SEMATORSEMAOS CREATOR SUITE · INCLUDED WITH SEMATOR
Draw a world. Give it rules. Make it move.
A connected desktop for building real ST and STE games,
from your first sprite to your own 68000 engine.
Windows & Linux · Mouse and keyboard · Violet & GEM themes
New in 1.1.589: jump between placed objects, navigate code by line and match, and keep sample loops intact across edits.
START VISUALLY / KEEP GOING
Rooms, artwork, types, rules, code and sounds share one searchable library. Focus on the canvas, then open the part you need to change.
Paint tiles, place objects and draw movement paths. Follow the player through rooms up to sixteen screens, with zoom, panning and a minimap.
Give an object type rules and event code, then reuse it across your game. Duplicate a type with its own rules and routines when you want a variation. Turn an independent placed object into a reusable type, or find every placement of an existing type.
F5 builds the native program and opens Playtest. Pause, inspect values and step through code, then return to the same editable project.
FIND THE OBJECT / KEEP YOUR PLACE
Find placed instances lists the selected type’s placements by room and position. Choose a row to open the room and centre that exact object.
Hidden objects become visible when you jump to them. Existing locks remain in place, and navigation does not change the project.
FIVE PLAYABLE STARTERS
Top-down · Platform · Arcade · Puzzle · Two-player
Replace the art, move a switch or change a rule. The examples use the same tools as your own project.
SEMAPAINT / EVERY PIXEL COUNTS
A 320 × 200 indexed canvas, layers beside your artwork and animation frames below it. Zoom in to see the individual ST pixels, with a pixel grid and a separate tile grid.
COLOUR, WITHOUT SURPRISES
New colour uses a free palette slot, or selects an exact match already in the palette. Edit palette colour deliberately changes every pixel using that slot. Both show a preview before you confirm. Use colour replacement when you want to replace an index within your selection, active layer or whole picture.
Used slots include hidden layers and animation frames. If all sixteen slots are occupied, the editor tells you; it does not quietly recolour another part of your picture.
VISUAL RULES → SEMABASIC → 68000
Add a few lines to an event, build shared modules or take control with a custom engine. SemaBASIC compiles to editable 68000 source; the machine’s memory and time remain the real limits.
Attach SemaBASIC to Create, Step, Collision, keys, alarms or game events. Use procedures, arrays, strings, files, drawing commands and shared modules. Terrain queries work in room coordinates, including scrolling worlds.
Edit assembly routines or open generated source in Program Lab. Use the assembler and debugger to inspect your work. A custom engine is an explicit project choice, with its source used for builds.
Up to 48 code units, 16 KB per unit and 128 KB of unit code in total. Maker checks the compiled program and target memory separately, including resources and supported packed loading.
ROOM AUDIO / SAMPLE EDITOR
Choose what a room plays, then open a sound in the Sample Editor for detailed work. Linked editing keeps the effect’s loop information with its audio.
Left and Right move one sample frame. Hold Shift to extend a selection, or Ctrl for steps of about 10 ms. Home and End reach the bounds; Ctrl+L selects the loop.
Loop positions follow cuts and rate changes. Undo restores the audio and markers together. Linked MOD instrument and STE effect edits return their loop information; WAV exports contain audio only.
Use the project song, silence or a supported room song. Include all, none or selected effects from the project’s existing PCM bank. Room choices do not create a separate sample bank.
THE REST OF YOUR STUDIO
Keep each task focused. Project links let you edit artwork and sound in their dedicated tools and bring changes back deliberately.
Compose patterns and arrange songs. Shape YM instruments, edit waveforms and macros, work with digi and Quartet samples, or add supported STE stereo sample tracks.
MIDI workflows, sub-songs, groove, transpose, SNDH and audio export, plus supported YM/VTX and MOD workflows.
Zoom into a waveform, select a range, trim, normalise and audition. Edit a MOD instrument or STE effect and return it with its loop intact. Loop markers follow cuts, resampling and Undo; keyboard controls select exact sample frames. WAV exports contain audio only.
Done returns the edited sound to Maker; Cancel leaves the original sound intact. Undo restores audio and loop markers together.
Write and assemble 68000 source, navigate code and inspect execution. Build errors link back to the relevant source, rule or routine. Ctrl+L opens Go to Line in Program Lab; Ctrl+G keeps its Find Next action.
Playtest supports breakpoints, stepping and named values, including SemaBASIC source-line debugging.
Compose a picture or a side-by-side comparison. Set the output shape, adjust the crop, add a caption and export PNG.
A large preview and focused inspector show what will be exported. Save an editable composition to revisit it later.
Also on the desktop: Disk Workshop for disk preparation, Explorer for files, Documents and Notes, Code Reader, and Help with searchable SemaBASIC and SemaSynth references.
REAL OUTPUT / REAL LIMITS
Your project becomes a native ST program on a floppy image. Choose the target before adding features that depend on the STE or more memory.
Native graphics, game rules, code and supported YM sound. Hardware Check enforces the selected RAM boundary during execution; it does not just watch a larger-memory run.
Choose more RAM or STE hardware. STE palettes, DMA samples and supported four-channel MOD playback expand your options, while audio and game code still share the frame budget.
Exports can include a matching enhancement profile for Smooth Motion and expanded views. These presentation features are supplied by SemaTor when it runs your game.
An automatic check covers the paths it executes. Play a live test to exercise gameplay. These are emulator checks, not physical ST/STE certification; demanding effects and audio can exceed an original machine’s frame budget.
BEFORE YOU START
No code is needed to begin with the editable starters and visual rules. Add SemaBASIC when you need more control, or work directly in assembly. The suite does not promise every game mechanic as a ready-made visual action.
Up to 64 sprite assets and 128 tiles. Sprites can be up to 32 × 32 pixels with four animation frames. A room supports up to 48 placed objects and a project up to 64 visual rules. Resource and target-memory limits still apply.
The standard indexed canvas has sixteen palette slots. On ST, each slot can use one of 512 colours; on STE, one of 4,096. Changing a used slot changes pixels that reference it. New colour is the safe way to add a different colour while a free slot remains.
Supported picture imports include Degas, NEOchrome, Spectrum 512, PNG, BMP, GIF and SemaPaint artwork, with target-palette conversion where needed. Music workflows include SemaSynth songs and supported MOD/SNDH imports. Conversions report features they cannot preserve.
Choose the project song, silence or an imported 50 Hz SemaSynth SNDH up to 128 KB. Select which effects from the existing sixteen-effect / 128 KB PCM bank load with the room. Per-room audio currently cannot be combined with global MOD music.
Maker supports packed programs, packed or disk-loaded room and scene resources, 360 KB or 720 KB disks and projects spanning up to nine disks. Build checks account for supported loading and unpacking as well as the running program.
They are editable starting points. The two-player starter now checks internal walls for both players. Test your own rules, artwork, controls and target before sharing a finished game.
The public Windows x64, Linux x86-64 and Linux ARM64 desktop builds include the suite inside SemaOS. Open the Create menu to begin. Android remains a separate private testing build; this page focuses on desktop authoring.
Start with something playable. Keep making it yours.
Read the complete 1.1.589 changelog. All screenshots on this page were captured from the 1.1.589 application UI with original demonstration content. Images show the complete captured desktop and open at full resolution; Violet is shown throughout, with GEM in Room settings.