76dca483e9
Displacing the swapped-out particle by the difference between the integer positions (derived from the float position via rounding) of the particles would sometimes cause the floats in Particle to switch to a lower precision range, and this would overflow them such that the integer position would change by an amount different from what was intended (exactly the difference between the integer positions of the particles). Such switches between precision ranges can only happen when a sufficiently big positive number is added to a positive float near the positive end of its current precision range. Swapping displacements are usually small, so this problem mostly manifested near the positive end of precision ranges, that is, near powers of 2. Informally, for illustrative purposes, consider the float position (either x or y, doesn't matter) 511.49995, fairly close to the positive end of the precision range [256, 512), and the swap displacement +1: these yield the position 512.49995. Assume that this is not be representable, and that the two nearest representable values are 512.4998 and 512.5. 512.49995 is closer to 512.5, so that's what it gets rounded to. But oops, 511 = round(511.49995) + 1 != round(512.5) = 513, so we're now overwriting the wrong pmap entry. Reproduce with sim.paused(true) sim.clearSim() local brmt = sim.partCreate(-1, 128, 100, elem.DEFAULT_PT_BRMT) local dust = sim.partCreate(-1, 127, 101, elem.DEFAULT_PT_DUST) sim.createBox(125, 98, 130, 103, elem.DEFAULT_PT_DMND) sim.partProperty(dust, "x", 127.49999) sim.frameRender(2) The BRMT and the DUST should swap places; instead, without the fix, the DUST gets stacked under a DMND. This commit fixes this problem by moving the swapped-out particle exactly where the moving particle is.
The Powder Toy - April 2024
Get the latest version from the Powder Toy website.
To use online features such as saving, you need to register an account. You can also visit the official TPT forum.
Have you ever wanted to blow something up? Or maybe you always dreamt of operating an atomic power plant? Do you have a will to develop your own CPU? The Powder Toy lets you to do all of these, and even more!
The Powder Toy is a free physics sandbox game, which simulates air pressure and velocity, heat, gravity and a countless number of interactions between different substances! The game provides you with various building materials, liquids, gases and electronic components which can be used to construct complex machines, guns, bombs, realistic terrains and almost anything else. You can then mine them and watch cool explosions, add intricate wirings, play with little stickmen or operate your machine. You can browse and play thousands of different saves made by the community or upload your own – we welcome your creations!
There is a Lua API – you can automate your work or even make plugins for the game. The Powder Toy is free and the source code is distributed under the GNU General Public License, so you can modify the game yourself or help with development.
Build instructions
See the Powder Toy Development Help section on the main page of the wiki.
Thanks
- Stanislaw K Skowronek - Designed the original
- Simon Robertshaw
- Skresanov Savely
- cracker64
- Catelite
- Victoria Hoyle
- Nathan Cousins
- jacksonmj
- Felix Wallin
- Lieuwe Mosch
- Anthony Boot
- Me4502
- MaksProg
- jacob1
- mniip
- LBPHacker
Libraries and other assets used
Instructions
Click on the elements with the mouse and draw in the field, like in MS Paint. The rest of the game is learning what happens next.
Controls
| Key | Action |
|---|---|
| TAB | Switch between circle/square/triangle brush |
| Space | Pause |
| Q / Esc | Quit |
| Z | Zoom |
| S | Save stamp (use with Ctrl when STK2 is out) |
| L | Load last saved stamp |
| K | Stamp library |
| 0-9 | Set view mode |
| P / F2 | Save screenshot as .png |
| E | Bring up element search |
| F | Pause and step to next frame |
| G | Increase grid size |
| Shift + G | Decrease grid size |
| H | Show/Hide HUD |
| Ctrl + H / F1 | Show intro text |
| D / F3 | Debug mode (use with Ctrl when STK2 is out) |
| I | Invert Pressure and Velocity map |
| W | Cycle gravity modes (use with Ctrl when STK2 is out) |
| Y | Cycle air modes |
| Ctrl + E | Cycle edge modes |
| B | Enter decoration editor menu |
| Ctrl + B | Toggle decorations on/off |
| N | Toggle Newtonian Gravity on/off |
| U | Toggle ambient heat on/off |
| Ctrl + I | Install powder toy, for loading saves/stamps by double clicking |
| Backtick | Toggle console |
| = | Reset pressure and velocity map |
| Ctrl + = | Reset Electricity |
| [ | Decrease brush size |
| ] | Increase brush size |
| Alt + [ | Decrease brush size by 1 |
| Alt + ] | Increase brush size by 1 |
| Ctrl + C/V/X | Copy/Paste/Cut |
| Ctrl + Z | Undo |
| Ctrl + Y | Redo |
| Ctrl + Cursor drag | Rectangle |
| Shift + Cursor drag | Line |
| Middle click | Sample element |
| Alt + Left click | Sample element |
| Mouse scroll | Change brush size |
| Ctrl + Mouse scroll | Change vertical brush size |
| Shift + Mouse scroll | Change horizontal brush size |
| Shift + R | Horizontal mirror for selected area when pasting stamps |
| Ctrl + Shift + R | Vertical mirror for selected area when pasting stamps |
| R | Rotate selected area counterclockwise when pasting stamps |
| F11 | Toggle fullscreen |
Command Line
| Command | Description | Example |
|---|---|---|
scale:SIZE |
Change window scale factor | scale:2 |
kiosk |
Fullscreen mode | |
proxy:SERVER[:PORT] |
Proxy server to use | proxy:wwwcache.lancs.ac.uk:8080 |
open FILE |
Opens the file as a stamp or game save | |
ddir DIRECTORY |
Directory used for saving stamps and preferences | |
ptsave:SAVEID |
Open online save, used by ptsave: URLs | ptsave:2198 |
disable-network |
Disables internet connections | |
disable-bluescreen |
Disable bluescreen handler | |
redirect |
Redirects output to stdout.txt / stderr.txt | |
cafile:CAFILE |
Set certificate bundle path | cafile:/etc/ssl/certs/ca-certificates.crt |
capath:CAPATH |
Set certificate directory path | capath:/etc/ssl/certs |