The Geometry class holds a collection of vertex array attributes representing a geometric primitive.
A geometry is considered a "primitive" when it can be rendered with a single GPU draw call. Multiple geometry primitives can be composed into a composite geometry using the Mesh
and Model
classes.
To learn more about attributes refer to the Accessor
class that holds metadata for each attributes.
Create a pyramid geometry (used in lesson 4 of learning WebGL examples).
const pyramidGeometry= new Geometry({
attributes: {
positions: new Float32Array([ ... ]),
colors: {
size: 4,
value: new Float32Array([ ... ])
}
}
});
id
- (string, optional)An id for the model. If not provided, a random unique identifier will be created.
The draw mode, or primitive type.
Some options are GL.TRIANGLES
(default), GL.TRIANGLE_STRIP
, GL.POINTS
, GL.LINES
.
attributes
- (object, optional)An object with buffer/attribute names and buffer/attribute descriptors to be set before rendering the model.
A map of Accessor
instances describing the geometry of this primitive.
An optional Accessor
instance that contains the indices (aka elements) for this geometry. Can be null
or undefined
if this primitive doesn't use indices. Note that indices can also be stored inside attributes
.
An object with key/value pairs that indicate how various uniforms should be set up before the GPU draw call. The Geometry
class itself does not directly use the contents of the material
field, however other classes such as Mesh
will refer to it if available, and normally expects it to be set to an instance of the Material
class.
The constructor for the Geometry
class. Use this to create a new Geometry
.
const geometry = new Geometry(props);
Update properties
Follows glTF/OpenGL/WebGL conventions:
Value | Primitive Mode |
---|---|
0 | POINTS |
1 | LINES |
2 | LINE_LOOP |
3 | LINE_STRIP |
4 | TRIANGLES |
5 | TRIANGLE_STRIP |
6 | TRIANGLE_FAN |
Attribute | Description |
---|---|
indices | (array, optional) An array of numbers describing the vertex indices for each face. |
positions | (array, optional) An array of floats that describe the vertices of the model. |
normals | (array, optional) An array of floats that describe the normals of the model. |
texCoords | (mixed, optional) Can be an array of floats indicating the texture coordinates for the texture to be used or an object that has texture ids as |
colors | (array, optional) An array of colors in RGBA. If just one color is specified that color will be used for all faces. |
pickingColors | (array, optional) A custom set of colors to render the object to texture when performing the color picking algorithm. |
WebGLRenderingContext
and is intentionallyGeometry
class holds the glTF2 "primitive" specification, although morph targets
are not yet supported.