Select 2 edges of model and display X Dimension and Y Dimension...

Blitz3D Forums/Blitz3D Programming/Select 2 edges of model and display X Dimension and Y Dimension...

hollifd

(Posted March) [#1]

Has anyone developed any code that you can share that will allow a user to select any 2 edges of the model on the screen and display the X and Y dimensions between the 2 edges the user selected? I need to provide a way for the user to select any 2 edges. The 2 edges could be horizontal or vertical. After selecting these 2 edges, I need to have the X and Y distance between these two edges displayed as text on the screen.

Currently, I have 2 cylinders that the user can move around on the screen until they touch the model. When they touch the model, I calculate the distance in X and Y the 2 cylinders are apart from one another. I was hoping for a better solution.

Thanks,
David

Bobysait

(Posted April) [#2]

something coded on the fly, probably contains a tons or errors ^^

;@pCamera : camera used for picking
;@pX,pY        : 2D coordinates of the picking
;@pMesh: mesh to check for edge detection.
;@pPixelRange : threshold (in pixel) to test the distance to the edge
;@pResult  : array
;                    pResult[0] = picked Mesh
;                    pResult[1] = picked Surface
;                    pResult[2] = Picked Triangle Index
;                    pResult[2] = Picked Vertex index
;                                          if vertex index is 0, the edge is 0->1
;                                          if vertex index is 1, the edge is 1->2
;                                          if vertex index is 2, the edge is 2->0
;@Returns : True if an edge has been picked.
Function PickEdge% (pCamera, pX,pY, pMesh, pPixelRange%, pResult%[3])
   Local NearestD# = -1;
   ; for each surfaces
   For is = 1 To CountSurfaces(pMesh)
      l_Surf=GetSurface(pMesh, is)
      ; for each triangles
      For t = 0 to CountTriangles(l_Surf)-1
          Local l_X#[3], l_Y#[3] ; store projected coords
         ; for each edges of the triangle
         For i= 0 to 2
             v = TriangleVertex(l_Surf, t, i)
             ; transform coords of v to world
             TFormPoint (VertexX(l_Surf, v), VertexY(l_Surf, v), VertexZ(l_Surf, v), pMesh, 0)
             CameraProject(pCamera, TFormedX(),TFormedY(),TFormedZ())
             l_X[i] = ProjectedX()
             l_Y[i] = ProjectedY()
         Next
         For i = 0 To 2
            Local d# = DistancePL2D(X,Y, l_X[i],l_Y[i], l_X[(i+1)Mod(3)],l_Y[(i+1)Mod(3)])
            If (d>=0) And (d<pPixelRange)
                  if ((NearestD<0) Or (d<NearestD))
                     Result[0] = pMesh
                     Result[1] = lSurf
                     Result[2] = t
                     Result[3] = i
                  EndIf
               EndIf
      Next
   Next
   Return NearestD>=0
End Function

Function DistancePL2D( px#,py#, ax#,ay#,bx#,by# )
 Local ix# = bx-ax, iy#=by-ay
 Local d# = (bx-ax)*(bx-ax)+(by-ay)*(by-ay)
 Local u# = ( ( ( px-ax)*ix)+((py-ay)*iy) ) /( d )
 If  ((u<0.0) Or (u>1.0)) Then Return -1
 ix=ax+u*ix
 iy=ay+u*iy
 Return Sqr((px-ix)*(px-ix)+(py-iy)*(py-iy))
End Function

So, once you picked an edge, store the result
pick a second edge
-> distance between edges is :

;e1 = result of first pick
;e2 = result of second pick

Function DistanceEdges#(e1%[3], e2%[3])
   Local M0 = e1[0], M1 = e2[0]
   Local S0 = e1[1], S1 = e2[1]
   Local V00 = TriangleVertex(S0, e1[2], e1[3]);
   Local V01 = TriangleVertex(S0, e1[2], (e1[3]+1)Mod(3));
   Local V10 = TriangleVertex(S1, e2[2], e2[3]);
   Local V11 = TriangleVertex(S1, e2[2], (e2[3]+1)Mod(3));
   TFormPoint (VertexX(S0, V00), VertexY(S0, V00), VertexZ(S0, V00), M0, 0)
   Local x00# TFormedX(), y00# = TFormedY(), z00#=TFormedZ()
   TFormPoint (VertexX(S0, V01), VertexY(S0, V01), VertexZ(S0, V01), M0, 0)
   Local x01# TFormedX(), y01# = TFormedY(), z01#=TFormedZ()
   TFormPoint (VertexX(S1, V10), VertexY(S1, V10), VertexZ(S1, V10), M1, 0)
   Local x10# TFormedX(), y10# = TFormedY(), z10#=TFormedZ()
   TFormPoint (VertexX(S1, V11), VertexY(S1, V11), VertexZ(S1, V11), M1, 0)
   Local x11# TFormedX(), y11# = TFormedY(), z11#=TFormedZ()
   ; use any formula here to return the nearest point between the two edges
   
   Return YourFormula(x00,y00,z00, x01,y01,z01, x10,y10,z10, x11,y11,z11)
End Function

According to your needs, I let you find a formula that will match your requirements
(if you want the shortest distance of edges, or distance between center of edges etc ...)