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Index › Programming Questions & Help › Syntax Questions › 2d grid with vertex
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2d grid with vertex (Read 494 times)
snorpey
2d grid with vertex
Jan 28th, 2010, 10:20am  
Hi. I would like to draw a 2-dimensional grid with the vertex function.
I need to change the position of some of the intersection points later on, so I store their position in an array.
Unfortunately, the result looks nothing like a grid.. What do I have to change?

Quote:
int xPos[] = new int[200];
int yPos[] = new int[200];
int aPos = 0;

void setup()
{
    size(150, 150);

    for(int i = 0; i < 9; i++)
    {
        for(int j = 0; j < 9; j++)
        {
            addPoint(i, j);
            addPoint(i+1, j);
            addPoint(i, j+1);
            addPoint(i+1, j+1);
        }
    }
}

void draw()
{
    background(80);
    translate(30, 30);

    beginShape();

    for(int i = 0; i < aPos + 1; i++)
    {       
        vertex(xPos[i] * 10, yPos[i] * 10);      
    }

    endShape();
}

void addPoint(int x, int y)
{
    boolean addValue = true;

    for(int i = 0; i < xPos.length; i++)
    {
        if(
        xPos[i] == x &&
            yPos[i] == y
            )
        {
            addValue = false;
        }
    }

    if(addValue)
    {
        aPos++;     

        xPos[aPos] = x;
        yPos[aPos] = y;
    }
}
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PhiLho 
Re: 2d grid with vertex
Reply #1 - Jan 28th, 2010, 12:11pm  
Well, a first step would be to use beginShape(LINES); instead.
Not enough, but better...

To be honest, I don't understand your algorithm...
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koogy
Re: 2d grid with vertex
Reply #2 - Jan 28th, 2010, 12:12pm  
you're drawing all your points as the same Shape (between beginShape and endShape). so it's joining them ALL together, hence the zigzag lines. it's also filling the resultant shape, hence the white.

try beginShape(LINES) which will join pairs of points (i doubt this is exactly what you want but it'll be closer. you probably want to draw them in groups using two nested for loops rather than 1 big one)

also put noFill(); in setup() to turn off the white.

(too long, too slow... does he never sleep?)
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