https://github.com/spiiin/CadEditor
CadEditor is the universal level editor for NES/SMD/SNES games, I describe project on steemit here.
CadEditor has plugin Anim Editor for showing object sprites for several Capcom NES games. I created it for testing my understanding of animation format for game Chip & Dale Rescue Rangers. This animation format also used in games Darkwing Duck, Duck Tales 1, Tale Spin, Little Mermaid (Settings for this games was added by romhacker Roket). It will also be used in several other Capcom games (some games of Mega Man series ), but not in all (Duck Tales 2, Chip & Dale 2 used another format).
In this update I improved plugins features for:
My idea is to use this plugin for preparing sprites for CadEditor Object Editor. I used it to research animation in this games and to create sprites for Object Editor. Export correct sprites is not a trivial process, so I describe it below.
Commits per games:
Object editor without sprites:
And with sprites:
Now, Object Editor by default shows sprites as numbers with an object type, but it also supports option to show prepared sprites instead of the default, for certain games (as shown at screenshots above).
One way to prepare these sprites is to make screenshots with every object in the emulator while playing the game, and cut objects from it.
But the more interesting way for research - is to build sprites from ROM data. It needs to make additional work for it, but after complete it, the researcher can view really all animations, even hidden secret animations, not used in the game at all.
For example, there are sprites of unused enemy in Duck Tales 2 (found by romhacker Ti_)
Every object in the game is described with two arrays per 4 bytes each. The first array contains objects lives and three zeros. Another array contains such object's properties:
byte 1 - unique object type number.
byte 2 - the number of object's behavior function (called every frame when the object is showed)
byte 3 - initial animation number
byte 4 - additional field. Can contains flags bits of second animation number
Object type number - with this number object on the level can be described with only this one byte.
Object's behavior function is called every frame when the object showed, and it describes, how the object will be updated.
Initial animation number defines, how the object will render when it appears on screen (animation number can be changed by behavior function. For example, initial animation "Robot stand" can be changed to "Robot walk" to the player.
Additional field saves all data related to object state (is enemy, is visible so on) needed to classify the object. In some games, it saves an additional animation number.
Animations themselves are described with fields:
{
1 byte - Frames count N
1 byte - Timer (defines the speed of change frames in animation)
N byte - Indexes of frames in the animation
}
Every frame defined with the structure:
{
1 byte - Tiles count N
1 byte - index in coordinates array (array with Xs and Ys of every tile). Coordinates stores as the separate array for compactness reasons. Some frames stores different tiles, but positions of tiles keep unchanged - they can share coordinates between frames.
N*2 byte - pairs of tile index and tile attribute (1st byte - tiles index, 2nd byte - tile attribute (standard NES system ability - tile mirroring by X and Y, transparency and palette bits) ).
}
For example, addresses of arrays for Chip and Dale
5:B55F-B4B6 (168 items) animations array
5:9CAE-9B82/
5:9DAE-9C82 (300 items, separated by 2 arrays) - frames arrays
5:B145-B08E (183 items) - coords arrays
AnimEditor plugin can show all animations as the tree:
Frame rendering has one problem - NES draws sprites with a prepared table with 256 tiles (called CHR bank). Enemies used in one level grouped in one tile bank. Almost always, the game contains several different banks, and bank switching is programmed in the game code, often before the level or sublevel start.
So, object editor doesn't know, what bank of tiles must be used for correct rendering. The only user of the editor can choose a correct bank from all banks used in the game.
For example, there is the same frame, rendered with the correct and incorrect bank:
But some NES games not stores full CHR-bank in ROM, and switch only part of the bank. For this games, it's hard to describe all combinations of banks in the settings file. For this case, Anim Editor can load bank from the file.
There is the lua script, that can make a dump of CHR-bank while play game in Fceux emulator.
The user can run it exactly at the moment when object rendered in game. For example, at this moment (Duck Tales logo screen):
For this case, tiles of sprites stores in bank 1 and use palette 2, and tiles of background stores in bank 2 and use palette 1. It's normal case, NES can use any combination of palette and bank for sprites. So, we need files with names chr1.bin and pal2.bin from directory with dump_chr_and_pal.lua script
We need to open these files from Anim Editor with "load CHR from file" and "load pal from file" buttons and search Scrooge's head animation:
Chip and Dale, Darkwing Duck and Tale Spin change full banks only, so it's no need to make dumps for this games (but this method can be applied with it also), and Duck Tales and Little Mermaid change banks by small parts, so dumps is only way to see all animations inside these games.
Sometimes it's not easy to understand, what sprite do you see (for example, if there is only one tile in it). But animations often grouped by numbers, so if you can identify adjacent animations and set correct bank for it, you will see the frame with this bank also).
After finding all sprites and export it, there is the last step for using it in Object Editor. You need to find object numbers that using animation files. It can be done with analyzing level in Object Editor and in the game - just see how an object looks in the game and find correspond sprite for it. Sprites must be renamed correspond to object number with postfix "b" ("big") after it. For example, for object 0, the file name must be "000b.png", and so on.
Folder with these sprites can be selected in game settings file:
public string getObjTypesPicturesDir() { return "obj_sprites_dwd"; }
After that, Object Editor will render prepared sprites:
