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sony trinitron + color emphasis bits = scrambled image?
Posted: Thu Feb 16, 2012 10:25 am
by GradualGames
Recently I decided to dim the screen when you hit "pause," in Nomolos. I used all three color emphasis bits. Works great in emulators, looks fine on a little 13 inch TV I have, but on my Sony Trinitron, it causes an extremely ugly bunch of scanline artifacts. I tried mucking with the settings on the TV, to no avail. Has anyone else seen this sort of thing on a crt tv, in a game that uses color emphasis?
I decided to use the monochrome bit instead for the pause screen, but it would have been slick to dim the screen with color emphasis.
Posted: Thu Feb 16, 2012 11:52 am
by tepples
Then perhaps the warning in some older documents against using more than one emphasis bit wasn't full of crap. RGB units (Famicom Titler, PlayChoice, some TVs with a built-in Famicom) don't take very well to multiple emphasis bits turned on either.
What you can do to simulate the old effect is dim all elements of the palette by subtracting $10.
Posted: Thu Feb 16, 2012 12:14 pm
by Dwedit
I have an ancient Trinitron that's older than I am, and Battle Kid's pause effect works fine.
Posted: Thu Feb 16, 2012 12:16 pm
by MottZilla
Don't some other games do this? I have a Sony Trinitron too and never saw anything like this.
Posted: Thu Feb 16, 2012 12:24 pm
by lidnariq
If all preemphasis bits are set, then color 1D ("black") becomes blacker-than-black and 01-0C no longer decode to a valid RGB color from the received YIQ values (Their brightness is approximately equal to unattenuated color 1D). So if it looks like scanlines restarting all over the place, maybe that's why?
Posted: Thu Feb 16, 2012 1:18 pm
by Bregalad
The game Just Breed have all the emphasis bits set (most of the time, I think sometimes during lightning effects the game might briefly clear them).
Noah's Ark it like that too if I remember.
Posted: Thu Feb 16, 2012 3:37 pm
by bunnyboy
Many clones also do not support the emphasis bits, if that is something you care about.
Posted: Thu Feb 16, 2012 3:44 pm
by 3gengames
Using the emphasis bits is the lazy mans way of dimming the screen IMO. Plus, good luck porting your game to any RGB NES arcade system. (Which I want to do one day, sue me.)
Posted: Thu Feb 16, 2012 4:04 pm
by Memblers
If it's not much trouble, maybe you could post the palette values you're using when that happens. But I guess it's specific to your TV, or some certain TV types.
I believe Super Spy Hunter sets all emphasis bits when you pause it. Munchie Attack does it when you lose all your lives (and yeah it didn't look too hot on the Playchoice, everything goes grey).
Posted: Thu Feb 16, 2012 5:57 pm
by tokumaru
bunnyboy wrote:Many clones also do not support the emphasis bits, if that is something you care about.
Really? I didn't know about that. I guess I'll have to test my clones!
Posted: Thu Feb 16, 2012 7:52 pm
by sdwave
Yep, I see some bending myself in one of the palette demos (pal test) on my Trinitron.
Try using $3f for black instead of $0d if possible and see if it helps any.
Posted: Thu Feb 16, 2012 9:08 pm
by bunnyboy
tokumaru wrote:bunnyboy wrote:Many clones also do not support the emphasis bits, if that is something you care about.
Really? I didn't know about that. I guess I'll have to test my clones!
I noticed it in one of Sivaks early games, so it was probably one of Yobo/NEX/RetroDuo. The 3 system clones weren't out yet.
Posted: Thu Feb 16, 2012 11:58 pm
by Jeroen
They don't support it in what way? Simply not working or don't give expected behavior?
Re: sony trinitron + color emphasis bits = scrambled image?
Posted: Fri Feb 17, 2012 6:49 am
by thefox
Gradualore wrote:I decided to use the monochrome bit instead for the pause screen, but it would have been slick to dim the screen with color emphasis.
Why not dim it by rewriting the palette instead?
Posted: Fri Feb 17, 2012 6:51 am
by thefox
3gengames wrote:Plus, good luck porting your game to any RGB NES arcade system. (Which I want to do one day, sue me.)
Screen turning white when pausing the game hardly is game breaking behavior. Of course if the emphasis bits are used for other purposes (like keeping the palette dimmed all the time, like in Jungle Book, James Bond Jr and Felix the Cat), it's an entirely different deal.