add dds header parsing and info tool

Scripts/dds.py

@@ -1,27 +1,50 @@
 import subprocess
+import os
+import typing
+import struct
 import re
+import io
+import enum
+
+if os.name == 'nt':
+    convertcmd = "convert.exe"
+    compresscmd = "nvcompress.exe"
+    decompresscmd = "nvdecompress.exe"
+    infocmd = "nvddsinfo.exe"
+else:
+    convertcmd = "convert"
+    compresscmd = "nvcompress"
+    decompresscmd = "nvdecompress"
+    infocmd = "nvddsinfo"
 
 def alpha(file):
-    result = subprocess.run([convertcmd, file, "-resize", "1x1", "-format", "%[fx:int(255*a+.5)]", "info:-"], capture_output=True)
+    result = subprocess.run([convertcmd, file, "-resize", "1x1",
+                             "-format", "%[fx:int(255*a+.5)]", "info:-"], capture_output=True)
     result.check_returncode()
     return int(result.stdout)
 
+
 def flip(file, output):
-    result = subprocess.run([convertcmd, '-flip', file, output], capture_output=True)
+    result = subprocess.run(
+        [convertcmd, '-flip', file, output], capture_output=True)
     result.check_returncode()
 
-def nvcompress(format, file, output, mips = True):
+
+def nvcompress(format, file, output, mips=True):
     args = [format]
     if not mips:
         args.append('-nomips')
 
-    result = subprocess.run([compresscmd] + args + [file, output], capture_output=True)
+    result = subprocess.run([compresscmd] + args +
+                            [file, output], capture_output=True)
     result.check_returncode()
 
+
 def nvdecompress(file, output):
     result = subprocess.run([decompresscmd, file, output], capture_output=True)
     result.check_returncode()
 
+
 def nvinfo(file):
     result = subprocess.run([infocmd, file], capture_output=True)
     result.check_returncode()
@@ -31,3 +54,86 @@ def nvinfo(file):
     }
 
     return info
+
+class DDSFlags(enum.IntFlag):
+    CAPS = 0x1
+    HEIGHT = 0x2
+    WIDTH = 0x4
+    PITCH = 0x8
+    PIXEL_FORMAT = 0x1000
+    MIPMAPCOUNT = 0x20000
+    LINEAR_SIZE = 0x80000
+    DEPTH = 0x800000
+
+class DDSPixelFlags(enum.IntFlag):
+    ALPHAPIXELS = 0x1
+    ALPHA = 0x2
+    FOURCC = 0x4
+    RGB = 0x40
+    YUV = 0x200
+    LUMINANCE = 0x20000
+
+class DDSHeader:
+    def __init__(self, f):
+        self.read(f)
+
+    def read(self, f):
+        if f.read(4).decode() != "DDS ":
+            raise ValueError(
+                "File is not a valid DDS f: Incorrect magic bytes")
+
+        dwords = struct.unpack('20I4s10I', f.read(124))
+
+        # check constants
+        if dwords[0] != 124:
+            raise ValueError(
+                "File is not a valid DDS file: Incorrect header size")
+        if dwords[18] != 32:
+            raise ValueError(
+                "File is not a valid DDS file: Incorrect pixelformat size")
+
+        # read basic info
+        self.flags = DDSFlags(dwords[1])
+        self.height, self.width = dwords[2:4]
+
+        if DDSFlags.PITCH in self.flags:
+            self.pitch = dwords[4]
+        else:
+            self.linear_size = dwords[4]
+
+        if DDSFlags.DEPTH in self.flags:
+            self.depth = dwords[5]
+
+        if DDSFlags.MIPMAPCOUNT in self.flags:
+            self.mipmapcount = dwords[6]
+
+        # read pixelformat
+        self.pixel_flags = DDSPixelFlags(dwords[19])
+
+        if DDSPixelFlags.ALPHAPIXELS in self.pixel_flags:
+            # texture has alpha data
+           self.a_bitmask = dwords[25]
+
+        if DDSPixelFlags.FOURCC in self.pixel_flags:
+            # texture is compressed, four_cc contains the format
+            self.format = dwords[20].decode()
+        else:
+            self.format = 'uncompressed'
+            if (DDSPixelFlags.RGB | DDSPixelFlags.YUV) & self.pixel_flags:
+                # uncompressed RGB texture
+                self.rgb_bit_count, self.r_bitmask, self.g_bitmask, self.b_bitmask = dwords[21:25]
+            elif DDSPixelFlags.ALPHA in self.pixel_flags:
+                # uncompressed alpha-only texture
+                self.rgb_bit_count = dwords[21]
+                self.a_bitmask = dwords[25]
+            elif DDSPixelFlags.LUMINANCE in self.pixel_flags:
+                # uncompressed luminance-only texture
+                self.rgb_bit_count = dwords[21]
+                self.r_bitmask = dwords[22]
+
+        # read caps
+        self.dw_caps, self.dw_caps2, self.dw_caps3, self.dw_caps4 = dwords[26:30]  # read dwCaps flags
+
+        if self.format == 'DX10':
+            dwords = f.read(20)
+            #TODO: actually read the DX10 data