| G_utilities.3d {lattice} | R Documentation |
Utility functions for 3-D plots
Description
These are (related to) the default panel functions for cloud
and wireframe.
Usage
ltransform3dMatrix(screen, R.mat)
ltransform3dto3d(x, R.mat, dist)
Arguments
x |
|
screen |
list, as described in |
R.mat |
4x4 transformation matrix in homogeneous coordinates |
dist |
controls transformation to account for perspective viewing |
Details
ltransform3dMatrix and ltransform3dto3d are utility
functions to help in computation of projections. These functions are
used inside the panel functions for cloud and
wireframe. They may be useful in user-defined panel functions
as well.
The first function takes a list of the form of the screen
argument in cloud and wireframe and a R.mat, a
4x4 transformation matrix in homogeneous coordinates, to return a new
4x4 transformation matrix that is the result of applying R.mat
followed by the rotations in screen. The second function
applies a 4x4 transformation matrix in homogeneous coordinates to a
3xn matrix representing points in 3-D space, and optionally does some
perspective computations. (There has been no testing with non-trivial
transformation matrices, and my knowledge of the homogeneous
coordinate system is very limited, so there may be bugs here.)
Author(s)
Deepayan Sarkar Deepayan.Sarkar@R-project.org