *init_squares(void *data)
{
    struct rubix *proc = (struct rubix *)data;

 /* 
 * for loops go here 
 * use the syntax (*proc->rubix_cube[0][0][0]) = RED;
 * you have to dereference the pointer or it won't work
 */

    return data; /* doesn't do anything, but makes gcc shut up */
}

struct rubix *blank;
blank = malloc(sizeof(struct rubix));

/* 
* create your thread, pass it (void *)blank 
* no example code, it depends on your computer
*/

/* use the data by dereferencing the data in the struct */

The simplest structure might be something like this, with the face numbers also being the color numbers (since the middle squares are immobile).

Code:

#define NFACES 6
#define NSQUARESPERFACE 9

int cube[NFACES][NSQUARESPERFACE];
int f, s;

/* init */
for (f=0; f<NFACES; ++f)
    for (s=0; s<NSQUARESPERFACE; ++s)
        cube[f][s] = f;

The display operation should be fairly simple with this structure. The rotates might be a little hairy, but probably not too bad (each requires moving 16 numbers, eight on the side you're rotating, and eight around the edges of the four other faces involved).

Originally Posted by iMalc

Before telling the OP that the idea chosen is unnecessarily complicated, try and come up with something better yourself. It really is quite a hard problem.

*Guilty*. It IS a hard problem. It was only when I tried to explain my approach in a reply that I realised it was probably not viable.

My idea was the same as oogabooga's, I think. Instead of building the big cube out of little cubes, I wanted to build it out of squares (9 squares on each face). Since these are the only things that'll be displayed, it seemed reasonable to not represent the interior sides of the little cubes.

I think it'd work -- but it'd be a dull slog of hand calculating what number square on each face moves to what number square on another face for each rotation. I think you can rig it to be easy to calculate for 2 planes, but the 3rd plane of movement will always be horrible.

I've been looking at this little java applet of a rotatable cube to help visualise the transformations needed - might be handy for others:
Virtual Cubes Rubik's Cube | Instructions | Instructions

Originally Posted by iMalc

Straight after answering this I went to another forum and look what I found: Rubik Cube C - GameDev.net

Well yes, I did post it in two forums, this and that one. I don't think it's a bad idea. But definitely, I've been getting a better study of my problem here, and I am thankful for that.

If it is a problem, just let me know...

Originally Posted by gremory

Thankyou. I will explain then.

I picked up a paper, drew and made everything look logic, and then tried to define the structure of what i made in the paper.

So, First I thought about it this way.

A cube has 27 cubes in it, that "would" have the same colors as the main cube if it was solved.
So I would make an array[3][3][3].

Seems to me the representation is much simpler than that...

You have 6 faces, each a 3x3 matrix...

Code:

int rubic[6][3][3];

The problem is not in how you depict it in data... the real task is how do you rotate the faces when rotating one of the 6 faces also rotates one row of the 4 adjoining faces... Seems to me the real magic is in the code not the picture.