15,702 reputation
23263
bio website sam.zoy.org
location Paris, France
age 35
visits member for 3 years, 1 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.


Apr
20
answered Find closest point from an origin, in a mesh
Apr
15
comment Relative Position/Rotation calculation
Almost everything is wrong in here. All lines mentioning someUnknownMatrix have the wrong multiplication order, and one even inverts the wrong matrix. And the last part ignores the impact the rotation has on the relative translation.
Apr
14
comment OpenGL: glRotatef cause performance drop while rotating -x and -y
glRotatef will cause performance drops, period. It’s been superseded by better mechanisms for 10 years and deprecated for 6 years now. You should learn yourself some modern OpenGL instead.
Apr
2
comment Having trouble setting color in fragment shader
You can divide integers, but in GLSL, as is the case in C, C++ and many other languages, the result of 127 / 255 will be 0.
Apr
2
answered Having trouble setting color in fragment shader
Apr
1
revised How to use mocaps in your game if they don't loop smoothly?
reword a few things
Apr
1
answered How to use mocaps in your game if they don't loop smoothly?
Apr
1
awarded  Nice Answer
Mar
28
awarded  mathematics
Mar
27
answered How can I project a 3D point onto a 3D line?
Mar
27
comment Compute world position by walking N units along spline?
You should fix your variable names. If Distance is the alpha value, why not call it Alpha? And… what is Alpha, then?
Mar
27
answered Compute world position by walking N units along spline?
Mar
26
comment What is Vector Projection and what is it's use in games?
“Couldn't find a clear enough answer on Google.” Really? The first Google hits for me include vector projection in game development, vector projection in a maths tutorial, and vector operations for game programmers. Have you read them?
Mar
25
comment Which Unreal Engine 4 project files can I ignore in source control?
Yes, the engine needs a lot of modifications, and upstream UE is regularly merged into the repository.
Mar
24
comment How do I lerp between values that loop (such as hue or rotation)?
Dividing a vector by its length is called normalization. It ensures it has length 1. The len ? len : 1.0 part just avoids a division by zero, in the rare case that the mouse is placed exactly at the joint position. It could have been written: if (len != 0) dx /= len;.
Mar
23
answered How do I lerp between values that loop (such as hue or rotation)?
Mar
23
comment Compute cone angle (cos) given side and hypotenuse vectors at time 0 and world matrix at time 1
If your tests show no difference between Transform and TransformNormal, you are not testing enough :-) Try adding a translation part to your tranformation matrix.
Mar
23
answered Compute cone angle (cos) given side and hypotenuse vectors at time 0 and world matrix at time 1
Mar
22
comment Calculating the point(s) at which two moving objects are a certain distance from each other
Just a note: the code would be simpler if you did veld = e1.vel - e2.vel and used that variable everywhere instead of p, r, q and s.
Mar
21
answered Which Unreal Engine 4 project files can I ignore in source control?