Rain trick

[omaremad]

Making Rain with a particle system is pretty standard, rectangular particles can simulate rain streaks, however since irrlicht's particles have no axis align feature when you look up the streaks would give a incorrect appearance to the rain



Here is some simple code for a rain system that handles this case:
Particle setup

Code: Select all

scene::IParticleSystemSceneNode* ps = 0;
    ps = smgr->addParticleSystemSceneNode(false);
    ps->setParent(smgr->getActiveCamera());
    scene::IParticleEmitter* em = ps->createBoxEmitter(
                                      core::aabbox3d<f32>(-10,-10,-10,20,20,20),
                                      core::vector3df(0.00f,0.00f,0.0f),
                                      700,1000,
                                      video::SColor(0,255,255,255), video::SColor(0,255,255,255),
                                      500,2000);
 
    ps->setEmitter(em);
    em->drop();
    scene::IParticleAffector* paf =
        ps->createGravityAffector(core::vector3df(0.00f,-0.25f, 0.0f), 1000);
 
    ps->addAffector(paf);
    paf->drop();
 
    ps->setMaterialFlag(video::EMF_LIGHTING, false);
    ps->setMaterialType(EMT_TRANSPARENT_ALPHA_CHANNEL);
    ps->setMaterialTexture(0, driver->getTexture("raindrop.png"));

main loop code

Code: Select all

core::vector3df camDir=smgr->getActiveCamera()->getTarget()-smgr->getActiveCamera()->getAbsolutePosition();
        camDir=camDir.normalize();
        f32 camPitch = camDir.dotProduct(core::vector3df(0,1,0));
        if(camPitch<0.0)
        camPitch = camDir.dotProduct(core::vector3df(0,-1,0));
        camPitch=(1.0f-camPitch)+0.01;
        ps->setParticleSize(core::dimension2d<f32>(0.05f, 1.5f*camPitch));

[CuteAlien]

Just noting that IParticleSystemSceneNode has a function setParticlesAreGlobal which switches beween local and global positions. It's been a while since I done something like that (snow), but I remember we used that.

[devsh]

cmon, omaremad with your shader skill I was expecting hardware particles or at least HW billboards

but anyway, great work.. will be a lot of use for sparks in explosions

[xDan]

that's a great trick.

also a beautiful scene!

[Kalango]

You could try adding support to mesh particles and then build a custom scene node that alighns with the Y axis.
mesh particls are a nice feature for the engien, and the custom SN is easy business..