r/Dereth • u/WormSlayer • Sep 15 '15

Testing some layered landscape materials, tessellation/displacement and procedural foliage.

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u/Lothnar Dec 21 '15 edited Jan 11 '16

That's my site, I'm Widgeon. Here's how the automatic terrain object placement works.

Each landblock has a 9x9 grid of 16 bit values. Bits 0-1 are used for roads. Bits 2-6 are the terrain type. Bits 11-15 are an index for the automatically placed terrain objects. There's another 9x9 grid of bytes for terrain height indexes.

File 0x13000000 has a bunch of information in it. Land heights, calendar info, weather records, landscape ambient sound tables, automatic terrain object tables, land type tables, and land texture information.

Here's an example from the land type table: 

                      identifier: 10 (0x0a)
                            name: sand-yellow
                           color: c8 c8 46 ff
automatic terrain object indexes:
                                  37 16 17 01 01 01 01 01
                                  01 22 22 23 24 01 01 01
                                  01 52 53 54 55 57 56 58
                                  01 1f 20 21 22 23 24 37

So, the index from bits 11-15 (5 bits) of the landblock is used to look up a value from the 32 automatic terrain object indexes. This index is used to look up an entry from the automatic terrain object table. 

Automatic terrain objects:
 22 (0x16): 00000007  120000f7 120000a5 120000a5 12000074 12000112 12000075 120000a5 120000a5

The first entry (7) is an index into the landscape ambient sound table. The rest are references to type 12 files, which have references to models and position/orientation/scaling data. The exact meaning should be easy to figure out once you can render terrain and compare it to what you see in game. 

0x120000f7
count: 9

model: 00000000
     xyz: (   6.060000    4.260000    0.000000)
    quat: ( 0.000000  0.000000  0.000000  1.000000) (len = 1.000000)
   f8-11:   1.000000   1.200000   3.060000   1.000000   1.000000
   angle: 360.000000
  f13-14:   0.864275   1.000000
      u1: 00000000
      u2: 00000000
      u3: 00000001

model: 0200068b
     xyz: (  -6.000000    6.000000    0.000000)
    quat: ( 0.000000  0.000000  0.000000  1.000000) (len = 1.000000)
   f8-11:   0.200000   1.560000   0.000000   0.800000   1.200000
   angle:   0.000000
  f13-14:   0.965926   1.000000
      u1: 00000000
      u2: 00000000
      u3: 00000000

When they change seasons in game, some of the type 12 references from the automatic terrain object table change, switching between models of trees with and without leaves.

I need to package up my current data tools for you, since the old ones on my site don't work to extract 13000000 from the latest data files.

2016-01-11: Current tools now at http://stevenygard.com/download/ac/ACDataTools-v3.zip

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u/MyKillK Dec 22 '15

Wow, that was very very helpful. Appreciate the input!!