Greetings,

I've been given a challenge to build a simple game for my daughter. The idea is that you smash the spacebar, and a ball drops into the game, goes down some ramps, and lands at the bottom. Being a newbie programmer, this is becoming a challenge.

I decided to use ray-tracing to determine if my ball has collided with the ramps, and I have a Polygon class that defines the vertices of the bounding boxes for collisions with the ramps. I know that I need to determine how many times the rays cross the edges of the polygon, and I couldn't think of any way to do that except to calculate all possible points along the edges. I wrote this function to do this task. Just two questions

) Is there a more efficient way I can accomplish calculating the points along the edge, and

) Is there a more efficient way to accomplish my overall task (determine collision between two objects)

Edges is

`private List<Point> Edges = new List<Point>();`

```
// Calculate all possible points along an edge, given two points.
private void InitializeEdge(Point p1, Point p2)
{
int ImagX, ImagY;
bool p1XGreater = false, p1YGreater = false;
// Imaginary point used for calculation.
if (p1.X > p2.X)
{
ImagX = p1.X - p2.X;
p1XGreater = true;
}
else
{
ImagX = p2.X - p1.X;
}
if (p1.Y > p2.Y)
{
ImagY = p1.Y - p2.Y;
p1YGreater = true;
}
else
{
ImagY = p2.Y - p1.Y;
}
Point ImagPoint = new Point(ImagX, ImagY);
// Determine how many calculations to make.
int NumPointsAlongEdge;
if (ImagX > ImagY)
NumPointsAlongEdge = ImagX;
else
NumPointsAlongEdge = ImagY;
// Calculate the points and add them to Edges.
for (int i = 0; i < NumPointsAlongEdge; i++)
{
int CalcX = ImagX;
CalcX = (CalcX * i) / NumPointsAlongEdge;
int CalcY = ImagY;
CalcY = (CalcY * i) / NumPointsAlongEdge;
if (p1XGreater)
CalcX += p2.X;
else
CalcX += p1.X;
if (p1YGreater)
CalcY += p2.Y;
else
CalcY += p1.Y;
Point p = new Point(CalcX, CalcY);
Edges.Add(p);
}
}
```

*Edited 6 Years Ago by jd_davis*: Left out important details