Update File Type Texture

File-Type---Texture.md

@@ -27,47 +27,80 @@ header {
 ---
 
 ```010editor
-uint32 type;
-// Presumably, there are other values as well, but `1` is the only case partially figured out, so far.
-Assert(type == 1);
 
-uint32 compressed_size;
-uint32 uncompressed_size;
+uint32 compression_type;
+Assert(compression_type == 1 || compression_type == 0);
 
-byte compressed_data[compressed_size];
+if (compression_type == 1) {
+    uint32 compressed_size;
+    uint32 uncompressed_size;
+    
+    byte data[compressed_size] <format=hex, bgcolor=0x888545>;
+    
+    // Seems to be skipped by the decompiled binary's code.
+    // Doesn't fit to be a length of a later data section. It doesn't match anything, and it's an uneven number.
+    uint32 unknown_1 <comment="Always 67 (0x43), so maybe a format/type specifier.">;
+    //Assert(unknown_1 == 0x43);
+    
+    // At this point, the code reads an array of 37 uint32 fields.
+    // This will be slowly split into individual named fields as I figure them out.
+    
+    typedef struct TextureHeader {
+        // Checked bits:
+        // >> 1: Some extra calculations are done with the next three fields around mipmaps
+        //       Also determines if `unknown_2` is saved into `TextureImage`
+        //       => Presumable means "has mipmaps" or VT2's "is streamable"
+        // >> 2: So far, I haven't found a line of code that actually uses this bit. But there is a line that does `flags & 3`,
+        //       indicating that this bit does get used somewhere else.
+        // >> 8: TextureFormat.srgb
+        uint32 flags <format=binary, comment="Some bitflags.">;
+    
+        uint32 n_streamable_mips;
+        uint32 width;
+        uint32 height;
+    
+        // At some point, the code will move 68 bytes from an offset to the start of this array.
+        uint32 unknown_2[(68 + 60) / 4] <bgcolor=0x9b86d3, fgcolor=0xb2dbeb>;
+    
+    };
+    
+    TextureHeader texture_header;
+    
+    uint32 meta_size;
+    
+    // According to limn, this is something that happens inside `meta_data`.
+    // But so far, I haven't found the part in the decompiled binary that handles this data.
+    if (meta_size > 0) {
+        uint32 num_chunks <comment="Connected to `largest_{width|height}`">;
+        Assert((num_chunks * 4) + 8 == meta_size);
+    
+        uint16 unknown_6 <hidden=true>;
+        Assert(unknown_6 == 0);
+    
+        uint16 num_chunks_2 <hidden=true, comment="Always the same as `num_chunks`">;
+        Assert(num_chunks == num_chunks_2);
+    
+        uint32 chunks[num_chunks];
+    }
+    
+    // A key to look up a value in the engine's internal render quality settings.
+    // Specifically, a value that VT2 calls `mip_drop`.
+    // TODO: Check how many unique values there are in the game files.
+    // Ideally, there would only be a handful that we can simply hard code.
+    uint32 category <format=hex, comment="Assumed, since VT2 has the same thing.">;
+    
+    // Shortcuts to get to compile this:
+    // - `flags = 0` -> skips most of the mipmap stuff in the bundle file
+    // - `width = 0`, `height = 0` -> also skips some of the mipmap stuff
+    // - `n_streamable_mipmaps = 0` -> seems to be an intended value to only rely on DDS mipmaps
+    //                                 It does force `srgb` on through setting a special value for `flags`, though. So if that produces issues, I might
+    //                                 need to fake it s
+} else if (compression_type == 0) {
+    uint32 unknown_1;
+    uint32 unknown_2;
 
-uint32 unknown_1;
-Assert(unknown_1 == 0x43);
-
-uint32 unknown_2;
-
-uint32 num_mipmaps;
-uint32 largest_width;
-uint32 largest_height;
-
-byte unknown_3[60];
-
-uint32 image_size;
-
-byte unknown_4[64];
-
-uint32 meta_size;
-
-if (meta_size == 0) {
-    uint32 unknown_5;
-} else {
-    uint32 num_chunks;
-    Assert((num_chunks * 4) + 8 == meta_size);
-
-    uint16 unknown_6;
-    Assert(unknown_6 == 0);
-
-    uint16 num_chunks_2;
-    Assert(num_chunks == num_chunks_2);
-
-    uint32 chunks[num_chunks];
-
-    uint32 unknown_7;
+    Assert(unknown_1 == 0);
+    Assert(unknown_2 == 0);
 }
 ```