Graphics Reference
In-Depth Information
scene
*
*
node
1
1
*
light
camera
mesh
*
*
*
attribute
material
indices
1
animation
*
1
1
*
*
technique
texture
buferview
skin
1
1
1
1
program
sampler
buffer
image
2
shader
Figure 2.3.
Structure of top-level glTF JSON properties. Properties in gray may
reference external files or have embedded data.
Animations and skins reference
bufferView
s in a similar fashion to attributes
and indices. They also reference nodes and other properties to change their values
over time.
A glTF asset may use most or all of these top-level properties to define a
scene, or it could contain just meshes or techniques, for example. Next, we'll
look at buffers, materials, and animations in more detail.
2.5 Integration of Buffer and Buffer View
Buffers and their associated buffer views are fundamental building blocks of glTF
assets. A glTF JSON file relies on binary data for heavy payloads such as vertices
and indices. Consequently, glTF needs to describe these data. The typed array
specification [Vukicevic 11] is a natural choice because
•
it was created by capturing the requirements of a GL-based API, namely
WebGL,
•
it provides a relevant API to describe arrays whether glTF is implemented
using JavaScript or C++,
•
when possible, glTF relies on proven APIs from widely adopted specs.
