EntropyCanvas::MeshData

EntropyCanvas::MeshData

Mesh geometry data suitable for rendering. More…

#include <MeshData.h>

Public Classes

	Name
struct	Vec4 4D vector for tangents (xyz = tangent, w = handedness)
struct	Vec3 3D vector
struct	Vec2 2D vector for UVs

Public Functions

	Name
size_t	vertexCount() const Get vertex count.
size_t	triangleCount() const Get triangle count.
MeshData	sphere(float radius =0.5f, uint32_t segments =32, uint32_t rings =16) Create a UV sphere.
VertexTier	requiredTier() const Determine the minimum vertex tier required for this mesh.
MeshData	plane(float width =1.0f, float depth =1.0f, uint32_t subdivisionsX =1, uint32_t subdivisionsZ =1) Create a plane on the XZ plane.
bool	isValid() const Check if mesh has valid geometry.
bool	hasUVs() const Check if mesh has UVs.
bool	hasTangents() const Check if mesh has tangents.
bool	hasNormals() const Check if mesh has normals.
bool	hasExtendedUVs() const Check if mesh has extended UV channels (uv2 or uv3).
bool	hasExtendedData() const Check if mesh requires Extended tier data.
bool	hasColors() const Check if mesh has vertex colors.
MeshData	cylinder(float radius =0.5f, float height =1.0f, uint32_t segments =32) Create a cylinder along the Y axis.
MeshData	cone(float radius =0.5f, float height =1.0f, uint32_t segments =32) Create a cone along the Y axis.
AssetId	computeAssetId() const Compute content-addressed AssetId for this mesh.
MeshData	box(float size =1.0f) Create a unit box centered at origin.
MeshData	box(float width, float height, float depth) Create a box with custom dimensions.

Public Attributes

	Name
std::vector< Vec2 >	uv3 Quaternary UV coordinates (Extended tier, packed with uv2).
std::vector< Vec2 >	uv2 Tertiary UV coordinates (Extended tier, packed with uv3).
std::vector< Vec2 >	uv1 Secondary UV coordinates (Basic tier, packed with uv0).
std::vector< Vec2 >	uv0 Primary UV coordinates.
std::vector< Vec4 >	tangents Tangent vectors (Tangent tier, xyz = tangent, w = handedness).
std::string	primPath Prim path in USD scene hierarchy (if from USD).
std::vector< Vec3 >	positions Vertex positions.
std::vector< Vec3 >	normals Vertex normals (may be per-vertex or per-face-vertex, indexed same as positions).
std::string	name Display name.
std::vector< uint32_t >	indices Triangle indices (always 32-bit).
std::vector< Vec4 >	colors Vertex colors (RGBA, Extended tier).
Vec3	boundsMin Axis-aligned bounding box minimum.
Vec3	boundsMax Axis-aligned bounding box maximum.

Detailed Description

struct EntropyCanvas::MeshData;

Mesh geometry data suitable for rendering.

This structure holds mesh geometry data in a format ready for GPU upload. The data is pre-triangulated and includes positions, normals, UVs, and indices.

Vertex data is organized into tiers for efficient GPU buffer allocation:

• Basic tier: positions, normals, uv0, uv1 (40 bytes/vertex)
• Tangent tier: adds tangents (16 bytes/vertex)
• Extended tier: adds uv2, uv3, colors (32 bytes/vertex)

Coordinate system follows USD conventions (Y-up, right-handed). Clients may need to transform for their rendering API.

Usage: auto result = UsdMeshExtractor::extract(stagePtr); for (const auto& mesh : result.meshes) { VertexTier tier = mesh.requiredTier(); // Create GPU mesh with appropriate vertex buffers }

Public Functions Documentation

function vertexCount

inline size_t vertexCount() const

Get vertex count.

function triangleCount

inline size_t triangleCount() const

Get triangle count.

function sphere

static MeshData sphere(
    float radius =0.5f,
    uint32_t segments =32,
    uint32_t rings =16
)

Create a UV sphere.

Parameters:

• radius Sphere radius (default 0.5)
• segments Horizontal segments (default 32)
• rings Vertical rings (default 16)

Return: MeshData for the sphere

function requiredTier

inline VertexTier requiredTier() const

Determine the minimum vertex tier required for this mesh.

Examines which vertex attributes are populated and returns the minimum tier needed to represent all data:

• Extended if uv2, uv3, or colors are present
• Tangent if tangents are present
• Basic otherwise

function plane

static MeshData plane(
    float width =1.0f,
    float depth =1.0f,
    uint32_t subdivisionsX =1,
    uint32_t subdivisionsZ =1
)

Create a plane on the XZ plane.

Parameters:

• width X dimension (default 1)
• depth Z dimension (default 1)
• subdivisionsX X subdivisions (default 1)
• subdivisionsZ Z subdivisions (default 1)

Return: MeshData for the plane

function isValid

inline bool isValid() const

Check if mesh has valid geometry.

function hasUVs

inline bool hasUVs() const

Check if mesh has UVs.

function hasTangents

inline bool hasTangents() const

Check if mesh has tangents.

function hasNormals

inline bool hasNormals() const

Check if mesh has normals.

function hasExtendedUVs

inline bool hasExtendedUVs() const

Check if mesh has extended UV channels (uv2 or uv3).

function hasExtendedData

inline bool hasExtendedData() const

Check if mesh requires Extended tier data.

function hasColors

inline bool hasColors() const

Check if mesh has vertex colors.

function cylinder

static MeshData cylinder(
    float radius =0.5f,
    float height =1.0f,
    uint32_t segments =32
)

Create a cylinder along the Y axis.

Parameters:

• radius Cylinder radius (default 0.5)
• height Cylinder height (default 1)
• segments Radial segments (default 32)

Return: MeshData for the cylinder

function cone

static MeshData cone(
    float radius =0.5f,
    float height =1.0f,
    uint32_t segments =32
)

Create a cone along the Y axis.

Parameters:

• radius Base radius (default 0.5)
• height Cone height (default 1)
• segments Radial segments (default 32)

Return: MeshData for the cone

function computeAssetId

AssetId computeAssetId() const

Compute content-addressed AssetId for this mesh.

Return: Content-addressed AssetId for this mesh

Computes a SHA-256 hash of the mesh geometry data to produce a deterministic, content-addressed identifier. Same geometry always produces the same AssetId.

The hash includes:

• name
• positions, normals, uv0-uv3, tangents, colors
• indices
• bounds

function box

static MeshData box(
    float size =1.0f
)

Create a unit box centered at origin.

Parameters:

• size Box dimensions (default 1x1x1)

Return: MeshData for the box

function box

static MeshData box(
    float width,
    float height,
    float depth
)

Create a box with custom dimensions.

Parameters:

• width X dimension
• height Y dimension
• depth Z dimension

Return: MeshData for the box

Public Attributes Documentation

variable uv3

std::vector< Vec2 > uv3;

Quaternary UV coordinates (Extended tier, packed with uv2).

variable uv2

std::vector< Vec2 > uv2;

Tertiary UV coordinates (Extended tier, packed with uv3).

variable uv1

std::vector< Vec2 > uv1;

Secondary UV coordinates (Basic tier, packed with uv0).

variable uv0

std::vector< Vec2 > uv0;

Primary UV coordinates.

variable tangents

std::vector< Vec4 > tangents;

Tangent vectors (Tangent tier, xyz = tangent, w = handedness).

variable primPath

std::string primPath;

Prim path in USD scene hierarchy (if from USD).

variable positions

std::vector< Vec3 > positions;

Vertex positions.

variable normals

std::vector< Vec3 > normals;

Vertex normals (may be per-vertex or per-face-vertex, indexed same as positions).

variable name

std::string name;

Display name.

variable indices

std::vector< uint32_t > indices;

Triangle indices (always 32-bit).

variable colors

std::vector< Vec4 > colors;

Vertex colors (RGBA, Extended tier).

variable boundsMin

Vec3 boundsMin {1e38f, 1e38f, 1e38f};

Axis-aligned bounding box minimum.

variable boundsMax

Vec3 boundsMax {-1e38f, -1e38f, -1e38f};

Axis-aligned bounding box maximum.

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Updated on 2026-01-26 at 16:50:32 -0500