17,690 reputation
23673
bio website sam.zoy.org
location Paris, France
age 36
visits member for 4 years, 4 months
seen 2 hours ago

I live in Paris, France.

I work on video games (computers and consoles) for a living. I write free software and all kind of crazy shit for fun. My interests: image processing, video coding, rendering, game development, maths, physics, compression, cryptography.


Jun
15
comment Transform Matrix multiplication order
The confusion comes from the fact that you are talking about local transformations (where the frame remains linked to the object), whereas the transformations described here happen in world space (where there is only one fixed reference frame, the world). Conceptually, your way of seeing things is valid, and it is equivalent to applying transformations in reverse order.
Jun
10
awarded  Nice Answer
May
24
answered How to calculate normal vector of a curve?
May
16
comment Finding which tiles are intersected by a line, without looping through all of them or skipping any
possible duplicate of How do I generalise Bresenham's line algorithm to floating-point endpoints? (the question isn’t actually about Bresenham)
May
10
answered What is an efficient packing algorithm for packing rectangles into a polygon?
May
5
comment Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
I have posted the code. Maybe refresh the page? But, anyway, your stubbornness is hopeless and your objections indicate that there are too many things you don’t understand and you should either read about them or trust the people who do. If after so much information has been given to you, you still “don't need to measure”, well you’re just not the kind of person I want to help; hopefully my answer can still be useful to someone else. Have fun!
May
5
revised Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
add murmurhash speed comparison
May
5
comment Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
@NovaCrist Gee, that C++ code is 5 times faster than MurmurHash3. I’m pretty sure you actually didn’t measure anything.
May
5
comment Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
You just do not seem to understand how a PRNG is a hashing function, and how a PRNG can be fast. Seriously, learn to listen to advice from professional developers who know their stuff. Don’t dismiss suggestions based on an “overhead” you didn’t measure. I edited my answer with a C++ implementation; it’s three lines of code; it’s a proven algorithm; it can be trivially adapted to 2 or 4 or 30 variables instead of 3 depending on your requirements. Unless you have a real reason, you should use established, available standards instead of rolling custom code you’ll have to debug and maintain.
May
5
revised Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
shorter code
May
5
revised Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
add C++ implementation
May
4
comment Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
@NovaCrist There is nothing wrong with “shuffling around values”, that’s someting most PRNGs and hashing algorithms have in common. You use words like “categorically”, “unsuitable”, “approximate”, “silly”, but are you sure you fully grasp the concepts you are tackling? If you are getting artifacts with the method I suggest, you are doing someting wrong, because it’s a mathematically correct solution to your problem. See for instance this code which I used to generate this image.
Apr
28
comment Java OpenGL Perspective matrix not working
It’s not particularly “incorrect”. It’s probably preferable to have an explicit constructor mat4(1.0) for this anyway.
Apr
27
comment How can I go about testing games on a console
UE4 does not support the PS3. Did you mean PS4? If so, you’d still need a PS4 test kit, and yes, that whole registration thing… but maybe your best bet would be to make friends with someone who has access to a test kit :-)
Apr
13
answered Usage of math.Atan2 in a 3D coordinate system with Unity
Apr
11
answered XNA Starting a parallel Thread during a draw loop is slower than doing the same task in the main thread in update loop
Apr
11
revised Quaternion Slerp and Lerp implementation (with overshoot)
better solution for lerp instead of slerp and a few tweaks
Apr
11
answered Bug in XNA Developer function CalculateEigenVector() from the file “xnacollision.cpp”?
Apr
11
answered Quaternion Slerp and Lerp implementation (with overshoot)
Apr
7
comment Algorithm that always returns the same pseudorandom output if given the same input of seed, x and y?
Dude, this is pseudocode. As I said, just use a different PRNG if you don’t like rand().