A mathematical concept that can be used to express position, direction or velocity and which can simplify or outright trivialise spatial problems.

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8
votes
2answers
16k views

Moving a sprite in XNA/C#, using vectors

I'm currently looking into XNA game development with the C# language. I have two classes: the main game handler and a "sprite" class. Following is some basic pseudo-code which I hope adequately ...
19
votes
4answers
17k views

How can I calculate the angle and proper turn direction between two 2D vectors?

I am working on some movement AI where there are no obstacles and movement is restricted to the XY plane. I am calculating two vectors, v, the facing direction of ship 1, and w, the vector pointing ...
1
vote
1answer
291 views

Determining relative velocities on impact?

I'm trying to figure out a way to determine the relative velocity of a body colliding with another in a 2D environment. For example if one body is moving at (1,0) and another traveling behind it ...
4
votes
2answers
10k views

Rotate vector by matrix?

If I have a Vector, say (1,1), how can I rotate it around the origin (0,0)? I'm working in XNA if that helps.
5
votes
1answer
4k views

How do I find rotation in 3D based on a vector/normal?

I've been playing with Blender and Python, doing basic things like accessing vertices/normals,etc. I can get the normal of each face of a mesh. I was wondering, how can I get the rotation of a face ...
3
votes
2answers
308 views

How do you transform a vector to use another objects orientation?

I want to take a vector that is using world coordinates and position it using the orientation of an object. So, if the direction of the object is the z-axis, and the vector is (0,0,1), then the ...
3
votes
4answers
4k views

Line triangle intersection - last bits

I'm doing line-triangle intersection. I have found the intersection point (vector) on the plane. All I need to do now is work out whether the point is inside the triangle it collided with (not the ...
3
votes
3answers
555 views

When to return a reference and when to return a copy?

I was looking at the d3dx math .h and noticed that a difference between the "+" and "+=" operators: D3DXVECTOR3& operator += ( CONST D3DXVECTOR3& ); D3DXVECTOR3 operator + ( CONST ...
6
votes
2answers
1k views

For a 2D XNA game, should I use the built in Vector2 or Vector3 or port my own class from ActionScript?

I use a lot of 2D vectors in my Flash games - basically all velocities, positions etc I store in this way. My Vector2D class has lots of built in functions for rotation, dotproduct, projectOnto etc. ...