This is one of the programs that Codeman wanted to see.
This is really simple, and just a 2D starfield, it is fully commented, a tutorial to accompany this will follow soon.
'
' FREEBASIC 2D STARFIELD USING TINYPTC FOR CODEMAN
' Tutorial Coming Soon!
'
' This program makes a very simple 5 layer parallax starfield
'
'
' Please use the extended version of Tinyptc by Rbraz when you use this listing
' it will run far too fast otherwise!!!!!!
'
'-------------------------------------------------------------------------------
' Fixed Size Arrays, All Variables must be declared;
OPTION STATIC
OPTION EXPLICIT
' Include the tinyptc library. Uncomment line for windowed mode.
' #DEFINE PTC_WIN
#INCLUDE "TINYPTC.BI"
'-------------------------------------------------------------------------------
' Variable Definitions.
'-------------------------------------------------------------------------------
' CONST Means Constant Value, cannot be changed in the program.
' CONST is recognised by all parts of the program, ie. it is treated
' as a global variable.
' INTEGER Means a whole number with no fraction part, no decimal
' point in other words
CONST XRES AS INTEGER = 640:' Screen Width In Pixels.
CONST YRES AS INTEGER = 480:' Screen Height In Pixels.
' DIM SHARED means create a global variable as integer (whole number)
' "BUFFER" IS A 1 DIMENSIONAL ARRAY OF (XRES * YRES) Elements.
DIM SHARED AS INTEGER BUFFER ( XRES * YRES ):' The Screen Array.
' This is how we define a variable;
DIM SHARED AS INTEGER NUMBER_OF_STARS = 1000:' How many stars to have.
DIM SHARED AS INTEGER SX(NUMBER_OF_STARS):' WILL STORE X POS
DIM SHARED AS INTEGER SY(NUMBER_OF_STARS):' WILL STORE Y POS
DIM SHARED AS INTEGER SS(NUMBER_OF_STARS):' WILL STORE SPEED
'-------------------------------------------------------------------------------
' Subroutine Definitions.. We Need 2, One to set up the starfield
' And one to draw / move it.
'-------------------------------------------------------------------------------
DECLARE SUB SET_STARS():' SET UP STARFIELD
DECLARE SUB DO_STARS():' MOVE / DRAW STARS ETC.
' This is how we call a subroutine;
SET_STARS():' Set Star Positions and speed.
' Open The Screen;
IF (PTC_OPEN("STARFIELD",XRES,YRES)=0) THEN
END-1
END IF
'
' Main Loop;
'
WHILE (1)
DO_STARS():' Do the starfield
PTC_UPDATE@BUFFER(0):' Update Screen
ERASE BUFFER:' Clear Screen
WEND
END
'
' Do The Starfield;
'
SUB DO_STARS()
' PLEASE NOTE THE VARIABLE "SL"
' ALTHOUGH THIS VARIABLE NAME IS THE SAME AS IN THE OTHER SUB, IT IS
' A COMPLETELY SEPERATE VARIABLE, AS IT IS A LOCAL VARIABLE :-)
' GENERALLY IT IS BAD PROGRAMMING PRACTICE TO DO WHAT I HAVE DONE HERE
' YOU SHOULD GIVE THE LOOP A PREFIX LIKE DO_STARS_SL
'
DIM AS INTEGER SL :' Used as a pointer in loop.
FOR SL=1 TO NUMBER_OF_STARS
SX(SL)=SX(SL)+SS(SL) : ' Move Star
IF SX(SL) > XRES THEN SX(SL)=SX(SL)-XRES :' reset it if off screen
IF SX(SL)>0 AND SX(SL)<XRES THEN:' Check if onscreen before drawing
'Draw in the correct colour according to speed.
IF SS(SL) =1 THEN BUFFER (SX(SL) + ( SY(SL) * XRES) ) = &H444444
IF SS(SL) =2 THEN BUFFER (SX(SL) + ( SY(SL) * XRES) ) = &H777777
IF SS(SL) =3 THEN BUFFER (SX(SL) + ( SY(SL) * XRES) ) = &HAAAAAA
IF SS(SL) =4 THEN BUFFER (SX(SL) + ( SY(SL) * XRES) ) = &HCCCCCC
IF SS(SL) =5 THEN BUFFER (SX(SL) + ( SY(SL) * XRES) ) = &HFFFFFF
END IF
NEXT
END SUB
'-------------------------------------------------------------------------------
' THIS SIMPLY MAKES A RANDOM X AND Y LOCATION FOR EACH STAR
'-------------------------------------------------------------------------------
SUB SET_STARS()
' Because this is being dimensioned inside a sub, the variable SL
' is inaccessible by any other part of the program, it will only work in
' THIS sub.
DIM AS INTEGER SL:' Loop counter variable
for SL = 1 TO NUMBER_OF_STARS
SX(SL) = INT(RND(1) * XRES):' GENERATE AND STORE NUMBER BETWEEN 0 AND XRES
SY(SL) = INT(RND(1) * YRES):' GENERATE AND STORE NUMBER BETWEEN 0 AND YRES
SS(SL) = INT(RND(1) * 5) + 1:' RANDOM SPEED
NEXT
END SUB
