R6 Class for glTF file objects

Description

The glTF file spec is described here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html. This object encapsulates most of the data from those files.

Super class

rgl::Buffer -> gltf

Public fields

Methods

Public methods

• Gltf$new()

• Gltf$addAccessor()

• Gltf$getScene()

• Gltf$setScene()

• Gltf$addScene()

• Gltf$addToScene()

• Gltf$defaultScene()

• Gltf$getNode()

• Gltf$setNode()

• Gltf$addNode()

• Gltf$addChild()

• Gltf$setParents()

• Gltf$getSkin()

• Gltf$setSkin()

• Gltf$getJoint()

• Gltf$getInverseBindMatrices()

• Gltf$getForwardBindMatrices()

• Gltf$getCamera()

• Gltf$getExtras()

• Gltf$setExtras()

• Gltf$getMesh()

• Gltf$setMesh()

• Gltf$addMesh()

• Gltf$getMaterial()

• Gltf$getTexture()

• Gltf$getImage()

• Gltf$addMaterial()

• Gltf$addTexture()

• Gltf$addImage()

• Gltf$addSampler()

• Gltf$getMaterialNumber()

• Gltf$writeVectors()

• Gltf$makePrimitive()

• Gltf$getAsset()

• Gltf$setAsset()

• Gltf$getTransform()

• Gltf$getRglMaterial()

• Gltf$getAnimation()

• Gltf$setAnimation()

• Gltf$timerange()

• Gltf$initAnimation()

• Gltf$settime()

• Gltf$print()

• Gltf$listCount()

• Gltf$clone()

Method new()

Usage

Gltf$new(json = NULL, defaultbin = NULL)

Arguments

Method addAccessor()

Write values to accessor, including min and max.

The glTF standard requires min and max values in accessors, whereas other uses of buffers may not. This function stores in the usual way using the Buffer$addAccessor() method, and then adds min and max values.

The standard also doesn't support signed 4 byte integers or double precision values, so we test for those here.

Usage

Gltf$addAccessor(values, target = NULL, types = "anyGLTF", normalized = FALSE)

Arguments

Returns

New accessor number.

Method getScene()

Get scene object.

Usage

Gltf$getScene(sc)

Arguments

Returns

Scene object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-scene.

Method setScene()

Update scene record.

Usage

Gltf$setScene(sc, scene)

Arguments

Method addScene()

Add a scene object.

Usage

Gltf$addScene()

Returns

Scene number.

Method addToScene()

Add node to scene.

Usage

Gltf$addToScene(scene, node)

Arguments

Method defaultScene()

Get default scene, creating it if necessary.

Usage

Gltf$defaultScene()

Returns

Scene number.

Method getNode()

Get node object.

Usage

Gltf$getNode(n)

Arguments

Returns

Node object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-node.

Method setNode()

Set node object.

Usage

Gltf$setNode(n, node)

Arguments

Method addNode()

Add a node object.

Usage

Gltf$addNode(mesh = NULL, matrix = NULL, extras = NULL)

Arguments

Returns

Node number.

Method addChild()

Add node as child of another.

Usage

Gltf$addChild(parent, node)

Arguments

Method setParents()

Set parent member for all nodes

Usage

Gltf$setParents()

Method getSkin()

Get skin object.

Usage

Gltf$getSkin(skin)

Arguments

Returns

Skin object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-skin.

Method setSkin()

Set skin object.

Usage

Gltf$setSkin(n, skin)

Arguments

Method getJoint()

Get joint node.

Usage

Gltf$getJoint(skin, num)

Arguments

Returns

Node object

Method getInverseBindMatrices()

Get "inverse bind matrices".

These matrices undo the existing transformation before applying the skin transformations.

Usage

Gltf$getInverseBindMatrices(skin)

Arguments

Returns

A 4x4xn array of matrices, one per joint.

Method getForwardBindMatrices()

Get "forward bind matrices".

These matrices applying the skin transformations.

Usage

Gltf$getForwardBindMatrices(skin)

Arguments

Returns

A 4x4xn array of matrices, one per joint.

Method getCamera()

Get camera object.

Usage

Gltf$getCamera(cam)

Arguments

Returns

Camera object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-camera.

Method getExtras()

Get top-level extras list.

Usage

Gltf$getExtras()

Returns

Extras list, including rgl objects.

Method setExtras()

Set extras list.

Usage

Gltf$setExtras(extras)

Arguments

Method getMesh()

Get mesh object.

Usage

Gltf$getMesh(m)

Arguments

Returns

Mesh object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-mesh.

Method setMesh()

Set mesh object.

Usage

Gltf$setMesh(m, mesh)

Arguments

Method addMesh()

Add a mesh object.

Usage

Gltf$addMesh(primitives)

Arguments

Returns

Mesh number.

Method getMaterial()

Get material object.

Usage

Gltf$getMaterial(m)

Arguments

Returns

Material object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-material.

Method getTexture()

Get texture object.

Usage

Gltf$getTexture(tex)

Arguments

Returns

Texture object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-texture.

Method getImage()

Get image object.

Usage

Gltf$getImage(im)

Arguments

Returns

Image object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-image.

Method addMaterial()

Construct and possibly add material.

This will return an existing material if possible.

Usage

Gltf$addMaterial(mat, defaultMaterial = list())

Arguments

Returns

Material number.

Method addTexture()

Add a texture.

Usage

Gltf$addTexture(mat)

Arguments

Returns

Texture number.

Method addImage()

Add an image for a texture.

Usage

Gltf$addImage(mat)

Arguments

Returns

Image number.

Method addSampler()

Add a sampler.

Usage

Gltf$addSampler(mat)

Arguments

Returns

Sampler number.

Method getMaterialNumber()

Add or return a material.

Usage

Gltf$getMaterialNumber(material)

Arguments

Returns

Material number.

Method writeVectors()

Write data.

Usage

Gltf$writeVectors(
  coords,
  target = targetArray,
  types = "anyGLTF",
  normalized = FALSE
)

Arguments

Returns

Accessor number, or NULL.

Method makePrimitive()

Create a primitive record.

Usage

Gltf$makePrimitive(inds, mode = NULL, attributes = NULL, matnum = NULL)

Arguments

Returns

Primitive record, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-primitive.

Method getAsset()

Get asset list.

Usage

Gltf$getAsset()

Returns

Asset object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-asset.

Method setAsset()

Set asset list.

Usage

Gltf$setAsset(version, generator)

Arguments

Method getTransform()

Get local transform.

Usage

Gltf$getTransform(n)

Arguments

Returns

4x4 matrix of local transform.

Method getRglMaterial()

Reconstruct rgl material.

Usage

Gltf$getRglMaterial(n)

Arguments

Returns

rgl material record.

Method getAnimation()

Get animation.

Usage

Gltf$getAnimation(ani)

Arguments

Returns

Animation object, documented here: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#reference-animation.

Method setAnimation()

Set animation.

Usage

Gltf$setAnimation(ani, animation)

Arguments

Method timerange()

Find time range of an animation

Usage

Gltf$timerange(ani)

Arguments

Returns

Min and max times from the samplers in the animation.

Method initAnimation()

Initialize animation.

This builds all of the interpolation functions in the samplers.

Usage

Gltf$initAnimation(ani)

Arguments

Returns

Modified animation object

Method settime()

Set time for an animation.

This evaluates all the interpolators and modifies self to reflect the specified time point.

Usage

Gltf$settime(time, ani = 0)

Arguments

Returns

Vector of node numbers that were changed.

Method print()

Print gltf objects with various levels of detail.

Usage

Gltf$print(verbose = FALSE, names = FALSE, showExtras = TRUE, ...)

Arguments

Examples

\donttest{
samples <- "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0"
gltf <- readGLB(paste0(samples, "/2CylinderEngine/glTF-Binary/2CylinderEngine.glb?raw=true"))
gltf$print(names = "meshes")
}

Method listCount()

Get number of items in private list.

Usage

Gltf$listCount(list)

Arguments

Method clone()

The objects of this class are cloneable with this method.

Usage

Gltf$clone(deep = FALSE)

Arguments

Examples

## ------------------------------------------------
## Method `Gltf$print`
## ------------------------------------------------


samples <- "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0"
gltf <- readGLB(paste0(samples, "/2CylinderEngine/glTF-Binary/2CylinderEngine.glb?raw=true"))
gltf$print(names = "meshes")

Produce glTF objects

Description

The glTF file is the JSON part of a glTF representation of a 3D scene. This function creates the R structure corresponding to one, and writes the binary buffer file for it.

Usage

as.gltf(x, ...)

## Default S3 method:
as.gltf(x, y = NULL, z = NULL, vertices,
                            material = NULL,
                            normals = NULL,
                            texcoords = NULL,
                            points = NULL, segments = NULL,
                            triangles = NULL,
                            quads = NULL,
                            transform = diag(4),
                            extras = NULL,
                            ...,
                            rglscene = list(),
                            previous = Gltf$new(),
                            newScene = FALSE,
                            parentNode = NULL,
                            dir = tempdir(),
                            scale = c(1,1,1))

## S3 method for class 'rglscene'
as.gltf(x, ..., previous = Gltf$new(),
                            newScene = FALSE)
## S3 method for class 'mesh3d'
as.gltf(x, ...)

Arguments

Details

as.gltf is a generic function.

The method for "rglscene" objects can handle most objects produced by scene3d, but not all objects will be handled. In particular:

• Lights, text, bounding box decorations and backgrounds are saved in “extra” fields, so they can be read by rgl2gltf, but most other software will ignore them or only display some parts.

• Most material properties are also stored in “extra” fields.

There are methods for many individual types of "rglobject", but these are intended for internal use.

Value

A "gltf" object.

Author(s)

Duncan Murdoch

References

The specification of the glTF format: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html

Examples

cube <- rgl::rotate3d(rgl::cube3d(col = "red"), -pi/10, 1,0,0)
gltf <- as.gltf(cube)
rgl::plot3d(gltf)
gltf$closeBuffers()

Convert a glTF object to an rglscene or mesh3d object.

Description

These methods convert a "gltf" object to a "rglscene" object, similar to what scene3d would produce, or a "mesh3d" object.

Usage

## S3 method for class 'gltf'
as.rglscene(x, scene = x$scene, nodes = NULL,
         useRGLinfo = TRUE, time = NULL, ani = 0, clone = TRUE,
         quick = FALSE, add = FALSE, ...)
## S3 method for class 'gltf'
as.mesh3d(x, ...)

Arguments

Details

These functions need to modify the glTF object, caching some information to help with the conversion. By default they do this on a cloned copy of it, and the original is left unchanged. If the object has already been cloned this can be skipped by setting clone = FALSE.

Value

An "rglscene" object.

Extract a texture file from a glTF object

Description

Extracts a texture from a glTF object, and writes it to a file.

Usage

extractTexture(gltf, index = 0,
               outfile = tempfile(),
               verbose = TRUE)

Arguments

Details

Since rgl doesn't support any texture format except PNG, this function will attempt to convert JPEG textures to PNG. To do that it needs to have the jpeg and png packages available.

Value

Returns the filename that was written, or NULL if the request failed.

If closeConnections = FALSE, the filename will have attribute "gltf" containing the gltf object which might now contain a new open connection.

If the texture has a recorded MIME type in gltf, that will be returned in attribute "mimeType".

Find a component of a recursive object

Description

findEntry searches recursive objects for components matching a condition. namePattern creates a test of whether the component name matches a pattern. hasClass creates a test of whether the component has a class.

Usage

findEntry(x, test, ..., path = c())
namePattern(pattern)
hasClass(class)

Arguments

Details

Utility/debugging functions to search a large recursive object for a particular component name or class.

The test function should have header function(name, value), and may include other arguments which will be taken from ....

Value

findEntry returns a list with one entry per hit. Each entry in the list is a named vector giving the path to the hit, numerically in the values, and as an R expression by concatenating the names. The test functions will be passed single names and values, and should return a single logical result.

Examples

x <- list( a = list( b = list(c(d="A", e="B"), 1L, 1:3)))
locations <- findEntry(x, namePattern("e"))
locations

#This shows how the result can be used:
x[[locations[[1]]]]
expr <- paste0(c("x", names(locations[[1]])), collapse = "")
expr
eval(parse(text=expr))

findEntry(x, hasClass("integer"))

Use the MikkTSpace code to generate tangent vectors.

Description

This function generates tangent vectors using the MikkTSpace code by Morten S. Mikkelsen.

Usage

getTangents(obj)

Arguments

Details

glTF files include normal textures, which require the tangent space to be specified: the normals at each vertex are supplemented with a tangent vector and a bitangent vector that is their cross product. The standard recommends that if the glTF file doesn't specify tangents, they should be generated using the MikkTSpace code.

Note that a comment in ‘mikktspace.h’ indicates that indexing needs to be recalculated after computing the tangents, so this function works on unindexed inputs, and reapplies indexing at the end.

Value

A modified copy of the original object, adding a 4 column tangents entry. The order and number of indices may have changed.

Author(s)

Morten S. Mikkelsen, Johannes Kuehnel and Duncan Murdoch.

References

The MikkTSpace code was obtained from https://github.com/mmikk/MikkTSpace. The interface code is based on code from https://www.turais.de/using-mikktspace-in-your-project/ by Johannes Kuehnel.

Create a widget for a glTF display.

Description

This creates a widget holding a glTF scene, with controls to animate it if it supports animation, and with shaders that implement normal textures.

Usage

gltfWidget(gltf,
           animation = 0,
           start = times[1], stop = times[2],
           times = gltf$timerange(animation),
           method = c("shader", "rigid"),
           add = FALSE, close = !add,
           verbose = FALSE,
           open3dParams = getr3dDefaults(),
           usePBR = hasPBRparams(gltf),
           PBRargs = list(), ...)

Arguments

Details

See playgltf for a description of the method used for animation. The "fixed" method is fast, but doesn't do a good job on some animations.

If the gltf object doesn't contain any animations, or animation = NA, this will simply display it as a widget with no controls.

Value

A widget suitable for display or inclusion in an R Markdown document.

Note

Physically based rendering (PBR, controlled by usePBR) is only used with method = "shader".

If PBR is not used, the V8 package is required so that the shaders can be modified.

Examples

if ((interactive() || rgl::in_pkgdown_example()) && requireNamespace("manipulateWidget")) {
  gltf <- readGLB(system.file("glb/RiggedSimple.glb", package = "rgl2gltf"))
  gltfWidget(gltf)
}

Imports from rgl

Description

These generic functions are imported from rgl.

Usage

plot3d(x, ...)
as.rglscene(x, ...)
as.mesh3d(x, ...)

Arguments

Details

The main documentation for these generics is in rgl: plot3d.

This package defines "gltf" methods for the generics. Documentation for as.rglscene.gltf is included.

Print the sequence of matrices affecting an object.

Description

This is used for debugging, to see how an object within nested rgl subscenes is affected by their user matrices.

Usage

matrixSequence(tag, scene = scene3d())
## S3 method for class 'matrixSequence'
print(x, n = 5, ...)

Arguments

Value

A list containing records with entries as follows:

Edit shader code

Description

This function applies specified edits to shader code to support new functions.

Usage

modifyShaders(shaders, mod, ...)

Arguments

Details

The mods argument is organized in a nested list.

1. The top level can contain vertexShader and fragmentShader components.

2. Each of those is a list of changes to apply to that shader.

3. Each change is a list with old and new entries.

4. The old entry is used as a "fixed" pattern to select one or more lines from the shader to be replaced. Multiple matches are allowed, but they shouldn't overlap. Changes will be applied in the order specified, so take care that a pattern doesn't match new text from an earlier change.

5. The new entry contains the replacement. It can either be a character vector or a function that returns a character vector. If it is a function, it will be passed the ... argument.

   See rgl2gltf:::shaderChanges for the built-in modifications.

Value

A new shader object incorporating the edits.

Play an animated glTF object.

Description

‘.gltf’ and ‘.glb’ files can contain animation instructions. This function interprets them and plays them.

Usage

playgltf(gltf, animation = 0,
         start = times[1], stop = times[2],
         times = gltf$timerange(animation),
         method = c("rigid", "wholeScene", "partialScene"),
         speed = 1, by = NULL, verbose = FALSE, ...)
showNodes(gltf, animation = 0,
          start = times[1], stop = times[2],
          times = gltf$timerange(animation),
          speed = 1, by = NULL)

Arguments

Details

glTF files are animated by time dependent changes to the transformations in their nodes. Those transformations correspond to RGL par3d("userMatrix") settings in subscenes and can sometimes be directly imported as such.

However, glTF files also support "skins", a computer graphics concept not supported in RGL. A skin is a way to say that different vertices of the same object (typically a triangle mesh) respond to different nodes. This allows shapes to be stretched, similar to skin on a moving body. RGL assumes that all graphics objects are rigid.

The playgltf function provides partial support for skins. Using the "wholeScene" method, it can modify the vertices of an entire scene and redraw the scene. Typically this is quite slow, and not very satisfactory. The "partialScene" method allows only the changed objects to be redrawn, which might help speed things up. Finally, the "rigid" method converts all polygons to rigid ones that are supported by rgl, so that motion is done by changes to the transformations. This is likely the fastest method, but for some animations the errors introduced by the conversion are unacceptably large.

The showNodes function displays each node number as text at the origin for that node. By default it plays the animation showing how the nodes move.

For both functions, the speed and by arguments specify the “times” at which the animation is drawn. If by is specified, then a frame is drawn at time start and subsequent frames increment the time by by. If it is NULL (the default), then the speed argument is used as a multiplier on the internal time (taken to be in seconds). For example, with the default speed = 1, the first frame will be drawn at time start, and when it is complete, the next one will be drawn according to how many seconds have passed in real time, etc.

Value

Called for the side effect of drawing the animation.

Examples

if (interactive() && !rgl::in_pkgdown_example()) {
# This example is fast enough using the "whole" method:

gltf1 <- readGLB(system.file("glb/RiggedSimple.glb", package = "rgl2gltf"))
playgltf(gltf1, start = 0, stop = 3, method = "whole")

# It looks terrible using the "rigid" method, because some triangles
# need to be deformed:

playgltf(gltf1, start = 0, stop = 3, method = "rigid")

# This example is too slow using anything but "rigid", but it's fine there:

samples <- "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0"
gltf2 <- readGLB(paste0(samples, "/BrainStem/glTF-Binary/BrainStem.glb?raw=true"))
playgltf(gltf2, start = 0, stop = 2, speed = 0.25, method = "rigid")
}

Read a GLB file.

Description

GLB is the self-contained binary format of glTF files. This function reads one, extracts the embedded files into the temporary directory, and returns a "gltf" object containing the information in R format.

Usage

readGLB(con, verbose = FALSE, ...)

Arguments

Value

An object of class "gltf". This is an R version of the structure represented by a “glTF” file's JSON information.

Author(s)

Duncan Murdoch

References

The specification of the glTF format: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html

See Also

readglTF

Examples

# This web page has lots of sample files

samples <- "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0"

# Get one of them:  an avocado

gltf <- readGLB(paste0(samples, "/Avocado/glTF-Binary/Avocado.glb?raw=true"))

if (interactive())
  rgl::plot3d(gltf)

if (rgl::in_pkgdown_example())
  gltfWidget(gltf)

gltf$closeBuffers()

Read a glTF file

Description

The glTF file is the JSON part of a glTF representation of a 3D scene. This function reads one and returns a "gltf" object containing the information in R format.

Typically most of the data for the scene is contained in other files named in this one, usually found in the same file folder.

Usage

readglTF(path, defaultbin = NULL, ...)

Arguments

Value

An object of class "gltf".

Author(s)

Duncan Murdoch

References

The specification of the glTF format: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html

Examples

# This web page has lots of sample files

samples <- "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0"
filename <- tempfile(fileext = ".gltf")

# Get one of them:  a 2 cylinder engine.  We need both parts
# to be able to view it, though only the .gltf part is
# needed for readglTF()

download.file(paste0(samples, "/2CylinderEngine/glTF/2CylinderEngine.gltf"),
  destfile = filename)
download.file(paste0(samples, "/2CylinderEngine/glTF/2CylinderEngine0.bin?raw=true"),
  destfile = file.path(tempdir(), "2CylinderEngine0.bin"),
  mode = "wb")

gltf <- readglTF(filename)
gltf

# gltf files contain references to other files using
# relative paths, so we can only use them from their
# own directory
olddir <- setwd(dirname(filename))
rgl::plot3d(gltf)
setwd(olddir)

Set shaders for physically based rendering.

Description

The glTF format is designed to hold objects which are intended for "physically based rendering", where the parameters of the object map to physical properties such as metallicity, roughness, etc. This function replaces the default rgl shaders with PBR shaders based on the reference implementation in https://github.com/KhronosGroup/glTF-Sample-Viewer/tree/88eda8c5358efe03128b72b6c5f5f6e5b6d023e1/shaders.

Usage

setPBRshaders(gltf, gltfMat, id,
              scene = scene3d(minimal = TRUE),
              useIBL = TRUE,
              brdfLUT = system.file("textures/brdfLUT.png", package = "rgl2gltf"),
              IBLspecular = system.file("textures/refmap.png", package = "rgl"),
              IBLdiffuse = system.file("textures/refmapblur.jpeg", package = "rgl2gltf"),
              debugBaseColor = 0,
              debugMetallic = 0,
              debugRoughness = 0,
              debugSpecularReflection = 0,
              debugGeometricOcclusion = 0,
              debugMicrofacetDistribution = 0,
              debugSpecContrib = 0,
              debugDiffuseContrib = 0,
              debugIBLDiffuse = 1,
              debugIBLSpecular = 1,
              defines = list(),
              uniforms = list(),
              attributes = list(),
              textures = list())

Arguments

Details

rgl is designed to work with WebGL version 1, which doesn't support all of the features used in the reference shaders. In particular, no extensions are assumed, and the IBL textures are single 2D textures rather than cube maps.

Value

This function modifies the id object in scene, and returns the modified scene.

Author(s)

Duncan Murdoch for the adaptation to rgl, various others for the original shaders.

References

https://github.com/KhronosGroup/glTF-Sample-Viewer

See Also

gltfWidget

Examples

# This web page has lots of sample files

samples <- "https://raw.githubusercontent.com/KhronosGroup/glTF-Sample-Models/master/2.0"

# Get one of them:  a 2 cylinder engine

gltf <- readGLB(paste0(samples, "/NormalTangentTest/glTF-Binary/NormalTangentTest.glb?raw=true"))
gltfMat <- gltf$getMaterial(0)
scene <- as.rglscene(gltf)
id <- scene$objects[[1]]$id
scene <- setPBRshaders(gltf, gltfMat, id, scene)
cat(scene$objects[[1]]$userFragmentShader)

Debugging tool: show tags for objects in rgl scene

Description

This function uses text3d to display the tags at the center of the objects they label.

Usage

showTags(tags = NULL, ids = NULL,
         subscenes = ids3d("subscene", subscene = 0)$id,
         depth_test = "always", ...)

Arguments

Details

If selected objects don't have tags, they will be labelled using their id value instead.

Value

The rgl ids of the text objects added (one text object per tagged object, with tags as names).

Examples

example("plot3d", package = "rgl")
showTags()

Show the tree structure of nodes in a glTF object or rglscene object.

Description

glTF files contain nodes corresponding to objects and groups of objects in 3D scenes. They must be a tree or forest: a node can only have zero or one parent. This function displays that structure, or the similar structure for rglscene objects.

Usage

showtree(x, ...)
## S3 method for class 'gltf'
showtree(x, ...)
## S3 method for class 'rglscene'
showtree(x, transform = FALSE, ...)

Arguments

Write a glTF or GLB file.

Description

GLB is the self-contained binary format of glTF files. These functions write a "gltf" object to one of these formats.

Usage

writeglTF(x, path, bin = TRUE)
writeGLB(x, con)

Arguments

Details

If bin = TRUE (the default), writeglTF will write the binary part of the object to one or more separate files with filename constructed by concatenating the main part of path, followed by a number and the extension ‘.bin’.

Value

writeglTF returns path invisibly. writeGLB returns NULL invisibly.

Author(s)

Duncan Murdoch

References

The specification of the glTF format: https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html

See Also

readglTF

Examples

filename <- tempfile(fileext = ".glb")
writeGLB(as.gltf(rgl::cube3d(col = "red")), filename)