Bresenham ALGORITHM

Comments

• Leon Posts: 7,620

  2009-05-22 22:13 edited 2009-05-22 22:13

  Don't you mean the Bresenham algorithm?
  
  Leon
  
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• mxg331 Posts: 5

  2009-05-23 00:28 edited 2009-05-23 00:28

  Yes, but any line algorithm will do.· I've already developed my own but it has many issues.
• Bean Posts: 8,129

  2009-05-23 02:04 edited 2009-05-23 02:04

  Here is one in SX/B
  
  

  ' Variables used by graphics subroutines 
  cnt   VAR Byte 
  cnt2  VAR Byte 
  x1    VAR Byte 
  x2    VAR Byte 
  y1    VAR Byte 
  y2    VAR Byte 
  color VAR Byte 
  
  Line SUB 4 
  
  Line: ' (x1,y1,x2,y2) ; Set color before calling 
    x1 = __PARAM1 
    y1 = __PARAM2 
    x2 = __PARAM3 - x1 
    y2 = __PARAM4 - y1 
    IF x2 >= y2 THEN 
      cnt2 = x2 >> 1 
      FOR cnt = 0 TO x2 
        PutPixel x1, y1, color 
        INC x1 
        IF cnt2 >= y2 THEN 
          cnt2 = cnt2 - y2 
        ELSE 
          cnt2 = cnt2 - y2 
          cnt2 = cnt2 + x2 
          INC y1 
        ENDIF 
      NEXT 
    ELSE 
      cnt2 = y2 >> 1 
      FOR cnt = 0 TO y2 
        PutPixel x1, y1, color 
        INC y1 
        IF cnt2 >= x2 THEN 
          cnt2 = cnt2 - x2 
        ELSE 
          cnt2 = cnt2 - x2 
          cnt2 = cnt2 + y2 
          INC x1 
        ENDIF 
      NEXT 
    ENDIF 
    x2 = x1 
    y2 = y1 
  RETURN
  

  
  
  
  Bean
  
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• mxg331 Posts: 5

  2009-05-23 22:25 edited 2009-05-23 22:25

  Thank you for your response.· As I'm sure you can appreciate, the process I'm·implementing·is very time critical.· I would prefer (need) a line algorithm in SX assembly.· Thanks to all who are thinking about this!
• JonnyMac Posts: 9,527

  2009-05-23 22:57 edited 2009-05-23 22:57

  Remember, SX/B compiles to Assembly and you may find that Bean's code works as well as you need. If nothing else, run it through the compiler and then take the output and see if you can optimize it (I do this a lot as it helps me learn Assembly).