plasma - frame

gistfile1.asm

plasma_frame:

	; jump over the local variables
	jmp plasma_frame_code

	temp_phase_1 DB	0
	temp_phase_2 DB 0
	temp_phase_3 DB 0
	temp_phase_4 DB 0

	y_loc 		 DW 0

plasma_frame_code:	

	; setup where we'll draw to
	xor		di, di

	; setup a pointer to our cos table
	lea		si, costab

	; iterate over every pixel
	mov		cx, 64000

	; setup temp state into 3 and 4
	mov		al, phase_3
	mov		temp_phase_3, al
	
	mov		al, phase_4
	mov		temp_phase_4, al
	
reset_1_and_2:

	; re-setup temp state into 1 and 2
	mov		al, phase_1
	mov		temp_phase_1, al
	
	mov		al, phase_2
	mov		temp_phase_2, al
	
	; save our overall progress
	push	cx
	; process the next row of pixels
	mov		cx, 320

plasma_frame_pixel:

	; calculate the pixel value
	; col = costab[t1] + costab[t2] + costab[t3] + costab[t4] 

	xor		bx, bx
	
	mov		bl, temp_phase_1
	mov		al, ds:[si + bx]
	
	mov		bl, temp_phase_2
	add		al, ds:[si + bx]
	adc		ah, 0
	
	mov		bl, temp_phase_3
	add		al, ds:[si + bx]
	adc		ah, 0
	
	mov		bl, temp_phase_4
	add		al, ds:[si + bx]
	adc		ah, 0

	; draw the pixel
	mov		es:[di], al

	; adjust counter 1
	mov		al, temp_phase_1
	add		al, 2
	mov		temp_phase_1, al
	
	; adjust counter 2
	mov		al, temp_phase_2
	sub		al, 1
	mov		temp_phase_2, al

	; move onto the next pixel
	inc		di
	dec		cx
	jnz		plasma_frame_pixel

	; adjust the y location by 1
	inc		y_loc

	pop		cx
	
	; adjust counter 3
	mov		al, temp_phase_3
	add		al, 2
	mov		temp_phase_3, al
	
	; adjust counter 4
	mov		al, temp_phase_4
	sub		al, 1
	mov		temp_phase_4, al		
	
	sub		cx, 320
	jnz		reset_1_and_2
	
	ret