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thanx! You're right. that would look cool. I've downloaded the Atari 5200 version of Ballblazer see what's really going on. Yep, it's about time I will work something out.

Just a small update to keep it alive. I did not have much time to work on the project but some improvements have been made. Things improved this time: 1. vertical resolution is now doubled. 2. precalculation of the movement is now correct maybe some small glitches, but much better then before. 3. I use a vanishing point up in the sky, where it really is. 4. the horizontal scrolling is now at a high precision at 1 virtual colorclock The precalculated vector for the movement is still at half the vertical resolution of the checkerboard.... ballblazer.bin

Too bad this system was never released. According to wiki, this system was scheduled to be released in 1991. With 2000 sprites and a 32-channel ensoniq sound processor. This kind of specs just made me drewl back in those days

I've touched one once if that counts . A big black box with some connectors. Never seen one running.

Sounds nice. How did you do that? Is two channels also possible?

Juno First looked really good, it's exactly what I am looking for. I just hope that I have enough cycles left for sprites...

I'll make it cleaner when I have the time. Edit: As Andrew suggested, the project is now opensource! I truly believe it will be better if everyone is able to put their part in it. There is lot's to be done like game play-code, sounds.

the board says 'Upload failed. You are not permitted to upload this type of file'... The project in it's current state: It's a modified 'hello' demo. Maybe It's ugly, and not cleaned up... Please shoot on it File main3.asm: processor 6502 include vcs.h include macro.h include lines.h org $F000 Temp = $80 PlayfieldY = $90 Direction = $91 ScanLine = $92 SubLineCount = $93 offsetLine0_7 = $94 offsetLine8_15 = $95 offsetLine16_19 = $96 PositionX = $97 invert = $98 Start SEI ; Disable interrupts, if there are any. CLD ; Clear BCD math bit. LDX #$FF TXS ; Set stack to beginning. ; ; Now the memory and TIA registers must be cleared. You may feel the ; need to write a subroutine that only clears out a certain section of ; memory, but for now a simple loop will suffice. ; ; Since X is already loaded to 0xFF, our task becomes simply to ocunt ; everything off. ; LDA #0 B1 STA 0,X DEX BNE B1 ; ; The above routine does not clear location 0, which is VSYNC. We will ; take care of that later. ; ; At this point in the code we would set up things like the data ; direction registers for the joysticks and such. ; JSR GameInit ; ; Here is a representation of our program flow. ; MainLoop JSR VerticalBlank ;Execute the vertical blank. JSR CheckSwitches ;Check console switches. JSR GameCalc ;Do calculations during Vblank JSR DrawScreen ;Draw the screen JSR OverScan ;Do more calculations during overscan JMP MainLoop ;Continue forever. VerticalBlank ;*********************** VERTICAL BLANK HANDLER LDX #0 LDA #2 STA WSYNC STA WSYNC STA WSYNC STA VSYNC ;Begin vertical sync. STA WSYNC ; First line of VSYNC STA WSYNC ; Second line of VSYNC. ; ; But before we finish off the third line of VSYNC, why don't we ; use this time to set the timer? This will save us a few cycles ; which would be more useful in the overscan area. ; ; To insure that we begin to draw the screen at the proper time, ; we must set the timer to go off just slightly before the end of ; the vertical blank space, so that we can WSYNC up to the ACTUAL ; end of the vertical blank space. Of course, the scanline we're ; going to omit is the same scanline we were about to waste VSYNCing, ; so it all evens out. ; ; Atari says we have to have 37 scanlines of VBLANK time. Since ; each scanline uses 76 cycles, that makes 37*76=2888 cycles. ; We must also subtract the five cycles it will take to set the ; timer, and the three cycles it will take to STA WSYNC to the next ; line. Plus the checking loop is only accurate to six cycles, making ; a total of fourteen cycles we have to waste. 2888-14=2876. ; ; We almost always use TIM64T for this, since the math just won't ; work out with the other intervals. 2880/64=44.something. It ; doesn't matter what that something is, we have to round DOWN. ; LDA #44 STA TIM64T ; ; And now's as good a time as any to clear the collision latches. ; LDA #0 STA CXCLR ; ; Now we can end the VSYNC period. ; STA WSYNC ; Third line of VSYNC. STA VSYNC ; (0) ; ; At this point in time the screen is scanning normally, but ; the TIA's output is suppressed. It will begin again once ; 0 is written back into VBLANK. ; RTS ; ; Checking the game switches is relatively simple. ; ; It just so happens that I'm not going to check any game switches ; here. I'm just going to set up the colors, without even checking ; the B&W switch! HA! ; CheckSwitches ;*************************** CONSOLE SWITCH HANDLER LDA #0 STA COLUBK ; Background will be black. RTS ; ; Minimal game calculations, just to get the ball rolling. ; GameCalc ;******************************* GAME CALCULATION ROUTINES CLC LDX PositionX LDA SWCHA ;read joystick AND #$80 CMP #$80 BCS CONT INX STX PositionX CPX #20 BCC CONT LDA invert EOR #$01 STA invert LDX #0 STX PositionX CONT LDA SWCHA ;read joystick AND #$40 CMP #$40 BCS CONT2 DEX STX PositionX CPX #255 BCC CONT2 LDA invert EOR #$01 STA invert LDX #19 STX PositionX CONT2 LDA OFFSET_DATA_0_7,X STA offsetLine0_7 LDA OFFSET_DATA_8_15,X STA offsetLine8_15 LDA OFFSET_DATA_16_19,X STA offsetLine16_19 RTS ChangeDir LDA Direction EOR #$FE STA Direction RTS ; ; This is the scariest thing I've done all month. ; DrawScreen ;**************************** SCREEN DRAWING ROUTINES LDA INTIM BNE DrawScreen ; Whew! STA WSYNC STA VBLANK ;End the VBLANK period with a zero. LDA #2 STA CTRLPF LDA #171 STA ScanLine BlueLines JSR BlueLine DEC ScanLine LDA ScanLine CMP #120 BNE BlueLines LDA #$88 STA COLUBK DEC ScanLine STA WSYNC LDA #$8A STA COLUBK DEC ScanLine LDX invert LDY #$CC LDX #$C4 LDA invert CMP #$01 BNE NOT_INVERT LDX #$CC LDY #$C4 NOT_INVERT STA WSYNC LDA #$9B STA COLUBK DEC ScanLine LDA PositionX CMP #07 BCS Skip1 Skip1 CMP #14 BCS Skip2 Skip2 SLEEP 62 ;LINE 0 SLEEP 12 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 LINEY 3 LINEX 3 SLEEP 14 LINEX 4 LINEY 3 LINEX 4 LINEY 3 LINEX 4 LINEY 3 LINEX 4 LINEY 3 LINEX 4 ; center L LINEY 3 ;center R LINEX 3 LINEY 4 LINEX 3 LINEY 4 LINEX 3 LINEY 4 LINEX 3 LINEY 4 ;LINE 1 LDA offsetLine0_7 AND #%00000010 BNE Line1NoOffset Line1NoOffset SLEEP 13 LINEY 4 LINEX 4 LINEY 4 LINEX 4 LINEY 4 LINEX 4 LINEY 4 LINEX 4 LINEY 4 LINEX 4 LINEY 4 LINEX 4 LINEY 4 SLEEP 18 STX.w COLUBK STY.w COLUBK STX.w COLUBK nop STY COLUBK STX.w COLUBK STY.w COLUBK nop STX COLUBK ;L STY.w COLUBK ;R STX.w COLUBK nop STY COLUBK STX.w COLUBK STY.w COLUBK STX.w COLUBK STY.w COLUBK ;LINEX 4 ;LINEY 4 ;LINEX 4 ;LINEY 4 ;LINEX 4 ;LINEY 4 ;LINEX 5;L ;LINEY 4;R ;LINEX 4 ;LINEY 4 ;LINEX 4 ;LINEY 4 ;LINEX 4 ;LINEY 4 ;LINE 2 LDA offsetLine0_7 AND #%00000100 BNE Line2NoOffset Line2NoOffset SLEEP 11 LINEY 5 LINEX 5 LINEY 5 LINEX 5 LINEY 5 LINEX 5 ;L LINEY 5 ;R LINEX 5 LINEY 5 LINEX 5 LINEY 5 LINEX 5 SLEEP 13 LINEY 5 LINEX 6 LINEY 5 LINEX 6 LINEY 5 LINEX 6 ;L LINEY 5 ;R LINEX 5 LINEY 6 LINEX 5 LINEY 6 LINEX 5 ;LINE 3 LDA offsetLine0_7 AND #%00001000 BNE Line3NoOffset Line3NoOffset SLEEP 12 LINEY 6 LINEX 6 LINEY 6 LINEX 6 LINEY 6 LINEX 6 LINEY 6 LINEX 6 SLEEP 27 LINEY 6 LINEX 6 LINEY 6 nop LINEX 5;L LINEY 6;R LINEX 6 nop LINEY 5 LINEX 5 ;LINE 4 LDA offsetLine0_7 AND #%00010000 BNE Line4NoOffset Line4NoOffset SLEEP 18 LINEY 7 LINEX 7 LINEY 7 LINEX 7 LINEY 7 LINEX 7 LINEY 7 LINEX 7 SLEEP 19 LINEY 7 LINEX 7 LINEY 7 LINEX 8;R LINEY 7;L LINEX 7 LINEY 8 LINEX 7 ;LINE 5 LDA offsetLine0_7 AND #%00100000 BNE Line5NoOffset Line5NoOffset SLEEP 7 LINEY 8 LINEX 8 LINEY 8 LINEX 8 LINEY 8 LINEX 8 LINEY 8 LINEX 4 SLEEP 15 LINEY 8 LINEX 8 LINEY 8 nop LINEX 7 ;L LINEY 8 ;R LINEX 8 nop LINEY 7 LINEX 8 LINEY 4 ;LINE 6 LDA offsetLine0_7 AND #%01000000 BNE Line6NoOffset Line6NoOffset SLEEP 6 LINEX 9 LINEY 9 LINEX 9 LINEY 9 LINEX 9 LINEY 9 LINEX 9 LINEY 3 SLEEP 9 LINEX 9 LINEY 9 LINEX 10 ;L LINEY 9 ;R LINEX 9 LINEY 10 ;LINE 7 LDA offsetLine0_7 AND #%10000000 BNE Line7NoOffset Line7NoOffset SLEEP 10 LINEX 10 LINEY 10 LINEX 10 LINEY 10 LINEX 10 LINEY 10 SLEEP 16 LINEX 10 LINEY 10 LINEX 10 LINEY 10 LINEX 10 LINEY 10 ;line 8 LDA offsetLine8_15 AND #%00000001 BNE Line8NoOffset Line8NoOffset SLEEP 7 LINEX 11 LINEY 11 LINEX 11 LINEY 11 LINEX 11 LINEY 5 SLEEP 15 LINEX 11 LINEY 11 LINEX 10 ;L nop LINEY 11 ;R LINEX 11 LINEY 3 ;line 9 LDA offsetLine8_15 AND #%00000010 BNE Line9NoOffset Line9NoOffset SLEEP 7 LINEX 12 LINEY 12 LINEX 12 LINEY 12 LINEX 12 LINEY 4 SLEEP 12 LINEX 12 LINEY 12 LINEX 12 LINEY 12 LINEX 12 LINEY 4 LINEX 8 ;line 10 LDA offsetLine8_15 AND #%00000100 BNE Line10NoOffset Line10NoOffset SLEEP 8 LINEY 13 LINEX 13 LINEY 13 LINEX 13 LINEY 3 LINEX 3 SLEEP 18 LINEY 13 LINEX 13 LINEY 13 LINEX 13 LINEY 3 LINEX 3 ;line 11 LDA offsetLine8_15 AND #%00001000 BNE Line11NoOffset Line11NoOffset ;SLEEP 18 SLEEP 8 LINEY 14 LINEX 14 LINEY 14 LINEX 14 SLEEP 20 LINEY 14 LINEX 14 LINEY 14 LINEX 4 ;line 12 LDA offsetLine8_15 AND #%00010000 BNE Line12NoOffset Line12NoOffset SLEEP 22 LINEY 15 LINEX 15 LINEY 15 LINEX 3 SLEEP 28 LINEY 15 LINEX 15 LINEY 15 LINEX 3 ;line 13 LDA offsetLine8_15 AND #%00100000 BNE Line13NoOffset Line13NoOffset SLEEP 18 LINEY 16 LINEX 16 LINEY 16 LINEX 4 SLEEP 24 LINEY 16 LINEX 16 LINEY 16 LINEX 4 ;line 14 LDA offsetLine8_15 AND #%01000000 BNE Line14NoOffset Line14NoOffset SLEEP 16 LINEY 17 LINEX 17 LINEY 17 LINEX 3 SLEEP 22 LINEY 17 LINEX 17 LINEY 17 LINEX 3 ;line 15 LDA offsetLine8_15 AND #%10000000 BNE Line15NoOffset Line15NoOffset SLEEP 12 LINEY 18 LINEX 18 LINEY 18 LINEX 4 SLEEP 18 LINEY 18 LINEX 18 LINEY 18 LINEX 4 ;line 16 LDA offsetLine16_19 AND #%00000001 BNE Line16NoOffset Line16NoOffset SLEEP 10 LINEY 19 LINEX 19 LINEY 19 LINEX 3 SLEEP 16 LINEY 19 LINEX 19 LINEY 19 LINEX 3 ;line 17 LDA offsetLine16_19 AND #%00000010 BNE Line17NoOffset Line17NoOffset SLEEP 6 LINEY 20 LINEX 20 LINEY 20 LINEX 4 SLEEP 12 LINEY 20 LINEX 20 LINEY 20 LINEX 4 ;line 18 LDA offsetLine16_19 AND #%00000100 BNE Line18NoOffset Line18NoOffset SLEEP 4 LINEY 21 LINEX 21 LINEY 21 LINEX 3 SLEEP 10 LINEY 21 LINEX 21 LINEY 21 LINEX 3 ;line 19 LDA offsetLine16_19 AND #%00001000 BNE Line19NoOffset Line19NoOffset ;SLEEP 7 LINEY 22 LINEX 22 LINEY 22 LINEX 4 SLEEP 6 LINEY 22 LINEX 22 LINEY 22 LINEX 6 LDA #$0 STA COLUBK ; Draw other lines DrawLines STA WSYNC DEC ScanLine BNE DrawLines STA WSYNC ;Finish this scanline. STA VBLANK ; Make TIA output invisible, RTS ; ; For the Overscan routine, one might take the time to process such ; things as collisions. I, however, would rather waste a bunch of ; scanlines, since I haven't drawn any players yet. ; OverScan ;***************************** OVERSCAN CALCULATIONS LDX #30 KillLines STA WSYNC DEX BNE KillLines RTS BlueLine LDA #$85 STA COLUBK STA WSYNC RTS Line1 STA COLUBK NOP SLEEP 4 LINEX 5 LINEY 5 LINEX 5 LINEY 5 LINEX 5 LINEY 5 LINEX 5 LINEY 5 LINEX 5 LINEY 5 STA WSYNC RTS Line2 STX.w COLUBK SLEEP 5 LINEY 6 LINEX 6 LINEY 6 LINEX 6 LINEY 6 LINEX 6 LINEY 6 LINEX 6 STA WSYNC RTS Line3 SLEEP 6 LINEY 7 LINEX 7 LINEY 7 LINEX 7 LINEY 7 LINEX 7 LINEY 7 LINEX 3 STA WSYNC RTS Line4 SLEEP 9 LINEX 8 LINEY 8 LINEX 8 LINEY 8 LINEX 8 LINEY 8 LINEX 3 STA WSYNC RTS Line5 SLEEP 7 LINEX 9 LINEY 9 LINEX 9 LINEY 9 LINEX 9 LINEY 9 STA WSYNC RTS Line6 SLEEP 3 LINEX 10 LINEY 10 LINEX 10 LINEY 10 LINEX 10 LINEY 8 STA WSYNC RTS Line7 ;SLEEP 1 LINEX 12 LINEY 11 LINEX 11 LINEY 11 LINEX 11 LINEY 3 STA WSYNC RTS Line8 ;SLEEP 1 LINEX 9 LINEY 12 LINEX 12 LINEY 12 LINEX 12 LINEY 4 STA WSYNC RTS Line9 ;SLEEP 1 LINEX 8 LINEY 13 LINEX 13 LINEY 13 LINEX 3 STA WSYNC RTS Line10 ;SLEEP 1 LINEX 5 LINEY 14 LINEX 14 LINEY 4 LINEY 11 LINEX 3 STA WSYNC RTS ; ; GameInit could conceivably be called when the Select key is pressed, ; or some other event. ; GameInit LDA #0 STA PlayfieldY LDA #1 STA Direction; Set Direction to 1 LDA #0 STA PositionX LDA #0 STA invert RTS ; ; Graphics are placed so that the extra cycle in the PFData,X indexes ; is NEVER taken, by making sure it never has to index across a page ; boundary. This way our cycle count holds true. ; org $FF00 ; *********************** GRAPHICS DATA ; ; This is the tricky part of drawing a playfield: actually ; drawing it. Well, the display routine and all that binary ; math was a bit tricky, too, but still, listen up. ; ; Playfield data isn't stored the way most bitmaps are, even ; one-dimensional bitmaps. We will use the left side of the ; screen only, knowing that the right side is either repeated ; or reflected from it. ; ; In PF0 and PF2, the most significant bit (bit 7) is on the RIGHT ; side. In PF1, the most significant bit is on the LEFT side. This ; means that relative to PF0 and PF2, PF1 has a reversed bit order. ; It's just really weird. ; ; PF0 | PF1 | PF2 ; 4 5 6 7|7 6 5 4 3 2 1 0|0 1 2 3 4 5 6 7 ; ; This is important to remember when doing calculations on bytes intended ; for the PF registers. Defender gives a good example of this. ; ; It will become necessary to write a program that makes this easier, ; because it is easy to become confused when dealing with this system. ; OFFSET_DATA_0_7 .byte $0,$0,$80,$20,$10,$88,$48,$24,$94,$54,$B4,$AC,$6C,$DA,$BA,$76,$F6,$DE,$FE,$FE OFFSET_DATA_8_15 .byte $0,$4,$20,$84,$11,$24,$4A,$95,$2A,$55,$AA,$B5,$DB,$6E,$BB,$DF,$FB,$7F,$FB,$FF OFFSET_DATA_16_19 .byte $0,$0,$0,$0,$2,$4,$4,$8,$2A,$A,$2A,$C,$C,$36,$36,$1A,$3A,$3E,$1E,$1E org $FFFC .word Start .word Start File Lines.h: MAC LINEY .CYCLES SET {1} IF .CYCLES < 3 ECHO "MACRO ERROR: 'SLEEP': Duration must be > 2" ERR ENDIF IF .CYCLES & 1 STY COLUBK .CYCLES SET .CYCLES - 3 ELSE STY.w COLUBK .CYCLES SET .CYCLES - 4 ENDIF REPEAT .CYCLES / 2 nop REPEND ENDM MAC LINEX .CYCLES SET {1} IF .CYCLES < 3 ECHO "MACRO ERROR: 'SLEEP': Duration must be > 2" ERR ENDIF IF .CYCLES & 1 STX COLUBK .CYCLES SET .CYCLES - 3 ELSE STX.w COLUBK .CYCLES SET .CYCLES - 4 ENDIF REPEAT .CYCLES / 2 nop REPEND ENDM MAC LINEY2 .CYCLES SET {1} IF .CYCLES < 3 ECHO "MACRO ERROR: 'SLEEP': Duration must be > 2" ERR ENDIF IF .CYCLES & 1 .CYCLES2 SET .CYCLES - 3 ELSE .CYCLES2 SET .CYCLES - 4 ENDIF REPEAT .CYCLES2 / 2 nop REPEND IF .CYCLES & 1 STY COLUBK ELSE STY.w COLUBK ENDIF ENDM MAC LINEX2 .CYCLES SET {1} IF .CYCLES < 3 ECHO "MACRO ERROR: 'SLEEP': Duration must be > 2" ERR ENDIF IF .CYCLES & 1 .CYCLES2 SET .CYCLES - 3 ELSE .CYCLES2 SET .CYCLES - 4 ENDIF REPEAT .CYCLES2 / 2 nop REPEND IF .CYCLES & 1 STX COLUBK ELSE STX.w COLUBK ENDIF ENDM ; EOF

Yep, lots of STY, STY.w, STX, STX.w and NOP's. Trail and error based ;D. flipping colors happens already when you've moved 1 tile to the right/left. What is needed for sprites? I'm programming the 2600 since Thursday and I've read some tutorials. Positioning is tricky, could that be done outside the board? Then data has to be loaded at the beginning of a scanline right? Lot's of shifting around I guess. Now I have the bonus of 3pixel resolution instead of 4. scrolling a part of the checkerboard is now just wait for 1 cycle and everything that comes next is moved 1 cycles (I don't wait for WSYNC)

Two players should be possible. I'll take just small steps for now I'm now doubling the vertical resolution, the tiles at the sides will benefit from this, well... it makes everything look better. I also want to make a finer grained control of the movement to get that 'techy'-look. The horizontal movement is now 20 pixels, I precalculated a vector that turns 45 degrees in 20 steps and used that to control the movement of the grid. I like to calculate 256 pixels heigh vector and use only the upper 20 pixels of it so the horizontal movement has 256 possible positions. Anyone know how to calculate vectors? For vertical tiles I have to make a sort of sinus-table to make the tiles smaller in the distance. Any ideas on this are also welcome. The brown border of the checkerboard needs als to be done. I'll get to this when I've the checkerboard the way I want.

Added some horizontal movement. You can use left/right to move! Some small glitches in the lookup table to fix. I've only tested it in Stella so far. What do you think about it? ballblazer.bin

3 color sprites? Looks very good.

It's looking more like Ballblazer now, so I call it ballblazer.bin The checkerboard is now 20 lines heigh. It consists only of vertical stripes, but it looks pretty good for a atari 2600 game. I also added some sky just to make it look nice. Now all I have to do is some animation and turn the stripes into tiles... ballblazer.bin

I've used it and I found it extremely convinient. Of course I will never sell my original cartridges, but as an addition, to get downloaded stuff on my atari. So for me its: 1. Cartridges, cause they are real plug and play. 2. SIO2PC for the rest.

Maybe if I make the tiles bigger (start with 18 pixels) so the difference isn't as extreem... (18-21-24 instead of 9-12-15 etc.) I'll try that.

How would the game look with three-pixel resolution for the checkerboard (i.e. using lots of well-timed STA COLUBK / STY COLUBK / etc.)? Are the squares ever less than nine pixels wide? My guess would be that three-pixel resolution would be too chunky, but if it would look okay the lots-of-stores approach would allow the use of all five sprites for other purposes. I made a test with 2 lines and I stopped, it looked damn crappy. I've attached the bin so you can see. Maybe you could build the checkerboard with sprites, but I've not reached that part of the tutorial yet testje.bin

Seeing so many IBM PC + Clones being sold just hurts...

Sorry for redundant posts, but are there some specs about that video-enhanchment cartridge?

http://news.cnet.com/8301-17938_105-10029963-1.html Remove the internals and put an FPGA Atari in it

If the atari only has to tell the videoboard to draw which sprite on what location, I don't see any problem.

Wow these are real treasures. It explains what was really going on when I was six and played DK Well documented too. It would be nice if someone could compile those sources. Are there also sources from Pacman?

I would like to see a game like Lethal Weapon 3 on the amiga. So I voted for 'Shoot 'm up'

Outrun!!!

Sounds like a good idea, but would it actually be possible to guaratneed that the Antic were in perfect sync? For example, could one Atari run at say 1.780000MHz (as an example) and another at 1.78001000 through natural deviations within the system? Would this 1Khz make a difference? Possibly not. I guess you could fix that by generating one clock signal and feed it to the two ataris.

Agreed. I'm an 8-bit fan too, and I would just keep just 1 8-bit computer to have 'the real thing', instead of emulation, and then stream disks with APE or something like that.