Source code for simvx.graphics.scene.draw_batch

"""Indirect draw buffer generation — vectorized with numpy."""


from __future__ import annotations

import logging

import numpy as np

from .._types import INDIRECT_DRAW_DTYPE

log = logging.getLogger(__name__)

__all__ = ["DrawBatch"]




class DrawBatch:
    """Generates VkDrawIndexedIndirectCommand arrays from entity data."""

    def __init__(self) -> None:
        self.commands = np.zeros(0, dtype=INDIRECT_DRAW_DTYPE)



    def build(
        self,
        index_counts: np.ndarray,
        first_indices: np.ndarray,
        vertex_offsets: np.ndarray,
    ) -> np.ndarray:
        """Build the indirect draw buffer from per-mesh data (vectorized)."""
        n = len(index_counts)
        self.commands = np.zeros(n, dtype=INDIRECT_DRAW_DTYPE)
        self.commands["index_count"] = index_counts
        self.commands["instance_count"] = 1
        self.commands["first_index"] = first_indices
        self.commands["vertex_offset"] = vertex_offsets
        self.commands["first_instance"] = np.arange(n, dtype=np.uint32)
        return self.commands