Class: Geometry

Geometry

new Geometry()

3D geometry class.

Name Type Default Description
options.attributes GeometryAttributes optional

Attributes that constitute the vertices of the geometry.
options.primitiveType PrimitiveType PrimitiveType.TRIANGLES optional

The type of primitive of the geometry.
options.indices Uint16Array | Uint32Array optional

Optional index data used to determine primitives in the geometry.
options.boundingSphere BoundingSphere optional

Optional bounding sphere that fully encloses the geometry.
See:
Example
// Create geometry with a position attribute and indexed lines.
var positions = new Float64Array([
  0.0, 0.0, 0.0,
  7500000.0, 0.0, 0.0,
  0.0, 7500000.0, 0.0
]);

var geometry = new SuperMap3D.Geometry({
  attributes : {
    position : new SuperMap3D.GeometryAttribute({
      componentDatatype : SuperMap3D.ComponentDatatype.DOUBLE,
      componentsPerAttribute : 3,
      values : positions
    })
  },
  indices : new Uint16Array([0, 1, 1, 2, 2, 0]),
  primitiveType : SuperMap3D.PrimitiveType.LINES,
  boundingSphere : SuperMap3D.BoundingSphere.fromVertices(positions)
});

Members

attributesGeometryAttributes

Attributes that constitute the vertices of the geometry. Each attribute in this object corresponds to a GeometryAttribute containing the attribute data. Attributes are always stored non-interleaved in the geometry. Reserved attribute names have well-known semantics. The following attributes are created by Geometry (depending on the VertexFormat provided).

  • position - 3D vertex position. 64-bit floating point (for precision). Three components per attribute. See VertexFormat#position.
  • normal - (normalized), commonly used for lighting. 32-bit floating point. Three components per attribute. See VertexFormat#normal.
  • st - 2D texture coordinates. 32-bit floating point. Two components per attribute. See VertexFormat#st.
  • bitangent - (normalized), used for tangent space effects such as bump mapping. 32-bit floating point. Three components per attribute. See VertexFormat#bitangent.
  • tangent - (normalized), used for tangent space effects such as bump mapping. 32-bit floating point. Three components per attribute. See VertexFormat#tangent.
The following attribute names are usually not created by Geometry, but are added to Geometry viaPrimitive or GeometryPipeline functions to prepare the geometry for rendering.
  • position3DHigh - The high 32 bits of the encoded 64-bit position computed by GeometryPipeline.encodeAttribute. 32-bit floating point. Four components per attribute.
  • position3DLow - The low 32 bits of the encoded 64-bit position computed by GeometryPipeline.encodeAttribute. 32-bit floating point. Four components per attribute.
  • position3DHigh - The high 32 bits of the encoded 64-bit 2D (Columbus view) position computed by GeometryPipeline.encodeAttribute. 32-bit floating point. Four components per attribute.
  • position2DLow - The low 32 bits of the encoded 64-bit 2D (Columbus view) position computed by GeometryPipeline.encodeAttribute. 32-bit floating point. Four components per attribute.
  • color - RGBA color (normalized) typically from GeometryInstance#color. 32-bit floating point. Four components per attribute.
  • pickColor - RGBA color used for picking. 32-bit floating point. Four components per attribute.
Default Value:
undefined
See:
Example
geometry.attributes.position = new SuperMap3D.GeometryAttribute({
  componentDatatype : SuperMap3D.ComponentDatatype.FLOAT,
  componentsPerAttribute : 3,
  values : new Float32Array(0)
});

boundingSphereBoundingSphere

Optional bounding sphere that fully encloses the geometry. Typically used for culling.

Default Value:
undefined

indicesArray

Optional index data - together with Geometry#primitiveType - determines the primitives in the geometry.

Default Value:
undefined

primitiveTypePrimitiveType

The type of primitive in the geometry. This is usually PrimitiveType.TRIANGLES, but can vary depending on the specific geometry.

Default Value:
undefined

Methods

static computeNumberOfVertices(geometry){Number}

Computes the number of vertices in a geometry. The runtime is linear with respect to the number of attributes, not the number of vertices.

Name Type Description
geometry Geometry

Geometry.
Returns:
Type Description
Number The number of vertices in the geometry.
Example
var numVertices = SuperMap3D.Geometry.computeNumberOfVertices(geometry);