03117: harddriv and clones: On elevation changes, there is a seam in the ground

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
03117	Graphics	Minor	Always	Apr 22, 2009, 19:12	Feb 18, 2022, 08:41

Tester	Luigi30	View Status	Public	Platform	MAME (Self-compiled)
Assigned To		Resolution	Bugs That Aren't Bugs	OS	Windows XP/Vista 32-bit
Status [?]	Resolved			Driver	atari/harddriv.cpp
Version	0.130u4	Fixed in Version		Build	Normal
		Fixed in Git Commit		Github Pull Request #

Summary	03117: harddriv and clones: On elevation changes, there is a seam in the ground
Description	When going up an incline such as a hill or a ramp, there will be a seam in the polygon road when the road goes flat again.
Steps To Reproduce	Go down the straight route to see it on the first few hills.
Additional Information
Github Commit

Flags
Regression Version
Affected Sets / Systems	harddriv and clones

Attached Files	0000.png (14,100 bytes) Apr 22, 2009, 19:12

No.04240 Tafoid Administrator Apr 22, 2009, 20:43	This behavior is present even back in 0.77 - as far back as I can test it with the current romset. Do I think it's an emulation bug? I'd like to see some PCB proof that these little glitches didn't happen in the original hardware. Confirming, but setting as possible. It would be nice if Aaron could chime in since the driver and most parts used in it are entirely of his design.
No.04241 Haze Senior Tester Apr 22, 2009, 23:11	there is a gap in the car too, surprised that wasn't pointed out as well... I seem to remember the game being a little rough around the edges, so it wouldn't surprise me if these were actual game bugs. I agree tho, would need checking on a PCB.
No.04248 aaron Developer Apr 23, 2009, 05:32 edited on: May 31, 2012, 05:31	Not a bug. You can see the gap in the road pretty clearly in this video: There are many gaps in the game. It's just the way it is.
No.19794 CYBERYOGI -CO-Windler Viewer Feb 18, 2022, 08:41 edited on: Feb 18, 2022, 08:56	- graphic glitches (flowers in the sky) In "Race Drivin" on the "Original Track" driving down the trough, sometimes shows flowers floating in the sky. This does not happen in "Hard Drivin". Is this a Slapstick bug? In "Hard Drivin" cockpit there are small rocks (milestones?) on the orange sides of the road. But in all other game variants (upright, "Race Drivin" etc.) there are none. Is this authentic game behaviour? (The rock looks flat when seen from the side and seems to be the only pixel graphics sprite in the entire game, so it was likely a leftover from early graphics engine experiments with textures.) Generally these games have many graphics glitches. Particularly polygon priority bugs also exist on the arcade machine (and home versions). But occasionally the road and other objects look "bent" when driven onto from an unexpected angle. Is this a game bug or do helper chips in MAME run out of sync (like suggested by the save state bug)? I suspect that because the coordinate system of the players view has low bit resolution (16 bit?), all graphics objects are drawn into the viewfield of the car (instead of a car driving through a static world), i.e. mathematically the world and not the car is moving, which causes numerical bugs when the world gets stitched together while the player is turning or changing speed (particularly when driving in strange angles onto a road, passing road segments in wrong order), which may have to do with the multi-processor arcade hardware getting out of sync. By very slowly approaching e.g. mountains in the "Super Stunt Track", the mountain becomes invisible and you see through it. Driving far offroad on the brown hill makes your car even drive through the sky (like on a glass floor extending the road) until the offroad timer puts you back onto road. By skipping large parts of the curved road keeps the "offroad" message on (until the timer puts you back) and the road looks folded like patched together from graphics segments. When at the start of the "Speed Track" you turn left 90°, you can drive on the drift training track (a round track around a column, missing in most home versions) which is a well known feature. Do you remember the movie "Ready Player One"!? When at start of the race I instead make a full 180° U-turn, I can drive the whole track wrongways without getting stopped (AFAIK home versions showed the 10s timer like driving offroad), but here you can really dive deeply down the rabbit hole. So the train is visible through the right of the orange bridge side and you can drive trough that orange wall to it. If you slowly approach the locomotive front until you touch it (happens with some other objects like building walls too), the car positions suddenly teleports back onto a nearby road segment. (This may have been an emergency measure to prevent getting stuck in props. Bumping objects slow enough to not destroy your car may do strange things.) When you drive wrongways and take the road fork to the left, you enter the Stunt Track, which has some drawing bugs in the road pavement of bridges and such. Also the tail of the truck looks somewhat incomplete when you see it from the wrong side. If you drive over the terrain from Speed Track to Stunt Track or vice versa (which is likely recognized as cheating), the message "wrongways" does not disappear and so after a while you are put back on the road segment you came from. - car crash into invisible object In these games when on the "race track" the car crashes somewhere near the grey drawbridge, after the usual "instant replay" the car is dropped back onto the 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 1m 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. I am not sure if this is a MAME bug or game bug or even nasty little prank played by a poorly simulated Slapstick chip. The car also can fall through the road in various other spots when slightly offroad. E.g. on the original track when after the U-turn your car slowly drives down the talus at the right road side (a bit like a bicycle jamming its wheel in a tram rail?), it plummets down a timehole and keeps spinning and tumbling in the sky with graphics mess for about 30s(?) while gaining >30k points(!). This may be a cheat but is likely just a pug. The car finally will explode and is put back on the road. The score apparently counts the time your car is in the air during stunts, and goes nuts when it is no regular jump. (Logically it should only count after your car lands intact and not earn points for crashes.) Are these original game bugs or related to MAME?