Falling attached objects

Lunacore · Post by **Lunacore** » Wed Mar 16, 2011 6:25 pm

My new problem, i get, is the following:
On setPosition, my player and all objects attached on it will change it's position, but while my player is falling due to gravity, the attached objects are
falling slower until the player reaches the ground.

Code: Select all

//Load meshes
IMesh* Hairs = smgr->getMesh("../models/Hair.obj");
IAnimatedMesh* MeshModel0 = smgr->getMesh("../models/player.ms3d");
IMesh* MeshModel1 = smgr->getMesh("../models/Sword.obj");
IMesh* MeshModel2 = smgr->getMesh("../models/Sword.ms3d");


//Load player
Player[0] = smgr->addAnimatedMeshSceneNode(MeshModel0);
Player[0]->setFrameLoop(31,37); Player[k]->setAnimationSpeed(15);
Player[0]->setTransitionTime(0.2);
//Create collisions
anim[0] = smgr->createCollisionResponseAnimator( //Kollision für Spieler i einfügen
										selector, Player[0], core::vector3df(30,100,30),
										core::vector3df(0,-3,0), //gravity
										core::vector3df(0,-100,0));
Player[0]->addAnimator(anim[0]);

//Add hair
Head             = Player[0]->getMS3DJointNode("Head");
StaticObjects[0] = smgr->addMeshSceneNode(Hairs);
StaticObjects[0] -> setRotation(vector3df(-90,0,90));
StaticObjects[0] -> setPosition(vector3df(-3,0,-13));
Head             ->addChild(StaticObjects[0]);

//Add Weapons
Weapon[0] = smgr->addMeshSceneNode(MeshModel1);
Weapon[1] = smgr->addMeshSceneNode(MeshModel2);           
//Get pointer
RechteHand[0] = Player[0]->getMS3DJointNode("WeaponR");
LinkeHand[0] = Player[0]->getMS3DJointNode("WeaponL");
//Add weapon to pointer
RechteHand[0]->addChild(Weapon[0]); 
LinkeHand[0]->addChild(Weapon[1]);

When i move along X/Z-axes, the attached models will be on their correct position. The problem only occurs at Y-axis during gravity.

ChaiRuiPeng · Post by **ChaiRuiPeng** » Wed Mar 16, 2011 6:42 pm

how are you "applying gravity"

simply through setPosition() applied ONLY to parent?

are there any rotations you are applying to parent?

Lunacore · Post by **Lunacore** » Wed Mar 16, 2011 6:50 pm

I move only through setPosition() and setRotation on Player[0], weapons and hair will move automatically. This is not the problem.

As shown above I apply the gravity only to my player character, because the position of the attached objects are relpative to the characters position.

Code: Select all

anim[0] = smgr->createCollisionResponseAnimator(
                              selector, Player[0], core::vector3df(30,100,30),
                              core::vector3df(0,-3,0), //gravity
                              core::vector3df(0,-100,0));
Player[0]->addAnimator(anim[0]);

While he is falling, the mesh of the character falls faster then attached objects..

shadowslair · Post by **shadowslair** » Wed Mar 16, 2011 7:02 pm

You need to update all children transformations. Try creating some help function to update all children recursively. Put it on place where you`re done moving/rotating your character. Sth like (untested, but should(™) work):

Code: Select all

void updateChildrenTransf(scene::ISceneNode *node)
{
   node->updateAbsolutePosition();
   core::list<scene::ISceneNode*>::ConstIterator it = node->getChildren().begin();
   for (; it != node->getChildren().end(); ++it)
   {
      updateChildrenTransf((*it));
   }
}

May be a bit slower, but should fix your problem.

Lunacore · Post by **Lunacore** » Wed Mar 16, 2011 7:33 pm

I updated all nodes (parents and children), but the problem still exist.
Here a little cutscene, what I mean: Youtube

Another problem:
On the first program start, only the hair has the exact position while falling (like in the video).
On another program start without changing anything, only the shield has the exact position and the hair is like the sword above the player while falling.
Is this a bug by Irrlicht? o0

shadowslair · Post by **shadowslair** » Wed Mar 16, 2011 8:23 pm

Ah, just spotted you`re using collision animator. Most probably it`s causing the problem, because it`s affecting the node position right before being rendered, so the bone children are being positioned one frame later, because most probably they`re not in the ISceneNode::Children list. Unfortunately I personally cannot think of an easy way around that, except to not use the build-in collision animator, but some other system instead. May be wrong though- it`s been a while since I used the irr collision.

About the other problem- it may be caused by many things like using uninitialized values (for ex. initialized, but like: int myValue; then used, before being set to some real value) or sth else. And no, I doubt its an Irrlicht bug, because I have never had such problems. But you`re free to use the debugger for that.