Read Files obj

[stevmjon]

howdy

i have just made some code that reads .obj files. this is the first time i have done this, so can someone look at the code demo and tell me if i have gone about this the correct way.
i only wanted some of the code in the file, so focused only on that. also i would put this data into another array for use in game, but didn't do this for this test demo, nor did i use the surface data in the .mtl file for textures (i left it in there anyway).
i just wanted to see the data on screen and see if it was correct.

the commands i used was SplitToArray() that uses a temp array to read the data.
> first searched the file for "v " (v + space) as the first data on the line, then read the text data into float array.
> then searched the file for "f " (f + space) as the fisrt data on the line, then read the text data into string array (step 1/2).
   >then read that string array to split it by the "//" , as there was numbers before and after this, then put data into int array (step 2/2).

you can use notepad / notepad 2.0 to see the data yourself.

  i appreciate any advice, stevmjon

[kevin]

Just putting this link here for reference.   

OBJ FILE FORMAT

[stevmjon]

thanks for the link kev, that has interesting reference i didn't know about.

the point of posting this thread, was mainly to know if my use of "SplitToArray" was the correct way to read the string data, one line at a time.

> so, reading the vector data "v " was straight forward, i only used "SplitToArray" once per line here. the data was seperated by blank spaces so was simple check.
> then, reading the face data "f " was multiple use of "SplitToArray" per line. first i needed the data between spaces, then needed each seperate data checked again by seperating data by // .

so is this correct, or should i go through the "f " line one character at a time instead, grabbong data this way? i don't know how check one character at a time...

  any advice is welcomed, stevmjon

[kevin]

 

 so is this correct, or should i go through the "f " line one character at a time instead, grabbong data this way? i don't know how check one character at a time.

 

 I was writing an example but life got in the way, but prolly both ways.  So for lines that are always known to be simple, like a vertex with 3 values separated by spaces, then split is a nice easy and quick way.  But if the values have some secondary data, then parsing is character by character might indeed be a better way.    You can prolly get away with doing an instring on the face lines for Hash characters and then choosing how to proceed.   I don't really know what formats to expect so I can't really help there.    Might be an idea to have a look at some more object files.  See if any common and easy patterns seem obvious.    

PlayBASIC Code: [Select]

Function LoadOBj(File$)
   
   if Fileexist(file$)=false then exitfunction false   

   size=filesize(file$)   
   fh=readnewfile(file$)
   if fh
      // Load entire file into a string
      s$=readchr$(fh,Size)
      closefile fh   

      //  Strip line feeds
      s$=replace$(s$,chr$(10),"")
      
      
      //  Split to this array
      Dim Obj$(10000)
      RowCount = splittoarray(s$,chr$(13),Obj$())

      //  Array use to translate floats into
      Dim _FloatArray#(256)


      // Scan the file for control codes
      For lp =0 to RowCount-1
         
         s$=Obj$(lp)
         
         
         ThisCHR = mid(s$,1)
         
         //  check for comment row, if so, skip
         if ThisCHR=asc("#") then continue


         Pos = instring(s$," ")
         if pos<1 then continue  ;  Skip with no spaces
         Opcode$=left$(s$,pos-1)   
         Params$ =cutleft$(s$,pos)

         // ---------------------------------------------------
         Select Opcode$
         // ---------------------------------------------------
            
                  // --------------------------------------------------
                  //  v = Vertex 
                  // --------------------------------------------------
                  case "v"
                        //  Vertex data separated by spaces
                        Count= splittoarray(Params$," ",_FloatArray#())
                        if Count=3   
                           print _FloatArray#(0)
                           print _FloatArray#(1)
                           print _FloatArray#(2)
                        else
                           print "Error in vertex ?"   
                        endif                                 

                     //  vn = vertex normal
                  case "vn"
                     
                  //  vt = vertex  face ? 
                  case "vt"
                     

                  // --------------------------------------------------
                  //  f = Face
                  // --------------------------------------------------
                  case "f"

            
         EndSelect
         
      next
      
      
   endif


   
EndFunction Status

[stevmjon]

thanks for the input kev.

thought i would post a screenshot of the file loaded into my game, and displayed as wireframe for now.
the object is the house, and i added a few cubes in the scene as well.

very exciting for me, as this is the first time i have done this. so now i can make 3D objects using 3D software, then load them into the game, yay.

stevmjon