9.3
103 3D: Meshes
3D reference map · First 3D picture
procedure
(mesh3d #:id id #:vertices vertices [ #:triangles triangles #:edges edges #:vertex-ids vertex-ids #:edge-ids edge-ids #:face-ids face-ids #:normals normals #:colors colors] #:material material [ #:transform transform #:opacity opacity #:wireframe-color color #:wireframe-width width]) → mesh3d? id : symbol? vertices : vector? triangles : vector? = #() edges : (or/c #f vector?) = #f vertex-ids : (or/c #f vector?) = #f edge-ids : (or/c #f vector?) = #f face-ids : (or/c #f vector?) = #f normals : (or/c #f vector?) = #f colors : (or/c #f vector?) = #f material : material3d? transform : transform3? = identity-transform3 opacity : (and/c real? (between/c 0 1)) = 1 color : any/c = "steelblue" width : positive-real? = 2
Creates an immutable indexed mesh. Vertices are vec3 values. Triangles
are vectors of three valid vertex indices and edges are vectors of two valid
indices. Inputs are copied to immutable vectors. When edges is
#f, a stable de-duplicated edge list is derived from triangles.
In 'wireframe mode the stable edge order remains visible. In 'opaque mode triangles are flattened in declared order, clipped, depth-tested, and shaded with material. Flat and smooth materials use the declared face or interpolated vertex normals respectively; per-vertex colours are interpolated perspective-correctly. Material, wireframe, and per-vertex colours are color-spec? values, so literals, theme roles, and colour expressions remain part of the immutable mesh and resolve together when a renderer prepares a frame.
Optional semantic ID vectors are immutable vectors of unique symbols, aligned
with vertices, edges, and declared triangle faces respectively. They describe
author-visible mathematical parts, not GPU geometry. A symbol may appear in
more than one kind because the part kind distinguishes it. Omit a vector to
use the stable numeric source indices rather than manufacturing names.
Recognizes an immutable indexed mesh.
procedure
(mesh3d-vertices mesh) → vector?
mesh : mesh3d?
Returns immutable vertices.
procedure
(mesh3d-triangles mesh) → vector?
mesh : mesh3d?
Returns immutable triangle indices.
procedure
(mesh3d-edges mesh) → vector?
mesh : mesh3d?
Returns immutable wireframe edge indices.
procedure
(mesh3d-vertex-ids mesh) → (or/c #f vector?)
mesh : mesh3d?
Returns optional immutable semantic vertex IDs.
procedure
(mesh3d-edge-ids mesh) → (or/c #f vector?)
mesh : mesh3d?
Returns optional immutable semantic edge IDs.
procedure
(mesh3d-face-ids mesh) → (or/c #f vector?)
mesh : mesh3d?
Returns optional immutable semantic triangle-face IDs.
procedure
(mesh3d-vertex-id mesh index)
→ (or/c symbol? exact-nonnegative-integer?) mesh : mesh3d? index : exact-nonnegative-integer?
Returns the explicit vertex
semantic ID or, if absent, its stable source index.
procedure
(mesh3d-edge-id mesh index)
→ (or/c symbol? exact-nonnegative-integer?) mesh : mesh3d? index : exact-nonnegative-integer?
Returns the explicit edge
semantic ID or, if absent, its stable source index.
procedure
(mesh3d-face-id mesh index)
→ (or/c symbol? exact-nonnegative-integer?) mesh : mesh3d? index : exact-nonnegative-integer?
Returns the explicit face
semantic ID or, if absent, its stable source index.
struct
(struct geometry-key3d ( digest byte-length vertex-count triangle-count edge-count)) digest : bytes? byte-length : exact-nonnegative-integer? vertex-count : exact-nonnegative-integer? triangle-count : exact-nonnegative-integer? edge-count : exact-nonnegative-integer?
#:transparent]{A
renderer geometry identity. It intentionally excludes semantic part IDs.}
procedure
(mesh3d-geometry-key mesh) → geometry-key3d?
mesh : mesh3d?
Returns the
immutable render-geometry key, excluding material, placement, and semantic IDs.
struct
(struct mesh3d-semantic-key3d ( geometry vertex-ids edge-ids face-ids provenance-schema) #:transparent) geometry : geometry-key3d? vertex-ids : (or/c #f vector?) edge-ids : (or/c #f vector?) face-ids : (or/c #f vector?) provenance-schema : symbol?
An authoring identity layered over geometry.
procedure
mesh : mesh3d?
Returns
the immutable semantic key. It is not a renderer cache key.
struct
(struct mesh-part-reference3d (kind id) #:transparent) kind : (or/c 'vertex 'edge 'face) id : any/c
An
immutable reference to one source or result mesh part. The kind is explicit so
a topology-changing operation can accurately record cross-kind derivation,
such as a primal face becoming a dual vertex.
struct
(struct mesh-part-provenance-entry3d ( source-part result-parts relation) #:transparent) source-part : (or/c #f mesh-part-reference3d?) result-parts : vector? relation : (or/c 'preserved 'merged 'split 'generated 'discarded 'ambiguous 'derived)
One source-to-result multimap entry. A generated
entry has no source; a discarded entry has no result parts.
struct
(struct mesh-part-provenance3d (vertices edges faces warnings) #:transparent) vertices : vector? edges : vector? faces : vector? warnings : vector?
Shared immutable provenance for a topology-changing
mesh operation. Entries are grouped by source part kind; warnings document
intentional identity loss or ambiguity.
procedure
(make-mesh-part-provenance3d [ #:vertices vertices #:edges edges #:faces faces #:warnings warnings]) → mesh-part-provenance3d? vertices : vector? = #() edges : vector? = #() faces : vector? = #() warnings : vector? = #()
Builds a
validated provenance value.
procedure
(mesh-part-provenance3d-source-results provenance source) → (or/c #f vector?) provenance : mesh-part-provenance3d? source : mesh-part-reference3d?
Looks up one
source part’s zero, one, or many result parts.
procedure
(mesh-part-provenance3d-result-sources provenance result) → vector? provenance : mesh-part-provenance3d? result : mesh-part-reference3d?
Returns every source part
that contributes to the specified result part.