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Writing to the screen from a buffer

Mr MillsideMr Millside
edited July 2009 in Development
I?m designing a game and am spending a bit of time trying different ideas before I commit my self. I?m currently thinking of writing data to a buffer and then writing this ?back buffer? to the screen. Can the whole screen be drawn from the buffer without flicker ? If not, what is the maximum amount of data that can be drawn without flicker ?
Post edited by Mr Millside on
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Comments

  • frobushfrobush
    edited June 2009
    Yes. The screen willl not flicker at all. You will get horizontal 'tears' or 'ripples' though - very noticable if you are not 'free running'.

    Manic Miner copies the top two thirds of the screen from a back buffer if you want to see the ripple effect.

    Oh, and there is a reason why no-one hardly ever does what you are trying to do.

    Can


    You


    Guess


    What


    It


    Is


    ?
  • IvanzxIvanzx
    edited June 2009
    Nice to see you coding again Mr Millside! another Iron Sphere ;) on its way?
    <a href="http://rincondelspectrum.blogspot.de/" target="_blank" rel="nofollow">http://rincondelspectrum.blogspot.de/</a>;
  • DunnyDunny
    edited June 2009
    frobush wrote: »
    Oh, and there is a reason why no-one hardly ever does what you are trying to do.

    Can


    You


    Guess


    What


    It


    Is


    ?

    Wow, that looks helpful, you can have a slow hand-clap. What would you say to double buffering using the 128k shadow screen?

    D.
  • frobushfrobush
    edited June 2009
    Why don't you just fuck off. I'm not in the mood. Sorry.
  • rich_chandlerrich_chandler
    edited June 2009
    frobush wrote: »
    Why don't you just fuck off. I'm not in the mood. Sorry.
    Why would you tell the double buffering screen to fuck off?
    I wanna tell you a story 'bout a woman I know...
  • DunnyDunny
    edited June 2009
    frobush wrote: »
    Why don't you just fuck off. I'm not in the mood. Sorry.

    No apology needed, I was just quite surprised that an obviously talented developer like yourself would talk down to someone as if they were a five year-old.

    D.
  • frobushfrobush
    edited June 2009
    Becauce things are happening here that are winding me up.

    I'm sorry, all.

    No need for my back-lash!
  • MrCheeseMrCheese
    edited June 2009
    I thought he was doing a Rolf Harris impersonation "Can you tell what it is yet?"
  • frobushfrobush
    edited June 2009
    And he never mentioned the extra hardware! (I've calmed down a bit now)

    MM could be so much faster, with more going on, if whomever didn't piss around with the SLOW!
  • DunnyDunny
    edited June 2009
    frobush wrote: »
    Becauce things are happening here that are winding me up.

    I'm sorry, all.

    No need for my back-lash!

    Forgiven, forgotten.

    So, quickest method of copying a screen, then? <hides>

    D.
  • frobushfrobush
    edited June 2009
    MrCheese wrote: »
    I thought he was doing a Rolf Harris impersonation "Can you tell what it is yet?"

    It's usually a member of the Royal Family. He said he was going to be bigger than 'The Beatles', you know!
  • MrCheeseMrCheese
    edited June 2009
    I guess you are referring to the hot LDIR action to draw the screen?
  • rich_chandlerrich_chandler
    edited June 2009
    Naah, use the stack.
    I wanna tell you a story 'bout a woman I know...
  • frobushfrobush
    edited June 2009
    Dunny wrote: »
    Forgiven, forgotten.

    So, quickest method of copying a screen, then? <hides>

    D.

    Quickest? Don't.

    Try another method.
  • frobushfrobush
    edited June 2009
    MrCheese wrote: »
    I guess you are referring to the hot LDIR action to draw the screen?

    Well, you could unroll the LDIR and have a mass of LDIs.

    It depends what you want to do.

    If the whole screen is animating and there are a million sprites everywhere, then no. Just don't do it.
  • MrCheeseMrCheese
    edited June 2009
    Yes I know, Manic Miner uses LDIR, which I presumed you were talking about. A rewrite of that would speed it all up or save time for more sprite action.
  • frobushfrobush
    edited June 2009
    It just seems a waste of time, (although MM it is great), to delete sprites and then print sprites to a background screen, and then copy the background screen to the main screen.

    Much faster to just use the main screen and find a way to stop flickers. Which is easy.
  • frobushfrobush
    edited June 2009
    Anyways. I don't know what it is you are trying to do and for what reason. So what do I know? Ask Dunny! He's a big girl's blouse! <smilie icon thing here>
  • Mr MillsideMr Millside
    edited June 2009
    I'm doing a bit of brain storming with different ideas for a game I'm planning. My normal approach is to just start and see where it goes. Having done this several times and found this to be bad practice I've decided to plan the game this time. It's hard to describe what I'm trying to do as nothing is cast in stone yet. What I do know is that it will be similar to "Hall of the things". A key element of the game is that the bad guys will roam around the maze on fixed paths rather than all the action happening on the current screen. I guess its a similar idea to the balls in a game called Gyron. Anyway I don't want to give too much away and no I'm not obsessed with games with balls :). My code needs to update where everything is but only needs to draw the balls when they appear in the screen the player is currently in. This is a flip screen game not a scroller. I had the idea of using a backbuffer as it seemed (in the bath) like an easier way to display the screen. It won't be a full screen game so that is why I asked what the limit is for a backbuffer on a 48k spectrum which can be splatted on the screen before flicker / ripping became a problem.
  • Mr MillsideMr Millside
    edited June 2009
    Ivanzx wrote: »
    Nice to see you coding again Mr Millside! another Iron Sphere ;) on its way?

    It's that time of year where the day job is getting on my tits so I need to leave the world of .net behind and grapple with Z80. If this game gets finished it will be the sequal to Iron Sphere. More fun and easier :)
  • frobushfrobush
    edited June 2009
    Well, my advice, for what it is worth, is to do away with the back buffer and copy.

    Find another way.

    It IS more of a pain to 'just' use the display screen, but much faster, and gives you the extra processor time to fart about. You work it out. Doing all the sprite stuff AND lugging around a 6k(?) back screen to boot, or just doing the sprite stuff and whistling!
  • FikeeFikee
    edited July 2009
    Mr Millside wrote: »
    I?m designing a game and am spending a bit of time trying different ideas before I commit my self. I?m currently thinking of writing data to a buffer and then writing this ?back buffer? to the screen. Can the whole screen be drawn from the buffer without flicker ? If not, what is the maximum amount of data that can be drawn without flicker ?

    http://www.worldofspectrum.org/forums/showthread.php?t=24788&page=2
  • chevchev
    edited July 2009
    frobush wrote: »
    Doing all the sprite stuff AND lugging around a 6k(?) back screen to boot, or just doing the sprite stuff and whistling!

    Could be worse. I've got a 12K screen to deal with. Fortunately the thing I'm working on is tile based. I wasn't planning on using a back buffer.
    zx.itch.io
  • frobushfrobush
    edited July 2009
    cheveron wrote: »
    Could be worse. I've got a 12K screen to deal with. Fortunately the thing I'm working on is tile based. I wasn't planning on using a back buffer.

    Look at "Mikie". It has the most horendous back-buffering thing ever coded! A nightmare! And it looks so simple! D'oh! There's a bit map and a character map and bit - bit collision map and a priority map, all twisted and turned! The sprite routine is about 20k long!

    OH! Never again!

    And for what?
  • torottorot
    edited July 2009
    frobush wrote: »
    And for what?

    a crash smash?
  • GrazGraz
    edited July 2009
    torot wrote: »
    a crash smash?

    One of my all-time-faves!
  • frobushfrobush
    edited July 2009
    torot wrote: »
    a crash smash?

    Oh yeah, I forgot about that. And the weeky wage. And all the amazing people you meet. And the places you go.

    HOORAY FOR MIKIE! It is now GREAT!
  • ZnorXmanZnorXman
    edited July 2009
    frobush wrote: »
    HOORAY FOR MIKIE! It is now GREAT!

    Had to load it up and listen to the tune.

    Thanks for the mammaries ... errr ... memories Mr. Bush, F.
  • frobushfrobush
    edited July 2009
    ZnorXman wrote: »
    Had to load it up and listen to the tune.

    Thanks for the mammaries ... errr ... memories Mr. Bush, F.

    That's down to C64 musician Martin Galway. He's bigger than 'The Beatles' you know, and wanted royalties, for doing a shit tune, off of Saucer!

    Mate or no-mate! Fuck off!
  • rich_chandlerrich_chandler
    edited July 2009
    frobush wrote: »
    That's down to C64 musician Martin Galway. He's bigger than 'The Beatles' you know, and wanted royalties, for doing a shit tune, off of Saucer!

    Mate or no-mate! Fuck off!
    His Dad is bigger...
    I wanna tell you a story 'bout a woman I know...
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