How Can I Select A Vertex With The Mouse

Blitz3D Forums/Blitz3D Programming/How Can I Select A Vertex With The Mouse

Delerna (Posted 2005) [#1]

What happened to the PickedVertex command??? I can select a surface and a triangle with the mouse through PickedSurface and PickedTriangle but can someone please educate me on how to do the same with vertices Thanks

DJWoodgate (Posted 2005) [#2]

You find the minimum distance vertex for the picked triangle. Tformpoint the picked x,y,z to local space and check each vertex of the picked triangle to find the closest vertex to this point.

Delerna (Posted 2005) [#3]

OK tried that David and it works fine, thanks for the input

BlitzSupport (Posted 2005) [#4]

Just in case anyone else wants a way to do this: ; ----------------------------------------------------------------------------- ; Vertex projection functions... ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; WHAT'S THIS? ; ----------------------------------------------------------------------------- ; Convert vertex co-ordinates within mesh into global co-ordinates. ; Convert vertex 3D co-ordinates to 2D co-ordinates. ; Pick nearest vertex when a mesh is clicked on. ; ----------------------------------------------------------------------------- ; The main functions of interest here are: ; ----------------------------------------------------------------------------- ; MakePickable -- makes a mesh 'pickable' by PickNearestVertex (and the ; native Blitz 'pick' commands). ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; PickNearestVertex -- gets surface and index of nearest vertex to requested ; 2D x/y position if within requested mesh. If this returns ; True, you can then use the global variables V_PickedMesh, ; V_PickedSurface and V_PickedIndex to get the picked mesh, ; surface and vertex index respectively. Remember UpdateWorld! ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; VertexProject -- calculates 2D co-ords of given vertex. They are retrieved via ; VertexScreenX () and VertexScreenY () after calling this function. ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; GlobalizeVertex -- gets global 3D co-ords of given vertex. Retrieved via VertexGlobalX (), ; VertexGlobalY () and VertexGlobalZ () after calling this function. ; ----------------------------------------------------------------------------- ; NOTE: The 'usecam' parameter in these functions is the camera currently in use. ; ----------------------------------------------------------------------------- ; *** START OF INCLUDES... ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; IMPORTANT: All globals are required! ; ----------------------------------------------------------------------------- Global V_PickedMesh ; Last mesh picked during PickNearestVertex () Global V_PickedSurface ; Last surface picked during PickNearestVertex () Global V_PickedIndex ; Last vertex index picked during PickNearestVertex () ; ----------------------------------------------------------------------------- ; IMPORTANT: All functions are required! ; ----------------------------------------------------------------------------- Function MakePickable (mesh, pickmode = 2, obscurer = True) EntityPickMode mesh, pickmode, obscurer End Function Function GlobalizeVertex (mesh, surface, index) vx# = VertexX (surface, index) vy# = VertexY (surface, index) vz# = VertexZ (surface, index) TFormPoint (vx, vy, vz, mesh, 0) End Function Function VertexGlobalX# () Return TFormedX () End Function Function VertexGlobalY# () Return TFormedY () End Function Function VertexGlobalZ# () Return TFormedZ () End Function Function VertexProject (usecam, mesh, surface, index) GlobalizeVertex (mesh, surface, index) CameraProject usecam, VertexGlobalX (), VertexGlobalY (), VertexGlobalZ () End Function Function VertexScreenX () Return ProjectedX () End Function Function VertexScreenY () Return ProjectedY () End Function Function PickNearestVertex (usecam, x, y) picked = CameraPick (usecam, x, y) ; Find entity at pointer position If picked surf = PickedSurface () ; Get selected surface tri = PickedTriangle () ; Get selected triangle within surface t0 = TriangleVertex (surf, tri, 0) ; Find vertex 0 of triangle t1 = TriangleVertex (surf, tri, 1) ; Find vertex 1 of triangle t2 = TriangleVertex (surf, tri, 2) ; Find vertex 2 of triangle VertexProject (usecam, picked, surf, t0) ; Project vertex 0 screen position vx0 = VertexScreenX () ; Get x position of vertex 0 vy0 = VertexScreenY () ; Get y position of vertex 0 VertexProject (usecam, picked, surf, t1) ; Project vertex 1 screen position vx1 = VertexScreenX () ; Get x position of vertex 1 vy1 = VertexScreenY () ; Get y position of vertex 1 VertexProject (usecam, picked, surf, t2) ; Project vertex 2 screen position vx2 = VertexScreenX () ; Get x position of vertex 2 vy2 = VertexScreenY () ; Get y position of vertex 2 pd0# = Abs (Sqr ((x - vx0) ^ 2 + (y - vy0) ^ 2)) ; Distance from vertex 0 to pointer pd1# = Abs (Sqr ((x - vx1) ^ 2 + (y - vy1) ^ 2)) ; Distance from vertex 1 to pointer pd2# = Abs (Sqr ((x - vx2) ^ 2 + (y - vy2) ^ 2)) ; Distance from vertex 2 to pointer closest# = pd0: vindex = t0 ; Assume vertex 0 is closest to pointer If pd1 < closest ; See if vertex 1 is closer... closest = pd1 ; ... if so, that's now 'closest'... vindex = t1 ; ... and the vertex index is #1 EndIf If pd2 < closest ; See if vertex 2 is closer... vindex = t2 ; ... if so, vertex index is #2 EndIf V_PickedMesh = picked V_PickedSurface = surf V_PickedIndex = vindex Return True Else V_PickedMesh = 0 V_PickedSurface = 0 V_PickedIndex = 0 Return False EndIf End Function ; ----------------------------------------------------------------------------- ; *** END OF INCLUDES... ; ----------------------------------------------------------------------------- ; ----------------------------------------------------------------------------- ; Demo... ; ----------------------------------------------------------------------------- AppTitle "MOUSE: get nearest vertex | CURSORS & A/Z: move" Graphics3D 640, 480, 0, 2 ; Our camera... cam = CreateCamera () CameraClsColor cam, 32, 64, 96 MoveEntity cam, 0, 0, -5 ; A cube, yesterday... cube = CreateCube () EntityColor cube, 128, 128, 64 ; Make cube 'pickable' -- IMPORTANT! MakePickable (cube) ; A light... light = CreateLight () PositionEntity light, -100, 20, -50 PointEntity light, cube ; The red 'cursor' ball... piv = CreateSphere (8, cube) ScaleEntity piv, 0.1, 0.1, 0.1 EntityColor piv, 255, 0, 0 HidePointer Repeat If KeyDown (203) TurnEntity cube, 0, 1, 0, 1 If KeyDown (205) TurnEntity cube, 0, -1, 0, 1 If KeyDown (200) TurnEntity cube, 1, 0, 0 If KeyDown (208) TurnEntity cube, -1, 0, 0 If KeyDown (30) TranslateEntity cube, 0, 0, 0.1 If KeyDown (44) TranslateEntity cube, 0, 0, -0.1 mx = MouseX () my = MouseY () ; If mouse button is clicked on a mesh, find the nearest vertex... If MouseHit (1) If PickNearestVertex (cam, mx, my) ; ----------------------------------------------------------------- ; V_PickedMesh, V_PickedSurface and V_PickedIndex are now valid... ; ----------------------------------------------------------------- vx# = VertexX (V_PickedSurface, V_PickedIndex) vy# = VertexY (V_PickedSurface, V_PickedIndex) vz# = VertexZ (V_PickedSurface, V_PickedIndex) PositionEntity piv, vx, vy, vz ; The 'piv' cursor is parented to the cube. VertexX/Y/Z return the ; position of the vertex within its mesh, so the above line positions ; the cursor at the picked vertex's position. EndIf EndIf UpdateWorld RenderWorld ; Crosshair with shadow... Color 0, 0, 0: Line mx - 4, my, mx + 4, my: Line mx, my - 4, mx, my + 4 Color 255, 255, 255: Line mx - 5, my - 1, mx + 3, my - 1: Line mx - 1, my - 5, mx - 1, my + 3 ; Plotting a crosshair over picked vertex to show off 2D vertex projection stuff... If V_PickedMesh ; Just checking a vertex has been picked... ShowEntity piv VertexProject (cam, V_PickedMesh, V_PickedSurface, V_PickedIndex) vx# = VertexScreenX () vy# = VertexScreenY () Color 0, 255, 0: Line vx - 4, vy, vx + 4, vy: Line vx, vy - 4, vx, vy + 4 Color 255, 255, 255: Line vx - 5, vy - 1, vx + 3, vy - 1: Line vx - 1, vy - 5, vx - 1, vy + 3 Else HideEntity piv EndIf Flip Until KeyHit (1) End