74 3D: Objects, groups, and paths

9.3

Racket

74 3D: Objects, groups, and paths🔗ℹ

Spatial content uses a protocol distinct from ordinary two-dimensional visual? values. This prevents an ordinary scene path or two-dimensional animation request from silently treating a mesh as a Pict. Only its enclosing view3d is an ordinary two-dimensional Visual.

procedure
(spatial-visual? value) → boolean?
value : any/c

Recognizes an immutable spatial Visual.

procedure
(spatial-container? value) → boolean?
value : any/c

Recognizes an immutable spatial container. It is deliberately separate from the ordinary 2D container protocol.

procedure
(spatial-id object) → symbol?
object : spatial-visual?

Returns its stable identity within one spatial container.

procedure
(spatial-transform object) → transform3?
object : spatial-visual?

Returns its local transform.

procedure
(spatial-with-transform object transform) → spatial-visual?
object : spatial-visual?
transform : transform3?

Returns a transformed immutable copy.

procedure
(spatial-opacity object) → (and/c real? (between/c 0 1))
object : spatial-visual?

Returns the opacity inherited by descendants.

procedure
(spatial-with-opacity object opacity) → spatial-visual?
object : spatial-visual?
opacity : (and/c real? (between/c 0 1))

Returns an immutable opacity update.

procedure
(spatial-local-bounds object) → aabb3?
object : spatial-visual?

Returns local untransformed spatial bounds.

procedure
(spatial-position object) → vec3?
object : spatial-visual?

Returns the translation component of the local transform.

procedure
(spatial-with-position object position) → spatial-visual?
object : spatial-visual?
position : vec3?

Replaces that local translation.

procedure
(spatial-rotation object) → rotation3?
object : spatial-visual?

Returns the local rotation.

procedure
(spatial-with-rotation object rotation) → spatial-visual?
object : spatial-visual?
rotation : rotation3?

Replaces that local rotation.

procedure
(spatial-scale object) → vec3?
object : spatial-visual?

Returns the local scale.

procedure
(spatial-with-scale object scale) → spatial-visual?
object : spatial-visual?
scale : vec3?

Replaces the nonzero local scale components.

struct
(struct spatial-child (id visual)
    #:transparent)
  id : symbol?
  visual : spatial-visual?

An immutable direct-child entry. Its id must be the child Visual’s spatial-id. Direct-child order is significant and stable.

procedure
(group3d children
#:id id
[ #:transform transform
#:opacity opacity]) → group3d?
  children : (listof spatial-visual?)
  id : symbol?
  transform : transform3? = identity-transform3
  opacity : (and/c real? (between/c 0 1)) = 1

Creates an immutable spatial container. Direct child identities must be unique and cannot equal the group’s identity.

procedure
(group3d? value) → boolean?
value : any/c

Recognizes a spatial group.

procedure
(group3d-children group) → (listof spatial-visual?)
group : group3d?

Returns direct children in their declared order.

procedure
(group3d-with-children group children) → group3d?
group : group3d?
children : (listof spatial-visual?)

Returns an immutable direct-child replacement.

procedure
(spatial-path? value) → boolean?
value : any/c

Recognizes a nonempty list of symbols.

procedure
(spatial-relative-ref container path) → spatial-visual?
container : spatial-container?
path : spatial-path?

Resolves a nonempty path relative to a spatial container.

procedure
(spatial-relative-replace container
path
replacement) → spatial-container?
  container : spatial-container?
  path : spatial-path?
  replacement : spatial-visual?

Rebuilds an immutable spatial ancestry, requiring the replacement to retain the final path identity.

I	Concepts
II	Cookbook
III	Guide
IV	Complete Example Programs
V	Reference

52	Find a task or a name
53	Modules to require
54	Scenes and sampling
55	Scene states
56	Animation requests
57	Native model details
58	Visuals
59	Geometry
60	Number Lines and Coordinate Decorations
61	Point Markers, Scatter Plots, and Filled Areas
62	Probability and Statistical Diagrams
63	Calculus lessons
64	Colors
65	Slides
66	Slide command-line tools
67	Source Programs and Authored Timelines
68	Interactive Preview and Inspection
69	Preview controls and diagnostics
70	Projects and Final Rendering
71	Project execution and cache details
72	Pict Renderer Protocol
73	3D reference map
74	3D: Objects, groups, and paths
75	3D: Cameras and projection
76	3D: Views inside a Scene
77	3D: Animating 3D objects
78	3D: Animating the 3D camera
79	3D: Cuts, caps, and section measurements
80	3D: Supplementary surface, section, and annotation bindings
81	3D: Cuts, sections, and numerical volume
82	3D: Vectors
83	3D: Linear maps and rotations
84	3D: Affine transforms
85	3D: Bounds, rays, and planes
86	3D: Spatial maps and homotopies
87	3D: Materials and lights
88	3D: Lighting inspection
89	3D: Shadow descriptors and stable bounds
90	3D: Finite-light animation
91	3D: Software finite-light evaluation
92	3D: Colour space and final output
93	3D: Relations and geometric annotations
94	3D: Projected labels
95	3D: Textured billboards
96	3D: Spatial curves and vector diagrams
97	3D: Spatial anchors and label layout
98	3D: Anchors and projected labels
99	3D: Parametric surfaces and calculus
100	3D: Adaptive, trimmed, and implicit surfaces
101	3D: Constructive solids
102	3D: Surface constructors and queries
103	3D: Meshes
104	3D: Triangle topology
105	3D: Polygonal faces
106	3D: Deterministic convex hulls
107	3D: Polyhedral duals
108	3D: Schlegel diagrams and polyhedral nets
109	3D: Conservative mesh correspondence
110	3D: Topology-safe mesh matching
111	3D: Checking and repairing mesh orientation
112	3D: Clipping, sections, and transparency
113	3D: Prepared spatial ODE trajectories and vector fields
114	3D: Seeds and streamline sets
115	3D: Poincare sections and return maps
116	3D: Equilibria and local linearization
117	3D: Flow maps and volume change
118	3D: Drawing and inspecting trajectories
119	3D: Reading prepared trajectories
120	3D: Drawing vector fields and particles
121	3D: Trajectory display
122	3D: Spatial inspection and exact picking
123	3D: Retained renderer backends
124	3D: Compiled geometry and instances
125	3D: Frame requests and results
126	3D: Software rendering and statistics
127	3D: Optional Racket/ Open GL backend
128	Experimental Derived Visuals
129	Source Package Hygiene