From 5f4b0070a6b3a7e1476b196133be392556c14e52 Mon Sep 17 00:00:00 2001
From: Zack Buhman <zack@buhman.org>
Date: Fri, 31 Jan 2025 15:48:40 -0600
Subject: [PATCH] add twiddle

---
 .gitignore                  |  1 +
 color_convert.py            | 44 +++++++++++++++++++++++------
 render_material_textures.py | 56 ++++++++++++++++++++-----------------
 twiddle.py                  | 43 ++++++++++++++++++++++++++++
 4 files changed, 109 insertions(+), 35 deletions(-)
 create mode 100644 .gitignore
 create mode 100644 twiddle.py

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ba0430d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+__pycache__/
\ No newline at end of file
diff --git a/color_convert.py b/color_convert.py
index b457c68..23aa85c 100644
--- a/color_convert.py
+++ b/color_convert.py
@@ -2,6 +2,7 @@ import struct
 import sys
 
 from PIL import Image
+from twiddle import texture as twiddle_texture
 
 class color_format:
     def gbgr1555(r, g, b, a): # nintendo ds
@@ -29,7 +30,7 @@ class color_format:
         r5 = (r >> 3) & 31
         g6 = (g >> 2) & 63
         b5 = (b >> 3) & 31
-        return (r5 << 11) | (g5 << 5) | (b5 << 0)
+        return (r5 << 11) | (g6 << 5) | (b5 << 0)
 
     def axxx4444(r, g, b, a):
         a4 = (a >> 4) & 15
@@ -44,12 +45,12 @@ class color_format:
             ("axxx4444", color_format.axxx4444),
         ])[s]
 
-def convert_colors(f, convert, colors):
+def convert_colors(convert, colors):
     for color in colors:
         value = convert(*color)
-        f.write(struct.pack("<H", value))
+        yield value
 
-def convert_indices(f, palette, pixels):
+def convert_indices(palette, pixels):
     if len(palette) <= 4:
         for i in range(len(pixels) // 4):
             a = pixels[i * 4 + 0]
@@ -73,22 +74,47 @@ def convert_indices(f, palette, pixels):
     else:
         assert False, len(palette)
 
+def pack_colors(f, colors):
+    for value in colors:
+        f.write(struct.pack("<H", value))
+
+def pack_indices(f, indices):
+    for value in indices:
+        f.write(struct.pack("<B", value))
+
 if __name__ == "__main__":
     in_file = sys.argv[1]
     format = sys.argv[2]
-    out_file = sys.argv[3]
+    assert sys.argv[3] in {"twiddled", "non_twiddled"}
+    is_twiddled = sys.argv[3] == "twiddled"
+    out_file = sys.argv[4]
 
     convert = color_format.from_string(format)
 
     with Image.open(in_file) as im:
+        width, height = im.size
         if not im.palette:
             pixels = list(im.convert("RGBA").getdata())
+            colors = list(convert_colors(convert, pixels))
+            if is_twiddled:
+                new_colors = [0] * len(colors)
+                twiddle_texture(new_colors, colors, width, height)
+                colors = new_colors
             with open(out_file, 'wb') as f:
-                convert_colors(f, convert, pixels)
+                pack_colors(f, colors)
         else:
             pixels = list(im.convert("P").getdata())
             palette = list(im.palette.colors)
-            with open(out_file, 'wb') as f:
-                convert_indices(f, palette, pixels)
+            indices = list(convert_indices(palette, pixels))
+            colors = list(convert_colors(convert, [(*c, 255) for c in palette]))
+
+            if twiddle:
+                new_indices = [0] * len(indices)
+                twiddle_texture(new_indices, indices, width, height)
+                indices = new_indices
+
             with open(out_file + '.pal', 'wb') as f:
-                convert_colors(f, convert, [(*c, 255) for c in palette])
+                pack_colors(f, colors)
+
+            with open(out_file, 'wb') as f:
+                pack_indices(f, indices)
diff --git a/render_material_textures.py b/render_material_textures.py
index f7ae804..a51987d 100644
--- a/render_material_textures.py
+++ b/render_material_textures.py
@@ -8,17 +8,19 @@ from PIL import Image
 
 from parse_material import parse_mtl_file
 
-material_filenames = sys.argv[1:]
-
-def render_material_enum(newmtl_mapkd):
+def render_material_enum(prefix, newmtl_mapkd):
     yield f"enum material {{"
     for newmtl, mapkd in newmtl_mapkd:
-        yield f"{newmtl.name},";
+        yield f"{prefix}_{newmtl.name},";
     yield "};"
 
-def render_pixel_descriptor(offset, mapkd, dimensions):
+def transform_filename(prefix, name):
+    name = name.replace("/", "_")
+    return f"model_{prefix}_{name}"
+
+def render_pixel_descriptor(prefix, offset, mapkd, dimensions):
     name, _ext = mapkd.name.rsplit('.', maxsplit=1)
-    pixel_name = f"{name}_data"
+    pixel_name = f"{transform_filename(prefix, name)}_data"
     width, height = dimensions
     yield ".pixel = {"
     yield f".start = (uint8_t *)&_binary_{pixel_name}_start,"
@@ -54,12 +56,10 @@ def round_up_colors(name, colors):
     else:
         assert False, (name, colors)
 
-def image_metadata(mapkd):
+def image(mapkd):
     path = texture_path(mapkd.name)
-    with Image.open(path) as im:
-        dimensions = im.size
-        colors = len(im.palette.colors)
-    return dimensions, colors
+    im = Image.open(path)
+    return im
 
 def round_up_n(x, multiple):
     return ((x + multiple - 1) // multiple) * multiple
@@ -68,27 +68,30 @@ def bytes_per_pixel(palette_size):
     bits_per_pixel = int(log(palette_size)/log(2))
     return bits_per_pixel / 8
 
-def render_material(offset, mapkd):
-    dimensions, colors = image_metadata(mapkd)
-    palette_size = round_up_colors(mapkd.name, colors)
+def render_material(prefix, offset, mapkd):
+    im = image(mapkd)
+    dimensions = im.size
+    #colors = len(im.palette.colors)
+
+    #palette_size = round_up_colors(mapkd.name, colors)
 
     # pixel descriptor
-    yield from render_pixel_descriptor(offset, mapkd, dimensions)
-    pixel_size = bytes_per_pixel(palette_size) * dimensions[0] * dimensions[1]
-    #pixel_size = 2 * dimensions[0] * dimensions[1]
+    yield from render_pixel_descriptor(prefix, offset, mapkd, dimensions)
+    #pixel_size = bytes_per_pixel(palette_size) * dimensions[0] * dimensions[1]
+    pixel_size = 2 * dimensions[0] * dimensions[1]
     assert int(pixel_size) == pixel_size
     offset.pixel += round_up_n(int(pixel_size), 8)
 
     # palette descriptor
-    yield from render_palette_descriptor(offset, mapkd, palette_size)
-    offset.palette += round_up_n(colors * 2, 16)
+    #yield from render_palette_descriptor(offset, mapkd, palette_size)
+    #offset.palette += round_up_n(colors * 2, 16)
 
-def render_materials(newmtl_mapkd):
-    yield "struct material_descriptor material[] = {"
+def render_materials(prefix, newmtl_mapkd):
+    yield f"const struct material_descriptor {prefix}_material[] = {{"
     offset = Offset(0, 0)
     for newmtl, mapkd in newmtl_mapkd:
-        yield f"[{newmtl.name}] = {{"
-        yield from render_material(offset, mapkd)
+        yield f"[{prefix}_{newmtl.name}] = {{"
+        yield from render_material(prefix, offset, mapkd)
         yield "},"
     yield "};"
 
@@ -101,7 +104,8 @@ def render_header():
     yield ""
 
 if __name__ == "__main__":
-    material_filenames = sys.argv[1:]
+    prefix = sys.argv[1]
+    material_filenames = sys.argv[2:]
     assert material_filenames
     newmtl_mapkd = []
     for material_filename in material_filenames:
@@ -114,6 +118,6 @@ if __name__ == "__main__":
 
     render, out = renderer()
     render(render_header())
-    render(render_material_enum(newmtl_mapkd))
-    render(render_materials(newmtl_mapkd))
+    render(render_material_enum(prefix, newmtl_mapkd))
+    render(render_materials(prefix, newmtl_mapkd))
     sys.stdout.write(out.getvalue())
diff --git a/twiddle.py b/twiddle.py
new file mode 100644
index 0000000..1bafdef
--- /dev/null
+++ b/twiddle.py
@@ -0,0 +1,43 @@
+def log2(n):
+    return {
+        8: 3,
+        16: 4,
+        32: 5,
+        64: 6,
+        128: 7,
+        256: 8,
+        512: 9,
+        1024: 10,
+    }[n]
+
+def from_xy(x, y, width, height):
+  # maximum texture size       : 1024x1024
+  # maximum 1-dimensional index: 0xfffff
+  # bits                       : 19-0
+
+  # y bits: 0, 2, 4, 6, 8, 10, 12, 14, 16, 18
+  # x bits: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19
+
+  width_max = log2(width)
+  height_max = log2(height)
+
+  twiddle_ix = 0
+  for i in range(20 // 2):
+      if (i < width_max and i < height_max):
+          twiddle_ix |= ((y >> i) & 1) << (i * 2 + 0)
+          twiddle_ix |= ((x >> i) & 1) << (i * 2 + 1)
+      elif (i < width_max):
+          twiddle_ix |= ((x >> i) & 1) << (i + height_max)
+      elif (i < height_max):
+          twiddle_ix |= ((y >> i) & 1) << (i + width_max)
+      else:
+          break
+
+  return twiddle_ix
+
+def texture(dst, src, width, height):
+    for y in range(height):
+        for x in range(width):
+            twiddle_ix = from_xy(x, y, width, height)
+            value = src[y * width + x]
+            dst[twiddle_ix] = value