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Finding quaternion representing the rotation from one vector to another
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Quaternion q;
vector a = crossproduct(v1, v2);
q.xyz = a;
q.w = sqrt((v1.Length ^ 2) * (v2.Length ^ 2)) + dotproduct(v1, v2);
Don't forget to normalize q.
Richard is right about there not being a unique rotation, but the above should give the "shortest arc," which is pro...
HTML5 Pre-resize images before uploading
...function(e) {img.src = e.target.result}
reader.readAsDataURL(file);
var ctx = canvas.getContext("2d");
ctx.drawImage(img, 0, 0);
var MAX_WIDTH = 800;
var MAX_HEIGHT = 600;
var width = img.width;
var height = img.height;
if (width > height) {
if (width > MAX_WIDTH) {
height *= MAX_WIDT...
Is there a query language for JSON?
Is there a (roughly) SQL or XQuery-like language for querying JSON?
22 Answers
22
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Is MATLAB OOP slow or am I doing something wrong?
I'm experimenting with MATLAB OOP , as a start I mimicked my C++'s Logger classes and I'm putting all my string helper functions in a String class, thinking it would be great to be able to do things like a + b , a == b , a.find( b ) instead
of strcat( a b ) , strcmp( a, b ) , retrieve first...
How to calculate a Mod b in Casio fx-991ES calculator
Does anyone know how to calculate a Mod b in Casio fx-991ES Calculator. Thanks
10 Answers
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How to Convert JSON object to Custom C# object?
...re an easy way to populate my C# Object with the JSON object passed via AJAX?
13 Answers
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How to use a variable for the key part of a map
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Use this:
def map = [(A):1, (X):2]
For the value-part it's even easier, since there is no automagic "convert text to string" happening:
def map = [keyA:A, keyX:X]
share
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Android Replace “…” with ellipsis character
... Why is it "better"? This complicates things when giving the text to translators. Can we somehow kill this stupid warning? Thanks
– swinefeaster
Jan 2 '12 at 3:04
25
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What is the Ruby (spaceship) operator?
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Exactly. I think of it as a very elegant version of Java's Comparable.
– Mike Reedell
May 6 '09 at 12:42
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How to convert a string from uppercase to lowercase in Bash? [duplicate]
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If you are using bash 4 you can use the following approach:
x="HELLO"
echo $x # HELLO
y=${x,,}
echo $y # hello
z=${y^^}
echo $z # HELLO
Use only one , or ^ to make the first letter lowercase or uppercase.
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