Aiming.

[DigitalHax]

Hello. I was wondering how I would create something similar to the turret in half life 2. Specifically the aiming side. I want to have so when I move the mouse on the screen, it sets the a model to point to where I am pointing - including the distance so if I point really far, it will set the right angle. This is a bit of a tricky one, but I hope someone here understands me.

 

Thanks in advance.

[Pixel Perfect]

Take a look at the function CameraProject. This projects the specified screen coordinates into world coordinates. Once you have that the rest should be fairly straight forward.

[DigitalHax]

Will that include distance or depth?

[Pixel Perfect]

Try the examples, they appear to use a depth buffer but I've never actually used it. Failing that you could alternatively use CameraPick. I use that in my Editor for placing items in the world based on the mouse position on the screen:

 

gotSurface = CameraPick(&pickStruct, camera,Vec3(MouseX(),MouseY(), 1000),0,0,NULL);

 

you can extract the position from the pickStruct. If nothing is returned you can assume it exceeds the raycast distance and assume a default far distance value.

[DigitalHax]

I seem to be encountering some compile problems...

 

 

 

[error C2440: 'initializing' : cannot convert from 'int' to 'LE::TPick'

No constructor could take the source type, or constructor overload resolution was ambiguous]

 

this is my basic code,

 

 

TPick pickS;

 

gotSurface = CameraPick(&pickS, camera,Vec3(MouseX(),MouseY(), 1000),0,0,NULL);

 

What is going wrong?

[Road Kill Kenny]

Have you defined 'gotSurface' ... if so what did you define it as?

[DigitalHax]

I tried both a TVec3 and a TPick...

 

Both had errors

[Road Kill Kenny]

That's because it should be an 'int' because CameraPick() returns and integer.

 

In fact you don't even need the gotSurface, just delete it. All it will store is a 1 or a 0. 1 if it hit and 0 if it didn't, nothing else. You only need it if you want to check later in your code if it hit something.

 

The data of the position hit is stored in pickS.x, pickS.y, pickS.z as shown here http://www.leadwerks.com/wiki/index.php?title=Raycasting

[Pixel Perfect]

That's correct, it should be an int. It is just used to check whether something was hit or not