From: Joey Jojo Shabadoo Newsgroups: comp.os.msdos.djgpp Subject: Screen Offset register + Gravity Force Date: Wed, 10 Dec 1997 04:24:47 +0000 Organization: Bacardi Ferrari V12 Lines: 33 Message-ID: <348E198F.4CAE@manc.u-net.com> NNTP-Posting-Host: 193.119.189.51 Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Precedence: bulk Hello fellow coders! Anyone remember Gravity Force on the Amiga? Well I sure do and I'm trying to write a PC version, but seeing as how this is early days of serious coding for me I've run into a few hurdles, ie smooth scrolling. I've sussed waiting for the vertical blank in machine code (kind of!) but have probs with screen offsets and pages/double buffering etc. I know the screen is at 0xA0000 but what PORT is the x/y offset for a particular page? (I know 0x13 -> 0x3D4, 0x3D5 is the virtual page width but so far to no avail..) Can anyone direct me to a FAQ that gives all the PORTs (like 0x417 for keyboard) and Interrupt calls available? Please?! Also I'm having trouble reading the joystick x/y so player 2 can only shoot & thrust so far. Flying with the mouse works cool tho! Well, to see how VIOLENTLY unoptimised I can write check out my version of Gravity Force so far (+source). You can fly (2 players) and shoot. Notice how the ships vanish near the top? Double buffering would sort that out but how do I do a fast bulk mem copy in C++? http://www.manc.u-net.com/gforce.zip [85k] Probs with it, or help either here or email, cheers! Jim PS is it worth me the time of getting DJGPP? Has it got an IDE? I'd like the 32bit code bit but TurboC++ 3 DOS is OK for now? -- ------------------------------------------------------- James Shaughnessy Bacardi Ferrari V12 Ace Class james AT manc DOT u-net DOT com http://www.manc.u-net.com/gp2.htm -------------------------------------------------------