Surpriseee! Long time no see.

I have been busy with other things in life and other projects in the past 2 years that I've taken a break from Shakedown Rally. But happy to be back!

Lets get to the business and let me show you this massive update:

Welcome Tsubasa

Hello to the first new car in Shakedown Rally! It's an early 90s group A Japanese rally car, inspired by a few famous models, hope you can guess which!

I hope it will become the main star of the game, and I can push the spec17 beside a bit (but love you still <3).

Note that for now, it's only available in the full game.

Launcher

Now you can select cars and maps using a Launcher!

Remember having to use command line arguments and .bat files? Yeah, they're now long gone! Since adding new cars and maps means that I would need to add a combinatorial explosion of .bat files for launching each combo, and since making switching of cars and maps in-game would take more time to implement (eventually I want to do that), an external launcher was the perfect intermediate solution. It's a separate exe, it has been available on github for a while, but now it comes with the game.

It's super simple, starts with no delay, written in Zig, and it's actually open source and code is available here: https://github.com/nothke/shakedown-rally-launcher. And thanks to it being open source, pikqi added keyboard navigation to it.

Complete rewrite of the drivetrain physics

I have finally finished the long awaited realistic drivetrain refactoring, two years in the making! No, I'm joking it maybe took a month to do in total. This has been the biggest under the hood change in Shakedown since the beginning.

Back before this update, everything relating to the engine, clutch and tires has been completely hacked in and eyeballed. Feedback forces were completely wrong, and it was really hard to tweak it to realistic or just even stable values. For example when editing tire parameters, the cars would either stick to the ground with extreme grip, or slide with no traction. Another huge issue was instability which made me have to increase inertias of the engine and wheels to unrealistic levels. This would especially be noticeable if you crash into a tree and your wheels keep on spinning like they were made of uranium. And even if they do stop, there was a high chance they would reverse spinning in the other direction, and if you were stuck in an alleyway, you would be bouncing from wall to wall in unpredictable manner. The high inertias were simply a hack to make the game work at all.

Now, not only everything uses realistic values, but the stability issues have been fixed!

Engine and driveline torques, power, gear ratios, inertias of driven elements are now pretty realistic, and you can type in appropriate values from spec sheets and get pretty predicable results when driving in a straight line. Note that this game is still not a simulation and it's just an arcade, but being able to use realistic, predictable values is nice.

However, because the change has been so massive, I've also used this chance to change up car.ini parameters. This means that unfortunately all old mods are incompatible with the new version of Shakedown. Modders will have to update them. Spec17 also now handles a lot differently and is actually lot more powerful than before, especially at how it accelerates at low speed. So, time to set some new records!

I am really satisfied with the result, although I have to say I used to like the old transmission wobble a lot more, I will keep on improving it.

Expect more handling changes in following updates. I will be adding more advanced suspension, implementing the traction circle and proper tire-surface relationships. Spec17 is also very very fast now, but it has no downforce at all, I will have to add it too.

Particles and windows sorting

Even though this section is not that important to the drivers, I just wanted to share this technical tidbit with you.

Before this update, when viewing cars from the outside, you could have noticed that your car's windows would completely disappear when looking at the car when there's a lot of particles around. This is because both particles and windows are rendered with blended transparency, and they need to be sorted explicitly. Usually, you either render the particles first, and then windows, or windows first and then particles. It's an age old problem of computer graphics.

Old: You can notice in this image from the previous version that the names on the side window, and the windshield sun strip have disappeared completely, because particles are behind:

So in the update, I solved this by sorting the particles, determining where the car is relative to the particles, and then splitting all the particle billboards into two buckets, one that renders before, and one after the windows. This perfectly solves my problem!

On the left you can see the debug view that colors particles by those two buckets, and on the right you can see the result.

New: As you can see you can now have particles in front or behind, no problem!

Now of course this isn't scalable if you have many objects and cars, you'd need a different sorting method, but for my game which only features one car, it's good enough!

This sort of stuff would be difficult to do without a custom engine that usually has particle systems simulation and rendering bundled up in some impenetrable class.

Dithering

You may have noticed already, another cool novelty in the new update is dithering post-processing effect. This prevents obvious color banding with a limited palette while keeping the aesthetics old fashioned and cool. It has been originally made by Bumbadida on Discord. Thank you so much for the idea!

Here it is with even less colors in dusk:

Sound Reverb and Occlusion

Go back to the top and play that video again and turn up the speakers.

As you can hear, there's reverb now! It's not that good, as it's provided by soloud's standard implementation, but it's light, and honestly for a retro game like this it's more than enough! Aaand there's sound occlusion too! When the car is behind solid surfaces, its sound will get muffled.

I am yet to add config parameters so that the reverb can be edited.

More modding tools

I've also slightly improved the Dev GUI, included are torque and power curve plots and gear ratios to torque. Remember that you can edit all those values live in-game, to easily tweak your mods! And reminder that the Dev GUI can be activated using backtick (`).

Other smaller requested features

I've also implemented a few highly requested features and fixes!

Cars will now by default automatically reverse when you stop and hold brakes. I always thought of this as a "skill issue" thing, but since it was so much requested, and I agree that default location of shift-up and down keys was not intuitive, so I had to add it. You can of course turn it off in config.

Big trail particles are now pushed down from the camera when in chase (3rd person) camera mode. Many people complained that the dust being kicked in your face is extremely annoying, and I agree on that one. Additionally, you can completely turn off trail particles but leave the small wheel-kick particles in the menu, if you prefer that.

Each separate element of the HUD can now be turned on and off, some people just don't want to see the splits and times to be able to focus on driving.

Additionally, I've added HUD scaling option to the in-game menu. 4k screen drivers rejoice!

Note that I have NOT updated the Demo in this update. So the whole devlog refers to the paid version.

Full changelog:

- New car: Tsubasa - an early 90s group A Japanese rally car
- Launcher (car and map selector) now bundled with the game. No more .bat files!
- Drivetrain rewrite
  - Now uses realistic values for engine and drivetrain inertias, speeds and torques, tire grips, clutch impulses, etc.
  - Tire grip now depends on vertical compression
  - Throttle-cutting RPM limiter
  - Fixed instability issues
  - spec17 now uses more realistic values, making it a lot more powerful in low speeds, and can now reach very high speeds
- Added auto-reversing when stationary in 1st gear and holding brakes
- Windows no longer disappear behind particles, particles and windows now sort correctly
- Added dithering to postprocess. Reduces banding while adding A E S T H E T I C S
- Overhauled chase camera, will not jitter wildly with sudden frame drops any more, but behaves sligthly differently
- Audio overhaul:
  - Added reverb, especially noticed in the replays when car is in the distance
  - Added occlusion and distance low pass filter
  - Fixed audio glitch where gear shift sounds would be heard loudly for a split second no matter how far the camera is
  - Collision sounds now attenuate with distance
- Car configs have completely changed, now use segments. See spec17.car.ini for details
- Gear ratios can now be set in the dev GUI
- Number of gears can now be limited, up to 10 forward gears are available
- Automatic gearbox downshift and upshift values can now be set
- Main menu options now save to the main config on change
- Fixed issue where exiting the main menu would not reset it
- Trail particles are now pushed away from the camera when in chase camera mode, improving visibility
- Dust trail particles can now be toggled separate from tire-kick particles
- Added HUD scaling to the menu
- Each element of the HUD can now be toggled
- Fixed lights shader issue for some (mostly Intel integrated) GPUs
- Split `spec17_gravel.car.ini` into `spec17_kenya` and `spec17_finland`. Finland setup needs stiffer suspension to cope with jumps, while Kenya requires softer to remain stable on small bumps
- Added Dev GUI plot windows for speed-gear-torque and engine torque and power map
- Minor optimizations