[Oberon] FPGA - Bitmap Replace Horizontal Line

[Tomas Kral]

Hi Joerg,

I am digesting your post, while looking into `Display.Mod'.

I believe the colour may be encoded into bitmap itself, the below is
unrolled loop of `ReplaceHLine'. I hope I am not being too silly here,
but it does things for me with x,w pixel granularity.


PROCEDURE ReplaceHLine(x, src, dst, w: INTEGER);
  VAR bt: BYTE; w0, wd: INTEGER; pix: SET;   
BEGIN
 
  (* (pix * {maskleft*8..31} * {0..maskright*8-1}) *)

  w0 :=  w MOD 32; 
  WHILE w > 0 DO
    
    (* begin - clear rectangle white *)
    (* begin - paint black rectangle *)
    DEC(w, 32); wd := -1;
    IF w < 0 THEN wd := SYSTEM.VAL(INTEGER, SYSTEM.VAL(SET,
    wd)*{0..w0}) END; 
    SYSTEM.GET(dst, pix);
    SYSTEM.PUT(dst, SYSTEM.VAL(SET, LSL(wd, x MOD 32)) + pix);

    IF (x MOD 32 > 0) & (w > 0) THEN
      SYSTEM.GET(dst+4, pix);
      SYSTEM.PUT(dst+4, SYSTEM.VAL(SET, -1)*{0..x MOD 32-1} + pix)
    END;
    (* end - paint black rectangle *)

    (* begin - invert black rectangle *)
    wd := -1;
    IF w < 0 THEN wd := SYSTEM.VAL(INTEGER, SYSTEM.VAL(SET,
    wd)*{0..w0}) END;

    SYSTEM.GET(dst, pix);
    SYSTEM.PUT(dst, SYSTEM.VAL(SET, LSL(wd, x MOD 32)) / pix);

    IF (x MOD 32 > 0) & (w > 0) THEN
      SYSTEM.GET(dst+4, pix);
      SYSTEM.PUT(dst+4, SYSTEM.VAL(SET, -1)*{0..x MOD 32-1} / pix)
    END;
    (* end - invert black rectangle *)
    (* end - clear rectangle white *)

    (* begin - PaintHLine.Mod *)
    SYSTEM.GET(src, wd); INC(src, 4);
    IF w < 0 THEN wd := SYSTEM.VAL(INTEGER, SYSTEM.VAL(SET,
    wd)*{0..w0}) END;

    SYSTEM.GET(dst, pix);
    SYSTEM.PUT(dst, SYSTEM.VAL(SET, LSL(wd, x MOD 32)) + pix);

    INC(dst, 4);
    IF x MOD 32 > 0 THEN
      SYSTEM.GET(dst, pix); wd := ASR(wd, -(x MOD 32));
      SYSTEM.PUT(dst, SYSTEM.VAL(SET, wd)*{0..x MOD 32-1} + pix)
    END
    (* end - PaintHLine.Mod *)
 
  END
END ReplaceHLine;

I wish to support 16 coulours in future (after necessary vid.v
changes), that is my life long challenge next to Verilog comprehension.

Tomas


On Mon, 22 May 2017 11:14:05 +0200
Jörg <joerg.straube at iaeth.ch> wrote:

> Hi Tomas
> 
> These are the definitions Oberon uses
> 0 = background = black
> 1 = foreground = white
> 
> Paint   = src AND pat (1 in pattern is interpreted as "white")
> Invert  = src XOR pat
> Replace = draw pattern with "col"
>           black: src AND ~pat
>           white: src AND pat   (= paint)
> 
> br
> Jörg
> -----Original Message-----
> From: Oberon [mailto:oberon-bounces at lists.inf.ethz.ch] On Behalf Of
> Tomas Kral
> Sent: Montag, 22. Mai 2017 10:34
> To: Oberon@ <lists.inf.ethz.ch.Oberon at lists.inf.ethz.ch>
> Subject: [Oberon] FPGA - Bitmap Replace Horizontal Line
> 
> Hi,
> 
> I was scratching my head over how to implement the `replace' 
> mode. Seems more complicated than `invert' mode, which only applies
> `/' set operator in place of `+' in the PaintHLine.Mod (see earlier
> post)
> 
> I thought to erase destination rectangle with $0000$ first than paint
> bitmap in the cleared area.
> 
> To erase destination rectangle, appears to be done in two steps, paint
> black rectangle, then invert it.
> 
> The replace mode can be done in three steps:
> [a] paint black rectangle
> [b] invert black rectangle
> [c] paint bitmap in the cleared area
> 
> The above replace mode performs 3 times worse to Paint/Invert modes.
> 
> What do you think?
> 



-- 
Tomas Kral <thomas.kral at email.cz>