vbmScreenShiftRight

vbmScreenShiftRight( [byte-start], [byte-end] );

• [byte-start] - row in the bitmap to start scrolling from
• [byte-end] - row in the bitmap to end scrolling

Description

Scrolls the bitmap, between the start row and end row, by 1 pixel to the right. The whole screen can be scrolled with a start of 0 and end of 192, however, this will take some time to do and the best your game will perform is 25/30 frames per second. Reducing the area of the bitmap that is scrolled will improve the speed.

Pixels that move off one side will emerge on the other.

Use vbmSetDisplayMode(1) to hide the last column (19) on the screen. The column will still be present in the bitmap but will not be displayed on the Vic 20 screen. Use this last column to draw new tiles / graphics to scroll in to view, rather than 'popping' into view if column 19 was visible.

Example

vbmScreenShiftRight( 16, 192 ); // scroll from line 16, end at line 192

See also

• vbmScreenShiftLeft