game_pong:
   call .draw_screen
   call .detect_input

; Clears screen and draws both players and ball
.draw_screen:
   call os_set_graphics_mode ; Clear screen
.draw_p1:
   ; Player 1
   mov ax, [p1_x]
   mov [x_start], ax
   mov [x_end], ax

   mov bx, [p1_y]
   mov [y_start], bx
   add bx, [bat_height]
   mov [y_end], bx

   call os_draw_graphical_rectangle ; Draw player 1
.draw_p2:
   ; Player 2
   mov ax, [p2_x]
   mov [x_start], ax
   mov [x_end], ax

   mov bx, [p2_y]
   mov [y_start], bx
   add bx, [bat_height]
   mov [y_end], bx

   call os_draw_graphical_rectangle ; Draw player 1
.draw_ball:
   ; The ball
   mov ax, [ball_x]
   mov [x_start], ax
   mov [x_end], ax

   mov bx, [ball_y]
   mov [y_start], bx
   mov [y_end], bx

   call os_draw_graphical_rectangle ; Draw the ball

   ret

; Player 1 movements
.p1_up:
   mov dx, [p1_y]
   sub dx, 5
   mov [p1_y], dx
   ret
.p1_down:
   mov dx, [p1_y]
   add dx, 5
   mov [p1_y], dx
   ret

; Player 2 movements
.p2_up:
   mov dx, [p2_y]
   sub dx, 5
   mov [p2_y], dx
   ret
.p2_down:
   mov dx, [p2_y]
   add dx, 5
   mov [p2_y], dx
   ret

; Ball bouncing
; This should move the ball along one frame
; The ball moves 1 pixel per frame, however this is usually
; at an angle, so we need sin and cos
.bounce_ball:
   ; Change the x coords
   fld dword [ball_angle]
   fcos
   fld dword [precise_ball_x]
   faddp
   frndint
   fstp dword [ball_x]

   ; Change the y coords
   fld dword [ball_angle]
   fsin
   fld dword [precise_ball_y]
   faddp
   frndint
   fstp dword [ball_y]

   ret

.detect_input:
   call os_read_input
   cmp al, 08h
   je .finish

   ; Player 1
   cmp al, 77h       ; Pressed 'w' (player 1 up)
   call .p1_up
   cmp al, 73h       ; Pressed 's' (player 1 down)
   call .p1_down

   ; Player 2
   cmp al, 5bh       ; Pressed '[' (player 2 up)
   call .p2_up
   cmp al, 27h       ; Pressed ''' (player 2 down)
   call .p2_down

   ;call .bounce_ball
   call .draw_screen

   jmp .detect_input

.finish:
   call os_set_text_mode
   call os_start_cli

section .data
   ball_x dw 100
   ball_y dw 100
   precise_ball_x dw 100
   precise_ball_y dw 100
   ball_angle dw 1 ; In radians
   cos_ball_angle dw 0
   sin_ball_angle dw 0

   p1_x dw 5
   p1_y dw 5

   p2_x dw 315
   p2_y dw 5

   bat_height dw 20