Remove vertex? (clean mesh)
Blitz3D Forums/Blitz3D Programming/Remove vertex? (clean mesh)
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| Hi all, If I create two cubes and place them right next to each other on the x-axis (one is a child of the other), is it possible to weld the two shapes together by identifying the overlapping vertices and removing one of them? I didn't see a 'delete vertex' command when I was browsing the docs, sorry if I missed it! Basically in my editor I place a load of meshes then save them out as a single mesh for collision, but there are times when I place one wall next to another, and there are 'extra' poly/verts where two shapes overlay exactly, so for performace I'd like to detect and remove these for more geometrically sound models. Thoughts welcome! Cheers, LW. |
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| Maybe you could create a function that copies the whole surface without without those vertices |
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| There isn't a 'delete vertex' command. To delete a vertex you must manually rebuild the entire mesh, sans-aforementioned vertex. If you want to weld vertices then you should do it the same way 3DS Max etc does it; i.e. with proximity checks between each vertex. |
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| use ClearSurface Surface,true => It cleans ALL vertices within the surface. The way to weld vertex together : ( according, you 'll maybe weld two vertices with different UV ... so take car what you expect ^^ ) +> Copy vertices into array/Types etc... ( copy infos : Coords,Normals,UV, Color ) +> Copy triangle into an array copy the 3 TriangleVertex(Surfave,Triangle,0/1/2) Clearsurface Surface,True,True => it will "delete" every vertices and every triangles. +> rebuild surface using the stored array. Take care with the Id you'll use too rebuild, according you deleted some one those ^^ |
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| Thanks, looks like this is going to be possible with some work. Cheers, LW. |
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| Entityalpha StevieG, 1 @ LamptonWorm, I have a function which I use for this very purpose. Code and example below. Note that the function expects the mesh which is passed to be unwelded. Graphics3D 640,480,16,1 Global LIGHT = CreateLight() Global CUBE = MESHcull( CreateCube() , C_Top+C_Right ) EntityFX CUBE, 4 Global CAMERA = CreateCamera() PositionEntity CAMERA, 0,5,-10 PointEntity CAMERA, CUBE Const C_Front = 1 Const C_Rear = 4 Const C_Left = 8 Const C_Right = 2 Const C_Top = 16 Const C_Bottom = 32 While Not KeyDown(1) TurnEntity CUBE, 0,1,0 ;1,0,1 RenderWorld() Flip Wend ;===================================================================================== ;===================================================================================== ;===================================================================================== Function MESHcull( Mesh , Flags = 0 ) If Flags = 0 Return Mesh copy = CopyMesh( Mesh ) s = GetSurface( copy, 1 ) Cs = GetSurface( mesh , 1 ) ClearSurface Cs, 1, 1 For t = 0 To CountTriangles( s )-1 ;calculate triangle normal v0 = TriangleVertex( s, t, 0 ) v1 = TriangleVertex( s, t, 1 ) v2 = TriangleVertex( s, t, 2 ) ax# = VertexX( s, v1 ) - VertexX( s, v0 ) ay# = VertexY( s, v1 ) - VertexY( s, v0 ) az# = VertexZ( s, v1 ) - VertexZ( s, v0 ) bx# = VertexX( s, v2 ) - VertexX( s, v1 ) by# = VertexY( s, v2 ) - VertexY( s, v1 ) bz# = VertexZ( s, v2 ) - VertexZ( s, v1 ) Nx# = ( ay * bz ) - ( az * by ) Ny# = ( az * bx ) - ( ax * bz ) Nz# = ( ax * by ) - ( ay * bx ) Ns# = Sqr( Nx * Nx + Ny*Ny + Nz*Nz ) Nx = Nx / Ns Ny = Ny / Ns Nz = Nz / Ns OK = True For l = 0 To 5 Flag = 2^l If ( Flags And Flag) = Flag ;determine plane normal Select Flag Case C_Front px# = 0 : py# = 0 : pz# = 1 Case C_Rear px# = 0 : py# = 0 : pz# = -1 Case C_Left px# = -1 : py# = 0 : pz# = 0 Case C_Right px# = 1 : py# = 0 : pz# = 0 Case C_Top px# = 0 : py# = 1 : pz# = 0 Case C_Bottom px# = 0 : py# = -1 : pz# = 0 End Select If Nx = Px And Ny = Py And Nz = Pz OK = False EndIf Next If OK nv0 = AddVertex( Cs, VertexX( s , v0 ) , VertexY( s, v0 ) , VertexZ( s, v0 ) ) nv1 = AddVertex( Cs, VertexX( s , v1 ) , VertexY( s, v1 ) , VertexZ( s, v1 ) ) nv2 = AddVertex( Cs, VertexX( s , v2 ) , VertexY( s, v2 ) , VertexZ( s, v2 ) ) VertexNormal Cs , nv0 , Nx, Ny, Nz VertexNormal Cs , nv1 , Nx, Ny, Nz VertexNormal Cs , nv2 , Nx, Ny, Nz AddTriangle( Cs , nv0, nv1, nv2 ) EndIf Next FreeEntity copy Return Mesh End Function Entityalpha StevieG, 0 |
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| lmao @ stevie Your collision responce is still being processed. Best watch yourself. Oh wait, your making yourself visible. I see. :oS HideEntity RossC |
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| Thanks Stevie G, I'll have a play. Cheers, LW. |
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| I'm trying to understand this function StevieG. Is it a function that deals with cubes only? Cheers, and thanks for any detail on the workings. |
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| The cube just looks like a test mesh. The function copies the original mesh, iterates through all tris, and then returns the newly processed mesh. |
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| I'm trying to understand this function StevieG. Is it a function that deals with cubes only? It can deal with other shapes but can only cull triangles which have face normals which exactly match one of the 6 culling normals. So, for example if you created a cylinder and wanted to remove the bottom triangles only you would have to apply an unweld function which combines the cylinder into one surface ( blitz normally creates 2 x surfaces ) and then call MESHcull( cyclinder, C_Bottom ). I use it to build meshes in code and remove triangles which aren't seen. Big10p has a function in the archives which culls triangles based on a rotated plane which would probably be better for you. Stevie |
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| Hi, Quick question - can the function be adapted to preserve any texture applied to the mesh that gets culled? I tried re-texturing after but no joy (yet). Cheers! LW. |
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I think that you need to set the UV coordinates for each vertex. You can read them with VertexU and VertexV and set them with VertexTexCoords.nv0 = AddVertex( Cs, VertexX( s , v0 ), VertexY( s, v0 ), VertexZ( s, v0 ), VertexU(s, v0), VertexV(s, v0) ) nv1 = AddVertex( Cs, VertexX( s , v1 ), VertexY( s, v1 ), VertexZ( s, v1 ), VertexU(s, v1), VertexV(s, v1) ) nv2 = AddVertex( Cs, VertexX( s , v2 ), VertexY( s, v2 ), VertexZ( s, v2 ), VertexU(s, v2), VertexV(s, v2) ) |
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| Nice - thanks! |
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