Glitch effect for Pico-8

glitchfx.p8

function glitchfx(lines)
	local lines=lines or 64
	
	for i=1,lines do
		row=flr(rnd(128))
		row2=flr(rnd(127))
		if (row2>=row) row2+=1
		
		// copy a row from the
		// screen into temp memory
		memcpy(0x4300, 0x6000+64*row, 64)
		
		//copy another row from the
		// screen to our original row
		memcpy(0x6000+64*row, 0x6000+64*row2, 64)
		       
		//copy the temp row into row2's
		//original slot
		memcpy(0x6000+64*row2, 0x4300,64)
	end
end