From mesh3d to rayshader

Sébastien Rochette

2019-07-24

Packages

library(Rvcg)
library(mesh2ray)
library(rgdal)
#> Loading required package: sp
#> rgdal: version: 1.4-4, (SVN revision 833)
#>  Geospatial Data Abstraction Library extensions to R successfully loaded
#>  Loaded GDAL runtime: GDAL 2.2.2, released 2017/09/15
#>  Path to GDAL shared files: /usr/share/gdal/2.2
#>  GDAL binary built with GEOS: TRUE 
#>  Loaded PROJ.4 runtime: Rel. 4.9.2, 08 September 2015, [PJ_VERSION: 492]
#>  Path to PROJ.4 shared files: (autodetected)
#>  Linking to sp version: 1.3-1
library(raster)
library(rayshader)

Transfrom mesh3d to raster

humface data is a mesh3d object. It is transformed as a raster object with mesh_to_raster()

data(humface)
humface_r <- mesh_to_raster(humface)
plot(humface_r)

Transform raster to rayshader elevation matrix

raster humface_r is extracted to be transformed as a matrix that can be used with {rayshader}.
A list is returned.

humface_ray <- stack_to_ray(humface_r)

# Rayshade raster
zscale <- 0.1
ambmat <- ambient_shade(humface_ray$elevation, zscale = zscale)
raymat <- ray_shade(humface_ray$elevation, zscale = zscale, lambert = TRUE,
                    sunangle = 45)

ray_image <- humface_ray$elevation %>%
  sphere_shade(texture = "unicorn") %>%
  add_shadow(raymat, max_darken = 0.1) %>%
  add_shadow(ambmat, max_darken = 0.5)

plot_map(ray_image)

Get elevation matrix and calculate image overlay

img <- system.file("img/ThinkR_logo_500px.png", package = "mesh2ray")
humface_img <- stack_to_ray(humface_r, img)

# Rayshade raster
zscale <- 0.25
ambmat <- ambient_shade(humface_img$elevation, zscale = zscale)
raymat <- ray_shade(humface_img$elevation, zscale = zscale, lambert = TRUE)

ray_image <- humface_img$elevation %>%
  sphere_shade(texture = "imhof4") %>%
  add_overlay(humface_img$overlay, alphalayer = 0.99) %>% # Note overlay
  add_shadow(raymat, max_darken = 0.01) %>%
  add_shadow(ambmat, max_darken = 0.5) # %>% 
# add_water(watermap, color = "#57B6FF") 

plot_map(ray_image)