Leaves emitter with irrlicht

Hi i need some help for creating a leaves emitter.

I have a heightfield and a
float getHeight(float x, float y)
method
wich gets the interpolated height of a terrain

as particles i will use a sprite set : a unique texture file wich have different leaves types (green leaves, yellow leaves, leaves of different shapes ecc).


what i need is to create an emitter and a animator wich can handle multiple leavese falling down around the player.
every leaves uses 32x32 and 16x16 portions of the sprite set (usually a 512x512 with 30-32 differente leaves).

so i have to set the initial position of a leave

initialHeight=getHeight(x,y)+tree height

and make them falling down until they reach the end of the terrain

finalHeight =getHeight(x,y)-epsilon

the most difficult part is animate leaves. i have no idea of what kind of function can reach a realistic falling down. I have tried with a spline but it is not clockwise with many leaves (up to 64 gives a realistic result, but this were done without a particle engine.)

I want to do that with irrlicht rendering plugin.
The project i'm working will be released opensource and much thanks to anyone can help me in a significative manner.

Another difficult point is how to use different UV sets using sparkirr for make possible render different leaves types using only 1 material.

Hi, I have moved the topic to "questions"

Regarding the use of "sprite set", you can do it with spark by using texture index parameter and IRRQuadRenderer::setAtlasDimensions. There are some examples in the demos using those (the fire demo for instance).

About the movement of falling leaves, you ll have to try and test. A modifier with a random force evolving per particle and a high friction should do it. There s a modifier in SPARK 2 called the random modifier. However SPARK 2 is not fully finished yet. But you can code your own modifier for SPARK 1 based on the random modifier. In this modifier you can also include a test to kill particles when they hit the ground and use immortal particles (with no defined life span).

So I suggest you try to get a nive behaviour by trying and testing in a custom modifier.

If you have some questions, dont hesitate.