Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!uwm.edu!ogicse!pdxgate!eecs!bairds From: bairds@eecs.cs.pdx.edu (Shawn L. Baird) Newsgroups: comp.sys.amiga.programmer Subject: Re: Lemmings - a tutorial Part V (last) Message-ID: <2162@pdxgate.UUCP> Date: 31 Mar 91 23:17:07 GMT References: <23788@well.sf.ca.us> <23837@well.sf.ca.us> <781@tnc.UUCP> <2149@pdxgate.UUCP> <91089.200133DXB132@psuvm.psu.edu> Sender: news@pdxgate.UUCP Lines: 49 DXB132@psuvm.psu.edu writes: >In article <2149@pdxgate.UUCP>, bairds@eecs.cs.pdx.edu (Shawn L. Baird) says: >That example doesn't help your point. CED uses blitting which is many many >times slower than using the copper to aid scrolling. But it has no choice >in order to remain Intuition compatible. The point was fast blitting. It is rather unreasonable for an editor such as CED to waste its memory holding a bitmap version of the text. Also, CED doesn't scroll an entire viewport at once. Otherwise the scrollbar at the left would be a bad placement. If you want to see an example of what should have used a custom copper and the bitmap scrolling abilities of the hardware (for that matter, it didn't really need smooth scrolling even) take a look at SimCity. All I am saying is that any performance needs can be met by simply taking the machine over while still under the operating system. It is only performance accompanied with the need to run in 512k and on an 880k disk that prevents game makers from doing so. What is this about having no choice and not being able to use the copper to aid scrolling? It is perfectly legal to do whatever the hell you want with your copper list once you've grabbed your custom screen. Take off menus by ignoring the right mouse button and not having one present and you don't have to worry about Intuition coming along and messing up the contents of your screen. Nothing else should be attempting to put windows up on it unless it's either public via the screenshare.library or via 2.0's public screen functions (which I really don't know much about). The point is that a lot of games could do this to increase performance in a multi-tasking environments. These are games that usually don't need as much performance as games that usually take over the OS. Still, you can get all the speed you need, even under an Intuition screen. Just pop a call to Disable() and start doing everything yourself. I can even imagine writing a demo that shows people this could be done. Something that looks like CED without a scrollbar which uses a second viewport to display the data. Then the user just holds down the left mouse button and moves up or down to scroll or something. Should be plenty fast. In fact, I bet I can guarantee 60 frames/sec with multi-tasking. (True, I wouldn't be doing very much.) Turn off multi-tasking at this point and I can guarantee 60 frames/sec with just about any normal game activity going on where the game itself would run at 60 frames/sec as well. >-- Dan Babcock --- Shawn L. Baird, bairds@eecs.ee.pdx.edu, Wraith on DikuMUD The above message is not licensed by AT&T, or at least, not yet.