Calculate rotation between two Vector2s around a pivot

Posted by Nick on Stack Overflow See other posts from Stack Overflow or by Nick
Published on 2011-01-09T13:33:34Z Indexed on 2011/01/09 13:53 UTC
Read the original article Hit count: 309

Filed under:

c#

|

XNA

|

rotation

|

xna4.0

alt text Hello all.

After a good long Sunday google I am going to have to hang my head in shame and ask the question...

What I have is a pivot vector2, a "Previous" vector2 and a "Current" vector2.

I would like to be able to calculate the rotation in radians between them. A slight complication is the fact that the pivot may moved between previous and current but ill deal with the offsetting as a separate issue if you don't have the time to bring that into the fold.

To clarify, an object which has two vectors, a pivot and a base ... the pivot sitting in the centre and the base at the bottom is rotated around an external pivot. I need to work out the rotation of the object itself around its centre using the two mentioned vectors.

Very big thanks to anyone that can help.

Background to problem

I have a game where an object is rotated around an external pivot. By using using two points (one in the centre, one at the base of the object) I am wanting to to work out the rotation that needs to be applied to the objects sprite around its centre to conform to the larger rotation that has been applied.

© Stack Overflow or respective owner

Related posts about c#

.NET WebRequest.PreAuthenticate not quite what it sounds like

as seen on West-Wind - Search for 'West-Wind'
I’ve run into the problem a few times now: How to pre-authenticate .NET WebRequest calls doing an HTTP call to the server – essentially send authentication credentials on the very first request instead of waiting for a server challenge first? At first glance this sound like it should be easy:… >>> More
HttpWebRequest and Ignoring SSL Certificate Errors

as seen on West-Wind - Search for 'West-Wind'
Man I can't believe this. I'm still mucking around with OFX servers and it drives me absolutely crazy how some these servers are just so unbelievably misconfigured. I've recently hit three different 3 major brokerages which fail HTTP validation with bad or corrupt certificates at least according to… >>> More
The dynamic Type in C# Simplifies COM Member Access from Visual FoxPro

as seen on West-Wind - Search for 'West-Wind'
I’ve written quite a bit about Visual FoxPro interoperating with .NET in the past both for ASP.NET interacting with Visual FoxPro COM objects as well as Visual FoxPro calling into .NET code via COM Interop. COM Interop with Visual FoxPro has a number of problems but one of them at least got a lot… >>> More
Dynamic Type to do away with Reflection

as seen on West-Wind - Search for 'West-Wind'
The dynamic type in C# 4.0 is a welcome addition to the language. One thing I’ve been doing a lot with it is to remove explicit Reflection code that’s often necessary when you ‘dynamically’ need to walk and object hierarchy. In the past I’ve had a number of ReflectionUtils that used string based expressions… >>> More
Finding a Relative Path in .NET

as seen on West-Wind - Search for 'West-Wind'
Here’s a nice and simple path utility that I’ve needed in a number of applications: I need to find a relative path based on a base path. So if I’m working in a folder called c:\temp\templates\ and I want to find a relative path for c:\temp\templates\subdir\test.txt I want to receive back subdir\test… >>> More

Related posts about XNA

Camera for 2.5D Game

as seen on Game Development - Search for 'Game Development'
I'm hoping someone can explain this to me like I'm 5, because I've been struggling with this for hours and simply cannot understand what I'm doing wrong. I've written a Camera class for my 2.5D game. The intention is to support world and screen spaces like this: The camera is the black thing on… >>> More
Using XNA ContentPipeline to export a file in a machine without full XNA GS

as seen on Game Development - Search for 'Game Development'
My game uses the Content Pipeline to load the spriteSheet at runtime. The artist for the game sends me the modified spritesheet and I do a build in my machine and send him an updated project. So I'm looking for a way to generate the xnb files in his machine (this is the output of the content pipeline)… >>> More
XNA - Strange Texture Rendering Issue Using XNA BasicEffect

as seen on Game Development - Search for 'Game Development'
I have been reading and working through Riemers 3D XNA tutorials to expand my knowledge of XNA from 2D into 3D. Unfortunately I am having rendering issues that I am unable to solve and I need a point in the right direction. I am not expecting the Models to look identical to Blender but there is… >>> More
XNA Notes 009

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
This past week the MVPs (myself included) were on Microsoft campus for the MVP summit. So I apologize in advance if you did something cool or heard of something cool happening with XNA and XBLIGs and it’s not in my notes. I did my best to stay on top of things, but honestly this community is fast… >>> More
XNA Notes 006

as seen on Geeks with Blogs - Search for 'Geeks with Blogs'
If you used to think the XNA community was small and inactive, hopefully these XNA Notes are opening your eyes. And I honestly feel like I’m still only catching the tail end of everything that’s going on. It’s a large and active community and you can be so mired down in one part of it you miss all… >>> More