What is everything?

Someone asked me to explain all the files. Let’s try to do that. Look at the most complicated one.


in BG/

The .tmx files are from tiled map editor. Tiled uses the Metatiles.png and Sprites.png files to as its tileset, and the exported tilemaps are the .csv files. You can’t import a csv into a c project, so I wrote some python scripts to convert .csv files into .c files. Two different python files, one for background and one for sprites, so all the .c files with “SP” are sprite object lists.

All the .c files are included into the project.


The .nes file is our game that can be run in an emulator.

The .s file is the assembly generated by the cc65 compiler, just in case you want to debug by looking though the ASM.

The labels.txt file is a list of all the addresses of every label in the code. You can also use this for debugging, by setting breakpoints for these addresses.

in LIB/

is all the neslib files (neslib.h and neslib.s) and all the funtions that I wrote (nesdoug.h and nesdoug.s). The .s files are included in crt0.s near the bottom. The .h files are included in the main c file.


The .ftm files are Famitracker 0.4.6 files. 1 for music and 1 for sfx. The music file was exported as a .txt file (included here) and processed with text2data (from Shiru’s famitone2 files) into TestMusic3.s. The sfx was exported as .nsf (Nintendo Sound Format) and then processed with nsf2data (also famitone2) into SoundFx.s.

famitone2.s is the famitone code (again, Shiru’s website). All the .s files are included somewhere in crt0.s. If we had DPCM samples, they would also be included in crt0.s in the “SAMPLES” segment.

in NES_ST/

The .nss files are NES Screen Tool 2.3 files. I saved one (title) as a .h compressed RLE, which the game includes and decompresses. I made a .nss file with all the kinds of block in the game (metatiles), and save to .nam (uncompressed list of the entire screen), which meta.py python script converted into a C array in metatiles.txt. Also I did a print screen from both the metatile.nss and sprite.nss files and cropped down in GIMP and save those as the .png files up in the BG/ folder (used by tiled map editor).

The other files are…

License.txt – just the MIT licence

Sprites.h – arrays of all the metasprite definitions, generated by NES Screen Tool (or by hand, which is sometimes faster)

compile.bat – to recompile the project (on Windows)

crt0.s – is all the startup code, but also a convenient place to include asm or binary files.

full_game.c – the game code. I like to use notepad++ to write my code.

full_game.chr – the graphics file, split into 2 sections, the 256 BG tiles, and the 256 Sprite tiles.

full_game.h – variables and constants and prototypes, and some constant arrays

level_data.c – lists of game data and things included for each level

nrom_32k_vert.cfg – the linker file for ld65, tells where each segment goes in the final binary.

screenshot26.png – just a picture of the game.

And some more info on compile.bat

This is a list of command line inputs for compiling the game from scratch. If you change the name of your project, change set name=full_game” to match the main code filename. Or you can change this line

cc65 -Oirs %name%.c –add-source


cc65 -Oirs filename.c –add-source

where filename is the name of the .c file. You can process multiple C files this way, just make sure to also use ca65 to convert each .s file into a .o object file.

-Oirs are optimizations.

–add-source tells it to put the source code in comments in the asm file.

If you have multiple object files you need to change the linker (ld65) line to list every .o file.

ld65 -C nrom_32k_vert.cfg -o %name%.nes crt0.o %name%.o nes.lib -Ln labels.txt


ld65 -C nrom_32k_vert.cfg -o targetname.nes crt0.o file1.o file2.o file3.o nes.lib -Ln labels.txt

-o blah tell it what to name the output file.

If you use cl65 instead of cc65/ca65/ld65, then make sure to set target = NES. It sets a strange default target, which does not use standard ASCII encoding.

del *.o deletes the object files.

move /Y labels.txt BUILD\
move /Y %name%.s BUILD\
move /Y %name%.nes BUILD\

moves these files into the BUILD folder


just runs the game, which is in the BUILD folder.


Hope this helps.




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