1. No response?
What no response to my challenge?
Well, the Bogo Vault has no bounds:
Using only the "open" function, write a function which returns all files
in a directory.
snortboy
2. Re: No response?
Hey,
>What no response to my challenge?
>
>Well, the Bogo Vault has no bounds:
>
>Using only the "open" function, write a function which returns all
files
>in a directory.
>
>snortboy
Hey man, give people a chance. I'm considdering your chalenge but I
have other things to do as well. Just slow down and you could start
some cool threads.
Right now I'm trying to figure out the formula for the distance between
two 3D points. My math teacher wasn't any help. He said he couldn't
remember but that it would probably be in a calculus book somewhere in
chapters 12-14. And he didn't even loan me a book, he told me to get
one at the library (yeah right 
or ask a math Tutor. So, can anyone
help me here? What I'm trying to do is enhance the 3d function that
Lithex (I think) posted in response to a question. It works fine except
that it calculates perspective with Z-distance rather than real
distance.
-- original function
function perspective (sequence thing, sequence eye)
sequence t, i
atom r
r = thing [Z] / (thing [Z] - eye [Z]) -- Notice this line****
t=thing[X..Y] i=eye[X..Y]
return (t + r * (i - t))
end function
I want a function that replaces this line:
r = thing [Z] / (thing [Z] - eye [Z])
with something that uses the 3D distance formula instead of:
(thing [Z] - eye [Z])
which is only 100% accurate when "thing" is in a strait Z-direction from
"eye"
Any help would be appreciated; also functions for rotating 3D objects
and the camera (eye) are welcome.
Sincerely,
Lewis Townsend
PS No, I'm not making another 3D graphics game engine with gourad
shading, texture maping etc... I'm just trying to learn all I can about
3D stuff so I can use the REAL engines better and maybe make a few
graphics demos and games while I'm at it.
PPS Also, the function above seems to be able to to "see" things that
are "behind" the eye and that just doesn't seem right some how.
______________________________________________________
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3. Re: No response?
For any of those interested in the Bogo Ellipse Function, email me at
nhs6080 at unix.tamu.edu and I'll send you my "algebraic ellipse" package. Its
a webpage which describes the definition and construction of an ellipse,
algebraically.
snortboy
4. Re: No response?
Hi
The formula for 3d distance is almost the same as the one for 2d
distance
for the points (x1, y1, z1) and (x2, y2, z2)
instead of distance=((x2-x1)^2+(y2-y1)^2)^.5 as in 2d just do
distance=((x2-x1)^2+(y2-y1)^2+(z2-z1)^2)^.5
I think in Euphoria we might do something like this:
--Start of Euphoria Code
sequence p1, p2
atom distance
p1={1,2,3) ---- 3d coordinates of point 1
p2={4,5,6) ---- 3d coordinates of point 2
distance=((p2[1]-p1[1])^2 + (p2[2]-p1[2])^2 + (p2[3]-p1[3])^2)^.5
-- End of Euphoria Code
This code is just off the top of my head - I'm sure a much more
elegant and compact expression is possible in Euphoria.
Bye
Martin
5. Re: No response?
Lewis Townsend wrote:
>
> Hey,
>
> >What no response to my challenge?
> >
> >Well, the Bogo Vault has no bounds:
> >
> >Using only the "open" function, write a function which returns all
> files
> >in a directory.
> >
> >snortboy
>
> Hey man, give people a chance. I'm considdering your chalenge but I
> have other things to do as well. Just slow down and you could start
> some cool threads.
>
> Right now I'm trying to figure out the formula for the distance between
> two 3D points. My math teacher wasn't any help. He said he couldn't
> remember but that it would probably be in a calculus book somewhere in
> chapters 12-14. And he didn't even loan me a book, he told me to get
> one at the library (yeah right or ask a math Tutor. So, can anyone
> help me here? What I'm trying to do is enhance the 3d function that
> Lithex (I think) posted in response to a question. It works fine except
> that it calculates perspective with Z-distance rather than real
> distance.
>
> -- original function
> function perspective (sequence thing, sequence eye)
> sequence t, i
> atom r
> r = thing [Z] / (thing [Z] - eye [Z]) -- Notice this line****
> t=thing[X..Y] i=eye[X..Y]
> return (t + r * (i - t))
> end function
>
> I want a function that replaces this line:
> r = thing [Z] / (thing [Z] - eye [Z])
> with something that uses the 3D distance formula instead of:
> (thing [Z] - eye [Z])
> which is only 100% accurate when "thing" is in a strait Z-direction from
> "eye"
>
> Any help would be appreciated; also functions for rotating 3D objects
> and the camera (eye) are welcome.
>
> Sincerely,
> Lewis Townsend
<snip>
the distance between two points in 3d space is almost the
same as for 2d, it's the suare root of the sum of the squares
of the disatnce along each axis.
eg:
distance = sqroot(xdistance+ydistance+zdistance)
Kasey
6. Re: No response?
- Posted by lithex <lithex at INTERGATE.BC.CA>
Sep 18, 1998
-
Last edited Sep 19, 1998
I made a bit of a mistake
>
> I think in Euphoria we might do something like this:
>
> --Start of Euphoria Code
> sequence p1, p2
> atom distance
>
> p1={1,2,3) ---- 3d coordinates of point 1
> p2={4,5,6) ---- 3d coordinates of point 2
> distance=((p2[1]-p1[1])^2 + (p2[2]-p1[2])^2 + (p2[3]-p1[3])^2)^.5
lets make this:
distance=(power((p2[1]-p1[1]),2) +power((p2[2]-p1[2])^2 +
(p2[3]-p1[3]),2))^.5
>
> -- End of Euphoria Code
>
>
Bye
Martin
7. Re: No response?
- Posted by Hawke <mdeland at NWINFO.NET>
Sep 18, 1998
-
Last edited Sep 19, 1998
Noah Smith wrote:
>Using only the "open" function, write a function
>which returns all files in a directory.
here's my attempt...
seems to work and is tested code...
this is almost assuredly *not* the fastest way to
do this, but it meets the given problem's criteria...
Enjoy the wait...
------------begin
--I hereby declare and understand that ValidChars may *NOT*
--represent *all* possible characters that can appear in a filename.
--It's a good stab at it tho...and it's easy enuff to change...
constant ValidChars=" abcdefghijklmnopqrstuvwxyz1234567890-_~@${}"
--these are actually devices, not files, so we exclude them...
constant Bad={ "nul . ","prn . ",
"aux . ","con . ",
"com1 . ","com2 . ",
"com3 . ","com4 . " }
constant TRUE=1, FALSE=0
sequence try,found
integer lengthVC
atom now
function IsBadName(sequence test)
for i = 1 to length(Bad) do
if compare(test,Bad[i]) = 0 then return TRUE end if
end for
return FALSE
end function
function Exists(sequence filename)
if open(filename,"r") = -1 then return FALSE end if
return TRUE
end function
procedure ShowList(sequence list)
--Go crazy here, make it as fancy as you want. I opt for simple since
--the output for the problem wasn't specified.
position (2,1)
for i = 1 to length(list) do
puts (1,"'" & list[i] & "' ")
end for
end procedure
procedure ScrollNames()
for try12 =1 to lengthVC do
try[12] = ValidChars[try12]
for try11 =1 to lengthVC do
try[11] = ValidChars[try11]
for try10 =1 to lengthVC do
try[10] = ValidChars[try10]
for try8 =1 to lengthVC do --note:skip 9 here, it's the '.'
try[8] = ValidChars[try8]
for try7 =1 to lengthVC do
try[7] = ValidChars[try7]
for try6 =1 to lengthVC do
try[6] = ValidChars[try6]
for try5 =1 to lengthVC do
try[5] = ValidChars[try5]
for try4 =1 to lengthVC do
try[4] = ValidChars[try4]
for try3=1 to lengthVC do
try[3] = ValidChars[try3]
for try2=1 to lengthVC do
try[2] = ValidChars[try2]
for try1=1 to lengthVC do
try[1] = ValidChars[try1]
--for speed, these lines are commented out
--to see it work, uncomment the next 2 lines
--position(1,1)
--puts(1,try)
if Exists(try) and (not IsBadName(try)) then
found = append(found,try)
--for speed, leave this commented
--to see it work, uncomment it
--ShowList(found)
end if
end for end for end for end for end for end for
end for end for end for end for end for
end procedure
--MAIN
clear_screen()
found = {}
try=repeat(' ',12)
try[9]='.'
lengthVC=length(ValidChars)
now = time()
ScrollNames()
ShowList(found)
printf(1,"It took %f seconds to do this DIR",time()-now)
--did you actually wait to see the above line printed??? ;)
---------------end
--Hawke'
8. Re: No response?
What?! Return code so quickly? You mock the Bogo Vault!! Actually, both
responses were good responses (and nearly identical to the code that was
actually written to perform these tasks.)
The Score So Far?
Lithex: 1 point for solution; -1 point (lacking some algorithmic
optimization)
Hawke: 1 point for solution; -1,000,000 for brain cells wasted on algorithm
The next Bogo Problem?
A _random_ sort function. That's right, you may use any comparison
technique your little heart desires, as long as the next element is chosen
randomly.
,morF
yteicoS s'remmargorP ogoB ehT
9. Re: No response?
>,morF
yteicoS s'remmargorP ogoB ehT
<
From,
The Bogo Programmer's Society
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