08228: harddriv: Car keeps crashing into invisible object

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
08228	Gameplay	Minor	Sometimes	Feb 22, 2022, 06:59	Feb 23, 2022, 07:39

Tester	CYBERYOGI -CO-Windler	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows 10/11 (64-bit)
Status [?]	Acknowledged			Driver	atari/harddriv.cpp
Version	0.240	Fixed in Version		Build	64-bit
		Fixed in Git Commit		Github Pull Request #

Summary	08228: harddriv: Car keeps crashing into invisible object
Description	When in "Hard Drivin" on the Speed Track the player crashes into the blue compact car somewhere before the drawbridge, after the usual "instant replay" the car is dropped back onto road (falling 1m out of the sky?) at a certain spot with the drawbridge in sight. But if I push the gas pedal (rolling about 30cm in any direction) the car keeps crashing into an invisible barrier (windshield shatters), is dropped back on the very same spot and so on; crashing from there again and again until time runs out. The difference from many other invisible obstacles (those may have been intentional to prevent cheating by detours) is that this one makes the game basically impossible to finish, although sometimes the crash loop can be exited by very carefully steering the car sideways. I am not sure if this is a MAME bug at all or game bug. I mention this because it may be a nasty little prank played by a poorly emulated Slapstick chip. The symptom does not happen in "Race Drivin" (which has a different physics simulation engine).
Steps To Reproduce	See screenshots for the location on the Speed Track. While the blue car screenshot was taken separatedly (crash scene omitted), the others happen in the depicted order (see game timer). The pictures 2, 3 and 4 show the car plummet out of the sky. In picture 4 the car has driven few cm and the windshield shatters, so the "instant replay" will appear (picture 5, no collided obstacle seen) and the same happens over and over again until time runs out.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	harddriv

Attached Files	HardDrivin_plummetCrashLoop1.png (16,999 bytes) Feb 22, 2022, 06:59 Uploaded by CYBERYOGI -CO-Windler
	HardDrivin_plummetCrashLoop2.png (17,565 bytes) Feb 22, 2022, 06:59 Uploaded by CYBERYOGI -CO-Windler
	HardDrivin_plummetCrashLoop3.png (16,637 bytes) Feb 22, 2022, 06:59 Uploaded by CYBERYOGI -CO-Windler
	HardDrivin_plummetCrashLoop4.png (16,866 bytes) Feb 22, 2022, 07:00 Uploaded by CYBERYOGI -CO-Windler
	HardDrivin_plummetCrashLoop5.png (18,941 bytes) Feb 22, 2022, 07:00 Uploaded by CYBERYOGI -CO-Windler
	HardDrivin_plummetCrashLoop6.png (13,901 bytes) Feb 22, 2022, 07:00 Uploaded by CYBERYOGI -CO-Windler

No.19832 Haze Senior Tester Feb 22, 2022, 10:12	this reminds me of the 'fall through floor' glitch I had near the barn, where I could repeat the same glitch each and every time I respawned.
No.19833 Haze Senior Tester Feb 22, 2022, 10:21 edited on: Feb 22, 2022, 10:24	what would be most useful to know with this is if there's a version of MAME where it doesn't happen. the thing is the original Hard drivin' Does NOT have a Slapstic, so it can't be a Slapstic bug, it would have to be something else, maybe a DSP maths error.
No.19837 CYBERYOGI -CO-Windler Viewer Feb 23, 2022, 06:49 edited on: Feb 23, 2022, 06:51	I only tried to repeat the crash loop on 0.240. It was hard to remember how I got there first time long ago, but driving normal and then crashing that blue car seems to work. The "fall through floor" bug happens in many places, particularly when driving very slowly while steering at sharp angles. E.g. when at start position you make a 90° turn to the left to drive to the drift track/skid pad (the hidden parking lot with column in the middle - also depicted on the map), it can easily happen that on the threshold at the road rim you plummet through the pavement and earn several 10k points in mid air before you finally crash. (I also had this on Speed Track in front of the drawbridge, on top of bridges and so on.) Driving too slow while touching obstacles (buildings, mountains, train) often makes funny things. At start you can even do a 180° turn and drive the whole track wrongways, which causes plenty of strange glitches. But the checkpoints only add time when passed in correct order and direction (not wrongways) and you apparently need to touch certain start segments of road sections in correct order to make the game 1.) make checkpoints work and 2.) load the road props and physical collision model correctly. If driving too far offroad, the offroad timer will not disappear when getting on the road again (likely by design to prevent detour cheating). I tend to play Hard Drivin/Race Drivin more with the mindedness of a skateboarder than a car race driver (ignoring all game rules). E.g. a few times I managed to drive from the Speed Track onto the very end of the drawbridge, which occasionally disables the offroad timer, so I can drive around on the drawbridge (which now lacks black pavement) and drive onto Stunt Track or back towards start. Only the checkpoint will not add time and a car crash beams you back before the drawbridge. But this is likely all game glitches and not MAME bugs. The crash loop bug is different/more severe because it happens during a normal car race situation (crashing the blue car) and prevents the game from continuing normal. I can't imagine that Atari didn't test this on the arcade machine, so I think it was by MAME.