title: "vbmDrawSpriteSlice" description: TRSE built-in method (from IDE help)

`vbmDrawSpriteSlice`

Systems: VIC20
Parameters: a, b, b

vbmDrawSpriteSlice( [address1], [byte-start], [byte-end] );

[address1] - pre-shifted address table
[byte-start] - the row in the sprite to start drawing from, usually 0
[byte-end] - the row in the sprite to end drawing, usually the height of the sprite

Description

A flexible sprite routine to display a single 'slice' of a sprite on the bitmap.

The first parameter is an address table pointing to where each pre-shifted frame can be found in memory.

For example: $a000, $a080, $a1000, $a180

The address table will need to be defined if you import your sprites already pre-shifted. If you use the vbmSpriteShiftL / R commands, these will build the address table for you.

There are three ways to draw a sprite:

vbmDrawSpriteSlice - draws a sprite slice, merging it with the bitmap
vbmDrawSpriteSliceE - draws a sprite slice, merging it with the bitmap using the EOR operation
vbmClearSpriteSlice - clears a sprite slice from the bitmap, effectively 'cutting it out'

Example


    spr: incbin("spr24x40.bin", $4000); // this sprite is 24 x 40
    @define spra0 $4000
    @define spra1 $4028
    @define spra2 $4050

    ...    

    x,y :byte;

    // our sprite is 24 x 40.  So need 4 byte columns for pre-shifted data
    // will pre-shift in increments of 2 so 4 addresess per byte required
    spr0 : array[4] of integer; 
    spr1 : array[4] of integer; 
    spr2 : array[4] of integer; 
    spr3 : array[4] of integer; 

    ...

    // sprite is 24 x 40.  Need 40 bytes per shift ($28) x 4 shifts = $A0
    vbmSpriteShiftR( ^@spra0, ^$a000, 2, 40, spr0 ); 
    vbmSpriteShiftL( ^@spra0, ^$a0A0, 2, 40, spr1 ); 

    vbmSpriteShiftR( ^@spra1, ^$a140, 2, 40, spr2 ); 
    vbmSpriteStitch( ^$a140, ^$a0a0, 160 );  // 40 high * 4 = 160
    vbmSpriteShiftL( ^@spra1, ^$a140, 2, 40, spr2 ); 

    vbmSpriteShiftR( ^@spra2, ^$a1E0, 2, 40, spr3 ); 
    vbmSpriteStitch( ^$a1E0, ^$a140, 160 );
    vbmSpriteShiftL( ^@spra2, ^$a1E0, 2, 40, spr3 ); 

    y := 10;

    for x := 0 to 100 do
    begin

        vbmSetPosition2( x, y ); // position the sprite, 2 pixel increments
        vbmDrawSpriteSlice( spr0, 0, 40 );
        vbmNextColumn();
        vbmDrawSpriteSlice( spr1, 0, 40 );
        vbmNextColumn();
        vbmDrawSpriteSlice( spr2, 0, 40 );
        vbmNextColumn();
        vbmDrawSpriteSlice( spr3, 0, 40 ); 

        waitforraster( 0 ); // wait for raster

        vbmSetPosition2( x, y ); // position the sprite, 2 pixel increments
        vbmClearSpriteSlice( spr0, 0, 40 );
        vbmNextColumn();
        vbmClearSpriteSlice( spr1, 0, 40 );
        vbmNextColumn();
        vbmClearSpriteSlice( spr2, 0, 40 );
        vbmNextColumn();
        vbmClearSpriteSlice( spr3, 0, 40 );

    end;

vbmDrawSpriteSlice