Decals and Camerapicking

[Swampdonkey]

Well my eval period is just about over.. It's been a blast playing with the LE engine. I'd like to thank Leadwerks for the opertunity to try out the engine and I'd like to thank its community for help when I initality got started. During my month I've tried out a few projects but most recently I started working on some Tower Defense ideas using the sandbox and lua scripting. While I ran into many problems, some mine, some not; I felt that LE was all around ready to take on a major project. However some things held me back from 'jumping on board', camerapicks seemed flawed and differentiated from the documentation way to much - so much in fact i was forced to try a diffrent approach which ultimately failed, I never got Decals to work even though I followed the docs to the tee - later reading the older forums I found out they been broke since sometime from 2.0 to 2.27 but was never mentioned in any documentation or offical post by the LE team. This lead to many many wasted hours on my part. Overall I would like to keep LE in the back of mind for future projects, maybe once I feel i can trust it more. Granted I was bound to lua whereas normally I'd use a more optimized compiler but my over experience was very positive and I look forward to checking out this engine again in the future.

 

And to those wondering about tower defense in LE, I can only say "HELL YES". In 3 weeks time we almost had a prototype working in pure lua script... thats gotta' count for something aye?

 

Anyways, enough babbling from me.. I leave you all with a screenshot from my test pad Tower defense attempt under the Leadwerks label.. Fully working AI and Camera Railing.

 

[Marleys Ghost]

Nice screenie, I do like the look of that scene

[Canardia]

I use always EntityPick instead of CameraPick, because then you can have FPS/3rd person camera with the same logic. Never had any problems with EntityPick.

 

I think 2D decals are pretty useless, as they are just flat and don't give the look of a real 3D decal.

Same goes for emitters. I will try to implement a 3D way for both, since smoke emitters need also collisions, so they don't go through ceilings, same goes for rain emitters.

[Josh]

Nice work.

 

I am not aware of any problems with camera picking. I would not be surprised if there is a problem with mesh decals. I have not used the technique in a long time, and it is a little tricky to set up a proper material for it. Will look into it soon.

[Guest Red Ocktober]

post that screenshot in the gallery... it's great!!

 

one of the best i've seen...

 

--Mike

[AggrorJorn]

Very nice screenshot. Hope to see you active in the rest of the forum soon.

[Pixel Perfect]

That is the nicest 'in game' shot I've seen in Leadwerks.

 

Fully working AI and Camera Railing.

Wow ... I think that's worthy of a video

[Swampdonkey]

Thanks for the comments guys,

 

Lumooja Entitypick may work, does entity pick use callbacks? Havent looked into Entitypicks much yet as I figured camerapick would be the best choice but ..

[Canardia]

No, EntityPick doesn't use callbacks, it's just a simple function call and then you check the results:

	TPick pick;
if(EntityPick(&pick,eyemodel,3))
{
	TModel model=GetMeshModel(pick.entity);
	if(model)
	{
		pickedmodel=model;
		SetBodyGravityMode(pickedmodel,0);
	}
}

[Swampdonkey]

Thanks Lumooja, most helpful information there.

On a side note - have you a clue what Camerapick is returning to the pick.entity class? At first i thought it was the entity handle but clearly it isnt, then i tried the surface handle; still not, last i tried the material handle again not. For optmization purposes I would like to use Camerapick over Entitypick since I'll have many diffrent structures to determine a mouse click and preforming a seperate Entitypick per structure per loop dosen't seem logical to me.

[Canardia]

There's no difference in coding compared to CameraPick if you use the camera as source model for EntityPick.

[Swampdonkey]

Ah ha, thanks for that info - i was thinking entitypick was prefromed per entity not as a global sweep. That'll do it then. BTW is it possible that camerapick is returning the collision body to the picked.entity holder? Just curious but i think i'll go with entitypick for now. Thanks.

[Canardia]

CameraPick returns also the mesh, like EntityPick. However, radius must be always 0 with CameraPick, not sure if it works with EntityPick.

[Swampdonkey]

Seems the problem i was having with Camerapick lay within the model itself, to many subobjects attached to it. Appears to be wroking now after optimizing the mesh!. Although i've now constructed a better way to handle these picks by hiding the world pivot and placing cubes within the meshes bounding box parameters and just simply checking against those cubes for fast picking.

[Josh]

The camera pick function is a convenience function that calculates coordinates and then calls LinePick(). You do not need to use the callback for any pick function. It only provides an extra method of control.

 

The pick structure contains the picked entity, position, normal, and surface (if a mesh was picked). This structure is documented in the wiki:

http://leadwerks.com/wiki/index.php?title=Raycasting

 

You may also find this useful:

http://www.leadwerks.com/files/Tutorials/CPP/Collision_And_Raycasting.pdf

[Swampdonkey]

Thanks for the links, although I had previously sifted through those articles.. I eventually came to the realization the problem lay within the model and the way I had constructed it.. Further tinkering with the model I was able to achieve proper picking. Thanks for the help.