Model optimization

convert_model_to_binary.py

@@ -0,0 +1,142 @@
+#!/usr/bin/env python3
+"""
+Convert a text-based static mesh file (.txt) to binary format (.txt.bin).
+
+Usage:
+    python convert_model_to_binary.py <input.txt> [<output.bin>]
+
+If the output path is not given it is derived by appending ".bin" to the input path,
+e.g. resources/w/firebox.txt  ->  resources/w/firebox.txt.bin
+
+Binary format (BSMF v1) -- all values little-endian:
+
+    HEADER
+        4 bytes   magic "BSMF"
+        uint32    version (1)
+        uint32    numVertices
+        uint32    numTriangles
+
+    VERTICES (numVertices entries):
+        3 x float   position x, y, z  -- engine coordinate space
+        3 x float   normal   x, y, z  -- engine coordinate space
+        2 x float   UV       u, v
+
+    TRIANGLES (numTriangles entries):
+        3 x uint32  vertex indices i0, i1, i2
+
+The same Blender->engine axis swap applied by LoadFromTextFile02 is baked in here,
+so the C++ binary loader can read coordinates directly without any post-processing:
+    engine_x = blender_y
+    engine_y = blender_z
+    engine_z = blender_x
+"""
+
+import struct
+import re
+import sys
+import os
+
+
+def _parse_floats(text):
+    return [float(x) for x in re.findall(r'[-+]?\d*\.?\d+(?:[eE][-+]?\d+)?', text)]
+
+
+def _parse_ints(text):
+    return [int(x) for x in re.findall(r'[-]?\d+', text)]
+
+
+def _swap_axes(x, y, z):
+    """Blender Y-up -> engine coordinate system (mirrors LoadFromTextFile02)."""
+    return y, z, x
+
+
+def convert(input_path, output_path):
+    with open(input_path, 'r', encoding='utf-8') as f:
+        lines = [line.rstrip('\n') for line in f]
+
+    idx = 0
+
+    def next_line():
+        nonlocal idx
+        while idx < len(lines):
+            line = lines[idx]
+            idx += 1
+            return line
+        raise EOFError("Unexpected end of file while parsing: " + input_path)
+
+    # --- Vertices ---
+    while True:
+        line = next_line()
+        if '===Vertices' in line:
+            break
+
+    m = re.search(r'\d+', line)
+    if not m:
+        raise ValueError("Could not parse vertex count from: " + line)
+    num_vertices = int(m.group())
+
+    positions = []
+    normals   = []
+    uvs       = []
+
+    for i in range(num_vertices):
+        line = next_line()
+        # V N: Pos(x, y, z) Norm(nx, ny, nz) UV(u, v)
+        nums = _parse_floats(line)
+        # nums[0] = vertex index (float-parsed), then 3 pos, 3 norm, 2 uv
+        if len(nums) < 9:
+            raise ValueError(f"Malformed vertex line {i}: {line}")
+        px, py, pz = _swap_axes(nums[1], nums[2], nums[3])
+        nx, ny, nz = _swap_axes(nums[4], nums[5], nums[6])
+        positions.append((px, py, pz))
+        normals.append((nx, ny, nz))
+        uvs.append((nums[7], nums[8]))
+
+    # --- Triangles ---
+    while True:
+        line = next_line()
+        if '===Triangles' in line:
+            break
+
+    m = re.search(r'\d+', line)
+    if not m:
+        raise ValueError("Could not parse triangle count from: " + line)
+    num_triangles = int(m.group())
+
+    triangles = []
+    for i in range(num_triangles):
+        line = next_line()
+        ints = _parse_ints(line)
+        if len(ints) != 3:
+            raise ValueError(f"Malformed triangle line {i}: {line}")
+        triangles.append(tuple(ints))
+
+    # --- Write binary ---
+    with open(output_path, 'wb') as out:
+        out.write(b'BSMF')
+        out.write(struct.pack('<I', 1))
+        out.write(struct.pack('<I', num_vertices))
+        out.write(struct.pack('<I', num_triangles))
+
+        for i in range(num_vertices):
+            out.write(struct.pack('<3f', *positions[i]))
+            out.write(struct.pack('<3f', *normals[i]))
+            out.write(struct.pack('<2f', *uvs[i]))
+
+        for tri in triangles:
+            out.write(struct.pack('<3I', *tri))
+
+    in_size  = os.path.getsize(input_path)
+    out_size = os.path.getsize(output_path)
+    print(f"Converted: {input_path} ({in_size:,} bytes text) -> {output_path} ({out_size:,} bytes binary)")
+    print(f"  Vertices: {num_vertices}, Triangles: {num_triangles}")
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2 or len(sys.argv) > 3:
+        print(f"Usage: {sys.argv[0]} <input.txt> [<output.bin>]")
+        sys.exit(1)
+
+    input_path  = sys.argv[1]
+    output_path = sys.argv[2] if len(sys.argv) == 3 else input_path + '.bin'
+    convert(input_path, output_path)