_________________________________________________________________________ /#########################################################################\ |#####...####..######..######......####...####..#####..##......##......###| |####.....###..######..########..#####.....###...####..##..######..#######| |###..###..##..######..########..####..###..##....###..##..######..#######| |###..###..##..######..########..####..###..##..#...#..##..######......###| |###.......##..######..########..####.......##..##.....##..######..#######| |###..###..##..######..########..####..###..##..###....##..######..#######| |###..###..##...#####...#######..####..###..##..####...##..######..#######| |###..###..##......##......##......##..###..##..#####..##......##......###| |#########################################################################| |####################################################################{RB}#| |=========================================================================| | | | ----> PRESENTS <---- | | | | THE ABACUS SERIES - VOLUME 2 | | | | AMIGA GRAPHICS INSIDE AND OUT - THE COMPLETE BOOK | | | | Typed / Scanned / Edited By : RAZOR BLADE. | | Additional Typing by : GLITCH ( + 8 pages by Asterix ! ). | | Menu Coded by : RAISTLIN | | Original Supplied by : VIPER | | | |-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-| | CALL THE ALLIANCE WORLD HQ -> THE PLACE TO BE | | UNKNOWN PLEASURES --> +44 (0) 823 322 891 --> SYSOP: BARBARIAN | |_________________________________________________________________________| ----------------------------------------------------------------------------- 4.5 COPPER PROGRAMMING. The Copper has just demonstrated how powerful it is. We are going to take advantage of that power with our next program, which will use a technique known as double buffering. -------------------------------------------- 4.5.1 DOUBLE BUFFERING FOR LIGHTNING FAST GRAPHICS. The drawing speed of the Amiga does not affect the Copper because the Copper operates independantly at full speed. Because of this you can amaze the users of your programs with lightning fast graphics created with double buffering. To create this effect, show the user a display on which nothing is happening. While the user stares at this boring display, build your graphics in a second, invisible display. When your graphics are complete, switch on the second display and your graphics will instantly appear on the screen. We will now explain how this works. The pointer to the Copper lists of the old display are read from View and stored. The pointer in View is erased. Now a new bit-map with new bit-planes is prepared for the second display. MakeVPort and MrgCop are used to generate the new copper lists, which are then stored. To switch from one display to the other we just write the new pointer to the View structure and use LoadView to activate it. Again we have designed a small program package. If consists of the following SUB programs: MakeDoubleBuffer DoubleBufferOn DoubleBufferOff AbortDoubleBuffer transmit PAGE 175 ----------------------------------------------------------------------------- '################################################ '# '# Section : 4.5.1 '# Program : Double Buffered Display. '# Author : tob '# Version : 1.0 '# '################################################ ' ' This program creates a second screen that works ' as a backup buffer for the normal screen. ' PRINT "Searching for .BMAP file ............" 'GRAPHICS-library DECLARE FUNCTION BltBitMap& LIBRARY DECLARE FUNCTION AllocRaster& LIBRARY 'FreeRaster() 'MakeVPort() 'MrgCop() 'LoadView() 'FreeCprList() 'EXEC-library DECLARE FUNCTION AllocMem& LIBRARY 'FreeMem() 'CopyMem() 'INTUITION-library DECLARE FUNCTION ViewPortAddress& LIBRARY DECLARE FUNCTION ViewAddress& LIBRARY LIBRARY "intuition.library" LIBRARY "graphics.library" LIBRARY "exec.library" init: CLS PRINT "WITHOUT DOUBLE BUFFERING!" FOR t = 1 TO 20 PRINT STRING$(80,"+") NEXT t FOR t = 1 TO 20 x% = RND(1) * 600 y% = RND(1) * 150 r% = RND(1) * 100 CIRCLE (x%,y%),r% NEXT t CLS PRINT "AND NOW WITH DOUBLE BUFFERING!!!" MakeDoubleBuffer DoubleBufferOn FOR t = 1 TO 20 PRINT STRING$(80,"+") NEXT t transmit LOCATE 1,1 PAGE 176 ----------------------------------------------------------------------------- FOR t = 1 TO 20 x% = RND(1) * 600 y% = RND(1) * 150 r% = RND(1) * 100 CIRCLE (x%,y%),r% NEXT t transmit LOCATE 5,10 LINE (38,29)-(442,67),3,b PRINT "Even this works!" PRINT "Double Buffering = Backup Display" PRInt "These are two separate screen that" PRINT "are switched back and forth" FOR loop% = 1 TO 15 DoubleBufferOn FOR T = 1 TO 1000: NEXT t DoubleBufferOff FOR T = 1 TO 1000: NEXT t NEXT loop% PRINT PRINT "PRESS THE LEFT MOUSEBUTTON!" SLEEP:SLEEP AbortDoubleBuffer LIBRARY CLOSE END SUB MakeDoubleBuffer STATIC '* Create second display. SHARED TargetBitmap&, rasInfo&, SourceBitMap&, view& SHARED bufferx%, buffery%, vp& SHARED home1&, home2&, guest1&, guest2& view& = ViewAddress& vp& = ViewPortAddress&(WINDOW(7)) rasiInfo& = PEEKL(vp&+36) SourceBitMap& = PEEKL(rasInfo&+4) opt& = 2^0 + 2^1 + 2^16 TargetBitmap& = AllocMem&(40,opt&) '* Copy Bitmaps IF TargetBitmap& = 0 THEN ERROR 7 '* NOTE: FOR KICKSTART VERSION 1.2 AND ABOVE. '* FOR 1.0 AND 1.1 USE LINES BELOW. '* '* '* For loop& = 0 TO 40 STEP 4 '* POKEL TargetBitmap&+loop&,PEEKL(SourceBitMap&+loop&) '* NEXT loop& ' CALL CopyMem(SourceBitMap&,TargetBitmap&,40) ' Get Planes. bufferx% = PEEKW(SourceBitMap&)*8 buffery% = PEEKW(SourceBitMap&+2) PAGE 177 ----------------------------------------------------------------------------- depth% = PEEK(SourceBitMap&+5) FOR loop% = 0 TO depth% - 1 plane&(loop%) = AllocRaster&(bufferx%,buffery%) IF plane&(loop%) = 0 THEN ERROR 7 POKEL TargetBitmap&+8+loop%*4,plane&(loop%) NEXT loop% 'Copy active display to buffer. plc% = BltBitMap&(SourceBitMap&,0,0,TargetBitmap&,0,0,bufferx% buffery%,200,255,0) IF plc%<>depth% THEN ERROR 17 ' Store original Copper List home1& = PEEKL(view&+4) home2& = PEEKL(view&+8) 'Generate Second Copper List POKEL view&+4,0 POKEL view&+8,0 POKEL rasInfo&+4,TargetBitmap& CALL MakeVPort(view&,vp&) CALL MrgCop(view&) CALL LoadView(view&) guest1& = PEEKL(view&+4) guest2& = PEEKL(view&+8) 'Reset POKEL rasInfo&+4,SourceBitMap& POKEL view&+4,home1& POKEL view&+8,home2& CALL LoadView(view&) END SUB SUB DoubleBufferOn STATIC '* Activate new copper list. SHARED view&, guest1&, guest2& SHARED rasInfo&, TargetBitmap& POKEL view&+4,guest1& POKEL view&+8,guest2& CALL LoadView(view&) END SUB SUB DoubleBufferOff STATIC '* ACtivate old Copper List SHARED view&, home1&, home2& SHARED rasInfo&, SourceBitMap& POKEL view&+4,home1& POKEL view&+8,home2& CALL LoadView(view&) END SUB SUB transmit STATIC 'Copy old display to the new buffer. SHARED SourceBitMap&,TargetBitmap&,bufferx%,buffery% plc% = BltBitMap&(SourceBitMap&,0,0,TargetBitmap&,0,0,bufferx%, buffery%,200,255,0) END SUB PAGE 178 ----------------------------------------------------------------------------- SUB AbortDoubleBuffer STATIC SHARED rasInfo&, view&, TargetBitmap& SHARED vp&, bufferx%, buffery% SHARED home1%, home2%, guest1%, guest2% '* Restore Old Display and VPort copperlists. POKEL view&+4,home1& POKEL view&+8,home2& CALL MakeVPort(view&,vp&) CALL MrgCop(view&) CALL LoadView(view&) '* Delete new VPort Copper List Set CALL FreeCprList(guest1&) '* Delete Second Copper list set. IF guest2&<>0 THEN CALL FreeCprList(guest2&) add& = TargetBitmap&+8 pl& = PEEKL(add&) '* Delete BitPlanes and BitMap WHILE pl&<>0 CALL FreeRaster(pl&,bufferx%,buffery%) add& = add&+4 pl& = PEEKL(add&) WEND CALL FreeMem(TargetBitmap&,40) END SUB DESCRIPTION: You switch the double buffer system on with the command: MakeDoubleBuffer The double buffer is used to create the invisible display. This command can only be used once. When you are ready to start, execute: DoubleBufferOn This command activates the hidden display. Your old display, where you are drawing, becomes invisible. Now you can take your time to create you graphics, no drawing can be seen on the screen. As soon as your graphic is complete you only have to call: transmit PAGE 179 ----------------------------------------------------------------------------- to display the contents of the hidden display (in other words, to send your graphic to the visible screen). You can use the transmit command as often as desired. When you want to quickly switch to an unbuffered display simply call: DoubleBufferOff All graphic and print commands will, from this point on, appear immediately on the screen. With DoubleBufferOn, you can activate the buffered system again. Should you desire to leave the system entirly because your program is finished or you are tired of double buffer drawing, then use: AbortDoubleBuffer All memory areas used for the buffer displays are returned to the system. -------------------------------------------- 4.5.2 PROGRAMMING THE COPPER YOURSELF. So far we have let the Amiga create the copper lists for us, from the data we provided. Another possibility is to program the copper ourselves. Before you do this, you need to understand the Copper functions. The copper works very closely with the electronic beams of the display. These electronic beams scan from the upper left hand corner to the lower right hand corner of the screen sixty (50 uk) times a second. The copper is capable of waiting for this electronic beam to reach a specific position. This is handled by the WAIT instruction of the processor. The instruction requires a Y and X coordinate and tells the Copper to wait until the electronic beam has reached this coordinate. Until this occurs, the Copper will not process any more instructions. The MOVE instruction allows the copper to directly address hardware registers in the special purpose chips (the hardware registers are detailed in appendix C). The MOVE instruction requires an offset for the hardware register and a value to store in the register. The third and last instruction for the Copper is named SKIP. This instruction is used to actually skip past items in the copper list. PAGE 180 ----------------------------------------------------------------------------- Writing a Copper list for an entire display would be a very tedious job. Fortunately, this isn't necessary because most of the work can be accomplished easily by using MakeVPort. However, if you want to add your own Copper instructions to the Copper list for the displays, there is another method. In the structure of every ViewPort you will find a pointer for a user copper list. When you want to integrate your own instructions with a display, create a stand alone Copper list with the desired commands. Then store the starting address of your list to the User Copper list pointer. Now you can continue as usual. MakeVPort links the user list to the display list of the viewport, MrgCop links this list to the entire list in View and LoadView activates the manipulated copper lists. We will now show you how to create your own Copper list. The next program contains 4 SUB programs for this purpose. InitCop ActiCop WaitC MoveC First you need to create a data structure name UCopList. This structure requires 12 bytes of memory which is reserved with InitCop. We can program the user list with the commands MoveC and WaitC (skip is not necessary for our application). The call to the wait command looks like this: WaitC y%,x% The Y coordinate, which the Copper waits for, must be first. WaitC requires that this coordinate is first because it is easier to combine the copper lists using MrgCop if they all have the same order. MoveC can write any desired 16 bit value to a hardware register. In this chapter we use only a few of the many available registers. The complete register list is located in Appendix C. Here is the call : MoveC register%, value% register% : Offset of the desired hardware register. value% : 16 bit value. Here is a selection of the most important hardware registers we are going to use: PAGE 181 ----------------------------------------------------------------------------- Register Meaning --------- ------------------------------------------------ 384 Colour Register 0 (Background colour) 386 Colour Register 1 (Drawing Colour) 388 Colour Register 2 (...) 444 Colour Register 30 446 Colour Register 30 ------------------------------------------------------------- Now we can add to our user Copper list. After calling InitCop you can call as many MoveC's and WaitC's as you like. However, you must make sure that your WaitC's correspond with the screen coordinates you are calling. The top left hand corner of the display is at (0,0). This is where the electronic beam starts. Your WaitC coordinates must be in ascending X and Y coordinate sequence. When your user Copper list is finished, it is linked to the existing display with ActiCop. Your assigments will then be executed by the copper. In our example program, we open our new screen. In order to return the memory used by our copper instructions (including those in our reserved user list), we simply close the Intuition screen. Intuition automatically takes care of this. Do not attempt to create user instructions in the Workbench screen because when the instructions are executed, there will be no way to restore the normal display and release the assigned memory. The following program is an example of Copper programming basics. '############################################## '# '# Section: 4.5.2 '# Program: Copper Raster Interrupt. '# Date : 12/15/86 '# Author : tob '# Version: 1.0 '# '############################################### ' Demonstrates programming the Amiga graphic ' co-processor (copper) from AmigaBASIC PRINT "Searching for .BMAP file ..........." 'INTUITION-library DECLARE FUNCTION ViewAddress& LIBRARY DECLARE FUNCTION ViewPortAddress& LIBRARY PAGE 182 ----------------------------------------------------------------------------- 'RethinkDisplay() 'EXEC-library DECLARE FUNCTION AllocMem& LIBRARY 'FreeMem() 'GRAPHICS-library 'CWait() 'CMove() 'CBump() LIBRARY "intuition.library" LIBRARY "graphics.library" LIBRARY "exec.library" pre: CLS SCREEN 1,640,200,2,2 WINDOW 2,"COPPER!",(0,0)-(630,186),16,1 PRINT "Raster Interrupt through Copper programming:A Split Screen!" init: kolorregister% = 384 red% = 15,'0...15 green% = 4 , '0 to 15' blue% = 4 , '0 .... 15' kolorvalue% = red%*2^8+green%*2^4+blue% yCoordinate% = 100 xCoordinate% = 20 main: InitCop WaitC yCoordinate%, xCoordinate% moveC kolorregister%, kolorvalue% ActiCop PRINT " Press a Key ! " WHILE INKEY$ = "":WEND WINDOW CLOSE 2 SCREEN CLOSE 1 endprog: LIBRARY CLOSE END SUB InitCop STATIC SHARED UCopList& opt& = 2^0+2^1+2^16 UCopList& = AllocMem&(12,opt&) IF UCopList& = 0 THEN ERROR 7 END SUB SUB ActiCop STATIC SHARED UCopList& waitC 10000,256 PAGE 183 ----------------------------------------------------------------------------- viewport& = ViewPortAddress&(WINDOW(7)) POKEL viewport&+20,UCopList& CALL RethinkDisplay END SUB SUB waitC(y%,x%) STATIC SHARED UCopList& CALL CWait(UCopList&,y%,x%) CALL CBump(UCopList&) END SUB SUB moveC(reg%,value%) STATIC SHARED UCopList& CALL CMove(UCopList&,reg%,value%) CALL CBump(UCopList&) END SUB SUB program descriptions: InitCop : The exec function AllocMem assigns a 12 byte memory area for the UCopList data structure. WaitC : A wait instruction is placed in the user list. The graphic library command CWait, also called CBump(), raises the internal pointer for the user list. MoveC : Calls the function CMove, from the graphic library, which places a move instruction in the user list. CBump() raises the user list pointer again. ActiCop : a last WaitC is placed in the user list. This wait is for a screen position that the electron beam will never reach. This assignment closes the list and equals the macro CEND. The address of our user list is written to the appropriate pointer in ViewPort for the desired screen. The Intuition function RethinkDisplay generates the new copper list for View and sends it into the copper. The new display then appears. At the end, the screen is closed and the copper list is removed from the main copper list in View. All reserved memory is returned to the system. PAGE 184 ----------------------------------------------------------------------------- 4.5.3 PROGRAMMING 400 SIMULTANEOUS COLOURS. We now know the principle of Copper programming. The next program is a small demonstration of this powerful technique. We are going to change the background colour for each screen row by using WaitC. At the same time we will also be changing the drawing colour for each row. With 200 screen rows per display, we finish with 400 colours on the screen at the same time. Colours two and three remain normal. NOTE : Do not use more than 1600 Copper instructions in one list. '############################################## '# '# Section: 4.5.3 '# Program: Copper Raster Interrupt II '# Date : 12/15/86 '# Author : tob '# Version: 1.0 '# '############################################### ' Copper programmning can create 400 different colours in the ' background and foreground instead of the usual 4 colors ' with 2 bit-planes. PRINT "Searching for .BMAP file ..........." 'INTUITION-library DECLARE FUNCTION ViewAddress& LIBRARY DECLARE FUNCTION ViewPortAddress& LIBRARY 'RethinkDisplay() 'EXEC-library DECLARE FUNCTION AllocMem& LIBRARY 'FreeMem() 'GRAPHICS-library 'CWait() 'CMove() 'CBump() LIBRARY "intuition.library" LIBRARY "graphics.library" LIBRARY "exec.library" PAGE 185 ----------------------------------------------------------------------------- pre: CLS SCREEN 1,640,200,2,2 WINDOW 2,"COPPER!",(0,0)-(630,186),16,1 PRINT "Direct copper programming makes it possible." PRINT "200 background Colours!" PRINT "Patience Please ... Calculating Instruction lists.." init: kolorregister1% = 384 kolorregister2% = 386 xCoordinate% = 20 maxY% = 200 main: InitCop FOR loop% = 1 TO maxY% waitC loop%,xCoordinate% moveC kolorregister1%,loop% moveC kolorregister2%,4096-loop% NEXT loop% ActiCop ' Display text for this effect LOCATE 5,1 PRINT "The background colour shows 200 individual" PRINT "Colors! The text colors are also not plain" PRINT "anymore: 200 yellows, one per raster." PRINT "line. Here a useful program could" PRINT "take over the job instead of " PRINT "this useless program loop!...." LOCATE 15,1 PRINT "Please press a key when you" PRINT "Have finished reading." WHILE INKEY$="": WEND LOCATE 11,1 PRINT "Thats not going to happen this time!" FOR t=1 TO 2000: NEXT t CLS PRINT "Graphic Demo Coming up!" LINE (0,100)-(630,190),2,bf FOR loop% = 0 TO 630 STEP 30 LINE (loop%*1.5,190)-(loop%,100),1 NEXT loop% FOR loop% = 100 TO 190 STEP 20 LINE (0,loop%)-(630,loop%),1 NEXT loop% CIRCLE (300,80),120,3 PAGE 186 ----------------------------------------------------------------------------- PAINT (300,80),3,3 CIRCLE (300,80),100,1 PAINT (300,80),1,1 CIRCLE (300,146),180,3,,,1/15 PAINT (300,146),1,3 LOCATE 1,1 PRINT "Press a Key!"+SPACE$(40) WHILE INKEY$ = "":WEND WINDOW CLOSE 2 SCREEN CLOSE 1 ende: LIBRARY CLOSE END SUB InitCop STATIC SHARED UCopList& opt& = 2^0+2^1+2^16 UCopList& = AllocMem&(12,opt&) IF UCopList& = 0 THEN ERROR 7 END SUB SUB ActiCop STATIC SHARED UCopList& waitC 10000,256 viewport& = ViewPortAddress&(WINDOW(7)) POKEL viewport&+20,UCopList& CALL RethinkDisplay END SUB SUB waitC(y%,x%) STATIC SHARED UCopList& CALL CWait(UCopList&,y%,x%) CALL CBump(UCopList&) END SUB SUB moveC(reg%,value%) STATIC SHARED UCopList& CALL CMove(UCopList&,reg%,value%) CALL CBump(UCopList&) END SUB The text displayed by the program makes the details of the changed display clearer and more impressive. A simple graphic is created but it has a fascinatin appearance because of the Copper programming. This graphic is formed from more than 400 colors with only two bit-planes. After pressing a key the normal screen appears. PAGE 187 -----------------------------------------------------------------------------