BITS	32

EXTERN SDL_SetVideoMode
EXTERN SDL_ShowCursor
EXTERN SDL_PollEvent
EXTERN SDL_Flip
EXTERN SDL_GetTicks
EXTERN SDL_Quit

section .data

W: dd 640.0
H: dd 480.0

msg: db "%i",10,0

message_int: db "I-X:%i Y:%i",10,0
message_float: db "F-X:%f Y:%f",10,0
message_color: db "C-%i",10,0



SECTION	.bss

; for easy scaling
WIDTH equ 640
HEIGHT equ 480


X: resq 1
Y: resq 1

R:	resw 1
G:	resw 1 ; NEED ?!
B:	resw 1

SCREEN:  RESD 1
PIXELS:  RESD 1
EVENTS:  RESD 20 							;  sizeof(SDL_Event);
COUNT: RESD 1

SECTION .text
GLOBAL  _start


_start:
		push			0x20							; push SDL_FULLSCREEN for fulSCREEN window, or SDL_NOFRAME for a borderless normal window
		push 			32        						; BPP ( bits per pixel)
		push			HEIGHT							; height
		push			WIDTH							; width
		call			SDL_SetVideoMode				; display window with those attributes
		mov				[SCREEN], eax 					; SDL_Surface pointer from screen
		; Or use add eax, 20
		mov				eax, [eax+20]					; surface->PIXELS
		mov				[PIXELS], eax

		push			0x0								; hide cursor
		call			SDL_ShowCursor

mainloop:

		;call			SDL_GetTicks								; get current time
		;shr				eax, 4							; make it slower

		mov				DWORD [COUNT], HEIGHT*WIDTH ; number of PIXELS to fill
		mov				edi, [PIXELS]			; adress of pixels

drawloop:


		push			DWORD [COUNT] 							; push location
		call			calc_position
		add				esp, 4

		call 			calc_color


		mov				eax, [B]						; SDL COlor in SDl_Pixels.c  SDL_MapRGB
		shl				eax, 8
		or				eax, [G]
		shl				eax, 8
		or				eax, [R]
		shl				eax, 8



		mov				DWORD [edi] , eax
		add   			edi, 4

		dec				dword [COUNT]
		cmp 			dword [COUNT],0
		jnl				drawloop



		push			DWORD [SCREEN]					; push address of sdl screen surface
		call			SDL_Flip						; flip the SCREEN
		add				esp, 4							; clean up stack

		push 			EVENTS							; push the events variable onto the stack
		call			SDL_PollEvent					; get EVENTS and put them into the events variable
		add				esp, 4							; clean up stack

		cmp				BYTE [EVENTS], 0x2				; if event != SDL_KEYUP jump to mainloop
		jne				mainloop						; if event = SDL_KEYUP continue execution(exit).

exit:													; exit routine
		call 			SDL_Quit
		mov				eax, 0x01
		xor				ebx, ebx
		int				0x80


calc_color:

		fld				QWORD [X]
		mov				DWORD [R], 255
		fild 			DWORD [R]
		fmulp			st1, st0
		fistp 			WORD [R]

		fld				QWORD [Y]
		mov				DWORD [G], 255
		fild 			DWORD [G]
		fmulp			st1, st0
		fistp 			WORD [G]

		ret


calc_position:

		xor 			edx, edx 					; init edx ,so we get no SIGFPE
		mov 			eax, [esp+4] 				; get memory_location
		mov 			ebx, WIDTH					; prepare div
		div 			ebx							; eax = quotient | edx = remainder
													; X+Y*W 400+300*800
													; XPOS = (400+300*800) % 800 = 400
													; YPOS = (400+300*800) / 800 = 300

		mov 			DWORD [X], edx				; load x position from register

		fild 			DWORD [X]					; load and convert x position to fpu stack
		fdiv 			DWORD [W]					; divide by WIDTH
		fstp 			QWORD [X]					; store result

		mov 			DWORD [Y], eax				; load y position from reg
		fild 			DWORD [Y]
		fdiv 			DWORD [H]
		fstp 			QWORD [Y]

		ret