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# P0jahn

Member Since 21 Nov 2012
Offline Last Active Nov 26 2015 04:29 AM

### Find tile coordinates within a given radius

31 August 2015 - 08:41 AM

I am developing a game where the top left corner of the world is coordinate 0:0. Thus, x is increasing while moving right and y down.

I am trying to come up with an algorithm that finds the coordinates of the tiles within the given circle.

The method signature could look like this:

ArrayOfCoordinates findCoords(int centerX, int centerY, int radius)

Example, if radius is set to 1, it would search something like this:

If it is 2:

And 3:

4:

And so on.

### Iterate through the boundaries of an rotated rectangle?

29 July 2015 - 03:28 AM

I am developing a game where a rectangles position is the top-left corner where x is increasing rightwards and y downwards.

What I am trying to achieve is to iterate through the boundaries of an rotated rectangle. Did some googling with no luck.

### Best way to store a stage for a platformer?

09 July 2015 - 06:36 AM

In my current game, coded in Java, I store it in a 2D byte array(width, height). Each element is the size of a pixel.

When the stage gets large, the amount of ram used for it as high as 150 mb.

I dont know if this is the best approach. Any suggestions of an better way to store a stage efficiently?

### Coding a chain for a 2D Game

09 November 2014 - 03:58 PM

I want to code a chain for my game and am not sure how to do it so I am hoping to get some suggestions that get me started.

Details:

You create a chain object and specify two points: start and end point.

The image of the chain object is one piece of the chain. Example:

So it should look something like this ingame:

Ideas?

### Formula to calculate when a point is reached

14 October 2014 - 07:51 PM

I am developing a 2D game where x is increasing rightwards and y downwards. Thus, the top-left corner is 0,0.

I have an enemy that moves towards a set of waypoints. When one is reached, it will start moving towards the next waypoint in the list.

I use the following code to move towards a point:

```	Vector2 norP = normalize(this.x, this.y, target.x, target.y);

float accelx = thrust * -norP.x - drag * vx;
float accely = thrust * -norP.y - drag * vy;

vx = vx + delta * accelx;
vy = vy + delta * accely;

this.x += delta * vx;
this.y += delta * vy;
```

That piece works fine. The problem is detecting when a point has been reached.

Right now, I use the following:

```if(distance(this.x, this.y, target.x, target.y) < 25)
{
...
```

The value 25 is a fixed value and works sometimes. As you alter thrust and drag properties, the value 25 stops being effective.

So I need a formula that calculates this value that works good no matter what thrust and drag is(taking them into consideration).

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