Irrlicht Engine

Posted: **Thu Jul 15, 2004 8:54 am**

Hi

I'm creating my fps... now, i'm writing the shot part.

I've an FPS camera and a child shotgun attach to it. I should to calculate the line for the staight animator (bullet's trajectory). When I select as start point the camera position, all work correctly and irrlicht create bullet at same position of camera. but... if I select as start point the shotgun position... irrlicht create the bullet at position 0,0,0... WHYYYYYY (I've controlled the position of shotgun many times and it is NOT 0,0,0

)

Shotgun is a child of camera, and it's position not would have to be approximately the same position of camera?

Plese help me

and excuse my bad english

Posted: **Thu Jul 15, 2004 10:04 am**

Instead of:

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yourShotGunNode->getPosition ();

try using:

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yourShotGunNode->getAbsolutePosition ();

Posted: **Thu Jul 15, 2004 1:48 pm**

Using "getAbsolutePosition()" problem is partially resolved... now, irrlicht create bullet at same position of my shotgun... but the bullet dosen't fly in correct direction. I use this code:

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if (shotgun != 0 && event.EventType == EET_MOUSE_INPUT_EVENT &&
    event.MouseInput.Event == EMIE_LMOUSE_PRESSED_DOWN)
{
   if (ok == 1) {
   if (ammo > 0) {				
   vector3df start = (shotgun->getAbsolutePosition());
   vector3df end = (camera->getTarget()-start);
   end.normalize();
   end = start + (end * camera->getFarValue());
   IAnimatedMesh* mesh_bullet = smgr->getMesh("bullet.3ds");
   IAnimatedMeshSceneNode* bullet = smgr->addAnimatedMeshSceneNode(mesh_bullet, 0, -1, shotgun->getAbsolutePosition() );
   bullet->setMaterialTexture(0, driver->getTexture("texture_bullet.bmp"));
   bullet->setMaterialType(EMT_SPHERE_MAP);
   bullet->setMaterialFlag(EMF_LIGHTING, true);
   ISceneNodeAnimator* anim = 0;
   anim = smgr->createFlyStraightAnimator(start, end, 5000, false);
   bullet->addAnimator(anim);
   anim->drop(); 
       }
    }
 }
return true;

I think that code is correct but the bullet have a strange trajectory... can anyone help me?

Posted: **Fri Jul 16, 2004 10:53 pm**

Nobody can help me?

Then... exists some tutorial that explains how to make?

Thanks

Posted: **Sun Aug 22, 2004 5:58 pm**

Man I solved this problem this way:

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	vector3df start = gun->getAbsolutePosition();

	float xModulus = camera->getTarget().X - camera->getPosition().X;
	float yModulus = camera->getTarget().Y - camera->getPosition().Y;
	float zModulus = camera->getTarget().Z - camera->getPosition().Z;

	vector3df gunTarget = vector3df(gun->getAbsolutePosition().X + xModulus,
		                            gun->getAbsolutePosition().Y + yModulus,
									gun->getAbsolutePosition().Z + zModulus);

	vector3df end   = (gunTarget - start);
	end.normalize();
	end = start + (end * camera->getFarValue());

Posted: **Mon Aug 23, 2004 12:43 pm**

I ignore the camera in my shooting code, after all I might not always want to shoot where the camera is pointing and I consider it bad form to depend on the camera. Get the transformation matrix of the shotgun. You can create a target vector like this
vector3df(targetDist,0,0) targetVec;
matrix.transformVect(targetVec);

Assuming the x axis is the front of the shotgun (plenty use Z instead) and that the variably matrix holds the absolute transformation of the shotgun. You can now create a line with the shotgun position at one endpt and the transformed targetVec at the other endpt.

Irrlicht Engine

Argh!

Argh!

Bullets leaving from the right place