bresenham question :)

[Agamemnus]

i have a feeling that this could be impossible.. ah well. here goes:

say you have a line x1-x2, y1-y2.

I want to figure out where to go next according to bresenham, one point per x and one point per y at a time {-1, 0, 1}, without going diagonally then straight. (nice and even..)

Is this possible? :/

[na_th_an]

Well, that is what is done in each bresenham loop. If the line is more vertical than horizontal, it will always advance 1 pixel vertically and 0 to 1 horizontally, and if it is more horizontal than vertical, it will always advance 1 pixel horizontally and 0 to 1 vertically, in each loop.

[Agamemnus]

rel's link doesn't work anymore.

[Ninkazu]

I have a bresenham line tut in my buffering tutorial
check it out http://www.venosoft.com/articles/buffers.html

See? I knew this article would be helpful to people!

[Agamemnus]

Code:

SUB bline (x, y, x2, y2)
dx = x2 - x
dy = y2 - y
IF dy < 0 THEN dy = -dy: yinc = -1 ELSE xinc = 1
IF dx < 0 THEN dx = -dx: xinc = -1 ELSE yinc = 1
IF dx > dy THEN
d1 = dy + dy - dx - dx
d = d1 + dx
d0 = d + dx
DO
IF x = x2 THEN EXIT DO
x = x + xinc
IF d < 0 THEN d = d + d0 ELSE d = d + d1: y = y + yinc
PSET (x, y)
LOOP
ELSE
d1 = dx + dx - dy - dy
d = d1 + dy
d0 = d + dy
DO
IF y = y2 THEN EXIT DO
y = y + yinc
IF d < 0 THEN d = d + d0 ELSE d = d + d1
x = x + xinc
PSET (x, y)
LOOP
END IF
END SUB

eDited.

[Jark]

are implemented in the TC-Lib, downloadable from the Mandelbrot Dazibao. The full documentation is in french, I didn't have time for an english version, but you can try to Babelfish that, it could be fun :lol:

[relsoft]

rel's link doesn't work anymore.

Yeah, but why does my link have to do with Bresenham?

[Agamemnus]

cuz you said you had it there somewhere.

[Hexadecimal Disaster]

Rel, maybe it has something to do with RelLine, huh? :roll:

[relsoft]

QBrpgs.com>Utils>RelGFX. :*)