successfully convert pictochat data capture to png

8 files changed, 109 insertions, 0 deletions

diff --git a/assets/first-decode-pictochat.png b/assets/first-decode-pictochat.png
new file mode 100644
index 0000000..cede905
--- /dev/null
+++ b/assets/first-decode-pictochat.png
diff --git a/assets/first-decode-ws.png b/assets/first-decode-ws.png
new file mode 100644
index 0000000..0370ee2
--- /dev/null
+++ b/assets/first-decode-ws.png
diff --git a/assets/first-decode.png b/assets/first-decode.png
new file mode 100644
index 0000000..387aa50
--- /dev/null
+++ b/assets/first-decode.png
diff --git a/docs/notes.md b/docs/notes.md
index c4a72ab..9965544 100644
--- a/docs/notes.md
+++ b/docs/notes.md
@@ -324,6 +324,22 @@ code to reassemble these chunks, the following observations were made:
   drawings. These bytes appear to be some kind of padding as changing them
   appears to have no effect and does not show up in the drawing.
 
+Using the reassembled message data, the following message was decoded as an
+experiment:
+
+![](../assets/first-decode-pictochat.png)
+
+Wireshark allows you to easily save the binary content of a dissection field to
+a file:
+
+![](../assets/first-decode-ws.png)
+
+Resulting decoded image:
+
+<div style="background-color: black; padding: 4px; font-size: 0px; display: inline-block;">
+<img src="../assets/first-decode.png"/>
+</div>
+
 ## Unsure/notes
 
 - Is the endianness of the DS properly emulated?
diff --git a/experiments/conv/.gitignore b/experiments/conv/.gitignore
new file mode 100644
index 0000000..3b4db56
--- /dev/null
+++ b/experiments/conv/.gitignore
@@ -0,0 +1,4 @@
+venv
+__pycache__
+*.bin
+*.png
diff --git a/experiments/conv/consts.py b/experiments/conv/consts.py
new file mode 100644
index 0000000..898bd3d
--- /dev/null
+++ b/experiments/conv/consts.py
@@ -0,0 +1,18 @@
+PICTOCHAT_PALETTE = (
+  (0xff, 0xff, 0xff),
+  (0x00, 0x00, 0x00),
+  (0xd3, 0xcb, 0xc3),
+  (0xeb, 0x00, 0xeb),
+  (0xfb, 0x00, 0x8a),
+  (0xfb, 0x00, 0x28),
+  (0xfb, 0x49, 0x00),
+  (0xfb, 0xa2, 0x00),
+  (0xe3, 0xf3, 0x00),
+  (0x82, 0xfb, 0x00),
+  (0x10, 0xfb, 0x20),
+  (0x00, 0xfb, 0xba),
+  (0x00, 0xc3, 0xfb),
+  (0x00, 0x79, 0xfb),
+  (0x00, 0x30, 0xfb),
+  (0x28, 0x00, 0xfb),
+)
diff --git a/experiments/conv/pc2png b/experiments/conv/pc2png
new file mode 100755
index 0000000..4fa7a1a
--- /dev/null
+++ b/experiments/conv/pc2png
@@ -0,0 +1,70 @@
+#!/bin/python3
+
+import sys
+import re
+import math
+import io
+
+from PIL import Image
+
+from consts import PICTOCHAT_PALETTE
+
+DS_TILE_SIZE = 8
+TILE_BYTES = 32 # tiles are stored in 32 bytes chunks
+
+TILES_HORIZONTAL = 32
+
+# convert a single DS tile (8x8) from packed palette index format to RGB colors
+def convert_chunk(img, chunk, offset):
+	palette_indices = []
+	for byte in chunk:
+		palette_indices += [
+			(byte >> 0) & 0x0f,
+			(byte >> 4) & 0x0f,
+		]
+
+	for i, palette_idx in enumerate(palette_indices):
+		color = PICTOCHAT_PALETTE[palette_idx]
+		location = (
+			i % DS_TILE_SIZE + offset[0],
+			i // DS_TILE_SIZE + offset[1],
+		)
+		img.putpixel(location, color)
+
+# convert a string of tiles into a PNG image
+def pc2png(data):
+	tile_count = math.floor(len(data) / TILE_BYTES)
+	size = (
+		TILES_HORIZONTAL * DS_TILE_SIZE,
+		math.ceil(tile_count / TILES_HORIZONTAL) * DS_TILE_SIZE,
+	)
+	img = Image.new(mode="RGB", size=size)
+
+	for tile in range(tile_count):
+		chunk_idx = tile * TILE_BYTES
+		chunk = data[chunk_idx:chunk_idx+TILE_BYTES]
+		tile_offset = (
+			tile % TILES_HORIZONTAL,
+			tile // TILES_HORIZONTAL,
+		)
+		convert_chunk(img, chunk, [x * DS_TILE_SIZE for x in tile_offset])
+
+	output = io.BytesIO()
+	img.save(output, format='PNG')
+	return output.getvalue()
+
+def convert_file(input_filename, output_filename):
+	with open(input_filename, 'rb') as input_file:
+		content = input_file.read()
+		output = pc2png(content)
+		with open(output_filename, 'wb+') as output_file:
+			output_file.write(output)
+
+if __name__ == "__main__":
+	del sys.argv[0]
+	for input_filename in sys.argv:
+		output_filename = re.sub('.bin$', '.png', input_filename)
+		if not output_filename.endswith('.png'):
+			output_filename += '.png'
+		convert_file(input_filename, output_filename)
+
diff --git a/experiments/conv/requirements.txt b/experiments/conv/requirements.txt
new file mode 100644
index 0000000..4efc8c7
--- /dev/null
+++ b/experiments/conv/requirements.txt
@@ -0,0 +1 @@
+pillow==10.4.0