Add Shadow

Multiplies a texture array or shadow map by a shadow map.

add_shadow(hillshade, shadowmap, max_darken = 0.7, rescale_original = FALSE)

Arguments

hillshade

A three-dimensional RGB array or 2D matrix of shadow intensities.

shadowmap

A matrix that incidates the intensity of the shadow at that point. 0 is full darkness, 1 is full light.

max_darken

Default 0.7. The lower limit for how much the image will be darkened. 0 is completely black, 1 means the shadow map will have no effect.

rescale_original

Default FALSE. If TRUE, hillshade will be scaled to match the dimensions of shadowmap (instead of the other way around).

Value

Shaded texture map.

Examples

#First we plot the sphere_shade() hillshade of `montereybay` with no shadows

if(run_documentation()) {
montereybay %>%
 sphere_shade(colorintensity=0.5) %>%
 plot_map()
}


#Raytrace the `montereybay` elevation map and add that shadow to the output of sphere_shade()
if(run_documentation()) {
montereybay %>%
 sphere_shade(colorintensity=0.5) %>%
 add_shadow(ray_shade(montereybay,sunaltitude=20,zscale=50),max_darken=0.3) %>%
 plot_map()
}


#Increase the intensity of the shadow map with the max_darken argument.
if(run_documentation()) {
montereybay %>%
 sphere_shade(colorintensity=0.5) %>%
 add_shadow(ray_shade(montereybay,sunaltitude=20,zscale=50),max_darken=0.1) %>%
 plot_map()
}


#Decrease the intensity of the shadow map.
if(run_documentation()) {
montereybay %>%
 sphere_shade(colorintensity=0.5) %>%
 add_shadow(ray_shade(montereybay,sunaltitude=20,zscale=50),max_darken=0.7) %>%
 plot_map()
}