Here is a quick example of what I did to put the
image plot on the back wall, utilizing the Z buffer.
It obviously needs a call to Contour or something
to put the axis on the image plot.
In doing this, I learned that I really hadn't done
this as well as I had previously thought. I was
fortunate that in my data, the image data points
went to zero on the edges. This made it impossible
to tell that I hadn't got the vertical dimension
of the image correct.
In creating this example, I stole the bessel function
data that David used in his example of object graphics.
This didn't go to zero at the edges, so it is obvious
to see that I didn't get the size correct. *sigh*
I pasted it here because it still shows the use of
the Z buffer. Maybe this can all be done in easy to
understand normalized coordinates to finally peg it
down once and for all. In the mean time, I am lucky
because it looks great for my data, even if it isn't
correct (after all, we are the only ones that know....)
Raoul
Program to follow...cut and paste style
----------------------------------------------
; NAME:
; newsgroup
;
; PURPOSE:
; The purpose of this program is just a demonstration
; of what I did to put an image plot on the back wall
; of a cube. Basically, all I did was exchange the yz
; axis at the correct point in the show3.pro routine
; (sorry RSI). I will cut and paste RSI's routine in
; to this code, and mark my modications. Sorry about
; the lack of comments, but complain to RSI, as I can't
; figure out their code well enough to comment on ;
; it.
;
;
; AUTHOR: Raouldukey
;
;
; CALLING SEQUENCE:
; EXAMPLE_SURFACE, data
;
; REQUIRED INPUTS:
; None. Fake data will be used if no data is supplied in call.
; (Stole this from David - Thanks!)
;
; OPTIONAL INPUTS
;
; data: A 2D array of surface data.
;
pro newsgroup,image
;------------------------------
; Need fake data?
IF N_Elements(image) EQ 0 THEN BEGIN
image = BeselJ(Shift(Dist(40,40),20,20)/2,0)
ENDIF
;---------------------------------
set_plot,'z' ;Set graphics device to the Z buffer
;----------------------------------
;Get data dimensions
sizer = size(image)
numberx = sizer[1] ;columns
numbery = sizer[2] ;rows
if n_elements(x) eq 0 then x = findgen(numberx)
if n_elements(y) eq 0 then y = findgen(numbery)
;----------------------------------
img = image
xx = x
yy = y
ax = 40 ;Tweak Values to get
; it to look
az = 30 ;the way I like (axis
; angles, max values,etc.)
minz = min(img)
maxz = 3*max(img)
set_shading,values=[0,150],light=[0,0,1]
notick=[' ',' ',' ',' ',' ',' ',' ',' ']
;----------------------------------------
;Ok....below here is where I start the copyright infringement.
; The following all belongs to RSI, and I have just made modifications
; to their routines. I have stripped it down to the bare bones, just
; to make it more obvious what I have done. You can use this as an
; example to modify the full routine of show3.pro
; Also, I have switched everything to shaded surfaces because they
; just look more cool for my data.
shade_surf,img,xx,yy,/save,xstyle=1,ystyle=1,zaxis=0,$
zrange=[minz,maxz],zstyle=1,az = az,$
ax=ax,ztickname=notick,/nodata
; Call shade_surf to get the
; 3D coordinate matrix
xorig = [x[0],x[numberx-1],x[0],x[numberx-1]] ;x locations of corners
yorig = [y[0],y[0],y[numbery-1],y[numbery-1]] ;y locations of corners
xcoor = xorig * !x.s[1] + !x.s[0]
; normalized x coordinate
ycoor = yorig * !y.s[1] + !y.s[0]
; y coordinate
;----------------------------------------
; I added the following line to rotate the xy axis to the vertical
; as the show3 routine projected it to the xy plane already. Obviously,
; the proper way to do this would be to figure out the coordinates of
; the back wall (xz plane) and use polywarp to warp it there. I
; couldn't work out how to do this correctly, so good luck!
t3d,/yzexch
;----------------------------------------
;Back to the show3.pro routine with all of its great comments
; (thanks RSI)
;
; #!P.T is the transformation matrix we set up with shade_surf routine
; and the xcoor,ycoor correspond to the pixel coordinates of our surface
p = [[xcoor],[ycoor],[fltarr(4)],[replicate(1,4)]] # !P.T
u = p[*,0]/p[*,3] * !d.x_vsize ; Scale U coor to device
v = p[*,1]/p[*,3] * !d.y_vsize ; and v
u0 = min(u)
v0= min(v) ;lower left corner
sizeu = max(u) - u0+1
sizev = max(v) - v0+1 ;Size of new image
fact = 1
miss = 0
;----------------- Figure out kx, ky for our desired warped surface
polywarp,xorig,yorig,(u-u0)/fact,(v-v0)/fact,1,kx,ky
warpedimage = poly_2d(bytscl(img),kx,ky,keyword_set(interp),$
sizeu,sizev,missing=miss)
; ---------------------------
; We now have the image warped vertically. It doesn't seem to be
; perfect, but not too bad. Now...slide it to the back of the cube
; with the following numbers in the tv command.
tv,warpedimage,63,190,xsize = sizeu,ysize=sizev,order=0
;---------------------------
; Draw the shaded surface in front of our image
shade_surf,img,xx,yy,/save,xstyle=1,ystyle=1,zaxis=0,$
zrange=[minz,maxz], zstyle=1,az =az,$
ax=ax,/noerase,ztickname=notick
;---------------------------
;Get the image from the Z-buffer
; Adjust device for what you need - PS, Xwin,windows...etc
finalimage = tvrd()
set_plot,'win'
;---------------------------
;Draw the final image to screen
tv,finalimage
end
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