Hi folks!

Is anyone here coding blitter?

Here are the procedures, that draw a line from (x1,y1) to (x2,y2) with one pixel in line, accurately. Without unnecessary sub-pixel accuracy. BLTAPT ($dff050) has to be set, just like BLTAMOD, to: 4*(dy-dx). Not to 4*dy-2*dx, what's printed everywhere. In this case points of a line in SING mode are drawn with it's last pixel on top of the destination pixel of a line. Regardless to beginning and end coordinates. When it is set to usual values, noted everywhere, at some angles it is drawn
before reaching the end coordinate, leaving end coordinate with no pixel. It causes, what we continue polyline from destination of a previous line, that, at some
angles, in destination screen row of the first line point is drawn twice. While at other angles just once, overlapping start point of another line in polyline.
When BLTAPT is set to 4*(dy-dx), evrytime, at all angles last pixel of a line is draw on top of it destination coordinates. It overlaps with the first point of new
line, causing that only one point exist in a row, which makes proper blitter area filling possible. In usual case at some angles, close to destination point,
points are drawn twice in a screen row, which causes horizontal line existing on the screen and wrong filling.
