Path: chuka.playstation.co.uk!news From: Andrew Partington Newsgroups: scee.yaroze.freetalk.english Subject: Re: 2 techniques I need help with Date: Thu, 02 Dec 2004 23:35:29 +0000 Organization: PlayStation Net Yaroze (SCEE) Lines: 41 Message-ID: References: NNTP-Posting-Host: spr1-ward1-6-0-cust65.bagu.broadband.ntl.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040113 X-Accept-Language: en-us, en In-Reply-To: Matt Verran wrote: >>1st the rotating tower effect in Nebulus, it would be easy in 3D but >>that wasn't available on the spectrum, c64 or even Amiga > > > It's just sprites, you have the bricks and platforms and enemies drawn at > all the needed rotations. > > I think it was more to do with sprite priority trickey than pre-rotated sprites, though I could be wrong. I had a shot on the Speccy version to see what it did (which reminded me what an evil, EVIL game it was), and it looks as though block sprites towards the edge of the tower are overwritten by ones that are closer to the centre of the screen. i.e. imagine this is your tower block sprite: |xxxx| (where | is the left/right hand edge of the block) you would draw the tower (from the outside towards the centre) by shifting the blocks X position by a certain amount depending on the distance from the centre of the screen, sort of like this: ||x|xx|xxx|xxxx||xxxx||xxxx|xxx|xx|x|| ||x|xx|xxx|xxxx||xxxx||xxxx|xxx|xx|x|| etc.... Only the blocks in the centre of the screen are aligned so that they are next to each other, the rest overlap each other horizontally. You'd probably have to determine the priority of the sprites and platforms based on their distance from the centre (whether or not the platform, sprites etc should be behind or in front of the tower) Course, it could be done with prerendered rotations, or you could write a sprite scaler routine of some sort - depends on the hardware you want to target I suppose, and whether you have the memory/cpu to spare. Andy