Boing Demo

[CurtisP]

Anyone remember the Boing Demo from the Amiga. Don't know if it's been done on the 2600 before, but I thought I'd try it in bAtari Basic.

 

So far I've defined the sprites for the ball and made it rotate. Movement and sound will come later...

boing01.bas

boing01.bas.bin

[uosipa llamxew]

It's always good to see someone developing for the VCS.

 

I'm not sure if you were aware, so I'll post the link to David Galloway's version of the Boing! demo on the 2600:

http://www.atariage.com/store/index.php?ma...products_id=321

[Thomas Jentzsch]

The ROM is for download too. Cool stuff!

[SeaGtGruff]

Anyone remember the Boing Demo from the Amiga. Don't know if it's been done on the 2600 before, but I thought I'd try it in bAtari Basic.

 

So far I've defined the sprites for the ball and made it rotate. Movement and sound will come later...

Since Boing has already been done, you might want to call this one bB_Boing ("buh-buh-BOING").

 

Nice rotating ball, by the way!

 

Michael

[CurtisP]

Since Boing has already been done, you might want to call this one bB_Boing ("buh-buh-BOING").

I like that, I shall rename it accordingly.

 

Nice rotating ball, by the way!

Thanks. I made it lateral, instead of diagonal, since there is so little resolution in a 16x16 area.

[supercat]

Thanks. I made it lateral, instead of diagonal, since there is so little resolution in a 16x16 area.

 

Why not 18x18? BB lets you position the missiles arbitrarily, doesn't it?

[CurtisP]

Why not 18x18? BB lets you position the missiles arbitrarily, doesn't it?

 

That's true, I could use the missiles as the left and right side of the ball. But then I've already drawn the ball and it came out pretty nice. I wonder if there's something I could do with the ball...

[gambler172]

looks good

greetings gambler172

[djmips]

Looking forward to movement and sound. I hope you don't mind but here is snippet of code to help with the movement in bBasic. I wanted to point out the necessity in using the 0.0 - var format for inverting a fixed point var.

 

rem Setting up x position y position x velocity and y velocity as fixed point variables

dim xpos = a.b
dim ypos = c.d
dim xvel = e.f
dim yvel = f.g

rem Somewhere in your loop
rem update x position y velocity and y position (gravity constant is 0.8)

xpos = xpos + xspeed
yvel = yvel + 0.08
ypos = ypos + yvel

rem Bounce

if ypos < 90 then goto setPos

rem Reflect y velocity and restore y position, you must use this form instead of yvel = -yvel
yvel = 0.0 - yvel
ypos = ypos + yvel

setPos

[CurtisP]

Looking forward to movement and sound. I hope you don't mind but here is snippet of code to help with the movement in bBasic. I wanted to point out the necessity in using the 0.0 - var format for inverting a fixed point var.

 

I don't mind at all. Thanks for the code.

[CurtisP]

So I got the movement all working, then I figured, her why not add sound, which took me exactly 10 minutes (bAtari Basic rocks!).

 

So here it is.

bBboing.bas

bBboing.bas.bin

[SeaGtGruff]

Very nice!

 

Michael

[djmips]

If you just modify the code starting at line 55, you can get a nice bounce. Just adding the gravity to the yvel every frame and then make sure to restore the ypos in the bounce part of the if. Here is the mod in bold text.

 

yvel = yvel + 0.08

ypos = ypos + yvel

if ypos < 23 || ypos > 80 then yvel = 0.0 - yvel: ypos = ypos + yvel: temp1 = 1

[CurtisP]

If you just modify the code starting at line 55, you can get a nice bounce. Just adding the gravity to the yvel every frame and then make sure to restore the ypos in the bounce part of the if.

 

From what i recall the original Boing Demo didn't have gravity anyway. I think I'd rather make the ball bigger. One of the big deals on the Amiga was how large the ball was.

[CurtisP]

That black area at the bottom of the screen was totally bothering me. Since score was turned off, I simply set pfrowheight to a high enough value (10) to make the playfield fill the screen. I then decided to use PF0 to draw in the left and right borders, and cleared the borders from my playfield definition.

 

It turns out that bAtari Basic doesn't have a hard limit on the Sprite Y values, it will keep displaying sprites as long as it's displaying playfield, so I changed my boundaries accordingly, and now I'm bouncing aroud the whole screen.

bBboing.bas

bBboing.bas.bin

[+LS650]

A screenshot for your viewing pleasure...