SCREEN and VARPTR

[artrag]

I was trying to code a 4 frame animation: I need to plot a small 9x9 square of tiles on the screen taken from different positions in a large ROM area ad change the place from the data come at each frame

I was doing this 

 

    for i=0 to 3
        SCREEN VARPTR #room0_0(i*9*9),0,0,9,9,9
        wait
    next
 

BUT it seems that SCREEN does not support VARPTR....

 

Oscar can we add this feature if it is missing ?

Or

Is there a workaround I cannot see?

Maybe playing on the origin_offset....

 

 

Edited March 13, 2021 by artrag

[+DZ-Jay]

Hi, @artrag,

 

Looking at the source of the compiler, I see that SCREEN does not accept anything other than a "name" (label or variable symbol) as its first argument, so VARPTR is not allowed.

 

Notwithstanding, the documentation has this to say:

Quote

  SCREEN label[,origin_offset,target_offset,cols,rows]
  SCREEN label[,origin_offset,target_offset,cols,rows,origin_width]

 

  ...

 

  Label can be also a 16-bits array for dynamically-drawn elements.

 

        DIM #cards(4)

        SCREEN #cards,0,0,4,1

 

So it means that if you are using a 16-bit array, you shouldn't need the VARPTR at all.  Have you tried the following:

    for i=0 to 3
        SCREEN #room0_0(i*9*9),0,0,9,9,9
        wait
    next

 

Edited March 13, 2021 by DZ-Jay

[artrag]

thanks, I ended to use the first parameter as an offset

 

    SCREEN #room0_0,#j, 0,9,9,9

    #j = #j + 9*9

 

 

Edited March 13, 2021 by artrag