GeomVertexArrayData

from panda3d.core import GeomVertexArrayData

class GeomVertexArrayData

Bases:

Bases: CopyOnWriteObject, SimpleLruPage, GeomEnums

This is the data for one array of a GeomVertexData structure. Many GeomVertexData structures will only define one array, with all data elements interleaved (DirectX 8.0 and before insisted on this format); some will define multiple arrays.

DirectX calls this concept of one array a “stream”. It also closely correlates with the concept of a vertex buffer.

This object is just a block of data. In general, you should not be directly messing with this object from application code. See GeomVertexData for the organizing structure, and see GeomVertexReader/Writer/Rewriter for high-level tools to manipulate the actual vertex data.

Inheritance diagram

__getbuffer__(view: Py_buffer, flags: int) → int

__getbuffer__(view: Py_buffer, flags: int) → int

__init__(copy: GeomVertexArrayData)

__init__(array_format: GeomVertexArrayFormat, usage_hint: UsageHint)

__releasebuffer__(view: Py_buffer)

property array_format → GeomVertexArrayFormat

Returns the format object that describes this array.

clear_rows()

Removes all of the rows in the array. Functionally equivalent to set_num_rows(0).

compare_to(other: GeomVertexArrayData) → int

Returns 0 if the two arrays are equivalent, even if they are not the same pointer.

property data_size_bytes → int

Returns the number of bytes stored in the array.

get_array_format() → GeomVertexArrayFormat

Returns the format object that describes this array.

static get_book() → VertexDataBook

Returns the global VertexDataBook that will be used to allocate vertex data buffers.

static get_class_type() → TypeHandle

get_data_size_bytes() → int

Returns the number of bytes stored in the array.

get_handle(current_thread: Thread) → GeomVertexArrayDataHandle

Returns an object that can be used to read the actual data bytes stored in the array. Calling this method locks the data, and will block any other threads attempting to read or write the data, until the returned object destructs.

static get_independent_lru() → SimpleLru

Returns a pointer to the global LRU object that manages the GeomVertexArrayData’s that have not (yet) been paged out.

get_modified() → UpdateSeq

Returns a sequence number which is guaranteed to change at least every time the array vertex data is modified.

get_num_rows() → int

Returns the number of rows stored in the array, based on the number of bytes and the stride. This should be the same for all arrays within a given GeomVertexData object.

static get_small_lru() → SimpleLru

Returns a pointer to the global LRU object that manages the GeomVertexArrayData’s that are deemed too small to be paged out.

get_usage_hint() → UsageHint

Returns the usage hint that describes to the rendering backend how often the vertex data will be modified and/or rendered. See geomEnums.h.

has_column(name: InternalName) → bool

Returns true if the array has the named column, false otherwise. This is really just a shortcut for asking the same thing from the format.

is_prepared(prepared_objects: PreparedGraphicsObjects) → bool

Returns true if the data has already been prepared or enqueued for preparation on the indicated GSG, false otherwise.

static lru_epoch()

Marks that an epoch has passed in each LRU. Asks the LRU’s to consider whether they should perform evictions.

property modified → UpdateSeq

Returns a sequence number which is guaranteed to change at least every time the array vertex data is modified.

modify_handle(current_thread: Thread) → GeomVertexArrayDataHandle

Returns an object that can be used to read or write the actual data bytes stored in the array. Calling this method locks the data, and will block any other threads attempting to read or write the data, until the returned object destructs.

output(out: ostream)

prepare(prepared_objects: PreparedGraphicsObjects)

Indicates that the data should be enqueued to be prepared in the indicated prepared_objects at the beginning of the next frame. This will ensure the data is already loaded into the GSG if it is expected to be rendered soon.

Use this function instead of prepare_now() to preload datas from a user interface standpoint.

prepare_now(prepared_objects: PreparedGraphicsObjects, gsg: GraphicsStateGuardianBase) → VertexBufferContext

Creates a context for the data on the particular GSG, if it does not already exist. Returns the new (or old) VertexBufferContext. This assumes that the GraphicsStateGuardian is the currently active rendering context and that it is ready to accept new datas. If this is not necessarily the case, you should use prepare() instead.

Normally, this is not called directly except by the GraphicsStateGuardian; a data does not need to be explicitly prepared by the user before it may be rendered.

release(prepared_objects: PreparedGraphicsObjects) → bool

Frees the data context only on the indicated object, if it exists there. Returns true if it was released, false if it had not been prepared.

release_all() → int

Frees the context allocated on all objects for which the data has been declared. Returns the number of contexts which have been freed.

request_resident(current_thread: Thread) → bool

Returns true if the vertex data is currently resident in memory. If this returns true, the next call to get_handle()->get_read_pointer() will probably not block. If this returns false, the vertex data will be brought back into memory shortly; try again later.

reserve_num_rows(n: int) → bool

This ensures that enough memory space for n rows is allocated, so that you may increase the number of rows to n without causing a new memory allocation. This is a performance optimization only; it is especially useful when you know ahead of time that you will be adding n rows to the data.

set_num_rows(n: int) → bool

Sets the length of the array to n rows.

Normally, you would not call this directly, since all of the arrays in a particular GeomVertexData must have the same number of rows; instead, call GeomVertexData.set_num_rows().

The return value is true if the number of rows was changed, false if the object already contained n rows (or if there was some error).

The new vertex data is initialized to 0, including the “color” column (but see GeomVertexData.set_num_rows()).

Don’t call this in a downstream thread unless you don’t mind it blowing away other changes you might have recently made in an upstream thread.

set_usage_hint(usage_hint: UsageHint)

Changes the UsageHint hint for this array. See get_usage_hint().

Don’t call this in a downstream thread unless you don’t mind it blowing away other changes you might have recently made in an upstream thread.

unclean_set_num_rows(n: int) → bool

This method behaves like set_num_rows(), except the new data is not initialized. Furthermore, after this call, any of the data in the GeomVertexArrayData may be uninitialized, including the earlier rows.

Normally, you would not call this directly, since all of the arrays in a particular GeomVertexData must have the same number of rows; instead, call GeomVertexData.unclean_set_num_rows().

property usage_hint → UsageHint

Getter

Returns the usage hint that describes to the rendering backend how often the vertex data will be modified and/or rendered. See geomEnums.h.

Setter

Changes the UsageHint hint for this array. See get_usage_hint().

Don’t call this in a downstream thread unless you don’t mind it blowing away other changes you might have recently made in an upstream thread.

write(out: ostream, indent_level: int)