CameraPick

[Laurens]

Hi!

 

Do collisions have to be enabled in order for CameraPick to work?

 

I keep getting an AccessViolationException when trying to pick the terrain.

 

Thanks!

[L B]

Maybe Tyler could tell you a bit on this, but the raycasting is more than bugged in my version of the headers. I haven't experimented with it in LE or C/C++, so I didn't know how to translate it correctly. Here is my source for it. @Tyler, feel free to fix it:

 

using System;

namespace Leadwerks
{
public class Pick
{
	public Core.TPick Structure { get; private set; }

	public Vector3 Position
	{
		get
		{
			return new Vector3(Structure.x, Structure.y, Structure.z);
		}
	}

	public Vector3 Normal
	{
		get
		{
			return new Vector3(Structure.nx, Structure.ny, Structure.nz);
		}
	}

	public Entity Entity
	{
		get
		{
			return new Entity(Structure.entity);
		}
	}

	public Surface Surface
	{
		get
		{
			return new Surface(Structure.surface);
		}
	}
}

public static class Raycasting
{
	public static bool PointVisible(Vector3 origin, Vector3 end, float radius, int collisionType)
	{
		return Convert.ToBoolean(Core.PointVisible(origin.ToFloatArray(), end.ToFloatArray(), radius, collisionType, IntPtr.Zero));
	}

	public static bool EntityVisible(Entity origin, Entity end, float radius, int collisionType)
	{
		return Convert.ToBoolean(Core.EntityVisible(origin.Pointer, end.Pointer, radius, collisionType, IntPtr.Zero));
	}

	public static bool LinePick(Pick pick, Vector3 origin, Vector3 end, float radius, int collisionType)
	{
		return Convert.ToBoolean(Core.LinePick(pick.Structure, origin.ToFloatArray(), end.ToFloatArray(), radius, collisionType, IntPtr.Zero));
	}

	public static bool EntityPick(Pick pick, Entity entity, float range, float radius, int collisionType)
	{
		return Convert.ToBoolean(Core.EntityPick(pick.Structure, entity.Pointer, range, radius, collisionType, IntPtr.Zero));
	}

	public static bool CameraPick(Pick pick, Camera camera, Vector3 position, float radius, int collisionType)
	{
		return Convert.ToBoolean(Core.CameraPick(pick.Structure, camera.Pointer, position.ToFloatArray(), radius, collisionType, IntPtr.Zero));
	}
}
}

[Laurens]

I took a look at the TPick struct in the Core class. I noticed that the members of the struct are in a different order than specified here: http://www.leadwerks.com/wiki/index.php?title=Raycasting. Since it's a sequential layout kind, could this be causing the issue?

 

Cheers!

[TylerH]

Not sure what is going on with your Pick.Structure property there?

 

You need to use an attribute tag on your declaration of Pick:

 

I assume you have a using System.Runtime.InteropServices; at the top of your file, which you should always have if dealing with stuff between the managed <-> unmanaged boundary, which you are.

 

[MarshalAs(UnmanagedType.Struct),StructLayout(LayoutKind.Sequential]

public class Pick

{

...

}

 

That *should* be what you need to do, though I am not 100% sure. It seems most likely like you are dealing with an issue with the packing of your structure's members in memory.

 

Since these are private forums, I hope I don't get in trouble with posting this little bit of engine.dll source:

Function CameraPick_:Int(pick:Byte Ptr,camera:TCamera,p:Float Ptr,radius:Float=0.0,collisionType:Int,pickfilter:Byte Ptr=Null) "win32"
GCEnter()
UserPickFilter=pickfilter
Local pick1:TPick
pick1=CameraPick(camera,Vec3(p[0],p[1],p[2]),radius,collisionType,dllpickfilter)
If pick1
	MemCopy pick,pick1,4*9
	Return 1
EndIf
EndFunction

 

If you notice the call to MemCopy, it is copying 4 bytes per element * 9 elements.

 

EDIT: Ah, I see Structure is the core TPick thing, in that case, put the attribute tag on the declaration of the Core.TPick class, not the Pick class.

[TylerH]

So did that work, or no?

[Laurens]

Not sure if Ubu did any work on it, I havn't disassembled the new headers. I'll try it when I get home tonight.

[L B]

Haven't yet. Will be fixed in 1.2. I'm really busy right now, for personal reasons.

[Laurens]

Don't pace yourself, it should stay fun

[L B]

AccessViolationExceptions are the exact reason why people switch to C#: Avoid them.

In this case, it just can't be fun.

[Rekindled Phoenix]

Has the pick (struct) in the LE wrapper been updated? I haven't seen 1.2 released yet.

[L B]

No it hasn't.

[Rekindled Phoenix]

I'm really anticipating the fix for the picks in 1.2!

[Rekindled Phoenix]

 

EDIT: Ah, I see Structure is the core TPick thing, in that case, put the attribute tag on the declaration of the Core.TPick class, not the Pick class.

 

What'd you mean by this?

 

I can't get Picks to work.

[L B]

Tyler sent me a fix for the picks a couple of hours ago. I'll try to test it tomorrow. If it works, expect 1.2 soon.

[Rekindled Phoenix]

OMG you have just made my day. Thank you Ubu and Tyler!

 

I was getting so stressed about the Raycasting issue. My NPCs can't breathe without them. When you are done could you make an update to one of the pinned forum posts or note me?

[TylerH]

I can almost guarantee this fix will work.

 

If not, all the "out" keywords will just need changed to "ref" keywords and it is smooth sailing.

 

I had to consult my old Survival game I wrote in C# for Leadwerks 2.0, which had some LinePicks so the player could interact with entities and carry things around.