GeomVertexReader¶

from panda3d.core import GeomVertexReader

class GeomVertexReader¶

Bases: GeomEnums

This object provides a high-level interface for quickly reading a sequence of numeric values from a vertex table.

It is particularly optimized for reading a single column of data values for a series of vertices, without changing columns between each number. Although you can also use one GeomVertexReader to read across the columns if it is convenient, by calling setColumn() repeatedly at each vertex, it is faster to read down the columns, and to use a different GeomVertexReader for each column.

Note that a GeomVertexReader does not keep a reference count to the actual vertex data buffer (it grabs the current data buffer from the GeomVertexData whenever setColumn() is called). This means that it is important not to keep a GeomVertexReader object around over a long period of time in which the data buffer is likely to be deallocated; it is intended for making a quick pass over the data in one session.

It also means that you should create any GeomVertexWriters before creating GeomVertexReaders on the same data, since the writer itself might cause the vertex buffer to be deallocated. Better yet, use a GeomVertexRewriter if you are going to create both of them anyway.

Inheritance diagram

__init__(array_data: GeomVertexArrayData, current_thread: Thread)¶: Constructs a new reader to process the vertices of the indicated array only.

__init__(array_data: GeomVertexArrayData, column: int, current_thread: Thread): Constructs a new reader to process the vertices of the indicated array only.

__init__(vertex_data: GeomVertexData, name: InternalName, current_thread: Thread): Constructs a new reader to process the vertices of the indicated data object. This flavor creates the reader specifically to process the named data type.

__init__(vertex_data: GeomVertexData, current_thread: Thread): Constructs a new reader to process the vertices of the indicated data object.

__init__(copy: GeomVertexReader)

__init__(current_thread: Thread): Constructs an invalid GeomVertexReader. You must use the assignment operator to assign a valid GeomVertexReader to this object before you can use it.

assign(copy: GeomVertexReader) → GeomVertexReader ¶

clear()¶: Resets the GeomVertexReader to the initial state.

getArray() → int ¶: Returns the array index containing the data type that the reader is working on.

getArrayData() → GeomVertexArrayData ¶: Returns the particular array object that the reader is currently processing.

getArrayHandle() → GeomVertexArrayDataHandle ¶: Returns the read handle to the array object that the read is currently processing. This low-level call should be used with caution.

getColumn() → GeomVertexColumn ¶: Returns the description of the data type that the reader is working on.

getCurrentThread() → Thread ¶: Returns the Thread pointer of the currently-executing thread, as passed to the constructor of this object.

getData1() → float ¶: Returns the data associated with the read row, expressed as a 1-component value, and advances the read row.

getData1d() → float ¶: Returns the data associated with the read row, expressed as a 1-component value, and advances the read row.

getData1f() → float ¶: Returns the data associated with the read row, expressed as a 1-component value, and advances the read row.

getData1i() → int ¶: Returns the data associated with the read row, expressed as a 1-component value, and advances the read row.

getData2() → LVecBase2 ¶: Returns the data associated with the read row, expressed as a 2-component value, and advances the read row.

getData2d() → LVecBase2d ¶: Returns the data associated with the read row, expressed as a 2-component value, and advances the read row.

getData2f() → LVecBase2f ¶: Returns the data associated with the read row, expressed as a 2-component value, and advances the read row.

getData2i() → LVecBase2i ¶: Returns the data associated with the read row, expressed as a 2-component value, and advances the read row.

getData3() → LVecBase3 ¶: Returns the data associated with the read row, expressed as a 3-component value, and advances the read row.

getData3d() → LVecBase3d ¶: Returns the data associated with the read row, expressed as a 3-component value, and advances the read row.

getData3f() → LVecBase3f ¶: Returns the data associated with the read row, expressed as a 3-component value, and advances the read row.

getData3i() → LVecBase3i ¶: Returns the data associated with the read row, expressed as a 3-component value, and advances the read row.

getData4() → LVecBase4 ¶: Returns the data associated with the read row, expressed as a 4-component value, and advances the read row.

getData4d() → LVecBase4d ¶: Returns the data associated with the read row, expressed as a 4-component value, and advances the read row.

getData4f() → LVecBase4f ¶: Returns the data associated with the read row, expressed as a 4-component value, and advances the read row.

getData4i() → LVecBase4i ¶: Returns the data associated with the read row, expressed as a 4-component value, and advances the read row.

getForce() → bool ¶: Returns the value of the force flag. See setForce().

getMatrix3() → LMatrix3 ¶: Returns the 3-by-3 matrix associated with the read row and advances the read row. This is a special method that only works when the column in question contains a matrix of an appropriate size.

getMatrix3d() → LMatrix3d ¶: Returns the 3-by-3 matrix associated with the read row and advances the read row. This is a special method that only works when the column in question contains a matrix of an appropriate size.

getMatrix3f() → LMatrix3f ¶: Returns the 3-by-3 matrix associated with the read row and advances the read row. This is a special method that only works when the column in question contains a matrix of an appropriate size.

getMatrix4() → LMatrix4 ¶: Returns the 4-by-4 matrix associated with the read row and advances the read row. This is a special method that only works when the column in question contains a matrix of an appropriate size.

getMatrix4d() → LMatrix4d ¶: Returns the 4-by-4 matrix associated with the read row and advances the read row. This is a special method that only works when the column in question contains a matrix of an appropriate size.

getMatrix4f() → LMatrix4f ¶: Returns the 4-by-4 matrix associated with the read row and advances the read row. This is a special method that only works when the column in question contains a matrix of an appropriate size.

getReadRow() → int ¶: Returns the row index from which the data will be retrieved by the next call to get_data*().

getStartRow() → int ¶: Returns the row index at which the reader started. It will return to this row if you reset the current column.

getStride() → int ¶: Returns the per-row stride (bytes between consecutive rows) of the underlying vertex array. This low-level information is normally not needed to use the GeomVertexReader directly.

getVertexData() → GeomVertexData ¶: Returns the vertex data object that the reader is processing. This may return NULL if the reader was constructed with just an array pointer.

hasColumn() → bool ¶: Returns true if a valid data type has been successfully set, or false if the data type does not exist (or if getForce() is false and the vertex data is nonresident).

isAtEnd() → bool ¶: Returns true if the reader is currently at the end of the list of vertices, false otherwise. If this is true, another call to get_data*() will result in a crash.

output(out: ostream)¶

setColumn(name: InternalName) → bool ¶

Sets up the reader to use the data type with the indicated name.

This also resets the read row number to the start row (the same value passed to a previous call to setRow(), or 0 if setRow() was never called.)

The return value is true if the data type is valid, false otherwise.

setColumn(column: int) → bool

Sets up the reader to use the nth data type of the GeomVertexFormat, numbering from 0.

This also resets the read row number to the start row (the same value passed to a previous call to setRow(), or 0 if setRow() was never called.)

The return value is true if the data type is valid, false otherwise.

setColumn(array: int, column: GeomVertexColumn) → bool

Sets up the reader to use the indicated column description on the given array.

This also resets the current read row number to the start row (the same value passed to a previous call to setRow(), or 0 if setRow() was never called.)

The return value is true if the data type is valid, false otherwise.

setForce(force: bool)¶

Sets the value of the force flag. When this is true (the default), vertex data will be paged in from disk if necessary. When this is false, the GeomVertexData will simply return a failure code when attempting to read vertex data that is not resident (but will put it on the queue to become resident later).

Normally, vertex data is always resident, so this will not be an issue. It is only possible for vertex data to be nonresident if you have enabled vertex paging via the GeomVertexArrayData and VertexDataPage interfaces.

setRow(row: int)¶: Sets the start row to the indicated value. The reader will begin reading from the indicated row; each subsequent get_data*() call will return the data from the subsequent row. If setColumn() is called, the reader will return to this row.

setRowUnsafe(row: int)¶: Sets the start row to the indicated value, without internal checks. This is the same as setRow(), but it does not check for the possibility that the array has been reallocated internally for some reason; use only when you are confident that the array is unchanged and you really need every bit of available performance.