Multiple Linepicks?
Blitz3D Forums/Blitz3D Programming/Multiple Linepicks?
| ||
| This may be either a very reasonable question or a very stupid one: is it possible to have more than one linepick? |
| ||
| You can call any of the pick commands, LinePick included, any number of times. But too many calls to these can slow your program down, especially if you have a scene with lots of objects and if these objects have complex geometry. EDIT: Also be aware that each LinePick will overwrite the contact data of the last call to it. |
| ||
| There are some tricks to do many linepicks without producing too much slowdown : Each pickable must be a low tris mesh. (has the minimum number of tris possible) For each mesh that you want to be able to pick, calculate a max radius (depending on if the width or the depth of the mesh is the maximum, calculate the diagonal/2) Then instead of doing a linepick against all meshes of the world Set all meshes to not pickable entitypickmode(mesh,0) Then calculate which meshes are near enough the start point of the linepick, depending on the length of the linepick, and the radius of the mesh you want to be able to pick. if the mesh is near enough consider this mesh set this mesh as pickable entitypickmode(mesh,2) if the mesh is too far don't consider this mesh then do the linepicks one at a time if the linepicks have not a great length, the calculation will be very fast because there will be only a few low tris pickables to consider each time. I have done as much as 90x10 = 900 linepicks per frame in less than 20ms with this approach. Another tip is to specify a bigger radius. This decreases the number of linepicks you have to do. |
| ||
| I've done it. I wanted to know EVERYTHING a line would point to, so I did a linepick and excluded whatever is picked and then do another linkepick, etc... I turned it into a function call linepickall, lost track of it many years ago but the basics are simple enough to write it in half an hour or so. |
| ||
| Is it possible to hook a camera linepick ?, ie where the line pointing at the camera. |
| ||
| See command 'CameraPick'. |
| ||
| Stevie G, distance on cameraPick? |
| ||
| Yue, it doesn't use a distance, you can basically pick anything close OR far away from you as long as it is in view. Like so: picked = CameraPick(camera, MouseX(), MouseY()) |
| ||
| Therefore I would hitch a linepick to the camera, but it seems impossible, because with a line have a chance to set the distance of the line. |
| ||
If you want the line to have a specific distance use ...Tformvector 0,0,LengthOfLine, CameraEntity, 0 LinePick EntityX( CameraEntity , 1 ), EntityY( CameraEntity, 1 ), EntityZ( CameraEntity, 1 ), Tformedx(), Tformedy(), Tformedz() |
| ||
| Stevie G, Thanks You =) |
| ||
| This is good stuff, might be playing with a bit of linepicking maself tomorrow! |
   |