Changelog

2.3.5 (SNAPSHOT)

• added save of last TAP, SNAPSHOT, FLOPPY folders between restart
• improved JVM flags, switched to ZGC garbage collector
• the embedded JDK has been updated to 26+37
• added Low Pass Filter for sound output

2.3.4 (07-dec-2024)

• the minimum required JDK version has been raised to 21
• the embedded JDK has been updated to 23.0.1+13
• upgraded the JInput library to 2.0.10
• refactoring, fixes in Z80 CPU emulation

full change log

NB! The emulator has been developed as proof of concept of ZX-Poly and by default it starts in ZX-Poly mode, if you need ZX-Spectrum 128 mode then activate it through options!

Introduction

I am a ZX-Spectrum fan since 1989. ZX-Spectrum platform was very popular in the USSR. In april of 1994 I got some idea how to resolve attribute clash through moving the platform from mono-system to poly-system.

The idea was to start four ZX-Spectrum-128 in parallel with small modifications of graphics data. It didn't need any changes in ROM and SOS but only total synchronization between CPUs and sharing of all control signals.

I can't say that the idea was too original one because I was inspired by the book "COMPUTER IMAGES" ("Understanding computer" Time-Life books). There I found several strings about the Pixar platform (developed by the Lucasfilm team) which processes each color component by dedicated CPU. In ZX-Poly each CPU also processes dedicated color component (R,G,B,Y). Software no so often checks information written into VRAM so that big part of games and utilities could be adapted just through edition of their graphic data.

License

Both the concept and emulator and all its parts are published under GNU GPL3 license.

Pre-built versions

| OS | Download link | |----------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------| | | for Windows x64 (JRE included) | | | for OSX x64 (JRE included) | | | for OSX Arm64 (JRE included) | | | for Linux x64 (JRE included) | | | Linux AppImage x64 (JRE included) | | | cross-platform JAR file |

Because the emulator is written in Java, its JAR file can be started just through command line java -jar zxpoly-emul-2.3.4.jar
By default it starts embedded ZX-Poly Test ROM image, but it can be replaced by ZX-128 SOS in File->Options->Active ROM, the ROM will be downloaded from one of remote network resources.

Supported snapshot formats

• Snapshots: .Z80, .SNA, .SZX, .ZXP (ZX-Poly snapshot format), ZIP (Spec256 with SNA inside), .ROM (ROM images), .PROM ( ZX-Poly ROM images)
• Tape: .TZX (allows export as WAV), .TAP (allows export as WAV), .WAV
• Disks: .TRD, .SCL

Support of game controllers

Since 2.0.5 the emulator supports game-pads and joysticks. It uses X,Y position and recognizing all buttons as Fire. Mapping of game controller can be turned on through Service->Game controllers. I recommend restart emulator after new controller connect because JInput works not well for such situation. For work with joystick, the emulator uses library jinput so that it can work not for all host-platforms.

Theory and structure of the ZX-Poly platform

The base of the platform is the theory that stable synchronous systems (without any inside random processes) built on the same components (because different element base can be also source of random processes) by being started synchronously in the same time from the same state have the same state in any point of time if all synchronous system components get the same input signal states in the same time.
ZX-Poly platform adds several ports to manipulate work modes and the main port of the platform is #3D00. In more details it is desribed in wiki.

Supported video-modes

Standard ZX-Spectrum 256x192 (2 colors per pixel in 8x8 block) (mode 0,1,2,3)

It is just regular ZX-Spectrum mode 256x192 with 2 attributed colors for 8x8 pixel block.

ZX-Poly 256x192 (16 colors per pixel)

It is a family of video-modes and contain three sub-mode. All modes provide way for each pixel to get a color from standard ZX-Spectrum 16 color palette.

ZX-Poly 256x192 STANDARD (mode 4)

It is just regular video mode without any masking. It just integrates pixel info from video-ram of all CPU modules and form 4 bit index in ZX-Spectrum palette. TRD disk with the example can be downloaded from here, the game has been partly colorized

ZX-Poly 256x192 EXTENSION MASK_INK+PAPER (6)

It works as previous one and provide way to for 4 bit index for pixel, but also it analyses INK and PAPER colors from CPU0 video-ram and if INK = PAPER then whole block is filled by the INK color. It is made to provide way to make compatibility with games hidding some visual elements in areas with same INK and PAPER colors.

ZX-Poly 256x192 EXTENSION MASK_FLUSH+INK+PAPER (mode 7)

It is the most complex from the video-mode family. It analyses FLASH bit of each attribute from CPU0 video-memory and turn on ZX-Poly mode only for blocks where FLASH bit is ON. In the same time it analyses INK and PAPER attribute values and if they the same then whole block is filled by INK else form pixel colors as in standard ZX-Poly mode. All blocks where FLASH is OFF are processed as in standard ZX-Spectrum video-mode. FLASH is not working in the mode (but it is no so often feature in games). The video-mode provides way to colorize games with color dynamic indicators and duotone game-play areas.

ZX-Poly 512x384 (2 colors per pixel placed in chess order) (mode 5)

The Mode uses attributes but places pixels in chess order.
TRD disk with the example can be downloaded from here

Adaptation of games

To adapt old games, I have developed special utility called ZX-Poly Sprite corrector, which can be found in releases. It is a very easy editor which shows images in data blocks and allows to redraw them. It supports import from Z80 and SNA snapshots and as the result it generates ZXP snapshots.

Its pre-built versions can be found on the latest release page.

"Official Father Christmas" (1989)

Original look of the game

On Christmas 2017 I made some adaptation of the old game "Official Father Christmas" (1989) for ZX-Poly (mode 6). Of course not all was smoothly, some elements of third level could not be colorized because their colorization broke game process and made CPU modules out of sync, it looks like that the level contains some optimization in graphics processing for those elements and presented some check for empty areas to optimize speed.
Adapted game version in ZX-Poly emulator format can be downloaded from here.

"Summer Santa Update 2022" (2022)

On Christmas 2024, I made an adaptation of the game "Summer Santa Update 2022" (2022) originally created by Paul Jenkinson. This adaptation is optimized for the ZX-Poly emulator, specifically leveraging its 256x192 video mode 4. However, both the adapted and original TZX versions of the game have a limitation where gameplay is restricted to three sessions. This may be a bug in the original code.
Adapted game version in