missing spc_formatting file (#507)

Signed-off-by: operel <operel@nvidia.com>

Co-authored-by: operel <operel@nvidia.com>

examples/tutorial/spc_formatting.py

@@ -0,0 +1,59 @@
+from collections import deque
+from termcolor import colored
+
+def color_by_level(level):
+    _colormap = ["red", "blue", "green", "yellow", "magenta", "cyan", "grey"]
+    return _colormap[level % len(_colormap)]
+
+def push_pop_octree(q, oct_item):
+    prefix = q.popleft()
+    bit_idx = 0
+    parsed_bits = oct_item.item()
+    while parsed_bits:
+        bit_idx += 1
+        if parsed_bits & 1:
+            if len(prefix) > 0:
+                q.append(prefix + f'-{bit_idx}')
+            else:
+                q.append(prefix + f'{bit_idx}')
+        parsed_bits >>= 1
+    return prefix
+
+def format_octree_str(octree_byte, octree_path, level_idx, max_level):
+    text = []
+
+    level_color = color_by_level(level_idx - 1)
+    text += ['Level ' + colored(f'#{level_idx}, ', level_color)]
+
+    colored_path = []
+    for i in range(len(octree_path)):
+        level_color = color_by_level(i // 2)
+        if i % 2 == 0:
+            colored_path += [colored(octree_path[i], level_color)]
+        else:
+            colored_path += [octree_path[i]]
+    colored_path = ''.join(colored_path)
+    text += [f'Path{colored_path},    ']
+    text += [' ' for _ in range((max_level - level_idx) * 2)]
+
+    text += ['{0:08b}'.format(octree_byte)]
+
+    return ''.join(text)
+
+def describe_octree(octree, level, limit_levels=None):
+    bit_counter = lambda x: bin(x).count('1')
+    level_idx, curr_level_remaining_cells, next_level_cells = 1, 1, 0
+    octree_paths = deque('*')
+
+    for oct_idx, octree_byte in enumerate(octree):
+
+        octree_path = push_pop_octree(octree_paths, octree_byte)
+        if limit_levels is None or level_idx in limit_levels:
+            print(format_octree_str(octree_byte, octree_path, level_idx, level))
+        curr_level_remaining_cells -= 1
+        next_level_cells += bit_counter(octree_byte)
+
+        if not curr_level_remaining_cells:
+            level_idx += 1
+            curr_level_remaining_cells = next_level_cells
+            next_level_cells = 0