1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
include <imhdr.h>
include "pvol.h"
# VMATRIX -- Volume rotation, rotation matrix projection algorithm.
# Proceeds from origin at back of volume image toward front, writing
# output image lines in successive overlapping sheets. See "Back to
# Front Display of Voxel-Based Objects", G.Frieder, D.Gordon, R.Reynolds,
# IEEE Computer Graphics & Applications Jan. 85, p 52-60.
procedure vmatrix (im1, im2, vp)
pointer im1 # Input volume image
pointer im2 # Output projection image
pointer vp # Volume projection descriptor
real v, vx, vy, vz
real dcosa, dcosb, dcosc
#real t11,t21,t31, t12,t22,t32, t13,t23,t33
begin
vx = VECX(vp)
vy = VECY(vp)
vz = VECZ(vp)
v = sqrt (vx*vx + vy*vy + vz*vz)
dcosa = vx / v
dcosb = vy / v
dcosc = vz / v
# ???????
end
|
