Calling TraceLine

[ap0stle2482]

I started writing my first bot a few months back, it was pretty slow going at first as i havent been programming very long, but with alot of reading books, forums etc.. i now have a bot that can follow waypoints, use ppather for navigation(navmesh is beyond me at this point) mine herb, blah blah blah. Anyway my problem is, that i get a target by going through the objectmanager and finding the closest target to me and using that as my target, which works very well until... i get into an area with buildings, i can check to see if my target is indoors to filter out those targets, but targets on the opposite side of a building still give me los issues, so i figured the next logical step would be to implement traceline. Ive searched and read all the threads on this site, i understand the values you need to pass and the flags however i really dont understand how to call this, my bot is in c# and the only c# example ive been able to find is in this thread http://www.mmowned.com/forums/wow-memory-editing/278757-traceline-implementation.html
The only hook i use is endscene and im assuming the example in this thread is for an injected dll, i guess basically what im asking is, is it possible to call traceline without injecting a dll into wow, and if so can you give me a push in the right direction.

Thanks for any help and sorry for the wall o text :yuck:

[Mr.Zunz]

IIRC you an only call traceline when your in-process

[YetiHunter]

umm you said you have a endscene hook.. so you're inprocess or whatever you want to call it. so it should be possible for you to call traceline from inside your endscene hook.

[Robske]

The only hook i use is endscene /* snip */ without injecting a dll into wow

More in/out-process mixups, yay.

I have no clue of your program's architecture so:

If you're hooking WoW's EndScene from a remote process (your C# program I assume) using EasyHook or w/e it would be best to allocate some memory in the target process, write the asm opcodes for the TraceLine call and invoke CreateRemoteThread (?), the return value of the TraceLine call will be in the eax register, which CreateRemoteThread returns. (Or somehow feed those opcodes to your hook, whatever is possible - you shouldn't run into any threading issues with traceline though)

If you inject a C# dll (.NET CLR hosting) then you can use the following prototype in your code:

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        protected delegate byte Traceline(ref WoWPoint end, ref WoWPoint start, ref WoWPoint result, ref float distance, uint flags, ref WoWPoint Optional);

[Viano]

Robske what is the uint flags thing for?
And what is TraceLine giving you anyway, how do you know if s.th. is behind a building?

[Robske]

Robske what is the uint flags thing for?
And what is TraceLine giving you anyway, how do you know if s.th. is behind a building?

- Hitflags (WMO, Ground, Liquids...), look at the sticky
- The return value can be interpreted as a boolean, true if the traceline succeeds, false if there's something in the way. If that's the case, the actual point of intersection will be stored in 'result', the distance from 'start' to 'end' (or the intersection) is stored in 'distance'.

[Apoc]

More in/out-process mixups, yay.

I have no clue of your program's architecture so:

If you're hooking WoW's EndScene from a remote process (your C# program I assume) using EasyHook or w/e it would be best to allocate some memory in the target process, write the asm opcodes for the TraceLine call and invoke CreateRemoteThread (?), the return value of the TraceLine call will be in the eax register, which CreateRemoteThread returns. (Or somehow feed those opcodes to your hook, whatever is possible - you shouldn't run into any threading issues with traceline though)

If you inject a C# dll (.NET CLR hosting) then you can use the following prototype in your code:

        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
        protected delegate byte Traceline(ref WoWPoint end, ref WoWPoint start, ref WoWPoint result, ref float distance, uint flags, ref WoWPoint Optional);

The last param isn't a Vec3 btw. (It's a struct, roughly 0x77C large.) It's optional, so I suggest just passing an int with the value of 0.

[MaiN]

- Hitflags (WMO, Ground, Liquids...), look at the sticky
- The return value can be interpreted as a boolean, true if the traceline succeeds, false if there's something in the way. If that's the case, the actual point of intersection will be stored in 'result', the distance from 'start' to 'end' (or the intersection) is stored in 'distance'.

Actually, distance will be the percentage the ray was cast before hit. 0.5 = 50%, which means it intersected when it had completed half of the trace.

[Robske]

The last param isn't a Vec3 btw. (It's a struct, roughly 0x77C large.) It's optional, so I suggest just passing an int with the value of 0.

Actually, distance will be the percentage the ray was cast before hit. 0.5 = 50%, which means it intersected when it had completed half of the trace.

Thanks for clearing that up.