Help with rotating 2d vectors (C#, SDL.NET)
Author
Hi all!
I am using SDL.NET with C# and trying to understand 2d vectors.
Could someone help me with following or point me to a tutorial for dummies :)
I have four vectors/points
Vector Location
A 10,10
B 10,20
C 20,10
D 20,20
So its a square. How can I rotate all of them n degrees
a) from vector A,B,C or D
b) from point 15,15 (middle point of square)
and still keep the square shape?
A 2D point can be rotated around it's origin using the following formulas, where theta is the number of degrees you want to rotate:
x' = cos(theta) * x - sin(theta) * y
y' = sin(theta) * x + cos(theta) * y
Since 15, 15 is probably not the origin in your case, you can translate the negative point, rotate, and then reverse the translation.
x' = cos(theta) * x - sin(theta) * y
y' = sin(theta) * x + cos(theta) * y
Since 15, 15 is probably not the origin in your case, you can translate the negative point, rotate, and then reverse the translation.
Author
Quote:Original post by Kuraitou
Since 15, 15 is probably not the origin in your case, you can translate the negative point, rotate, and then reverse the translation.
Translate?
The situation is following http://tviljan.kapsi.fi/kuva1.png
On top is the original and below is the situation that I would like to get.
A C
X <- Point of rotation
B D
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