Attribute

OmfLocation

typedef enum {
    OMF_LOCATION_VERTICES,
    OMF_LOCATION_PRIMITIVES,
    OMF_LOCATION_SUBBLOCKS,
    OMF_LOCATION_ELEMENTS,
    OMF_LOCATION_PROJECTED,
    OMF_LOCATION_CATEGORIES,
} OmfLocation;

Defines what part of the geometry an attribute is applied to. The documentation of each geometry includes what locations are valid for it.

Options

OMF_LOCATION_VERTICES

The attribute contains one value for each point, vertex, or block corner.

OMF_LOCATION_PRIMITIVES

The attribute contains one value for each line segment, triangle, or block. For sub-blocked block models that means parent blocks.

OMF_LOCATION_SUBBLOCKS

The attribute contains one value for each sub-block in a block model.

OMF_LOCATION_ELEMENTS

The attribute contains one value for each sub-element in composite.

OMF_LOCATION_PROJECTED

Used for projected textures. The texture is projected onto the element.

OMF_LOCATION_CATEGORIES

Used for category sub-attributes. The attribute contains one value for each category.

OmfAttribute

typedef struct {
    const char *name;
    const char *description;
    const char *units;
    size_t n_metadata;
    const OmfValue *metadata;
    OmfLocation location;
    const OmfArray *boolean_data;
    const OmfArray *vector_data;
    const OmfArray *text_data;
    const OmfArray *color_data;
    const OmfNumberData *number_data;
    const OmfCategoryData *category_data;
    const OmfMappedTexture *mapped_texture_data;
    const OmfProjectedTexture *projected_texture_data;
} OmfAttribute;

Contains attribute data and defines how it is applied to an element. Exactly one data pointer must be non-null, defining the type of the attribute.

Fields

name: const char *

Attribute name, which should be unique within the containing element.

description: const char *

Optional attribute description or comments.

units: const char *

Optional attribute units, if applicable. OMF does not currently attempt to standardize the strings you can use here, but our recommendations are:

• Use full names, so "kilometers" rather than "km". The abbreviations for non-metric units aren't consistent and complex units can be confusing.
• Use plurals, so "feet" rather than "foot".
• Avoid ambiguity, so "long tons" rather than just "tons".
• Accept American and British spellings, so "meter" and "metre" are the same.

metadata: const OmfValue *

Pointer to an array of n_metadata metadata items, forming a set of key/value pairs.

n_attributes: size_t

Number of attributes.

location: OmfLocation

Defines where on the containing element this attribute is attached.

boolean_data: const OmfArray *

Boolean array containing true/false/null data. Applications that don't support three-valued logic may treat null as false.

vector_data: const OmfArray *

Vector array. Items are nullable.

text_data: const OmfArray *

Text array. Items are nullable.

color_data: const OmfArray *

Color array. Items are nullable.

number_data: const OmfNumberData *

Pointer to a number-data struct including the array and optional color-map.

category_data: const OmfCategoryData *

Pointer to a category-data struct including the index array, plus category names, optional colors, and sub-attributes.

mapped_texture_data: const OmfMappedTexture *

Pointer to a mapped texture struct.

projected_texture_data: const OmfProjectedTexture *

Pointer to a projected texture struct.

Methods

omf_attribute_init

OmfAttribute omf_attribute_init(const char *name, OmfLocation location);

Initializes or resets an attribute struct.

OmfNumberData

typedef struct {
    const OmfArray *values;
    const OmfContinuousColormap *continuous_colormap;
    const OmfDiscreteColormap *discrete_colormap;
} OmfNumberData;

Fields

values: const OmfArray *

Number array. Can have 32- or 64-bit floating-point, 64-bit signed integer, date, or date-time type.

continuous_colormap: const OmfContinuousColormap *

Optional continuous colormap. Only one of continuous_colormap and discrete_colormap may be non-null, or both may be null.

discrete_colormap: const OmfDiscreteColormap *

Optional discrete colormap.

Methods

omf_number_data_init

OmfNumberData omf_number_data_init(void);

Initializes or resets a number attribute data struct.

OmfCategoryData

typedef struct {
    const OmfArray *values;
    const OmfArray *names;
    const OmfArray *colors;
    const OmfAttribute *attributes;
    size_t n_attributes;
} OmfCategoryData;

Describes a category attribute.

Fields

values: const OmfArray *

Index array into names, colors, and other attributes. Indices are nullable.

names: const OmfArray *

Name array for category names or labels.

colors: const OmfArray *

Optional gradient array for category colors. If non-null, must be the same length as names.

attributes: const OmfAttribute *

Pointer to an array of n_attributes attribute structures. Each must use OMF_LOCATION_CATEGORIES and be the same length as names. This can be used to add extra details to a category, such as density on a rock-type attribute.

n_attributes: size_t

The number of sub-attributes.

Methods

omf_category_data_init

OmfCategoryData omf_category_data_init(void);

Initializes or resets a category attribute data struct.

OmfMappedTexture

typedef struct {
    const OmfArray *image;
    const OmfArray *texcoords;
} OmfMappedTexture;

A texture applied with UV mapping. Typically applied to surface vertices; applications may ignore other locations.

Fields

image: const OmfArray *

Image array containing the texture image.

texcoords: const OmfArray *

Texture coordinate array, Values outside of the range 0–1 will cause the texture to wrap.

Methods

omf_mapped_texture_init

OmfMappedTexture omf_mapped_texture_init(const OmfArray *image,
                                         const OmfArray *texcoords);

Initializes or resets a mapped texture struct.

OmfProjectedTexture

typedef struct {
    const OmfArray *image;
    OmfOrient2 orient;
    double width;
    double height;
} OmfProjectedTexture;

A texture that is orthographically projected through space. Use this for maps and section images. The fields define a rectangle in space and the texture is projected in both directions along its normal. Typically applied to surface vertices; applications may ignore other locations.

Fields

image: const OmfArray *

Image array containing the texture image.

orient: OmfOrient2

The position and orientation of the texture rectangle in space.

width: double

The width of the texture rectangle in space.

height: double

The height of the texture rectangle in space.

Methods

omf_projected_texture_init

OmfProjectedTexture omf_projected_texture_init(const OmfArray *image);

Initializes or resets a projected texture struct.