particle gravity affector

[riveranb]

Hi, everyone,
I think maybe I can share some experiences on my graphics coding about irrlicht.

I want to talk about the CParticleGravityAffector. The original version is as below:

Code: Select all

 
void CParticleGravityAffector::affect(u32 now, SParticle* particlearray, u32 count)
{
        if (!Enabled)
                return;
        f32 d;
        for (u32 i=0; i<count; ++i)
        {
                d = (now - particlearray[i].startTime) / TimeForceLost;
                if (d > 1.0f)
                        d = 1.0f;
                if (d < 0.0f)
                        d = 0.0f;
                d = 1.0f - d;
                particlearray[i].vector = particlearray[i].startVector.getInterpolated(Gravity, d);
        }
}
 

And I think it's better to modify the particle position with consideration to newton's movement law.

// approximate the newton's low
// X = V0 * t + (a + g) * t * t/2
particle-pos = ( particle-vector * ratio + gravity) * t * t / 2;
ratio is to decrease the influence of the particle-vector (as the a component)

I think I got better approximation of gravity this way.

Sorry for some reason, I modify the article to skip some source codes.

[CuteAlien]

Hm, should probably rather offer both options, otherwise the effects from people already using this are broken.

[Cube_]

nice