driver->setTextureCreationFlag(video::ETCF_ALWAYS_32_BIT, true);
scene::ITerrainSceneNode* terrain = smgr->addTerrainSceneNode("da.bmp");
terrain->setMaterialType(video::EMT_LIGHTMAP_ADD);
terrain->setMaterialTexture(0, driver->getTexture("da_tex.png"));
terrain->setMaterialFlag(video::EMF_LIGHTING, false);
terrain->setMaterialFlag(video::EMF_FOG, false);

scene::ITriangleSelector* selector = smgr->createTerrainTriangleSelector(terrain, 0);
terrain->setTriangleSelector(selector);
terrain->setDynamicSelectorUpdate(true);

IMeshBuffer  *mb = terrain->getRenderBuffer();

irr::core::triangle3df poly;
irr::core::vector3df collide;
ISceneCollisionManager  * cm = smgr->getSceneCollisionManager();
irr::core::line3df ray = cm->getRayFromScreenCoordinates(device->getCursorControl()->getPosition(),0);
ISceneNode *tmp = cm->getCollisionPoint(ray,selector,collide, poly,tmp);
if(&tmp != &terrain) break;

// poly.pointA .y +=
// poly.pointB .y +=
// poly.pointC .y +=

switch(mb->getVertexType())
{
       case EVT_STANDARD: 
            video::S3DVertex *vertices = (video::S3DVertex*)mb->getVertices();
             // je te laisse bosser un peut ici ...
       break;
       case EVT_2TCOORDS: 
            video::S3DVertex2TCoords *vertices = (video::S3DVertex2TCoords*)mb->getVertices();
             // ici ...
       break;
       case EVT_TANGENTS: 
            video::S3DVertexTangents *vertices = (video::S3DVertexTangents*)mb->getVertices();
             // et ici ...
       break;
}