quadmesh (version 0.5.5)

quadmesh: Create a quad-type mesh for use in rgl.

Description

Convert an object to a mesh3d quadrangle mesh, with methods for raster::raster() and matrix.

Usage

dquadmesh(
  x,
  z = x,
  na.rm = FALSE,
  ...,
  texture = NULL,
  texture_filename = NULL
)
# S3 method for default
dquadmesh(
  x,
  z = x,
  na.rm = FALSE,
  ...,
  texture = NULL,
  texture_filename = NULL
)
quadmesh(x, z = x, na.rm = FALSE, ..., texture = NULL, texture_filename = NULL)
# S3 method for BasicRaster
quadmesh(x, z = x, na.rm = FALSE, ..., texture = NULL, texture_filename = NULL)
# S3 method for matrix
quadmesh(x, z = x, na.rm = FALSE, ..., texture = NULL, texture_filename = NULL)

Value

mesh3d

Arguments

x

raster object for mesh structure

z

raster object for height values

na.rm

remove quads where missing values?

...

ignored

texture

optional input RGB raster, 3-layers

texture_filename

optional input file path for PNG texture

Details

quadmesh() generates the cell-based interpretation of a raster (AREA) but applies a continuous interpretation of the values of the cells to each quad corner. dquadmesh splits the mesh and applies a discrete interpretation directly. Loosely, the quadmesh is a continuous surface and the dquadmesh is free-floating cells, but it's a little more complicated and depends on the options applied. (The interpolation) applied in the quadmesh case is not entirely consistent.

The output is described as a mesh because it is a dense representation of a continuous shape, in this case plane-filling quadrilaterals defined by index of four of the available vertices.

The z argument defaults to the input x argument, though may be set to NULL, a constant numeric value, or another raster. If the coordinate system of z and x don't match the z values are queried by reprojection.

Any raster RGB object (3-layers, ranging in 0-255) may be used as a texture on the resulting mesh3d object. If texture is a palette raster it will be auto-expanded to RGB.

It is not possible to provide rgl with an object of data for texture, it must be a PNG file and so the in-memory texture argument is written out to PNG file (with a message). The location of the file may be set explicitly with texture_filename. Currently it's not possible to not use the texture object in-memory.

Examples

library(raster)
data(volcano)
r <- setExtent(raster(volcano), extent(0, 100, 0, 200))
qm <- quadmesh(r)