Thread: Line Math?

I'm trying to create a line algorithim. I'm going crazy.
I just can't seem to get the math strait. Heres what i'm doing...

First, i am getting two points from the user, then getting the slope.

Then i do this...

1. Check which percent is smaller.
2. Moved on the axis with the smaller percent.
3. Loop to 1

Oddly enough(not really)
i will end up with a line like this

Code:

KEY: 0's = BLANK, # = LINE

# # 0 0 0
0 # 0 0 0
0 # 0 0 0
0 # 0 0 0
0 ##0 0 0

instead of a line like this...

Code:

# 0 0 0 0
0 # 0 0 0
0 # 0 0 0
0 # 0 0 0
0 0 # 0 0

In short, i can't think of a way to calculate when to move diagonly, insted of horizontaly or verticaly. I've thought about comparing the percents, but i don't know how close they should be for a diagonal move. (If you check the percent of both axis when they (should) move diagonal, they are usually pretty close.)

Any info would be greatly appreciated.

Do a web search for "bresenham line algorithm"

Perfect, thanks salem. If anyone else is interested ...