Difference between revisions of "K65 Tutorial 3"

/*
*	Tutorial 03 - data... continued
*
*
*/
 
// RAM variables
var anim=0x80, cntX, cntY;	// you can declare consecutive variables in single statement
 
 
data sprite {
	align 256
	// image <file> <x0> <y0> <byte> <repeat> - gather bits from image
	//	<file>		- file name without ".bmp" extension
	//	<x0> <y0>	- first pixel to scan
	//	<byte>		- scanning mode for each single byte starting with MSB (count+direction)
	//	<repeat>	- scanning mode for consecutive bytes (count+direction)
 
	image sprites  0 0 8> 16v		// start at pixel (0,0), each byte is 8 bits to the right, repeat 16 times going up
	image sprites 10 0 8> 16v		// do the same from (10,0)
	image sprites 20 0 8> 16v		// and again starting at (20,0)
}
 
data SineX {
	align 256
	0
	for x=0..213 eval [ (sin(x/212*pi*2)*.499+.499)*130 ]
}
 
data SineY {
	align 256
	0
	for x=0..255 eval [ (sin(x/256*pi*2)*.499+.499)*180+1 ]
}
 
// entry point block is declared with "main"
main {
	init
	cntX=a=1
 
	{
		sync1
		sync2
		sync3
 
		// compute sprite frame and data start
		a=anim a<< a&0x30	// LDA+ASL+AND - you can write everything in single line, too
		a?0x30				// CMP
		=={ a=0x10 }		// if zero/equal (uses BNE)
		y=a
 
		// position sprite in X axis
		x=cntX
		a=SineX,x
		nocross {	// make sure following code doesn't cross page boundary
			wsync { a-15 }>=0 a<< a<< a<< a<< a^0x70 hp0=a *5 rp0=a		// sprite position trick
		}
		wsync hmove=a
 
		// ...and in Y axis
		x=cntY
		a=SineY,x
		x=a
		{ wsync x-- }!=		// one-liners rulez ;)
 
 
		// draw sprite
		x=16
		cp0=a=0x0F
		ns0=a=5		// double size
		{
			wsync
			gp0=a=sprite,y
			wsync
			y++
			x--
		}!=
		wsync
		gp0=a=0
 
		// animate
		anim++
		cntX-- =={ cntX=a=213 }
		cntY--
 
	} always	// loop forever
}