INTERACTIVE DEVELOPMENT AND PLAY VIDEO GAMES AT THE SAME TIME!
Tachyon is an interactive programming language and environment for the Parallax Propeller multicore microcontroller based on the Forth language. Even though the Propeller chip only has 32kB of RAM for code and data we can easily have a full Tachyon environment loaded along with FAT32 support, even FTP and HTTP servers AND play a video game. There's a trick to getting it into memory though, the VGA display uses a 32 character by 15 line mode where each character's color can be set. It also uses the Propeller ROM font so special lines and shapes are available. With this we can draw bricks, a ball, and a paddle. The ball is actually a programmble character that is rewritten to move the ball with finer movements than would be possible with just using character postiions.
Later version
CODE - just copy and paste into terminal then type BREAKOUT to run it. If you have a piezo transducer or speaker (other than pin 10) then for example P6 then type 6 SPKR before running BREAKOUT.
(BTW - This code needs a small module VGA.FTH loaded. I think there is a small bug in this version I need to track down. )
TACHYON V5 ( 1030 CODE BYTES ) { BREAKOUT for 32x15 VGA text Updated for V5 NEON Code bytes used = 1020 }
module BREAKOUT PRINT" VGA BREAKOUT GAME " ;
TIMER duration
--- hitting a wall sound pub BONK 300 HZ 50 duration TIMEOUT ;
--- palette to suit game TABLE gamepal $0800_0800 , $0808_0000 , $F000_F000 , $F0F0_0000 , $8000_8000 , $8080_0000 , $2000_2000 , $2020_0000 , $8800_8800 , $8888_0000 , $2800_2800 , $2828_0000 , $5400_5400 , $5454_0000 , $A800_A800 , $A8A8_0000 ,
--- palette colors 0 := red 1 := grn 2 := blu 3 := yel 4 := mag 5 := cyan 6 := gry 7 := wht
--- back of the brick wall - leave room for the ball to bounce behind 3 := backwall
$7F00 := bram $03FC := bval
byte score byte balls
pri BRICKS? ( -- cnt ) score C~ backwall cols * 2* screen + FROM 2 BY cols 4* FOR I C@ 14 <> IF score C++ THEN NEXT ; --- calculate how many bricks have been removed and display pri .SCORE BRICKS? grn HUE cols 7 - 0 VXY VGA score C@ .AS" ###/128" <CR> balls C@ .AS" # balls" ;
--- ball position variables word bx word by word abx word aby word bdir
--- initialize the brick wall with 4 rows of random colored bricks/tiles from backwall (gap) pub WALL 0 backwall VXY cols 4* FOR RND 8>> 7 AND HUE 14 VCHAR NEXT ;
{ The ball is drawn with a single character but by using codes which force the driver to access RAM for the font we can have finer movement by drawing a ball character dynamically in x 16x32 matrix Use code $3FA to access table at $7E80 This routine is essentially the same as VCHAR but optimized for directly writing without scroll Execution time: 48.8us --- 10-bit character } pub VCHAR! ( ch -- ) --- (color << 1 + c & 1 ) DUP 1 AND color C@ 2* + --- form color field 2* 1+ 9 << --- merge 7 msb of data SWAP 1 ANDN + --- current screen position row C@ 5 << col C@ + DUP 960 < --- write to the screen word & inc column IF 2* screen + W! col C++ ELSE 2DROP THEN ;
TIMER balldly --- timeout leads to next ball movement word speed
--- rebound translation table looks up the corresponding rebound direction ( 7 into left returns with 9 ) TABLE rebound --- 0 1 2 3 4 5 6 7 8 9 0 | 7 | 8 | 9 | 6 | 5 | 4 | 1 | 2 | 3 | --- bottom/top rebound 0 | 3 | 8 | 1 | 6 | 5 | 4 | 9 | 2 | 7 | --- left/right rebound
--- lookup the table for the rebound action & sound pub BOUNCE ( table-offset -- ) rebound + bdir C@ + C@ BONK ; pri BALL@ ( -- word ) bx W@ 2/ 2/ by W@ 3 >> cols * + 2* screen + W@ ;
--- read the contents of the screen cell/tile where the ball will be next
pub NOBALL bx W@ 2/ 2/ by W@ 3 >> VXY $20 VCHAR! ;
pri !BALL NOBALL pri NEWBALL 64 bx W! 60 by W! 50 speed W! 1 bdir C! --- delay serving 1st ball for 1.5secs 1500 balldly TIMEOUT pub BALL --- limit ball x bx W@ cols 2* 2* MIN bx W! --- limit ball y by W@ rows 2* 2* 2* MIN by W! --- bounce off special tiles (not blank or alphanumeric) BALL@ >B 20 'z' WITHIN NOT IF 0 BOUNCE EXIT THEN --- bounce off bottom by W@ rows 3 << 1- => IF 0 BOUNCE EXIT THEN --- bounce off top by W@ 1 < IF 0 BOUNCE EXIT THEN --- bounce off left wall bx W@ 0= IF 10 BOUNCE EXIT THEN --- bounce off right wall bx W@ 2/ 2/ cols => IF 10 BOUNCE EXIT THEN \ pub DRAWBALL ( -- ) --- plot ball as 4x4 block - 185us wht HUE bx W@ by W@ --- address the screen position for the tile - 17.2us OVER 2/ 2/ OVER 2/ 2/ 2/ VXY --- maps to programmable char at $7E80 - 63.6us bval VCHAR! --- generate a dot in the correct x position - 7.8us SWAP 3 AND 2* 2* 2* $AA SWAP << --- wipe the character clean - 64.6us bram 128 ERASE --- calculate y position in character - 8.4us SWAP 7 AND 4 << bram + ( mask addr ) --- create the pattern SWAP OVER ! DUP 4 + 12 CMOVE ;
--- setup constants for ball x and y movement increments which contain 2 fractional bits 1 := abxcon 1 := abycon
pri BALL+! ( x y -- ) NOBALL by W+! bx W+! BALL ;
--- Check if ball is ready for next movement and proceed pub ?BALL --- ready yet? balldly TIMEOUT? 0EXIT --- yes, set next timeout period speed W@ score C@ 2/ 2/ - 0 MAXS balldly TIMEOUT --- proceed using the ball direction bdir C@ SWITCH 7 CASE abxcon NEGATE abycon NEGATE BALL+! BREAK 9 CASE abxcon abycon NEGATE BALL+! BREAK 1 CASE abxcon NEGATE abycon BALL+! BREAK 3 CASE abxcon abycon BALL+! BREAK ;
--- paddle xy byte px byte py
--- two characters that make up the paddle $8E88 := mypad $2020 := nopad
--- draw the paddle pub ?PADDLE mypad pub PADDLE ( shape -- ) yel HUE px C@ py C@ VXY W>B VCHAR VCHAR ;
--- PADDLE MOVEMENTS pub L px C@ IF nopad PADDLE px C-- mypad PADDLE THEN ; pub R px C@ cols 2 - < IF nopad PADDLE px C++ mypad PADDLE THEN ;
pri NEWPADDLE rows 1- py C! 15 px C! mypad PADDLE ;
pub GAMEOVER red " GAME OVER" ( 11 8 TEXTBOX ) CON CONSOLE ;
pub NEWGAME VGA CLS NEWPADDLE NEWBALL WALL 7 0 VXY 2 HUE PRINT" TACHYON BREAKOUT " 3 balls C! score C~ ;
pri FASTER speed W@ IF speed W-- THEN ; pri SLOWER speed W++ ;
--- game control keys --- pub GAMEKEY KEY ?DUP 0EXIT SWITCHES 'Z' L 'X' R 'z' L 'x' R '+' FASTER '-' SLOWER 'B' !BALL $0D NEWGAME $1B GAMEOVER ;
pub ACTION --- make it speed up proportionaly to the score \ 130 score C@ - 3 / speed W! GAMEKEY ?BALL ?PADDLE duration TIMEOUT? IF MUTE THEN .SCORE --- testing: autostart a new game score C@ 128 = IF NEWGAME THEN ;
pub BREAKOUT !VGA 0 duration TIMEOUT gamepal colors 64 CMOVE NEWGAME 2 s pub RESUME 30 FLOAT VGA BEGIN ACTION AGAIN ;
10 SPKR ( assign a pin for audio ) END
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