Turret target tracking/Missile target tracking[solved]

[radishlaw]

Hi all,

I have been trying my hands at doing a 3D capital ship battle game in space. Irrlicht has been very useful until I got to the turret/missile part.
I have tried to search for a way to determine which way to turn for a turret/missile to track their target. Unfortunately, it's a lot more difficult than doing such things in 2D and all the method I can find either didn't work or become very strange when the target pass over the turret/missile (maybe it's the dreaded gimble lock?)
I have tried to look for solutions in this forum, GameDev.net and Google, and so far I do not have any code that has the function of "give amount of angle needed to turn to target".
Perhaps someone can be so kind as to enlighten me on this matter. Any example would be most welcome.

[Acki]

A simple solution I use for simple steering is to add a FPS camera to the turret...
Then set the target (look at) of the camera at the enemy...
If the turret is a child of the camera, the turret then will also look at the enemy...
And/or you can get the angles of the camera...

[radishlaw]

I tried something like this but get very strange results

Code: Select all

irr::core::matrix4 test;
		
GameEngine* game = GameEngine::Instance();

irr::core::matrix4 Rot;		
		
Rot.setRotationDegrees(this->ProjectileNode->getRotation());

core::vector3df up_vec = core::vector3df(0,1,0);

Rot.rotateVect(up_vec);
                           test.buildCameraLookAtMatrixLH(this->ProjectileNode->getAbsolutePosition(),game->GetShip(this->Target_ID)->getPosition(),up_vec);

this->ProjectileNode->setRotation(test.getRotationDegrees());

The projectile just go in the direction with opposite "yaw" (x-axis flipped?)

[vitek]

I think you want buildCameraLookAtMatrixRH.

I'm guessing that your ships and projectile are children of the root scene node. If they are not you need to be sure to use getAbsolutePosition() and to undo the rotation from parent to world so that the new rotation is just the rotation from parent to projectile.

Travis

[radishlaw]

I tried 9 methods and 2 finally works
it seems that there were some problem with my code such that
it didn't work before

Code: Select all

//
		//method 7 (Working)
		//http://irrlicht.sourceforge.net/phpBB2/viewtopic.php?t=18538
		//
		irr::core::matrix4 test;
		
		GameEngine* game = GameEngine::Instance();

		irr::core::matrix4 Rot;

		Rot.setRotationDegrees(this->ProjectileNode->getRotation());
		
		core::vector3df up_vec = core::vector3df(0,1,0);
		
		Rot.transformVect(up_vec);
		test.buildCameraLookAtMatrixLH(this->ProjectileNode->getAbsolutePosition(),game->GetShip(this->Target_ID)->getPosition(),up_vec);
		
		core::vector3df test_Rot = test.getRotationDegrees();		
		
		this->setRotation(core::vector3df(0,0,0));
		this->rotate(core::vector3df(0,0,test_Rot.Z));
		this->rotate(core::vector3df(test_Rot.X,0,0));
		this->rotate(core::vector3df(0,test_Rot.Y,0));

Code: Select all

//periodic change in height
					float Height_Diff = this->getPosition().Y - game->GetShip(this->Target_ID)->getPosition().Y;
					float Dist = sqrt( (this->getPosition().Z - game->GetShip(this->Target_ID)->getPosition().Z) * 
						(this->getPosition().Z - game->GetShip(this->Target_ID)->getPosition().Z)
						+ (this->getPosition().X - game->GetShip(this->Target_ID)->getPosition().X) *
						(this->getPosition().X - game->GetShip(this->Target_ID)->getPosition().X));
					float Y_angle = atanf(Height_Diff / Dist);

					//track hozi
					core::vector3df Difference = game->GetShip(this->Target_ID)->getPosition() - this->getPosition();
					core::vector3df XZ_Angle = Difference.getHorizontalAngle();

					
					this->setRotation(XZ_Angle);
					this->rotate(core::vector3df(0,Y_angle*2,0));