PlayBASIC Tutorial: From Variables To Arrays (Intro To Arrays) 2017-09-17Welcome programmers, in this tutorial we're going to introduce the concept of arrays starting out from variables. So first we build a simple game loop that controls two characters using only variables. The characters are represented on screen as filled circles. After we get up to speed with the variable version we then move onto how we can use parallel integer arrays to store the various properties of the characters. The array version can control as many or as few characters as you like, which is the benefit of Arrays over Variables
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Video: Example #1 - Variables Example [pbcode]
Xpos1 = 400
Ypos1 = 300
Xpos2 = 100
Ypos2 = 100
setfps 20
do
cls rgb(10,20,40)
; Draw circle 1
Circle Xpos1,Ypos1, 32, true
Xpos1 = Xpos1 + 2
Ypos1 = Ypos1 - 4
Xpos1 = WrapValue(Xpos1,0,800)
Ypos1 = WrapValue(Ypos1,0,600)
; Draw circle 2
Circle Xpos2,Ypos2, 64, true
Xpos2 = Xpos2 + 2
Ypos2 = Ypos2 + 2
Xpos2 = WrapValue(Xpos2,0,800)
Ypos2 = WrapValue(Ypos2,0,600)
sync
loop
[/pbcode]
Example #2 - Arrays Example - Using Parallel Arrays To Store Character Properties[pbcode]
Setfps 20
Number_Of_Characters = 50
dim Xpos( Number_Of_Characters )
dim Ypos( Number_Of_Characters )
dim size( Number_Of_Characters )
dim Xspeed( Number_Of_Characters )
dim Yspeed( Number_Of_Characters )
dim Colour( Number_Of_Characters )
for lp = 1 to Number_Of_Characters
Xpos(lp) = rnd(800)
Ypos(lp) = rnd(600)
Size(lp) = rndrange(16,50)
Xspeed(lp) = rndrange(-5, 5)
Yspeed(lp) = rndrange(-5,5)
Colour(lp) = rndrgb()
next
do
Cls rgb(0,400,20)
for lp=1 to Number_Of_Characters
Radius = Size(lp)
circlec xpos(lp),ypos(lp),Radius,true,Colour(lp)
// xpos(lp) = Xpos(lp) + Xspeed(lp)
// ypos(lp) = ypos(lp) + Yspeed(lp)
xpos(lp) = wrapvalue(xpos(lp) + Xspeed(lp) , -Radius, 800 + Radius)
ypos(lp) = wrapvalue(ypos(lp) + Yspeed(lp) , -Radius, 600 + Radius)
next
Sync
loop
[/pbcode]