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https://github.com/xyproto/pixelprotocol
Experimental protocol for streaming games
https://github.com/xyproto/pixelprotocol
binary convolution-filters for-fun gamedev games midi pixels protocol sprite streaming
Last synced: 2 days ago
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Experimental protocol for streaming games
- Host: GitHub
- URL: https://github.com/xyproto/pixelprotocol
- Owner: xyproto
- License: cc0-1.0
- Created: 2018-09-17T08:28:47.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2020-05-25T17:08:04.000Z (over 4 years ago)
- Last Synced: 2024-05-09T19:18:59.906Z (5 months ago)
- Topics: binary, convolution-filters, for-fun, gamedev, games, midi, pixels, protocol, sprite, streaming
- Homepage:
- Size: 29.3 KB
- Stars: 2
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# PixelProtocol 3
PixelProtocol 3 is a simple binary protocol for defining what is being sent between a GUI client and a game engine.
It's for implementing games where old-school looking pixel art can be appreciated.
## Features and limitations
* 256 indexed colors.
* A resolution of 320x200 pixels is recommended.
* Should be possible to implement both in 16-bit assembly for DOS and in a modern browser.
* Aiming to be WebSocket-friendly.
* Pixels are not sent over the network, only commands for drawing them.
* It should be possible to create a DosBox server for serving games over this protocol.
* It should be possible to create a mobile client for playing games over this protocol.
* The music is extremely simple 4-track MIDI.
# Protocol Definition
## Protocol Header
| Name | Type | Description |
|------------|-------------------|-----------------------------------------------------|
| `ver` |`uint16` | protocol version |
| `width` |`uint16` | width |
| `height` |`uint16` | height |
| `commands` | `[]uint16` | list of commands (`uint8` cmd + `uint8` argument) |
The commands can be streamed.
## Commands
### Color palette
| Cmd | Name | **uint8** argument | Description |
|--------|--------------|-----------------------------------------|----------------------------------------------------------------|
| `0x00` | `palsel` | color index, 0..255 | choose palette color, prepare for filling the palette |
| `0x01` | `setred` | red value, 0..255 | set red value of chosen palette color |
| `0x02` | `setgreen` | set green value of chosen palette color | set blue value of chosen palette color |
| `0x03` | `setblue` | set blue value of chosen palette color | set green value of chosen palette color |
### Drawing pixels
| Cmd | Name | **uint8** argument | Description |
|--------|----------|-----------------------------------------|------------------------------------------|
| `0x04` | `setcol` | pixel color from palette, 0..255 | set the active color |
---
| Cmd | Name | **uint16** argument | Description |
|--------|----------|-----------------------------------------|------------------------------------------|
| `0x05` | `setx` | x position, 0..65535 | set active x position |
| `0x06` | `sety` | y position, 0..65535 | set active y position |
---
| Cmd | Name | **uint8** argument | Description |
|--------|----------|-----------------------------------------|------------------------------------------|
| `0x07` | `plot` | n pixels | plot one or more pixels from (x,y) |
### Filling
| Cmd | Name | **uint8** argument | Description |
|--------|---------|-----------------------------------------|-----------------------------------------------------------------------------------|
| `0x08` | `clear` | fill color from palette, 0..255 | clear everything with the selected color |
| `0x09` | `rfill` | fill color from palette, 0..255 | draw linewise until nonzero color or end, for filling the pixel buffer |
| `0x0a` | `lfill` | fill color from palette, 0..255 | draw backwards linewise until nonzero color or end, for filling the pixel buffer |
### Flipping
| Cmd | Name | no argument | Description |
|--------|--------------|--------------|----------------------------------------------------------------------------------------|
| `0x0b` | `flip` | | update all pixels |
| `0x0c` | `spriteflip` | | update pixels where sprites have been drawn since last time this command was executed |
### Drawing lines
| Cmd | Name | **uint8** argument | Description |
|--------|----------|----------------------------------|---------------------------------|
| `0x0d` | `setlcs` | color for start of line | prepare to draw a line |
| `0x0e` | `setlce` | color for end of line | prepare to draw a line |
* colors are interpolated linearly, component-wise (r, g, b, a)
---
| Cmd | Name | **uint16** argument | Description |
|--------|--------|-----------------------------------------|--------------------------------|
| `0x11` | `lisx` | x coordinate for start of line | prepare to draw a line |
| `0x12` | `lisy` | y coordinate for start of line | prepare to draw a line |
| `0x13` | `liex` | x coordinate for end of line | prepare to draw a line |
| `0x14` | `liey` | y coordinate for end of line | prepare to draw a line |
---
| Cmd | Name | no argument | Description |
|--------|---------|----------------|----------------|
| `0x15` | `ldraw` | | draw the line |
### Drawing triangles
| Cmd | Name | **uint8** argument | Description |
|--------|----------|---------------------|-------------------------------|
| `0x1a` | `setcp0` | set color for p0 | prepare to draw a triangle |
| `0x1b` | `setcp1` | set color for p1 | prepare to draw a triangle |
| `0x1c` | `setcp2` | set color for p2 | prepare to draw a triangle |
---
| Cmd | Name | **uint16** argument | Description |
|--------|----------|--------------------------|--------------------------------|
| `0x1d` | `setxp0` | x coordinate for p0 | prepare to draw a triangle |
| `0x1e` | `setyp0` | y coordinate for p0 | prepare to draw a triangle |
| `0x1f` | `setxp1` | x coordinate for p1 | prepare to draw a triangle |
| `0x20` | `setyp1` | y coordinate for p1 | prepare to draw a triangle |
| `0x21` | `setxp2` | x coordinate for p2 | prepare to draw a triangle |
| `0x22` | `setyp2` | y coordinate for p2 | prepare to draw a triangle |
---
| Cmd | Name | **uint8** argument | Description |
|--------|---------|---------------------------------------|------------------------------------------|
| `0x23` | `tdraw` | 0 for empty, 1 for filled | draw a filled or empty triangle |
### Sprites
| Cmd | Name | **uint8** argument | Description |
|--------|------------|---------------------------------------------------|-----------------------------------------------------------------------|
| `0x30` | `spid` | sprite ID | select a sprite ID to work with |
| `0x31` | `spw` | sprite width | set sprite width |
| `0x32` | `sph` | sprite height | set sprite height |
| `0x33` | `spclr` | color | clear contents with the given color |
| `0x34` | `spush` | amount of pixels | add N pixels of the active color |
| `0x35` | `spt` | amount of pixels | add N transparent pixels |
| `0x36` | `sprot` | value from 0..255, used as float from `0..2*PI` | rotate the current sprite |
| `0x37` | `spscale` | value from 0..255, used as float from -20..20 | scale the current sprite |
| `0x38` | `spcopy` | sprite ID | copy to another sprite ID |
---
| Cmd | Name | **uint16** argument | Description |
|--------|------------|------------------------|---------------------------------------------------|
| `0x39` | `spx` | x coordinate | set x coordinate for where to draw the sprite |
| `0x3a` | `spy` | y coordinate | set y coordinate for where to draw the sprite |
---
| Cmd | Name | **uint8** argument | Description |
|--------|------------|------------------------------|-----------------------------------------------------------------------|
| `0x3b` | `blit` | number of sprites to draw | draw n instances of this sprite, following the pixel buffer direction |
| `0x3c` | `blitinc` | number of sprites to draw | like `blit`, but increases the sprite ID at every step |
* The "pixel buffer direction" is from left to right, then starting on the next y coordinate (+ sprite height) when reaching the end of the line.
* Several sprites can be placed in a row with the `blit` command. They are placed next to each other, without overlapping.
* For the `blitinc` command, increasing the value from 255 wraps around and sets to current sprite ID to 0.
* Sprites can have a resolution up to `128*128` (inclusive).
### Convolution Filters
| Cmd | Name | **uint8** argument | Description |
|--------|----------|-----------------------------------------------------------|------------------------------------------------|
| `0x40` | `con0` | value from 0..255, used as float from -20..20 | set convolution filter value 0 |
| `0x41` | `con1` | value from 0..255, used as float from -20..20 | set convolution filter value 1 |
| `0x42` | `con2` | value from 0..255, used as float from -20..20 | set convolution filter value 2 |
| `0x43` | `con3` | value from 0..255, used as float from -20..20 | set convolution filter value 3 |
| `0x44` | `con4` | value from 0..255, used as float from -20..20 | set convolution filter value 4 |
| `0x45` | `con5` | value from 0..255, used as float from -20..20 | set convolution filter value 5 |
| `0x46` | `con6` | value from 0..255, used as float from -20..20 | set convolution filter value 6 |
| `0x47` | `con7` | value from 0..255, used as float from -20..20 | set convolution filter value 7 |
| `0x48` | `con8` | value from 0..255, used as float from -20..20 | set convolution filter value 8 |
| `0x49` | `condiv` | convolution division, 0..255, used as float from -20..20 | set convolution division value |
| `0x4a` | `apply` | | apply convolution filter to all pixels |
| `0x4b` | `consp` | | apply convolution filter to the current sprite |
The convolution filter parameters 0..255 are treated as if they were floats between -20 and 20 (inclusive).
Example filters:
* blur is 0,1,0,1,1,1,0,1,0 div 5
* flame is 0,1,0,1,1,1,0,0,0 div 4
### Text
| Cmd | Name | **uint8** argument | Description |
|--------|-----------|--------------------|-----------------------------------------------|
| `0x50` | `radd` | utf-8 byte | add a byte to the current UTF-8 rune |
| Cmd | Name | no argument | Description |
|--------|-----------|-------------|-----------------------------------------------|
| `0x51` | `rclear` | | clear the current UTF-8 rune |
| `0x52` | `rsprite` | | fill the current sprite with the current rune |
At a minimum, these glyphs must exist:
0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ,._:;"'[]{}()-\/|*#@?!☃
Implementations should supply at least a font that works at 8x8 character size.
The snowman is useful for identifying if the protocol can correctly support at least one non-ASCII character.
Use an `ø` if no glyph is available for an UTF-8 rune.
## Keyboard, Joystick and Mouse
For returning the state of the client.
A channel must be set up for receiving the`uint16`values that are returned by these functions.
Commands that return an `uint16`:
| Cmd | Name | no argument | Description |
|--------|----------|--------------|-------------------------------------------------------------------------|
| `0x60` | `kesc` | | is Escape being pressed? |
| `0x61` | `kup` | | is W, up or joystick up pressed? args: 0 for any, 1..4 for Player 1..4 |
| `0x62` | `kleft` | | is A, left or joystick left pressed? args: 0..5 |
| `0x63` | `kdown` | | is S, down or joystick down pressed? args: 0..5 |
| `0x64` | `kright` | | is D, right or joystick right pressed? args: 0..5 |
| `0x65` | `ka` | | is Return, comma (,) or joystick A button pressed? args: 0..5 |
| `0x66` | `kb` | | is Space, dot (.) or joystick B button pressed? args: 0..5 |
* P1 means Player 1, P2 means Player 2.
* Player 1 has WASD keys, lshift, lctrl and/or Joystick 1.
* Player 2 has the arrow keys, comma (,), dot (.) and/or Joystick 2.
* Player 3 has the numpad arrows and/or Joystick 3.
* Player 4 has Joystick 4.
---
| Cmd | Name | **uint8** argument | Description |
|--------|----------|---------------------------------------|------------------------------------|
| `0x67` | `kshift` | 0 for left, 1 for right, 2 for any | returns 1 if Shift is held down |
| `0x68` | `kalt` | 0 for left, 1 for right, 2 for any | returns 1 if Alt is held down |
| `0x69` | `kctrl` | 0 for left, 1 for right, 2 for any | returns 1 if Ctrl is held down |
| `0x6a` | `ksuper` | 0 for left, 1 for right, 2 for any | returns 1 if Super is held down |
---
| Cmd | Name | no argument | Description |
|--------|--------|-------------|------------------------------------------------------------------------------|
| `0x6b` | `kget` | | returns 0 if keybuffer is empty, keycode of first in keybuffer if not empty |
---
| Cmd | Name | no argument | Description |
|--------|--------|-------------|-----------------------------------------------------------------------------------|
| `0x6c` | `mx` | | get mouse x coordinate |
| `0x6d` | `my` | | get mouse y coordinate |
| `0x6e` | `mbtn` | | get mouse buttons, returns: 0 for none, 1 for left, 2 for right and 3 for middle |
---
| Cmd | Name | **uint8** argument | Description |
|--------|--------|--------------------|-------------------------------------------------------------------|
| `0x6f` | `jbtn` | joystick button ID | check if joystick button is pressed, returns 1 for pressed |
### Music
| Cmd | Name | **uint8** argument | Description |
|--------|------------|---------------------|----------------------------------------------------------|
| `0x70` | `t0prog` | MIDI program | select a MIDI program for track 0 (there are 4 tracks) |
| `0x71` | `t1prog` | MIDI program | select a MIDI program for track 1 (there are 4 tracks) |
| `0x72` | `t2prog` | MIDI program | select a MIDI program for track 2 (there are 4 tracks) |
| `0x73` | `t3prog` | MIDI program | select a MIDI program for track 3 (there are 4 tracks) |
| Cmd | Name | **uint8** argument | Description |
|--------|--------------|---------------------|------------------------------------------------------------------------------------------|
| `0x80` | `t0note` | MIDI note | play the MIDI note for track 0 for 20 ms, where note 00 is C3, 01 is D3, 02 is D3 etc (A4 is 432 Hz) |
| `0x81` | `t1note` | MIDI note | play the MIDI note for track 1 for 20 ms, where note 00 is C3, 01 is D3, 02 is D3 etc (A4 is 432 Hz) |
| `0x82` | `t2note` | MIDI note | play the MIDI note for track 1 for 20 ms, where note 00 is C3, 01 is D3, 02 is D3 etc (A4 is 432 Hz) |
| `0x83` | `t3note` | MIDI note | play the MIDI note for track 1 for 20 ms, where note 00 is C3, 01 is D3, 02 is D3 etc (A4 is 432 Hz) |
### Program Control
| Cmd | Name | no argument | Description |
|--------|----------|-------------|---------------------------------|
| `0xff` | `exit` | | end the program, disconnect |
| `0x90` | `esc` | | exit if Escape has been pressed |
### Client Side State
All state values are expected to be zeroed at the start of the program.
| Description | Type |
|-----------------------------------------|-------------------|
| r, g, b, a * 256 palette info | 4 * 256 * uint8 |
| x position for pixel | uint16 |
| y position for pixel | uint16 |
| color index for pixel | uint16 |
| x1 position for line | uint16 |
| y1 position for line | uint16 |
| x2 position for line | uint16 |
| y2 position for line | uint16 |
| c1 color for line start | uint8 |
| c2 color for line end | uint8 |
| x1 position for triangle | uint16 |
| y1 position for triangle | uint16 |
| x2 position for triangle | uint16 |
| y2 position for triangle | uint16 |
| x3 position for triangle | uint16 |
| y3 position for triangle | uint16 |
| c1 color for triangle point 1 | uint8 |
| c2 color for triangle point 2 | uint8 |
| c3 color for triangle point 3 | uint8 |
| convolution filter + division, 10 bytes | 10 * uint8 |
| sprites | 128 * 128 * uint8 |
| current sprite ID | uint8 |
### Implementations
If you implement something using this protocol, please let me know. :)
### General info
* Version: 3.0.0
* Author: Alexander F. Rødseth
* License: CC0
* [GitHub Project](https://github.com/xyproto/pixelprotocol)