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1

General discussions / Vec3, Vec2 Speed Test

« on: September 08, 2009, 12:31:46 pm »

This weekend I spend some time looking for a performance boosts, one of the things I tested where our vec2/3/4 classes. First off we have our own, we are not using those provided by sfml, we only use sfml to open a window and manage input (atm). But sins the classes look alike I was left wondering way Vec3 and Vec2 are not declared inline and even further down way are some huge Unicode function inline ?

Below some of the different way's I tested …

Initial Code: Overload outside of the class

Code: [Select]

   template <typename T>
    class Vec2
    {
        public:
           ...
    };

    template <typename T>
    Vec2<T> operator* (const Vec2<T>& v1, const T& v2);

    ...
    template <typename T>
    inline Vec2<T> operator* (const T& v2)
    {
        return Vec2<T>(v[0]*v2, v[1]*v2);
    }

improvement 1: Overload inside the class

Code: [Select]

   template <typename T>
    class Vec2
    {
        public:
            ...
       Vec2<T> operator* (const Vec2<T>& v2);
            ...
    };

    ...
    template <typename T>
    Vec2<T> Vec2<T>::operator* (const T& v2)
    {
        return Vec2<T>(v[0]*v2, v[1]*v2);
    }

improvement 2: inline decelerations

Code: [Select]

   template <typename T>
    class Vec2
    {
        public:
            ...
       Vec2<T> operator* (const T& v2);
            ...
    };

    ...
    template <typename T>
    inline Vec2<T> Vec2<T>::operator* (const T& v2)
    {
        return Vec2<T>(v[0]*v2, v[1]*v2);
    }

- The actual test involved drawing 125k cubes and animating them, this lead to +-8 million operations with vec2/3 per frame. The test was repeated 100(frames) * 2 (linux, windows) * 3 different pc's …
- I tried a lot more then just the 2 above but those stood out and they did not break anything (in our engine)
- Only tested with gcc both on linux and windows …

So here are the results I got:

Initial Code = 100%
improvement 1 = 126,23% - 26% faster
improvement 2 = 277,60% - 177% faster

The classes in sfml kinda look like our initial code, so maybe it would be a boost for sfml as well ? Is there a specific reason sfml is overloading outside of the class ? Something I might have missed ?

 

2

General discussions / sf::string Vertex Array ?

« on: August 09, 2009, 07:15:57 pm »

so I'm looking at the stuff needed to build a gui in to my little engine and I was wondering way sf::string did not use a vertex array to reduce the amount of openGL calls. I can see way this of little use when rendering spirits and the likes but ... ?

vertex array are openGL 1.1 so they are supported on almost all hardware that I can think off or ? If I'm right sfml aims to be 1.2 minimum ?

just a random thought/question  :lol: