利用者:Ansimionescu/Notes/2

Data API: RNA

The data API is a layer over the DNA structs, abstracting how the data is actually stored, and providing information about structs and their properties.

Where to find the important files:

blender-svn/blender/source/blender/makesrna/
RNA_types.h: The important RNA data structures are defined here.
RNA_access.h: API for accessing structs and properties at runtime.
RNA_define.h: API for defining structs and properties.

All Blender data is presented as structs, each being a collection of properties. These properties are all of one of these types:

• boolean
• string
• integer
• float
• enum
• pointer to a struct
• collection of pointers to structs
• fixed-length array of booleans/integers/floats

Next to a type a subtype is also defined (e.g. file path, color, etc.).

Some less obvious Blender data structures:

• C chars and shorts representing numbers map to ints, they simply have different min/max.
• The vertices of a mesh are represented as a collection.
• Nested structs may be represented as pointers to structs that are not editable.
• Tristate values as used for texture mapping are represented as enum with 3 choices (disabled, enabled, enabled inverted).
• Colors are represented as float arrays with length 3 or 4 and subtype color, and matrices are represented as float arrays with length 9 (3x3) or 16 (4x4) and subtype matrix.

Pointers

There are three types of pointers.

/* Pointer
 *
 * These functions will fill in RNA pointers, this can be done in three ways:
 * - a pointer Main is created by just passing the data pointer
 * - a pointer to a datablock can be created with the type and id data pointer
 * - a pointer to data contained in a datablock can be created with the id type
 *   and id data pointer, and the data type and pointer to the struct itself.
 *
 * There is also a way to get a pointer with the information about all structs.
 */
void RNA_main_pointer_create(struct Main *main, PointerRNA *r_ptr);
void RNA_id_pointer_create(struct ID *id, PointerRNA *r_ptr);
void RNA_pointer_create(struct ID *id, StructRNA *type, void *data, PointerRNA *r_ptr);

Home:

[0] http://wiki.blender.org/index.php/User:Ansimionescu

Reference:

[1] RNA: http://wiki.blender.org/index.php/Dev:2.5/Source/Architecture/RNA

[2] Code examples: http://wiki.blender.org/index.php/Dev:2.5/Source/Architecture/RNA/ExampleCode

[3] Data API (design document): http://wiki.blender.org/index.php/Dev:2.5/Source/Architecture/DataAPI