picogl.backend.modern.core.vertex.base

vertex_base.py

This module defines the VertexBuffer class, a foundational abstraction for OpenGL objects that require explicit binding and unbinding during rendering.

VertexBuffer provides a common interface and context management protocol for derived classes such as VertexArrayObject, ModernVBO, and ModernEBO. It ensures consistent handling of OpenGL object lifetimes and usage patterns by enforcing the implementation of bind() and unbind() methods.

Features: - Stores a raw OpenGL object handle (ID) - Provides bind() / unbind() interface to be implemented by subclasses - Supports Python context manager protocol (with statement) - Useful for any OpenGL object that must be bound/unbound during draw calls

Example Usage:

class MyBuffer(VertexBuffer): …def bind(self): glBindBuffer(GL_ARRAY_BUFFER, self.handle) …def unbind(self): glBindBuffer(GL_ARRAY_BUFFER, 0) … …with MyBuffer(handle) as buf: … # buffer is bound

…

…# buffer is unbound

Note: This base class is abstract and cannot be used directly; bind and unbind must be implemented in subclasses.

Classes

VertexBuffer

VertexBuffer

Module Contents

class picogl.backend.modern.core.vertex.base.VertexBuffer(handle: int = None, data: numpy.ndarray = None, target: int = GL_ARRAY_BUFFER, size: int = 3, stride: int = 0, dtype: int = GL_FLOAT, index: int = None, pointer: ctypes.c_void_p = ctypes.c_void_p(0))

Bases: picogl.buffers.base.VertexBase

VertexBuffer

Base class for OpenGL vertex-related buffers (VBO, VAO, EBO).

This handles:

• Buffer binding/unbinding

• Data upload (glBufferData)

• Vertex attribute configuration

• Type mapping from NumPy dtype to GL constants

_GL_TYPE_MAP

index = None

normalized = False

target

size = 3

stride = 0

dtype

pointer

data = None

offset = 0

bind() → None

Bind this buffer.

unbind() → None

Unbind this buffer, ensuring the handle is valid.

update(data: numpy.ndarray)

set_data(data: numpy.ndarray, usage: int = GL_STATIC_DRAW) → None

Upload data to the GPU.

Parameters:

• data – NumPy array containing buffer data.

• usage – GL usage hint (e.g., GL_STATIC_DRAW, GL_DYNAMIC_DRAW).

set_vertex_attributes(index: int, data: numpy.ndarray = None, size: int = None, normalized: bool = False, stride: int = 0, offset: int = 0, dtype: int = None, pointer: ctypes.c_void_p = None) → None

Set the vertex attribute pointer configuration.

Parameters:

• index – Attribute index in the VAO.

• data – Optional data array to store alongside attribute info.

• size – Number of components per vertex (1-4).

• normalized – Whether values should be normalized.

• stride – Byte offset between consecutive attributes.

• offset – Byte offset of the first attribute.

• dtype – GL data type (e.g., GL_FLOAT).

• pointer – Offset pointer for glVertexAttribPointer.

configure() → None

Enable and configure the vertex attribute array.

property index_count: int

Number of vertices/indices in this buffer.

classmethod _map_dtype_to_gl(dtype) → int

Map a NumPy dtype to the corresponding GL constant.

__repr__() → str