Question

Is there a code formula for this? I am using C# and XNA, and in my class I have an array of three vectors (representing the vertices of the triangle), as well as a separate vector coordinate.

I plan to update these positions in the loop as it escalates further towards the top of the screen.

I’d ask maths.stackexchange.com, but seeing as how this applies to programming (and I personally am better at reading code as opposed to math itself – I’m still taking Algebra in school), I think it would make more sense for me to ask it here.

Edit
Yes, I am looking for an equilateral triangle. Or any triangle, for that matter. It doesn’t matter what it is. All I am looking for is a formula; is that so hard to ask for?

Teh Problem

Basically, the problem I am trying to solve is to shoot a triangle out of my player (think Space Invaders; i.e., the triangle acts as a ray from the ray gun). What I need is a formula of code which will allow the triangle to be rendered based on its center position and radius, as the triangle will move upwards on its Y coordinate. I have the draw calls, and they work, but the problem is that the triangle when put in a for loop draw iteration (where the center vector position – on the Y coordinate – is incremented by N) simply sits next to the player’s position when being drawn.

Answer 1

I think this is what you are looking for…
the angle is the orientation of the triangle…
this build a triangle….

void BuildTriangle(Vector2 Center, float Radius, float Angle, Vector2[] tri)
{
   for (int i=0; i<3; i++)
   {
      t[i].X = Center.X + Radius * (float) Math.Cos(Angle + i * 2 * MathHelper.PI/3);
      t[i].Y = Center.Y + Radius * (float) Math.Sin(Angle + i * 2 * MathHelper.PI/3);
   }
}

if you want to move it, add to the center a velocity vector and rebuild it…