ISSUE #1 ---------------------------------------- Page No. ## ------------ Contents Page ------------ Telecommunications in the near future Demo Reviews by FRAP of Magnetic Fields-- The STOLEN DATA Music Competition ------------ Classified Adverts ------------------- Kreators Coding Page ---------- An Introduction to Amiga Demo-Coding ------------ Closing Comments ----------- -------- Telecommunications in the near future ------- ----- By Count Zero ----- The future of telecommunications in Britain will see the emergence of two fundamentally different systems. One system will be have evolved, and is evolving at the present time, from the existing British Telecom network, this will be the ISDN system. The other system will be the most advanced system of its kind and will exist nowhere else on the world, this will be the PCN system. ISDN is an acronym ( stands for ) Intergrated Services Digital Network, and is being developed by BT.ISDN will replace BT`s ageing network of clock- work exchanges, and co-axial telephone lines, BT says that it will have a complete digital network by the middle of the next decade, around the year 1995, assuming the present rate of upgrading continues. At present this is the replacing of two old exchanges with digital ones, every day, but bear in mind BT has around 6,000 telephone exchanges. Okay, I hear you ask, exactly what is ISDN and will it be any better than the present system? Digital fibre optic cables have immense advantages over co-axial copper cable,but chiefly there are two reasons why. Bandwidth is a measure of the capacity of information that can be carried, for instance your phone has a bandwidth of 3,100 hz, this means that the frequency of the signal can be varied 3,100 times per second ( This method is called Frequency Modulation or FM). In theory this means you could only transmit 3,100 Bits Per Second, but modems achieve a much higher rate by using another method of modulation in addition, called phase modulation. Although the coaxial copper cable used for phone lines can carry more, it is not needed for voice grade trans- mission , where 3,100 hz provides acceptable quality. Fibre optic cables are fundamentally different, because the information is carried, or modulated, using a light wave, as opposed to a radio frequency wave,although both are electromagnetic waves they are at different ends of the EMG spectrum. Light has a much higher frequency than radio waves, typically around 1 million Giga Hertz ( 1,000 Million Million Hetrz!! ), and so has a much higher bandwidth enabling more information to be carried, around 140 million bps, or 12 million kilobytes per second! A single strand of fibre optic cable can carry about 2,000 telephone conversations,or 250 music channels, or 2 colour TV channels, or a combination of any of these. The second advantage of fibre optics is that it is digital, unlike copper cables which are not suited to precise digital transmission because they have have a very low signal to noise ratio, or decibel level (dB). This is caused because they are made of metal and are prone to having signals induced in them by other radio frequencies, this is the noise that can be heard over a bad telephone line. So the advantages of fibre optics are substantial, with only a few fibre optic cables running into your home you could have access to all sorts of services, like cable TV, or the new format High Definition Television (HDTV), or even cable `radio stations` with the advantage of CD quality music. But what will be vastly more interesting will be the implications it has for you as a computer user. Okay, thats fibre optics, but what about the other major development?, about which you`ve probably never heard anything. The alternative to a hard-wired digital network, is a completly wireless radio communication network which is similiar to the Cell- net or Vodaphone network already in existence. Give up?, well it`s called PCN and stands for Personnal Communications Network, and it is already being developed by several major companies. Basically it is the same as the system upon which car-phones work, but it is fundamentally different in that unlike car-phones it will not rely on the BT network. So in effect this means that it will be a mirror image of the BT network, enabling you to use your cheap personal phone almost anywhere in the country without having to find a call box. Although this does not have such far-reaching implications as fibre optics , it will act as a direct competitor for BT, and will provide the consumer with the first real alternative in domestic communications But PCN will be a massive commitment for any company, with over 1 billion having to be spent in the next five years. Although this has not put off major communications companies, like Telefonica (Spanish), Bellsouth (USA), along with other companies such as Philips, GEC, Motorola and Thorn EMI, from accepting the Department of Trade and Industry`s ( DTI ) offer for potential operators to forward their plans. Okay,and now for the intresting bit, how this will effect you as a computer user? Well, I think that fibre optics will be a revolution, and may herald the age of the `computer revolution`, as a progression from the industrial one. A digital network that connects every house in the country could have drastic implications on the way we live and work. A survey early this year by the industrial research group `Industrial Relations Services` found that 23% of the people questioned said they would prefer to work from home,or `telework` by being linked to the office by their computer. With the vastly reduced charges on data communications that will be economically possible with ISDN then this could easily be achieved. But specifically lets consider the computing implications: The ideas of the sci-fi genre concerned with computers in the near future, called `cyberpunk`,has already explored the ideas that such a comms net could achive. More exactly,William Gibson has been heralded as the creator of this genre, and his ideas about `cyberspace` as a medium in which all computers are linked, could be seen to be a partial reality by the turn of the century. Gibson`s exploration of society dominated by high technology, in such books as NEUROMANCER and COUNT ZERO, can be seen to be one of in the next century. But perhaps if his books can be seen as a prophecy of the future then a digital fibre optic network can be seen to be a step in the right direction. The most interactive computer system, espoused by Gibson`s cyberspace, which is every game-players dream, would be one in which the sensory input would be total, so along with direct visual and audio input to your brain you would also have sensory input such as touch. In effect it would be indistinguishable from reality itself, touched upon in the TV comedy RED DWARF, and strived for by all arcade game designers, with bigger and better hydraulic cabinets, and sit in enclosures. With big steps being taken towards this goal by California`s VPL company, who have designed Reality Okay dudes that`s it,was it good enough for you? Article written for STOLEN DATA by Andy,alias Count Zero of Rising Force. KREATOR- Thanks for that article Andy ! Just a little note; Here in Britain BT have now installed 565 Mbit/s optical fibres , and in the near future they intend to increase this to 2.2 Gigabit/s, which will ultimately permit transmission of some 32 TV channels on one fibre strand ( don't forget there are on average 8 of these fibres to a single cable ) Built for 2 (RB2), a computer system where two users can interact in a computer generated world by using 3D eye goggles and `Datagloves` to detect hand movement. The strive towards this perhaps ultimate goal in computing will have taken the first step with ISDN. With interaction in games being taken to the maximum capacity possible using visual means, by using movie quality graphics generated on supercomputers, and audio means via Compact Disk sound systems.So in perhaps 10 years,instead of blasting away all by yourself, you could be exterminating green aliens in full High Definition Television resolution with a few thousand colours and stereo CD sound,whilst hoping that the last green alien you blasted wasn`t your mate next door! ---------- The Demo Review Column ---------- ----- By FRAP of MAGNETIC FIELDS ----- Welcome to the first issue of STOLEN DATA and this is FRAP/MAGNETIC FIELDS bringing the up to date info on all the latest demos worldwide !!. I have seen most of the latest demos and intros and they are all basically the same with the usual scrollers and the same sort of effects. You'll probably know what I'm talking about. But there is some good stuff around, with some good music disks from various groups and a few very impressive demos.I've listed the three demos which I think are the best around at present : 1. SEVEN SINS by SCOOPEX/FINLAND. 2. SCROLLER DEMO by THE SILENTS. 3. DER BLOCKHAUS by SETROX. Let's take a closer look at each demo in turn : SEVEN SINS-SCOOPEX/FINLAND. This demo is very impressive indeed, it is very well coded and contains some really cool music. The grafix are very well done, with some novel sine scrollers and some truly excellent vector balls.Hard to fault and this is why the demo got 1st place this month. DANISH QUALITY - THE SILENTS. It nearly got 1st place until I saw the scoopex demo !!. It's a simple concept, containing a scroller made up of dots which twists and flips across the screen to the sound of a really cool tune.The logos at the top contain some good graphics and the scroller is really easy to read. DER BLOCKHAUS - SETROX. Well coded, with an option screen allowing you to toggle between a vector scroll and a sinus part. Some cool effects add to the enjoyment. If you think your demos are the most coolest around then please send them to us and let us all see them. If we agree with you, then your demo will be picked as one of the best 3 for that month and go onto the STOLEN DATA DISK ( if Kreator has room ) Send your productions to the following address : 37 STETCHWORTH DVE, BOOTHSTOWN, WORLSLEY, M28 4FU, MANCHESTER, ENGLAND. We guarantee all disks returned with latest stuff. Only send recent demos, utils & music. In future issues there will be 1 meg demos/music and best Amiga artwork. So if you do this stuff then send us a compact to look at. NO GAME SWAPPING (FUCK OFF FAST !!) KREATOR Thanks for that FRAP, I thought I would just add my own comments to the above three demos, so here they are. SEVEN SINS-SCOOPEX/FINLAND I must admit I was very impressed with this demo coded by SLAYER. The presentation is almost faultless, this is one of those progressive demos which introduces new effects as time moves on. However here we have a basis of a simple starfield a couple of copper bars bordering the action, and a truly excellent soundtrack composed by UNCLE TOM, on top of which just a single effect runs, a new one fading in as the previous one disappears. It starts out like a movie with the credits and titles; here we get to see the graphical talents of REWARD. Amongst the visuals thrown at us are a proportional sine-scroller,some vector balls another sine-scroller but with a large font which also moves in the horizontal direction , and some very smooth large solid 3D convex objects. The solid 3D is technically very impressive, each of the objects is in 3 bitplanes (8 colours) and all but very large objects run in just one frame. This is achieved by using what are called Convex objects. This eliminates the need to calculate plane priorities,and you can fill the object all in one operation. In all I would say this rates as one of the best demos I have seen in a long while, and I congratulate SLAYER for this, his first demo for SCOOPEX FINLAND. DANISH QUALITY - THE SILENTS This demo coded by MR PERFECT features some rather well drawn logos from MIKAEL BALLE and very good music by DESPER KYD. The whole demo revolves around a single routine: a scroller composed of dots, moving in varied twisting helical paths. There also features a simple scroller at the bottom which can be moved up and down. Technically this demo isn't too complex, but nevertheless it scores on originality. DER BLOCKHAUS - SETROX ZYR coded this demo featuring a 3D vector scroller ( well three of them to be precise ) and some simple sine effects. The graphics are purely functional, but where this demo scores most is in its controlability. By pressing the HELP key a screen pops up to explain the large selection of functions, enabling you to alter any of the demos variables.There are quite a large number of 3D vertices on screen, and the screen area is about 256 lines deep; I would say there's some clever programming here. Well thats all for the demo review this issue, watch out next month when we should be reviewing even more demos. But don't forget, you won't be featured in this magazine if you don't send us your latest demos. ================================================================== STOLEN DATA - A DCS-ANARCHY-TRISTAR CO-PRODUCTION ================================================================== Contents ------------ Shortcut Page Title Author ( F1 ) 1 Contents ( F2 ) 2-5 Telecommunications in the near future Count Zero ( F3 ) 6-8 The Demo Review Column Frap ( F4 ) 9 The STOLEN DATA Music Competition ( F5 ) 10 Classified Ads. Section ( F6 ) 11 Coders section inc. Problem page Kreator ( F7 ) 12-19 Beginners guide to demo coding Kreator ( F8 ) 20 Closing comments Kreator To order the paper magazine ( 30p + SAE in UK, see ads for more details) write to NOSAH, if you have anything we may be interested in, for the magazine, you can also write to us at : KREATOR-ANARCHY ( Michael ) NOSAH-DCS ( Dave ) 42 Browfield Terr. 99 St. Lucia Park, Silsden, BORDON, KEIGHLEY, Hants, W.Yorks, BD20 9PT GU35 OLD. Controls :- Function keys for quick shortcuts Cursor Left & Right step backwards and forwards Right mouse cycles forwards ******************************************************************************* ****** STOLEN DATA - MUSIC COMPETITION ****** ******************************************************************************* ****** ****** ****** This is one for all you Budding musicians out there ****** ****** ****** ****** If your musically inclined and think that your Amiga ****** ****** ****** ****** music is the best, then this is the competition for you. ****** ****** ****** ****** Just send your best track, written on any music utility ****** ****** ****** ****** ( send the replay routine or the music prog used ) ****** ****** ****** ****** to either of the addresses below, it costs one disk to ****** ****** ****** ****** enter and the winner(s) will get every disk that reaches ****** ****** ****** ****** us.The closing date is the 31st January so get composing ****** ****** ****** ****** Silver/Errors Superted ****** ****** J.K.Styve, Skytterveien, ****** ****** 5164 Hjelmas, 5035 Bergen/Sandviken, ****** ****** NORWAY. NORWAY. ****** ****** ****** ****** P.S. This is the same competition as in Iguana so don't worry if ****** ****** you entered that , your entry is still valid, we have just moved ****** ****** the closing date back a few months. ****** ****** ****** ******************************************************************************* -------------------------------------- If you don't already have a copy of the STOLEN DATA paper magazine then here are the details. Prices in the UK ---------------- 30p + S.A.E. ( + 1 Amiga disk ) 75p + S.A.E. ( 45p covers disk ) Price outside UK ---------------- A banknote closest to One pound sterling + 1 Amiga disk, remember it must be a banknote,we can't exchange coins. 'But' you ask 'what do I get for my money', well here is a little resume of the first issue: Interviews with VISION FACTORY and BAMIGA SECTOR 1 , the Hottest Gossip around , Demo reviews , the Amiga Music Competition , Dear Mr. DROKK featuring ANARCHY's own JUDGE DROKK, an article from SUBWAY, and one on the Development of the Amiga Scene, PLUS some really GREAT artwork by SILVER of the ERRORS including two excellent cartoons, Charts and more. -------------------------------------- -------------------------------------- OOH ! IT'S OBSCENE V Part five in this Exciting,Stimulating Mind Numbingly Awesome demo series from ANARCHY UK is OUT NOW !!!!!!!! Featuring some cool graphics, great sampled dirty or obscene phonecalls, and some excellent code by HAMMER. For a copy of O.I.O.V. ( 2 Disks ) write to one of these addresses: HAMMER (ADAM), JUDGE DROKK (MARK) 12 Windsor Place, 9 Back Lane East, Barnoldswich, Royston, Lancs. Barnsley, BB8 6HD. South Yorks, S71 4RZ. or my address on the contents page -------------------------------------- Here's an address I received at the last minute, write to this guy for swapping. SLIDER-TOPGUN ( John Bown ) 11 Greysand Crescent, Appledore, Bideford, DEVON, EX39 1SE. -------------------------------------- ----------- An Introduction to Demo Coding on the Amiga ----------- ----------- By Kreator of ANARCHY UK ---------- Welcome to the first of hopefully many articles I will be writing for STOLEN DATA on Demo coding for the Amiga. I must emphasise that the best way in which you can learn to produce demos is through practice. Now you will find on this disk some example source, designed on Devpac II Unfortunately due to using some of Devpac's more powerful features, the Source is incompatible with SEKA. I don't intend to cover material you can find in reference books, so if you do not own either the 'Amiga Hardware Reference Manual' or the 'System Programmers Guide' and are serious about coding, I suggest you buy, borrow or steal one of them. A reference on 68000 would also help. This issue I will explain the use of Bobs ( or sprites as Magazines like to incorrectly refer to them ). I will not be covering the type of bobs found in games ie. they move across some backdrop without disturbing it, as these are a simple extension of the bobs usually found in demos. What is a bob? A bob is just a piece of graphical data, which has a certain number of colours ( bitplanes ) and that can me moved smoothly around the screen. This is achieved by copying the data, and performing a Right shift on it in the process. The blitter is able to do this automatically, with what is known as a barrel shifter. Now one of the most important techniques used when working with large numbers of bobs is double buffering; so called because it involves using two screen buffers, one of them is displayed, whilst the other is being re-drawn. You will find the sine-bob source utilises this. The mechanics of this process are very simple, look in the source if you are unsure how it works. To begin with how do we use the blitter to draw a bob. Well a bob is generally composed of a sequence of bitplanes for the graphic, and a mask. The mask is used to 'mask' out the bits of the background, which you do not want to disturb, when copying the bob onto the screen. In practice you will normally just OR each of the bobs image bitplanes together to produce the mask, but it is possible to use alternative masks eg. You may have noticed that on some games, the 'sprites' have a black outline, this is achieved by adding an extra pixel all the way around your mask. For a fast bob routine, arrange the image planes next to each other, and similarly have multiple copies of the mask corresponding to the images.Also important, you must leave one blank word at the right of the image ( and mask ) so that the bob can be shifted into this area. eg. For a 3 bitplane bob ,48*64 ,the image data should be arranged : Word1 - plane1 --- Word4 - plane1 Word1 - plane2 --- Word4 - plane2 Word3 - plane3 --- Word4 - plane3 Word5 - plane1 --- Word7 - plane1 ................. Word252-plane3 --- Word255-plane3 But for the mask, instead of having three different lines of data, we have the same data for each plane. For this to work we must also have a similar format for the screen, this is achieved with the Bitplane modulos. eg. If we have a 3 bitplane screen of the required form at $70000, (320 x 256 pixels) then a suitable copperlist to set up this screen is, MOVE $3081,Diwstrt MOVE $30c1,Diwstop MOVE $0038,Ddfstrt MOVE $00d0,Ddfstop MOVE $0000,Bpl1ptl MOVE $0007,Bpl1pth MOVE $0028,Bpl2ptl MOVE $0007,Bpl2pth MOVE $0050,Bpl3ptl MOVE $0007,Bpl3pth MOVE 80,Bpl1mod MOVE 80,Bpl2mod MOVE $3200,Bplcon0 etc... The reason for going to such lengths is because now the bob routine is much simpler and we need only use the blitter once to plot the whole image. Whereas using consecutive planes we would need to copy each plane seperately. To get the bob into this format DON'T use an IFFconvertor use an IFFdepacker (one supplied on disk) or strip the IFF header from your IFF brush by hand ( generally DPaint does not compact small brushes, so just look for the word BODY with your monitor, the next longword is the length of the graphic followed by the data itself ) Now once we have our bob in the right form, how is it copied onto screen. As should already be known the blitter has four DMA channels ( Direct Memory Access ). The three inputs A,B,C can be combined using logical operations with what is called the MINTERM. This allows any form of logical function to be applied to these channels before output onto channel D. We address the channels through four pointers Bltxpt (x is A,B,C or D), whereas the Minterm is the bottom 8 bits of the blitter's first control word Bltcon0. Bltcon0 also tells the blitter how many DMA channels are in use and how far to shift channel A. One important point to notice right now, is that only channels A and B can be shifted. The blitters second control word Bltcon1 also has a shift counter for source B but its remaining functions are of no interest to us as they relate to line drawing, filling, and reversing the blitters direction. First we determine the correct Minterm. Now channel A is used for the image data, channel B for the mask and Channel C points to the screen at which we want to copy the data. This is essential as only Channels A and B can be shifted prior to combining with Source C, thus allowing the bobs to move smoothly one pixel at a time. We want data to be copied from A if the bit in B is set otherwise it comes from C. The final result is output in channel D. As a reminder here is a list of the LFx, Bltcon0 and Bltcon1 bits ( capitals mean bit set ) LFx 7 6 5 4 3 2 1 0 ABC ABc AbC Abc aBC aBc abC abc Bltcon0 15-12 11 10 9 8 7-0 A shift Aen Ben Cen Den LFx Bltcon1 15-12 11-0 B shift set these to zero If you didn't already know here is how to calculate the minterm. Find out what happens in each of the above bit combinations, if it is set put a 1 in the corresponding position in the minterm otherwise a zero. eg. ABC - If B is set data comes from A and C is ignored, therefore as A is set in this case ABC is also set. From these considerations we see that the required minterm is %11100010 or $e2 (check it if you don't believe me) We must now calculate Bltdpt ( and Bltcpt ) from the bobs X and Y coords. This is very simple and is given by the equation : Bltdpt = Screen + Y*Width*Number of planes + ( X and $fff0 )/8 So if X and Y are given in d0,d1 respectively then the following routine will calculate Bltdpt for you for a 2 bitplane, 320 pixels wide screen. ( this will now be the same for each step of the example, with a 32 (+16 blank) x 31 bob as used in the example source, which can be found on this disk ) Screen = $70000 Lea Screen,a0 Move d0,d2 Remember X Lsr #4,d0 Divide by 16 Add d0,d0 Multiply by 2 Mulu #80,d1 Add d0,d1 Lea (a0,d1),a1 ( cont. on next page ) BlitWait Btst #14,Dmaconr Bne.s BlitWait Move.l a1,Bltdpth Move.l a1,Bltcpth Next we set the pointers to the image data and mask with Move.l #Image,Bltapth Move.l #Mask,Bltbpth Now calculate by how much we need to shift the A-B sources, this is given by X and 15. We then combine this with the minterms and DMA enable bits, to go into Bltcon0 and Bltcon1 as follows ( we'll update both at once with a Move.l as they are adjacent registers) (don't forget we stored X in d2 ) And #$f,d2 Ror #4,d2 The shifts are in bits 12-15 of Bltcon0 and Bltcon1 Move d2,d0 Or #$fe2 $f00-all DMA channels active, $e2 is the minterm Swap d2 Move d0,d2 Bits 0-11 are already clear in d0 (ie. no lines or blitter fill) Move.l d2,Bltcon0 We now need to discuss Modulo values and the Bltsize register, for which I need to explain how the blitter operates in normal ascending mode. The Bltsize and modulo registers together define a window on the full-screen on which your blitter operations are to take place. The Bltsize register uses the lower 6 bits (0-5) to define the length of each line (ie the Bob width) in words ( this is important, remember Bltsize is not specified in bytes ). A value of 0 corresponds to 64 words in length. The upper 10 bits refer to the number of lines you wish to copy, again a zero value does in fact mean 1024 lines ( there is after all no point in copying zero lines ). When you set Bltsize the blitter begins its operation; it increments each of the Channel pointers in use, for every word copied until it has copied the specified number of lines; then the blitter adds the corresponding modulo values to each of the channels and continues with the next line until it has finished. Therefore by setting the modulos correctly, a window on the screen can be specified. This is what needs to be done with our bob routine, In our case the screen is 40 bytes across and the Bob is 6 bytes wide, so both Bltcmod and Bltdmod need to be set to 34 (40-6). Bltamod and Bltbmod are cleared to zero. Move #36,Bltcmod Move #36,Bltdmod Clr Bltbmod Clr Bltamod We have a final pair of registers which I have left out till now. These are Bltafwm and Bltalwm ( Blitter A first and last word masks ). Their primary use is for copying rectangles of screen data, which do not always lie on word boundaries. By setting the registers, you can mask out bits on either side of channel A's window. They can be used to save a small amount of memory with bob routines, but have no benefits in speed, as such I will simply set both to $ffff in order that they do not interfere with the blitter at all. Bltsize in our example is set to 31*64*2+3 which means draw 62 lines of 3 words each, as we have 2 bitplanes of 31 lines apiece. Move.l #$ffff0000,Bltafwm Move #31*2*64+3,Bltsize As soon as Bltsize is initialized the blitter gets to work, and begins plotting the bob. Before we redraw the bob in the next frame the previous bob must be deleted Two methods are available here : 1> If a large number of bobs are being used a fast screen clear routine is employed. This uses both the blitter and the processor; the blitter is set working forwards and the processor, which works in parallel, clears from the bottom of the screen backwards. eg. Move.l #Screen,Bltdpth Clr Bltadat (cont. on next page ) Move.l #$1f00000,Bltcon0 Clr Bltdmod Move #A*64+40,Bltsize Movem.l a1-a6/d0-d7,-(a7) Lea #Screen+(Nolines-1)*80,a0 Movem.l Blank,a1-a6/d0-d7 Repeat ....... B Movem.l Blank,a1-a6/d0-d7 Times Movem.l (a7)+,a1-a6/d0-d7 Blank points to an area of at least 14 blank longwords, A and B must be determined by experimentation, but the Blitter and Processor clears must overlap. 2> If using a smaller number of bobs clear them individually. with d0 and d1 as the X and Y coords as before, the routine below will clear the bob. Lea Screen,a0 Lsr #4,d0 Add d0,d0 Mulu #80,d1 Add d0,d1 Lea (a0,d1),a1 Move.l a1,Bltdpth Move #34,Bltdmod Move.l #$1f00000,Bltcon0 Clr Bltadat Move #31*2*64+3,Bltsize For a complete listing of the source outlined above, look in the source directory of this disk. One of the demos uses 16 bobs and is controlled with the mouse. The other employs double-buffering and a double sine for a simple (and very slow!) sine-bob routine.Both these routines are purely for demonstration purposes, as they are designed to be easy to follow. You will find that the faster the Bob routine the more difficult it is to follow, and as an example I have included my 196 animated bob routine. Be careful not to run it twice without re-assembling, it's a little temperamental. Some of the techniques for increasing speed include ; use of tables for converting the X,Y coordinates, using Address pointers for some of the Blitter registers as the Address register indirect ( and with displacement ) addressing modes are much faster than absolute addressing. I hope this has been of some help to coders starting out, next month I will possibly be covering 3D graphics,the equtions for their calculation, simple hidden-line removal, vector balls, and ordinary line-vector graphics. Until the next issue .. Kreator - Anarchy UK I have included a list of the blitter registers on the opposite column. You will also find an equates file in the source directory which contains most of the custom registers. It also has three Macros, which are designed to fascilitate the creation of Copperlists. If you have any suggestions or queries for this section of the magazine sned them to my address,which can be found on the contents page. Blitter Custom Register List ------------------------------ All registers have a base addess of $dff000. Bltcon0 $40 | Bltdpth $54 Bltcon1 $42 | Bltdptl $56 Bltafwm $44 | Bltsize $58 Bltalwm $46 | Bltcmod $60 Bltcpth $48 | Bltbmod $62 Bltcptl $4a | Bltamod $64 Bltbpth $4c | Bltdmod $66 Bltbptl $4e | Bltcdat $70 Bltapth $50 | Bltbdat $72 Bltaptl $52 | Bltadat $74 There is also a Blddat, but this is an early read register. Bltcon0 15-12 11-8 7-0 A shift Usex (A-D) Minterm Lfx Bltcon1 15-12 11-5 4 3 2 1 0 B shift Unused EFE IFE FCI DESC LINE EFE-Exclusive fill IFE-Inclusive fill FCI-Fill carry in LINE-Line draw mode DESC-Descending mode The Coders Section -------------------------- Problems, Hints & Tips ------------------------ Well as it's the first issue I don't have any problems to answer, but in future issues with the help of out readers I hope to run a Problems page. I will try to answer any queries you may have, for instance I have had a few people ask me how to code a bob routine, so that's the subject of my first article on Beginning Demo-Coding Anyway, I will just give a few tips to those coders just starting, these may seem trivial, but I have seen plenty of demos in which these pointers haven't been followed. 1> Always remember to switch off Sprite DMA if not using sprites. 2> Also clear the sprite data registers to prevent streaks appearing down the screen. Make sure you do it in that order aswell !! 3> NEVER access the Operating System directly ALWAYS go through the libraries. Kreator's Challenge ------------------- This may become a regular feature if I can think of enough suitable Challenges. I will set a problem for all you coders to have a crack at and you send me a disk with your solution source.The best one gets all the disks I receive. The problem for this issue is actually a routine I have wanted to write for a while now, but never found the time or the inspiration to begin. What I would like you to try, is to create a Racing game style moving landscape with hills and bends using only the copper. This could be the basis for a very fast Racing game, although the colours would be limited, it could also be used to create a pretty impressive demo. I will also try out the problem in order for me to be able to assess any routines I may receive. It seems like a difficult one to me, but it will be interesting to see how many can do it. Thanks for reading this magazine, I hope you found it interesting, if so get your orders in now for the next issue. We hope to bring one out every six weeks, and next month I will hopefully have some original music and graphics. Anyone having problems with coding, write to me and I'll try to help you out in the magazine ( Anonymously if you wish ). Also if you have any ideas for next issues challenge, write to me with that; also if you have any solutions to this months problem. Remember if you make a contribution to either magazines, you qualify for a free Advert in here. That's all for this issue, I hope to see lots of people reading the magazine at the 16-bit show. Kreator - Anarchy UK