[bb] Removing Triangles and Vertices by Mr Snidesmin [ 1+ years ago ]

[BlitzBot]

Title : Removing Triangles and Vertices
Author : Mr Snidesmin
Posted : 1+ years ago

Description : A few useful functions. Note: they will probably be slow for large meshes.

RemoveTriangle(surface%, triangle_index%)
-removes specified triangle from a surface

RemoveVertex(surface%, vertex_index%)
-removes specified vertex from a surface

VertexIsUsed(surface%, vi%)
-returns true if vertex index is used in a triangle.

ClearUnusedVertices%(surface%)
-removes unused vertices in a surface

Code :

Code (blitzbasic) Select Expand

Function VertexIsUsed(surface%, vi%)
For i% = 0 To CountTriangles(surface) - 1
If TriangleVertex(surface, i, 0) = vi Then Return True
If TriangleVertex(surface, i, 1) = vi Then Return True
If TriangleVertex(surface, i, 2) = vi Then Return True
Next
Return False
End Function

Function ClearUnusedVertices%(surface%)
For i% = 0 To CountVertices(surface) - 1
If Not VertexIsUsed(surface, i) Then
RemoveVertex surface, i
End If
Next
End Function


Function RemoveTriangle(surface%, triangle_index%)
s0% = surface
m% = CreateMesh()
s% = CreateSurface(m)

;copy, excluding triangle:
For i% = 0 To CountVertices(s0)-1
vi% = AddVertex(s, VertexX(s0, i),VertexY(s0, i),VertexZ(s0, i),VertexU(s0, i),VertexV(s0, i),VertexW(s0, i))
VertexNormal s, vi, VertexNX(s0, i), VertexNY(s0, i), VertexNZ(s0, i)
VertexColor s, vi, VertexRed(s0, i), VertexGreen(s0, i), VertexBlue(s0, i), VertexAlpha(s0, i)
Next
For i% = 0 To CountTriangles(s0)-1
If i <> triangle_index Then
AddTriangle s, TriangleVertex(s0, i, 0), TriangleVertex(s0, i, 1), TriangleVertex(s0, i, 2)
End If
Next

;copy back
CopySurface s, s0
FreeEntity m
End Function


Function RemoveVertex(surface%, vertex_index%)
s0% = surface
m% = CreateMesh()
s% = CreateSurface(m)

;copy, excluding vertex:
For i% = 0 To CountVertices(s0)-1
If i <> vertex_index Then
vi% = AddVertex(s, VertexX(s0, i),VertexY(s0, i),VertexZ(s0, i),VertexU(s0, i),VertexV(s0, i),VertexW(s0, i))
VertexNormal s, vi, VertexNX(s0, i), VertexNY(s0, i), VertexNZ(s0, i)
VertexColor s, vi, VertexRed(s0, i), VertexGreen(s0, i), VertexBlue(s0, i), VertexAlpha(s0, i)
End If
Next
For i% = 0 To CountTriangles(s0)-1
v0% = TriangleVertex(s0, i, 0)
v1% = TriangleVertex(s0, i, 1)
v2% = TriangleVertex(s0, i, 2)

If v0 > vertex_index Then v0 = v0 - 1
If v1 > vertex_index Then v1 = v1 - 1
If v2 > vertex_index Then v2 = v2 - 1
AddTriangle s, v0, v1, v2
Next

;copy back
CopySurface s, s0
FreeEntity m
End Function



Function CopySurface(source%, dest%, clear_unused_vertices%=False)
s0% = source
s% = dest
ClearSurface s

For i% = 0 To CountVertices(s0)-1
vi% = AddVertex(s, VertexX(s0, i),VertexY(s0, i),VertexZ(s0, i),VertexU(s0, i),VertexV(s0, i),VertexW(s0, i))
VertexNormal s, vi, VertexNX(s0, i), VertexNY(s0, i), VertexNZ(s0, i)
VertexColor s, vi, VertexRed(s0, i), VertexGreen(s0, i), VertexBlue(s0, i), VertexAlpha(s0, i)
Next
For i% = 0 To CountTriangles(s0)-1
AddTriangle s, TriangleVertex(s0, i, 0), TriangleVertex(s0, i, 1), TriangleVertex(s0, i, 2)
Next
End Function

Comments :


jfk EO-11110(Posted 1+ years ago)

 Unfortunately, as far as I see this works only with meshes with one single surface, right? all surfaces should be cloned and added to the recreated mesh instead.