Make TPick.Pick() respect entity order

BlitzMax Forums/MiniB3D Module/Make TPick.Pick() respect entity order

ima747 (Posted 2009) [#1]

I'm using a bunch of camera picks in my project for the user to interact with various objects. Some are at different EntityOrders since they are HUD's etc. and tracking their scaling and motion would just be a nightmare so I just make the order under 0 and move them away a bit. This looks right (more or less) however picking doesn't respect orders, it just cycles the list of entity's and finds the closest thing that hits, but since closest and on top are two different things it often grabs the wrong thing. Can someone give me a point in the right direction for how I might go about this? it looks like I either needs to find a way to break each order set into it's own list and cycle lowest to highest (really bad idea), keep picking through everything then sort that list by entity order lowest to highest, or do some poking in C_Pick... and I can only see that ending in tears... Thoughts?

Sledge (Posted 2009) [#2]

Telling you the first thing hit by a ray is exactly what a pick is! For a layered system I would set up a second camera specifically for rendering and picking (child) HUD elements -- squirrel 'em away at some desolate coordinate, set the camera's cls mode appropriately (so rendering the HUD does not obliterate the main scene render) and off you go.

* (Posted 2009) [#3]

simply make the hud unpickable when you want to pick the rest.

ima747 (Posted 2009) [#4]

the problem I'm facing is that "the rest" are getting picked ahead of the hub. Perhaps I'm not explaining myself well, and perhaps re:sledge's response it's a bug... I have a HUD element 10 ahead of the camera on the z axis, it's entity order is -1 so it is drawn on top of normal things no matter it's depth. It's depth is used for size because scaling it would be troublesome for other reasons. This element picks fine normally, or if things are behind it (depth > 10). I have a normal entity passing 2 ahead of the camera with an entity order of 0. since the hud is -1 the hud is drawn on top, however if I try to click the hud element with the normal entity in position I get the entity (depth 2 despite the entity order) and not the hud element. This is either a bug in the ray cast for the pick (it doesn't respect entity order, only distance) or it's working as intended which doesn't make sense to me so I need a work around.

Sledge (Posted 2009) [#5]

Picks tell you which object they hit first, which will be the closest, which has nothing to do with the order you've opted to render them. A pick has no concept of the full stack of objects in front of it -- if it did, picking would be very costly rather than just costly! If it's not already clear, I'm saying this isn't a bug. Seriously, a dedicated HUD camera is the most elegant way to achieve what you want.

ima747 (Posted 2009) [#6]

I follow now, I was misunderstanding your previous post. Off to camera #2 land for me.

Sledge (Posted 2009) [#7]

Thought you might've got the wrong end of the stick. Here's some decidedly inelegant code I whipped up as an example... it includes a few different ways of doing things hence the chaos. :D SuperStrict Import sidesign.miniB3D AppTitle$ = "HUDCam" SeedRnd( MilliSecs() ) Graphics3D 800,600,32,2,60 Local galacticCentralPoint:TPivot = CreatePivot() Local mainCam:TCamera = CreateCamera(galacticCentralPoint) PositionEntity mainCam,0,8,-30 InitialiseHUD() AddToHUD("Button 1",1,4) AddToHUD("Button 2",4,4) Local light:TLight = CreateLight() PositionEntity light,100,100,-100 InitialiseBuildings(100) While Not ( KeyHit(KEY_ESCAPE) Or AppTerminate() ) TurnEntity galacticCentralPoint,0,0.5,0 RenderWorld BeginMax2D() DrawText "Scene Pick: "+PickToBuildingRef( CameraPick( mainCam,MouseX(),MouseY() ) ),10,10 DrawText "HUD Pick: "+PickToHUDElement ( CameraPick(THUD.cam,MouseX(),MouseY() ) ),10,30 EndMax2D() Flip Wend Type TBuilding Global list:TList = CreateList() Field geom:TMesh Field ref:Int Function Init(buildingCount_arg:Int) If buildingCount_arg<1 Return For Local buildingCount:Int = 1 To buildingCount_arg Local newBuilding:TBuilding = New TBuilding newBuilding.geom = CreateCube() EntityPickMode newBuilding.geom,2 EntityColor newBuilding.geom,150+Rand(0,100),150+Rand(0,100),150+Rand(0,100) newBuilding.ref = buildingCount Repeat PositionEntity newBuilding.geom,Rand(-50,50),0,Rand(-50,50) Local proximityWarn:Int = 0 For Local currentBuilding:TBuilding = EachIn list If EntityDistance(newBuilding.geom,currentBuilding.geom) < 3.0 proximityWarn:+1 Next If proximityWarn<1 Exit Forever ListAddLast list,newBuilding Next End Function End Type Function InitialiseBuildings(buildingCount_arg:Int) TBuilding.Init(buildingCount_arg) End Function Function PickToBuildingRef:String(picked:TEntity) For Local currentBuilding:TBuilding = EachIn TBuilding.list If currentBuilding.geom = picked Return currentBuilding.ref Next Return "NIL" End Function Type THUD Global cam:TCamera Global elementMap:TMap = CreateMap() Function Init() cam:TCamera = CreateCamera() CameraProjMode cam,2 CameraZoom cam,.010 CameraClsMode cam,False,True PositionEntity cam,1000,1000,1000 CameraRange cam,.1,10 End Function End Type Function InitialiseHUD() THUD.Init() End Function Function AddToHud(name_arg:String,x_arg:Int,y_arg:Int) Local newElement:TEntity = CreateCube(THUD.cam) EntityPickMode newElement,2 PositionEntity newElement,x_arg-9,y_arg-9,2 MapInsert THUD.elementMap,name_arg,newElement EndFunction Function PickToHUDElement:String(picked:TEntity) For Local mapElement:TNode = EachIn THUD.elementMap If TEntity(mapElement.Value()) = picked Return mapElement.Key().ToString() Next Return "NIL" End Function

ima747 (Posted 2009) [#8]

Thanks sledge, I think I can dig through that. I used 2 cams once a long long time ago but having an example on hand is going to save a lot of time :0)