Set up background
Set up the background of the scene.
bg3d(...)
rgl.bg( sphere = FALSE, fogtype = "none", color = c("black", "white"),
back = "lines", fogScale = 1, ...)fogtype |
fog type:
Fog only applies to objects with |
sphere |
logical, if true, an environmental sphere geometry is used for the background decoration. |
color |
Primary color is used for background clearing and as fog color.
Secondary color is used for background sphere geometry. See |
back |
Specifies the fill style of the sphere geometry. See |
fogScale |
Scaling for fog. See Details. |
... |
Material properties. See |
If sphere is set to TRUE, an environmental sphere enclosing the whole scene is drawn.
If not, but the material properties include a bitmap as a texture, the bitmap is drawn in the background of the scene. (The bitmap colors modify the general color setting.)
If neither a sphere nor a bitmap background is drawn, the background is filled with a solid color.
The fogScale parameter should be a positive value
to change the density of the fog in the plot. For
fogtype = "linear" it multiplies the density of the
fog; for the exponential fog types it multiplies the density
parameter used in the display.
See
the OpenGL 2.1 reference
for the formulas used in the fog calculations within R (though the
"exp2" formula appears to be wrong, at least on my
system). In WebGL displays,
the following rules are used. They appear to match the
rules used in R on my system.
For "linear" fog, the near clipping plane is
taken as c=0, and the
far clipping plane is taken as c=1. The
amount of fog is s * c clamped to a 0 to 1
range, where s = fogScale.
For "exp" and "exp2" fog, the observer location
is negative at a distance depending on the field of view.
The formula for the distance is
c = [1-sin(theta)]/[1 + sin(theta)]
where theta = FOV/2. We calculate
c' = d(1-c) + c
so c' runs from 0 at the observer to 1 at the far clipping plane.
For "exp" fog, the amount of fog is
1 - exp(-s * c').
For "exp2" fog, the amount of fog is
1 - exp[-(s * c')^2].
material3d, bgplot3d to add a 2D plot as background.
open3d()
# a simple white background
bg3d("white")
# the holo-globe (inspired by star trek):
bg3d(sphere = TRUE, color = c("black", "green"), lit = FALSE, back = "lines" )
# an environmental sphere with a nice texture.
bg3d(sphere = TRUE, texture = system.file("textures/sunsleep.png", package = "rgl"),
back = "filled" )
# The same texture as a fixed background
open3d()
bg3d(texture = system.file("textures/sunsleep.png", package = "rgl"), col = "white")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.