Queries

Queries are a simple mechanism that allows the user to perform several operations in a contained way.

The supported operations are

• Project a point
• Unproject a point
• Intersection test
• Occlusion test

Queries are not meant to be used directly, but rather through the viewer’s query function

Typedefs

IntersectionQuery

interface IntersectionQuery extends Query {
  point: { x: number; y: number; z?: number; w?: number }
  tolerance?: number
  operation: 'Occlusion' | 'Pick'
}

• point: The point to test for intersections
• optional tolerance: Tolerance for intersection
• operation: The query operation type

Based on the operation modes:

• Occlusion: Test if a point in the scene is being occluded by the scene’s geometry
• Pick: Cast a camer ray to the specified point and return all intersection results

Pick filter from ObjectPickConfiguration do not apply here!

IntersectionQueryResult

interface IntersectionQueryResult {
  objects: Array<{
    guid: string
    object?: Record<string, unknown>
    point: { x: number; y: number; z: number }
  }> | null
}

• guid: The id of the object
• optional object: The raw data of the intersected object
• point: The point of intersection

PointQuery

interface PointQuery extends Query {
  point: { x: number; y: number; z?: number; w?: number }
  operation: 'Project' | 'Unproject'
}

• point: The point to run the operation on
• operation: The operation type

Based on the operation modes:

• Project: Projects a world point onto the screen. Result is in NDC
• Unproject: Unprojects an NDC point into a world point

PointQueryResult

interface PointQueryResult {
  x: number
  y: number
  z?: number
  w?: number
}

The result is a point of variable component length

Query

interface Query {
  id?: string
  operation: string
}

• optional id: Currently unused
• operation: The operation type

QueryArgsResultMap

type QueryArgsResultMap = {
  Project: PointQueryResult
  Unproject: PointQueryResult
  Occlusion: IntersectionQueryResult
  Pick: IntersectionQueryResult
} & { [key: string]: unknown }

Mapping between the query type and query result type.

QueryOperation

type QueryOperation = 'Project' | 'Unproject' | 'Occlusion' | 'Pick'

Query operation type values

QueryResult

type QueryResult = PointQueryResult | IntersectionQueryResult

Query result type values