rgl.user2window: Convert between rgl user and window coordinates

Description

This function converts from 3-dimensional user coordinates to 3-dimensional window coordinates.

Usage

rgl.user2window(x, y = NULL, z = NULL, projection = rgl.projection())
rgl.window2user(x, y = NULL, z = 0, projection = rgl.projection())
rgl.projection()

Arguments

x, y, z

Input coordinates. Any reasonable way of defining the coordinates is acceptable. See the function xyz.coords for details.

projection

The rgl projection to use

Value

The coordinate conversion functions produce a matrix with columns corresponding to the X, Y, and Z coordinates.
rgl.projection() returns a list containing the following components:
modelthe modelview matrix
projectionthe projection matrix
viewportthe viewport vector
See par3d for more details.

Details

These functions convert between user coordinates and window coordinates.

Window coordinates run from 0 to 1 in X, Y, and Z. X runs from 0 on the left to 1 on the right; Y runs from 0 at the bottom to 1 at the top; Z runs from 0 foremost to 1 in the background. rgl does not currently display vertices plotted outside of this range, but in normal circumstances will automatically resize the display to show them. In the example below this has been suppressed.

Examples

Run this code

open3d()
points3d(rnorm(100), rnorm(100), rnorm(100))
if (interactive() || !.Platform$OS == "unix") {
# Calculate a square in the middle of the display and plot it
square <- rgl.window2user(c(0.25, 0.25, 0.75, 0.75, 0.25), 
                          c(0.25, 0.75, 0.75, 0.25, 0.25), 0.5)
par3d(ignoreExtent = TRUE)
lines3d(square)
par3d(ignoreExtent = FALSE)
}