A word of caution ... I can't even under stand some of the stuff I am trying to say in this post, I've written too much to just delete it all and start from scratch, so you will have to muddle thru it just as I did ...
As per my prev posting http://www.vbgamer.com/msgboard/topic.asp?TOPIC_ID=56 the reason I was creating the ray rect function was this.
I am thinking about trying to make a doom clone for vb.net using directx9 and using quad BSP trees for the map etc.
I thought doing if I took the line and broke it down into blocks the size of a pixel, that It would be faster then calculating the path of a line. Here's what I mean ... (a basic premis for drawing the pixels that make up a line)
DeltaX = point2.X - point1.X
DeltaY = point2.Y - point1.Y
Slope = DeltaY / DeltaX
YPos = point1.Y
For idx = point1.X To point2.X
YPos += Slope
Next
... I realize that the code above is flawd but the basic math is there. Now from the code above, I had it in my head that doing it that way would be slower then calculating the hit boxes of a line etc.
My reasoning was that you could be transversing a line that is over 1000+ in length.
... heres my problem. I just wrote a sample app that draws a line manually using vb.net (Not asm not inline asm but slower than native VB.NET managed code!) and as it turns out drawing the line by hand in vb.net is instantaneous. I am running on a duel monitor rig and stretch the window to the max across both screens and draw a line as long as I could and still my timming code is saying that it's drawing it instantly with no delay. Let me re-iterate a line over 2500 in length does not in cure a speed penalty. That means that my managed code while still a debug build can execute a loop over 2500 times and not even flinch?
Mabe It's just because for most of my .. tech life ... I have been using a 486 and I am hoplessly brain drained to think that my athlon xp 1600 can't process a 2500+ loop without taking 5 seconds to do so...
I guess the whole point of this post was to vent my astonisment that my mid level system could handle 2500+ loop (plus code) and not even hickup .... Of course this means I have been wasting my time focusing on how to parse a line when I knew all along what the fasted way to do it was ... DOH! (In my best homer simpson impression)
drawing a line old school (IE: doing it by hand)
Posted - Aug 17 2003 : 03:48:33 AM
