I'm running DX on W2K with X-Win32.  As soon as I start DX and execute a
network, the CPU usage for dxexec.exe goes to 100% and stays at that level
until I quit DX.  I'm not sure if this is related to the very long delays (>
20 sec) I sometimes see between the mouse button click and something
happening.  Does everyone see this behaviour on NT (W9x doesn't show process
activity levels).  Is there a way to fix this, e.g. by setting process
priority levels?

Gib

> -----Original Message-----
> From: Gib Bogle [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, September 12, 2001 10:23 AM
> To: '[email protected]'
> Subject: RE: [opendx-users] Clipping
> 
> 
> Chris,
> 
> > -----Original Message-----
> > From: Chris Pelkie [mailto:[EMAIL PROTECTED]
> > Sent: Wednesday, September 12, 2001 12:38 AM
> > To: [email protected]
> > Subject: RE: [opendx-users] Clipping
> > 
> > 
> > >Thanks for the advice on using Slab.  That gets me a couple 
> > of steps closer
> > >to my goal.  I have now run into another difficulty.  I want 
> > to Construct a
> > >field corresponding to the TIFF image, but with actual (x,y) 
> > positions, then
> > >attach the image colors to this field.  My reason for doing 
> > this is so that
> > >I then hope to use Map to map these colors onto the 
> > rubbersheeted image of
> > >the field with the elevation data.  To use Map I believe I 
> > need the two
> > >fields to be in the same coordinate system.
> > 
> > 
> > They must overlap at least by some amount or you get a field of 
> > invalid positions from Map, so yes, the coordinates must be 
> similar. 
> > You are going to have a great deal of trouble mapping a 2D surface 
> > onto a 2.5D rubbersheet though so don't even try. (2.5D means a 2D 
> > surface projected into 3-space, i.e., the positions are 3D but the 
> > topology is 2D). Map will refuse to do it, period, but even if it 
> > didn't refuse, the only places where the two fields touched 
> would be 
> > where the 2D plane intersected the 2.5D object, so you'd get spotty 
> > coverage.
> 
> My explanation of what I plan to do was imprecise.  My 
> intention is to use
> the same method used in the Colorado River example (in the 
> distribution) to
> paint a TIFF onto the field containing elevation data, which 
> is subsequently
> rubbersheeted.
> 
> > 
> > >
> > >I have been doing some testing with Construct and Map to see 
> > how to map
> > >colors, without much success.
> > 
> > 
> > Um, that's why the gods invented Colormap. (:-)
> > Yes, you can do the same with Map but it's more trouble than it's 
> > worth usually.
> 
> I will explore this, but it would be a very good idea for me to fully
> understand Map anyway.
> 
> > >My simple test has two Constructed fields
> > >which are identically created.
> > 
> > 
> > Good so far
> > 
> > >I pass each through Autocolor (here I vary
> > >the parameters)
> > 
> > 
> > why? just map the data from one to the other then Colormap... but 
> > keep reading...
> 
> I Autocolored just to get some colors for testing.
> 
> > >  then use Map with Positions and Colors, i.e. I try to map
> > >the colors of one field onto the other.
> > 
> > 
> > Colors are RGB 3-vectors (usually, esp. if you used AutoColor and 
> > didn't set the "delayed" flag). Map ALWAYS interpolates (even if it 
> > doesn't have to). Interpolated RGB 3-vectors are usually not very 
> > good looking, since RGB is a very non-linear space (after 
> > transformation back to the visual representation we know and love). 
> > In other words, you can't move from point A to point B in RGB space 
> > in a straight line and expect the colors along the line to be 
> > "smooth" visually. So abandon this approach.
> 
> In this test case no interpolation would occur (since the 
> positions are
> identical), but in the real case of course I was expecting to employ
> interpolation, and as you point out I hadn't thought through the
> implications.
> 
> How about going the other way?  I can use the resolution of 
> the TIFF (since
> the colors are fixed to this grid) and map my elevation data 
> onto a field
> with the TIFF grid and colors.
> 
> > >  This gives an error message about
> > >unsupported color format.  If I send the output of each 
> > Autocolor module to
> > >Image it displays OK.  Am I trying to do something with Map 
> > that it was not
> > >designed to do?
> > >
> > 
> > 
> > Almost certainly, you created scalar data back in Construct 
> so you'd 
> > have something to Autocolor.
> > 
> > Now you've asked Map to do the following:
> > For each position in the input field, look up in the map field's 
> > positions to find a match. Interpolate the map field positions as 
> > necessary to get an exact match. Interpolate the map data 
> > corresponding to the  map positions that were used, to get an 
> > interpolated data value that corresponds to the interpolated map 
> > position. Carry that value back to input and stuff it into the 
> > designated component, indexed to the original position we were 
> > working on.
> > 
> > OK, you said: "look up by positions, retrieve data (which 
> is scalar), 
> > stuff into colors of input, then render."
> > Renderer says: "barf! colors cannot be scalar integers (or whatever 
> > you tried to feed me)."
> > (ok, it said "unsupported color format" but I like my error message 
> > better; it has more snap.)
> 
> What I had failed to grasp here is that it is the map data 
> that is being
> stuffed into the input color component.  I had thought the 
> map color was
> being used, which as you point out above wouldn't work if 
> interpolation was
> required.
> 
> > So let's roll way back up to where you said you had two identical 
> > fields. Why not just Replace the colors from the source field onto 
> > the destination field? They have the same exact positions 
> and number 
> > of colors and everything lines up beautifully and Replace does NO 
> > interpolation, so you don't even get weird round-off errors 
> or wacky 
> > RGB values, and it happens instantaneously since it's just 
> a pointer 
> > copy operation under the covers. Map involves some 
> heavy-duty number 
> > crunching. Big nasty Maps can take considerable time to chew on the 
> > problem. Map is NOT smart enough to recognize that the 
> positions are 
> > perfectly aligned. It will still do all the math. And due 
> to possible 
> > round-off error, it may not even come up with the same answer.
> 
> My simple test was using identical fields, but I started out 
> with something
> closer to my real problem, in which the elevations are in a 
> field with a
> grid that is completely different from the TIFF grid - 
> different numbers of
> positions, and real coordinates rather than 0...Nx, 0...Ny.
> 
> > Same for your TIFF: construct a "blank field" with the right number 
> > of positions and connections (delta 1 in both dimensions, 
> since it's 
> > a pixel map), then in one instantaneous sleight of hand, lift the 
> > colors of the TIFF and drop onto this field.
> > 
> > NOW rubbersheet (after Marking the elevation data), or just 
> directly 
> > Compute new positions based on X, Y, elevation, and any scaling 
> > factors you want to apply to X,Y, Z. You map a 2D surface to a 2D 
> > surface, THEN you make it 2.5D. Much simpler.
> 
> > Or, go all the way back to what Greg said. An image in DX is just a 
> > 2D field of positions and connections (quads) with colors 
> (no data). 
> > You should be able to Replace the elevation data (from wherever it 
> > comes), or calculate it in some interesting way (for 
> example, Convert 
> > colors to HSV, then elevate the "saturation") onto the 
> "image" field 
> > then rubbersheet or Compute positions. The original colors stay 
> > firmly attached to the transformed positions so you don't 
> need to do 
> > any mapping or colormapping or interpolation of colors.
> 
> If I understand correctly, I need to keep the grid of the 
> TIFF (in the sense
> of preserving Nx and Ny).  I just need to create a field in 
> which the TIFF
> positions are transformed into the same coordinate system as 
> the elevation
> data, then Map the elevations to this field.  I think I was 
> trying to do it
> back to front.  I'll give this a try.  
> 
> I am aware that my progress with OpenDX is painfully slow 
> (I'm not sure why,
> but maybe age is a factor), and I am very grateful to you and 
> Greg for your
> patience.
> 
> regards
> Gib
> 
>  
> 
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