initial commit!

graphics/preview_vb_colors.py

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+"""
+preview_vb_colors.py
+
+Convert images to the Virtual Boy 4-level monochrome red palette and save
+preview PNGs so you can see how they look on the VB display.
+
+Palette:
+  0 = (  0,   0,   0) -- black / transparent
+  1 = ( 80,   0,   0) -- dark red
+  2 = (170,   0,   0) -- medium red
+  3 = (255,   0,   0) -- bright red
+"""
+
+import os
+import sys
+from PIL import Image
+
+SCRIPT_DIR = os.path.dirname(os.path.abspath(__file__))
+
+VB_PALETTE = {
+    0: (0, 0, 0),
+    1: (80, 0, 0),
+    2: (170, 0, 0),
+    3: (255, 0, 0),
+}
+
+# Bayer 4x4 ordered dither matrix (normalized 0-1)
+BAYER_4x4 = [
+    [0/16, 8/16, 2/16, 10/16],
+    [12/16, 4/16, 14/16, 6/16],
+    [3/16, 11/16, 1/16, 9/16],
+    [15/16, 7/16, 13/16, 5/16],
+]
+
+DITHER_STRENGTH = 40  # tweak for more or less dithering
+
+
+def luminance(r, g, b):
+    return 0.299 * r + 0.587 * g + 0.114 * b
+
+
+def convert_to_vb(img):
+    """Convert an RGBA/RGB image to VB 4-level red palette with dithering."""
+    img = img.convert('RGBA')
+    w, h = img.size
+    pix = img.load()
+    out = Image.new('RGB', (w, h), (0, 0, 0))
+    opix = out.load()
+
+    for y in range(h):
+        for x in range(w):
+            r, g, b, a = pix[x, y]
+            if a < 128:
+                opix[x, y] = VB_PALETTE[0]
+                continue
+
+            lum = luminance(r, g, b)
+            bayer = BAYER_4x4[y % 4][x % 4]
+            dithered = lum + (bayer - 0.5) * DITHER_STRENGTH
+            dithered = max(0, min(255, dithered))
+
+            if dithered < 42:
+                vb = 0
+            elif dithered < 110:
+                vb = 1
+            elif dithered < 180:
+                vb = 2
+            else:
+                vb = 3
+
+            opix[x, y] = VB_PALETTE[vb]
+
+    return out
+
+
+def main():
+    images = [
+        "wolf_titlescreen.png",
+        "wolfen_doom_logo.png",
+    ]
+
+    for name in images:
+        path = os.path.join(SCRIPT_DIR, name)
+        if not os.path.exists(path):
+            print(f"  SKIP: {path} not found")
+            continue
+
+        img = Image.open(path)
+        print(f"Converting {name} ({img.width}x{img.height})...")
+
+        vb_img = convert_to_vb(img)
+
+        out_name = os.path.splitext(name)[0] + "_vb_preview.png"
+        out_path = os.path.join(SCRIPT_DIR, out_name)
+        vb_img.save(out_path)
+        print(f"  Saved: {out_path}")
+
+    print("\nDone!")
+
+
+if __name__ == '__main__':
+    main()