JSON Knowledge is recommended since this uses a lot of JSON terms.

JSON Structure

Since Nebassembly is a JSON based language, your program needs to have a proper structure.

Data section

The Data section contains program metadata such as Copyright.

Metadata Keys

copyright

Human readable copyright

nbgf

The application icon written in NBGF

EXE_TYPE

Whether it is an executable or a library
Can be either "standalone" or "library"

Example Data Section

        "data": {
            "EXE_TYPE": "standalone",
            "nbgf": [],
            "copyright": "© Annes Widow & Contributors - 2026 - Paint"
        }
        

Text section

This section is where the functions of your program are.

To create a function, simply create a dictionary key with the name of your function.

Note: the "main" function is your program's entrypoint.

Example Text Section

        "text": {
            "draw": [
                {"cal": ["_clearbg", 0, 0, 0, 255]}
            ],

            "main": [
                {"cal": ["_setupdrawbuffer", 400, 300]},
                {"cal": ["_setloop", "_DRAWLOOP", "draw"]},
                {"mov": ["_NEBWIN", true]},
                {"mov": ["_WINTITLE", "Paint"]}
            ]
        }
        

Mnemonics

To use a mnemonic, you need to put a dictionary in a function.

Syntax: { "mnemonic" : [args] }

mov

the mov istruction moves a value into an address. Can be used to make variables or modify NebulaOS values

Syntax: {"mov" : ["address", value]}

Example (setting the window title):
{"mov" : ["_WINTITLE", "Hello!"]}

Functions

These docs put functions in the way they were coded.

_setupdrawbuffer [WIDTH, HEIGHT]

This sets up the draw buffer that will be shown in the program window

_setloop [LOOP, FUNCNAME]

Set a loop so that when it is called, FUNCNAME is called.

_drawcircle [[X, Y], RADIUS, [R, G, B, A]]

Draw circle in selected framebuffer

_drawrect [[X, Y], [WIDTH, HEIGHT], [R, G, B, A]]

Draw Rectangle in selected framebuffer

_clearbg [R, G, B, A]

fill the selected framebuffer with a color

_startloop [LOOP]

Run LOOP

_len [LIST] -> (int in eax)

Get the length of a list, or other iterable

_checkcollisionrecs [[X1, Y1], [W1, H1]] [[X2, Y2], [H2, H2]] -> (bool in eax)

Return true if the rectangles are colliding

_rand [MIN, MAX] -> (int in eax)

Return a random number between MIN and MAX

_toint [OBJ] -> (int in eax)

Return OBJ converted to an integer

_tostr [OBJ] -> (string in eax)

Return OBJ converted to a string

_getfilecontents [PATH] -> (bytes in eax)

Get contents of a virtual file

_getfileext [PATH] -> (string in eax)

Get final extension of a virtual file

_getfilename [PATH] -> (string in eax)

Get final name of a virtual file

_createfile [NAME, EXT, CONTENTS]

_exportimage [rlIMG, PATH]

_loadtexture [PATH] -> (Image in eax)

_geticon [ICON] -> Image

_drawtexture [TEXTURE, X, Y, [R, G, B, A]]

_createbuffer [WIDTH, HEIGHT] -> FrameBuffer

_bindbuffer [BUFFER]

bind the BUFFER to start drawing to it.

_unbindbuffer

unbind the binded buffer to draw to the main screen again.

_drawbuffer [BUFFER]

_createcolor [R,G,B,A] -> Color

Helper function to convert an RGBA list into a Color.

_listcolor [COLOR] -> [R,G,B,A]

like _createcolor but reversed.

_guibutton [TEXT, X, Y, WIDTH, HEIGHT] -> bool

Draws a button and returns true if it is pressed.

_guicolorpicker [X,Y,W,H, TEXT, COLOR]

Draws a Color picker so that the user can modify COLOR directly

_guislider [X,Y,W,H, TEXTLEFT, TEXTRIGHT, VALUE, MINVALUE, MAXVALUE] -> float

Draws a slider so that the user can modify VALUE, returns the modified VALUE.

_drawtext [TEXT, X, Y, SIZE, R,G,B,A]

_guitextbox [TEXT, LENGTH, X,Y,W,H] -> str

Draws a textbox so that the user can modify TEXT and returns the modified TEXT.

_guimultitextbox [TEXT, X,Y, LENGTH, R,G,B,A] -> str

Similar to _guitextbox, but multiline is possible.

3D drawing

_make3dcam [[X,Y,Z], [TX,TY,TZ], [UX, UY, UZ], FOV, PROJ] -> Camera3D

NOTE: for camera to be shown it needs to be moved to address "cam"

_update3dcam [CAM, MODE]

_drawgrid [SLC, SPC]

_drawcube [[X,Y,Z], W, H, L, R,G,B,A]

_drawsphere [[X,Y,Z], RAD, R,G,B,A]

_loadmodel [PATH] -> Model

_drawmodel [MOD, [X,Y,Z], SIZE, CLR]

Generic functions

_getattr [OBJ, VAL] -> Any

_setattr [OBJ, VAL]

_print [OBJ]

_println [OBJ]

_equals [VAL1, VAL2] -> bool

_index [LIST, INDEX] -> Any

_listappend [LST, OBJ]

_listpopback [LST]

_listpop [LST, IND]

_listremove [LST, OBJ]

Input Functions

_iskeypressed [KEY] -> bool

_iskeydown [KEY] -> bool

_getmousepos -> [X,Y]

Python functions

_py [CODE]

_pytype [CODE] -> Any

_pyeval [CODE] -> Any