Calculates the normal unit vector for every point on the grid.
calculate_normal(heightmap, zscale = 1, progbar = FALSE)Arguments
- heightmap
A two-dimensional matrix, where each entry in the matrix is the elevation at that point. All points are assumed to be evenly spaced.
- zscale
Default 1.
- progbar
Default `FALSE`. If `TRUE`, turns on progress bar.
Value
Matrix of light intensities at each point.
Examples
#Here we produce a light intensity map of the `volcano` elevation map.
#Cache the normal vectors of the volcano dataset
if(run_documentation()) {
volcanocache = calculate_normal(volcano)
}
#Use the cached vectors to speed up calculation of `sphere_shade()` on a map.
if(run_documentation()) {
sphere_shade(volcano,normalvectors = volcanocache) %>%
plot_map()
}
