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4627 :: mutable object

• tbutton (orginal) [2019-02-05T11:51:48+01:00] view original

  hello everyone. i trying import this https://github.com/Bly7/OBJ-Loader/blob/master/Source/OBJ_Loader.h al day long! And nothing compiles! well, it works, but not completely. for example i can create loader

  
  type
    object3d=object
      objdata:Loader
  var a:object3d;
  Run

  and even, load 3d model!

  
  proc loadmesh(this: object3d, filename: string) =
    if(not this.objdata.loadfile(filename)):
      echo "error loading mesh ", filename
  a.loadmesh("cup.obj");
  Run

  but, when i want draw object, i cant do it. I tried load the vertices using seq, but compiler didnt work. then i found vector for nim https://github.com/3dicc/Urhonimo/blob/master/modules/container/vector.nim and wrote this:

   ../vector/vector
  const
    hdr = "\"C:\\Users\\max-5\\Documents\\lsdge\\opengl1\\libs\\objloader\\OBJ_Loader.h\""
  type
    Material* {.header: hdr, importcpp: "objl::Material".}= object
    Vector3* {.header: hdr, importcpp: "objl::Vector3".} = object
      X, Y, Z: cfloat
    Vector2 {.header: hdr, importcpp: "objl::Vector2".} = object
      X, Y: cfloat
    Vertex* {.header: hdr, importcpp: "objl::Vertex".} = object
      Position, Normal: Vector3
      TextureCoordinate: Vector2
    Loader* {.header: hdr, importcpp: "objl::Loader".} = object
      LoadedMeshes: Vector[Mesh]
    Mesh* {.header: hdr, importcpp: "objl::Mesh".} = object
      Indices: Vector[int]
      Vertices: Vector[Vertex]
      MeshName: cstring
      MeshMaterial: Material
  
  proc loadfile(this: Loader, filename: cstring): bool {.header: hdr, importcpp: "#.LoadFile(@)".}
  Run

  and when i tried call some element in vector

   drawobject(this: object3d) =
    for meshindex in 0..this.objdata.LoadedMeshes.size:
      var loadedmesh:Mesh
      loadedmesh = this.objdata.LoadedMeshes.at(meshindex)#objects.nim, line 10
  ...
  Run

  , nothing compiles, compiler just writes objects.nim(10, 43) Error: type mismatch: got <Vector[main.Mesh], uint32> but expected one of: proc at[T](this: var Vector[T]; index: cuint): var T for a 'var' type a variable needs to be passed, but 'this.objdata.LoadedMeshes' is immutable how can i make object mutable, or what do i need to get vector?

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• Stefan_Salewski (orginal) [2019-02-05T12:01:24+01:00] view original

  It seems obvious, the compiler told you. Use

  proc loadmesh(this: var object3d, filename: string) =
  Run

  So this variable is mutable inside of your proc. Or you may create a local mutable copy inside the proc with something like

  var this = this
  Run

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• tbutton (orginal) [2019-02-05T23:49:33+01:00] view original

  Wow, it works! I didn’t know what to do. Thanks

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