Missile variables question

[Byte Knight]

So if I use the no_blank_lines and player1colors kernel options, are missile0 & missile1 x,y, and height variables available for general use?

 

Thanks!

[SeaGtGruff]

So if I use the no_blank_lines and player1colors kernel options, are missile0 & missile1 x,y, and height variables available for general use?

You can look in the 2600basic.h file to see which variables get reused, and which are free. The following variables are devoted to missile0 and missile1:

 

missile0x = $82

missile0height = $90

missile0y = $91

 

missile1x = $83

missile1height = $87

missile1y = $88

 

What you want to do is look through the other equates to see if anything else is assigned to those six RAM addresses:

 

player0colorstore = $82 ; replaces missile 0

 

currentpaddle = $90 ; replaces missile 0 (and can't be used with playercolor)

player0color = $90 ; replaces missile 0

 

paddle = $91 ; replaces missile 0

 

player1color = $87 ; replaces missile 1

 

Nothing else is assigned to $83 or $88, so if you aren't using (or can't use) missile1, that means you should be able to safely dim two of your own variables to missile1x and missile1y. But the player1colors option uses $87, so you won't be able to dim anything to missile1height if you're going to use that option.

 

Something else is assigned to $82, $90, and $91, so whether or not you can dim anything to missile0x, missile0height, and missile0y depends on whether you're using an option that uses those RAM addresses. Basically, if you're going to use the playercolors option (which lets you change the color of player0 in addition to player1), then you can't dim anything to missile0x or missile0height. Or if you're going to use the readpaddle option, then you can't dim anything to missile0height or missile0y. But if you aren't going to use either of those options, then you should be able to safely dim three of your own variables to missile0x, missile0height, and missile0y.

 

Michael

[Byte Knight]

So if I use the no_blank_lines and player1colors kernel options, are missile0 & missile1 x,y, and height variables available for general use?

 

Nothing else is assigned to $83 or $88, so if you aren't using (or can't use) missile1, that means you should be able to safely dim two of your own variables to missile1x and missile1y. But the player1colors option uses $87, so you won't be able to dim anything to missile1height if you're going to use that option.

 

Something else is assigned to $82, $90, and $91, so whether or not you can dim anything to missile0x, missile0height, and missile0y depends on whether you're using an option that uses those RAM addresses. Basically, if you're going to use the playercolors option (which lets you change the color of player0 in addition to player1), then you can't dim anything to missile0x or missile0height. Or if you're going to use the readpaddle option, then you can't dim anything to missile0height or missile0y. But if you aren't going to use either of those options, then you should be able to safely dim three of your own variables to missile0x, missile0height, and missile0y.

 

Michael

 

Thanks Michael! That will be huge if I can use 5 more variables in my game...