rgl.material {rgl} | R Documentation

## Generic Appearance setup

### Description

Set material properties for geometry appearance.

### Usage

    rgl.material(
      color        = c("white"),
      alpha        = c(1.0),
      lit          = TRUE,
      ambient      = "black",
      specular     = "white",
      emission     = "black",
      shininess    = 50.0,
      smooth       = TRUE,
      texture      = NULL,
      textype      = "rgb",
      texmipmap    = FALSE,
      texminfilter = "linear",
      texmagfilter = "linear",
      texenvmap    = FALSE,
      front        = "fill",
      back         = "fill",
      size         = 3.0,
      lwd          = 1.0,
      fog          = TRUE,
      point_antialias = FALSE,
      line_antialias = FALSE,
      depth_mask   = TRUE,
      depth_test   = "less",
      polygon_offset = c(0.0, 0.0),
      ...
    )
    material3d(...)

### Arguments

`color` | vector of R color characters. Represents the diffuse component in case of lighting calculation (lit = TRUE), otherwise it describes the solid color characteristics.
`lit` | logical, specifying if lighting calculation should take place on geometry
`ambient, specular, emission, shininess` | properties for lighting calculation. ambient, specular, emission are R color character string values; shininess represents a numerical.
`alpha` | vector of alpha values between 0.0 (fully transparent) .. 1.0 (opaque).
`smooth` | logical, specifying whether Gouraud shading (smooth) or flat shading should be used.
`texture` | path to a texture image file. Supported formats: png.

`textype`

specifies what is defined with the pixmap

"alpha"

  alpha values

"luminance"

  luminance

"luminance.alpha"

  luminance and alpha

"rgb"

  color

"rgba"

  color and alpha texture

`texmipmap` | Logical, specifies if the texture should be mipmapped.

`texmagfilter`

specifies the magnification filtering type (sorted by ascending quality):

"nearest"

  texel nearest to the center of the pixel

"linear"

  weighted linear average of a 2x2 array of texels

`texminfilter`

specifies the minification filtering type (sorted by ascending quality):

"nearest"

  texel nearest to the center of the pixel

"linear"

  weighted linear average of a 2x2 array of texels

"nearest.mipmap.nearest"

  low quality mipmapping

"nearest.mipmap.linear"

  medium quality mipmapping

"linear.mipmap.nearest"

  medium quality mipmapping

"linear.mipmap.linear"

  high quality mipmapping

`texenvmap` | logical, specifies if auto-generated texture coordinates for environment-mapping should be performed on geometry.

`front, back`

Determines the polygon mode for the specified side:

"filled"

  filled polygon

"lines"

  wireframed polygon

"points"

  point polygon

"culled"

  culled (hidden) polygon

`size` | numeric, specifying the size of points in pixels
`lwd` | numeric, specifying the line width in pixels
`fog` | logical, specifying if fog effect should be applied on the corresponding shape
`point_antialias, line_antialias` | logical, specifying if points and lines should be antialiased
`depth_mask` | logical, specifying whether the object's depth should be stored.
`depth_test` | Determines which depth test is used to see if this object is visible, depending on its apparent depth in the scene compared to the stored depth. Possible values are `"never"`, `"less"` (the default), `"equal"`, `"lequal"` (less than or equal), `"greater"`, `"notequal"`, `"gequal"` (greater than or equal), `"always"`.
`polygon_offset` | If non-zero, offsets are added to the recorded depth of filled polygons. See Details below.
`...` | Any of the arguments above can be passed to `material3d`; see Details below. `rgl.material` will ignore others.

### Details

Values can be queried by specifying their names in a character vector, e.g. `material3d("color")`. There is one read-only property that can be queried but not set:

isTransparent

  Is the current colour transparent?

Only one side at a time can be culled.

The `polygon_offset` property is a two element vector giving the factor and units values to use in a `glPolygonOffset()` call in OpenGL. If only one value is given, it is used for both elements. The units value is added to the depth of all pixels in a filled polygon, and the factor value is multiplied by an estimate of the slope of the polygon and then added to the depth. Positive values “push” polygons back slightly for the purpose of depth testing, to allow points, lines or other polygons to be drawn on the surface without being obscured due to rounding error. Negative values pull the object forward. A typical value to use is `1` (which is automatically expanded to `c(1,1)`). If values are too large, objects which should be behind the polygon will show through, and if values are too small, the objects on the surface will be partially obscured. Experimentation may be needed to get it right. The first example in `?persp3d` uses this property to add grid lines to a surface.

`material3d` is an alternate interface to the material properties, modelled after `par3d`: rather than setting defaults for parameters that are not specified, they will be left unchanged. `material3d` may also be used to query the material properties; see the examples below.

The current implementation does not return parameters for textures.

If `point_antialias` is `TRUE`, points will be drawn as circles; otherwise, they will be drawn as squares. Lines tend to appear heavier with `line_antialias == TRUE`.

The `material` member of the `r3dDefaults` list may be used to set default values for material properties.

The `...` parameter to `rgl.material` is ignored.

### Value

`rgl.material()` is called for the side effect of setting the material properties. It returns a value invisibly which is not intended for use by the user.

Users should use `material3d()` to query material properties. It returns values similarly to `par3d` as follows: When setting properties, it returns the previous values in a named list. A named list is also returned when more than one value is queried. When a single value is queried it is returned directly.

### See Also

`rgl.primitive`, `rgl.bbox`, `rgl.bg`, `rgl.light`

### Examples

    save <- material3d("color")
    material3d(color = "red")
    material3d("color")
    material3d(color = save)

    # this illustrates the effect of depth_test
    x <- c(1:3); xmid <- mean(x)
    y <- c(2, 1, 3); ymid <- mean(y)
    z <- 1
    open3d()
    tests <- c("never", "less", "equal", "lequal", "greater",
                      "notequal", "gequal", "always")
    for (i in 1:8) {
      triangles3d(x, y, z + i, col = heat.colors(8)[i])
      texts3d(xmid, ymid, z + i, paste(i, tests[i], sep = ". "), depth_test = tests[i])
    }
    highlevel()  # To trigger display

[Package rgl version 0.100.19 Index]