Module: Gsplat::Backend::RubyIsectTiles

Defined in:
lib/gsplat/backend/ruby/isect_tiles.rb

Overview

Numo/Ruby tile intersection enumeration and offset encoding.

Constant Summary collapse

TILE_KEY_LOW_BITS = 
32

Class Method Summary collapse

Class Method Details

.forward(means2d, radii, depths, tile_size, tile_width, tile_height, sort:) ⇒ Object

rubocop:disable Metrics/ParameterLists



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# File 'lib/gsplat/backend/ruby/isect_tiles.rb', line 12

def forward(means2d, radii, depths, tile_size, tile_width, tile_height, sort:)
  # rubocop:enable Metrics/ParameterLists
  means2d, radii, depths = validate_inputs(
    means2d,
    radii,
    depths,
    tile_size,
    tile_width,
    tile_height
  )
  camera_count, gaussian_count = means2d.shape[0...2]
  bounds, tiles_per_gauss = tile_bounds(
    means2d,
    radii,
    tile_size,
    tile_width,
    tile_height
  )
  intersection_count = tiles_per_gauss.sum.to_i
  isect_ids = Numo::Int64.zeros(intersection_count)
  flatten_ids = Numo::Int32.zeros(intersection_count)
  tile_bits = tile_n_bits(tile_width, tile_height)
  validate_key_width!(camera_count, tile_bits)
  write_intersections!(
    isect_ids,
    flatten_ids,
    bounds,
    tiles_per_gauss,
    depths,
    gaussian_count,
    tile_width,
    tile_bits
  )
  if sort && intersection_count.positive?
    keys = isect_ids.to_a
    order = (0...intersection_count).sort_by { |index| [keys[index], index] }
    isect_ids = isect_ids[order].dup
    flatten_ids = flatten_ids[order].dup
  end
  [tiles_per_gauss, isect_ids, flatten_ids]
end

.offset_encode(isect_ids, camera_count, tile_width, tile_height) ⇒ Object

Raises:



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# File 'lib/gsplat/backend/ruby/isect_tiles.rb', line 54

def offset_encode(isect_ids, camera_count, tile_width, tile_height)
  validate_grid!(camera_count, tile_width, tile_height)
  raise ShapeError, "expected isect_ids [M]" unless isect_ids.is_a?(Numo::NArray) && isect_ids.ndim == 1

  keys = Numo::Int64.cast(isect_ids)
  counts = Numo::Int64.zeros(camera_count, tile_height, tile_width)
  tile_bits = tile_n_bits(tile_width, tile_height)
  tile_mask = (1 << tile_bits) - 1
  keys.each do |key|
    upper = key >> TILE_KEY_LOW_BITS
    camera_id = upper >> tile_bits
    tile_id = upper & tile_mask
    validate_decoded_key!(camera_id, tile_id, camera_count, tile_width, tile_height)
    counts[camera_id, tile_id / tile_width, tile_id % tile_width] += 1
  end
  offsets = Numo::Int32.zeros(camera_count, tile_height, tile_width)
  running = 0
  counts.size.times do |index|
    offsets[index] = running
    running += counts[index]
  end
  offsets
end