"""
A module for OpenGL draw operations using PicoGL-specific enumerations or raw gl constants.
This module provides functions to issue OpenGL draw calls, including support for
custom draw modes and index types. It simplifies the process of working with OpenGL by
handling conversion between PicoGL enums and raw gl constants, as well as managing pointer
data for indexed drawing.
Functions:
- gl_draw_arrays: Wrapper for glDrawArrays supporting PicoGL enums or raw gl constants.
- gl_draw_elements: Wrapper for glDrawElements with support for custom index pointers or offsets.
"""
from __future__ import annotations
import ctypes
from enum import Enum
from typing import Any
import numpy as np
from OpenGL.raw.GL.VERSION.GL_1_1 import glDrawArrays, glDrawElements
from picogl.backend.gl.enums import GLDrawMode, GLIndexType
[docs]
def _gl_enum(value: Any) -> Any:
"""gl enum"""
if isinstance(value, Enum):
return value.value
return value
[docs]
def _draw_pointer(pointer: Any | None, offset: int) -> Any:
"""draw pointer"""
if pointer is None:
return ctypes.c_void_p(offset)
if isinstance(pointer, list):
return np.asarray(pointer, dtype=np.uint32)
return pointer
[docs]
def gl_draw_arrays(
index_count: int,
mode: GLDrawMode | int,
first: int = 0,
) -> None:
"""Issue ``glDrawArrays`` with PicoGL draw-mode enums or raw gl constants."""
assert mode is not None
glDrawArrays(_gl_enum(mode), int(first), int(index_count))
[docs]
def gl_draw_elements(
index_count: int,
dtype: int | None = GLIndexType.UNSIGNED_INT,
mode: GLDrawMode | int | None = GLDrawMode.TRIANGLES,
pointer: Any | None = None,
offset: int = 0,
) -> None:
"""
Issue ``glDrawElements``.
*pointer* may be a client index array, ``None`` (EBO bound), or omitted to use *offset*.
"""
assert dtype is not None
assert mode is not None
pointer = _draw_pointer(pointer, offset)
glDrawElements(
_gl_enum(mode),
int(index_count),
_gl_enum(dtype),
pointer,
)