;
;    Raw Game Engine
;    Copyright (C) 2023  Ernest Deak
;
;    This program is free software: you can redistribute it and/or modify
;    it under the terms of the GNU General Public License as published by
;    the Free Software Foundation, either version 3 of the License, or
;    (at your option) any later version.
;
;    This program is distributed in the hope that it will be useful,
;    but WITHOUT ANY WARRANTY; without even the implied warranty of
;    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;    GNU General Public License for more details.
;
;    You should have received a copy of the GNU General Public License
;    along with this program.  If not, see <https://www.gnu.org/licenses/>.
;

; This is the main include file for external programs

%ifndef RAW_GAME_ENGINE_INC
%define RAW_GAME_ENGINE_INC

%include "inc/generic.inc"
%include "inc/sdl2.inc"

;; Rendering optimization flag that updates objects
;; right before rendering them

%ifndef RGE_OPTIM_UPDATE_DURING_RENDER
	%define RGE_OPTIM_UPDATE_DURING_RENDER 0
%endif


; Main include file for outside projects.
; Located here are all the RGE specific structures 
; and macros used with the engine

section .bss

struc AnimSprite
	.img 		resq 1 ; pointer to SDL_Texture
	.width 		resd 1 ; total width
	.height 	resd 1 ; total height
	.visible 	resq 1 ; if not 0 the image is drawn, else its hidden
	.tile_start	resq 1
	.tile_end 	resq 1
	.startframe resq 1
	.frame 		resq 1
	.endframe 	resq 1
	.speed 		resq 1 ; animation speed in milliseconds. if 0, wont animate
	.dt_accum 	resq 1 ; delta time storage for speed calc
	.srcrect 	resb SDL_rect_size
	.dstrect	resb SDL_frect_size  ; full struct of an sdl rect or sdl frect
	.flip 		resd 1
endstruc

defstruct_shortcuts AnimSprite


; Game related macros, simplifications, convenience and ease of use

;; Multiply delta time(ms) and desired value(ms)
;; and then divides by 1000 to get pixel movement per second
;; @param 1 - desired value in miliseconds (minimal value is 59 or 60)
;; @param 2 - register holding dt
;; @param 3 - temp. register to use for division
;; @param 4 (optional) - 'save' keyword. if supplied, temp. reg. will be preserved
;; @return rax - result movement in pixels per second
%macro mul_dt 2-4
	%ifidni %4, save
		push %3
	%endif
	%if %1 < 60
		%warning A value less than 60 will result in no movement!
	%endif
	; 1 - value in ms
	mov rax, %1
	mov %3, 1000
	; 2 - dt reg
	imul %2
	; rax = value * dt
	idiv %3
	; rax = final result
	%ifidni %4, save
		pop %3
	%endif
%endmacro

;; Multiply delta time with immediate operand
;; @param 1 - destination xmm register
;; @param 2 - value to multiply
;; @param 3 - xmm register holding dt
;; @return XMM - multiplited single prec. value in destination register
%macro mulss_dt 3
	mov eax, %2
	cvtsi2ss %1, eax
	mulss %1, %3
%endmacro

%macro RG_PRINTF 2
	string2reg areg1, %1
	%ifstr %2
		string2reg areg2, %2
	%else
		mov areg2, %2
	%endif
	exmcall RG_Printf
%endmacro

%endif

.