SOURCE CODE ()

REM Note that this example will be executed everywhere 
REM BUT Commodore VIC-20 and Philips VG5000.

PROCEDURE example ON ALL BUT VIC20, VG5000

	BITMAP ENABLE(16)
	
	DEFINE PALETTE NOT PRESERVE
	
	CLS BLACK
	
	mask := LOAD IMAGE("blit_mask.png") EXACT TRANSPARENCY BLACK OPACITY LIGHT WHITE
	background := LOAD IMAGE("blit_background.png")
	sprite := LOAD IMAGE("blit_sprite.png")
	
	CONST x = ( SCREEN WIDTH - IMAGE WIDTH(background) ) \ #2
	CONST y = ( SCREEN HEIGHT - IMAGE HEIGHT(background) ) \ #2
	
	PUT IMAGE background AT x,y
	
	REM In the first blit, the mask is blitted onto the background using 
	REM the raster operator AND. Because any value ANDed with 0 equals 0, 
	REM and any value ANDed with 1 is unchanged, black areas are created 
	REM where the actual sprites will appear, while leaving the rest of 
	REM the background alone.
	
	BLIT bop1 AS ( ( SOURCE ) AND ( DESTINATION ) )
	BLIT IMAGE mask AT x+10,y+10 WITH bop1
	
	REM In the second blit, the sprite is blitted onto the newly altered 
	REM background using the raster operator of OR. Because any value 
	REM ORed with 0 is unchanged, the background is unaffected and the 
	REM black areas are filled with the actual sprite image.
	
	BLIT bop2 AS ( ( ( INVERSE ( SOURCE 2 ) ) AND ( SOURCE 1 ) ) OR ( DESTINATION ) )
	BLIT IMAGES sprite, mask AT x+10,y+10 WITH bop2
	
END PROC

CALL example ON ALL BUT VIC20, VG5000
	
	
	

Dragon 32

In order to compile the example, type this command on the command line:

Linux

ugbc.d32 -O bin -o blit_basic_mask.bin blit_basic_mask.bas

Windows

ugbc.d32.exe -O bin -o blit_basic_mask.bin blit_basic_mask.bas

For Microsoft Windows users we suggest using UGBASIC-IDE, which allows you to download and compile this example with just one click.

SEGA SC-3000

In order to compile the example, type this command on the command line:

Linux

ugbc.sc3000 -O rom -o blit_basic_mask.rom blit_basic_mask.bas

Windows

ugbc.sc3000.exe -O rom -o blit_basic_mask.rom blit_basic_mask.bas

For Microsoft Windows users we suggest using UGBASIC-IDE, which allows you to download and compile this example with just one click.

TRS-80 Color Computer, TRS-80 Color Computer 2

In order to compile the example, type this command on the command line:

Linux

ugbc.coco -O bin -o blit_basic_mask.bin blit_basic_mask.bas

Windows

ugbc.coco.exe -O bin -o blit_basic_mask.bin blit_basic_mask.bas

For Microsoft Windows users we suggest using UGBASIC-IDE, which allows you to download and compile this example with just one click.