Hi guys, I searched the forum but found nothing about this issue. I found that some MD games have graphic problems displaing sprites in certain events, like as the character is damaged. The sprite disappears instead blinking... An example is Castle of Illusion starring Mickey Mouse. My Everdrive is: Fw. v12 OS: v23 anybody detected this issue? Regards!;-)
That sounds like typical sprite hardware restriction, the console can only display a limited number of sprite pixels per line and you get flickering or disappearing sprites under specific conditions. You can verify that by playing with real cartridges, it's the same as with ROMs and happen in many games actually...
it`s a CRT TV and I use a RGB cable (DIN to SCART) Seems the problem.. mmm I`ll try some things.. but it`s strange that only this game present this issue and in this condition..:shrug:
Have you tried Afterburner 2? I experience glitches along the screen and am wondering if you have the same problem?
It's not "strange", it's just that some games are "better" programmed than others, and that the problem only exhibits when too many sprites are programmed on the same line, which is not so common in Mega Drive games (more on Master System which is more restrictive). I doubt you played ALL games from start to end to say it only happens with this game (which one btw ?). It's visible in many games though, for example in the most famous one, Sonic the Hedgehog when running on bridges while being invicible... Those glitches on title screens are normal and happen with the real cart as well. The funny thing is that with emulators, people often reported glitches as emulator "bugs" when they actually happened on real hardware as well and now the same thing occurs for Everdrive . Remember the Everdrive is only a "pass-through" device that simulates a game cartridge, it doesn't affect the way the game is running (except maybe the "cheat" or "megakey" features) and it doesn't run the game itself, the console hardware is. So if you met an issue with a game, it's a problem with the ROM or the console. The only thing that can be affected by Everdrive is when the original game cartridge was using extra hardware which is unsupported.
true! like when Sonic (SMS) is inside the bubble:nod: Interesting: Seem a VDP chip version issue (hw issue): http://forums.sonicretro.org/index.php?showtopic=20020
Again, it's not an hardware bug but a deliberated limit of the sprite processing hardware, it's there in all versions of VDP and is actually used by some games to display things properly (Sonic title screen for example). To be more precise, there is an internal buffer for sprites than can only store 320 pixels and similarly, there is an internal RAM to store sprite informations, with room for only 20 sprites. It's how the hardware was designed and it's all about compromise between features you want to have and memory restrictions for that time ;-) The bug that is described in the post you linked is something different from what you described and nobody has been able to confirm it yet so I put it in the unverified rumor category.
It's not how much memory there was, it's how FAST it was for sprites. Depending on how fast the memory is, you get X number of access slots per line. Once you subtract all the slots needed to fetch the background layers, the rest get divided up amongst the sprites. The reason the MD only handles 20 sprites per line is there is only time to fetch the data for 20 sprites. That's why in 256 wide mode you only get 16 sprites per line - there's fewer access slots, so there's only time to fetch 16 sprites. Faster ram costs more than larger ram, particularly in the 90s. The MD already uses 64KB of VRAM (which is more expensive again compared to regular DRAM), so to pay extra for faster vram would have made it too expensive.
Hey Bertobp! Here you leave the video to test the cool spot, I think the problem must be the HZ of your TV. Greetings! https://picasaweb.google.com/batroxsunrise/Miscelanea#5622997248019860050
