#include "graphic.h"//this function draws a pixel of wanted color on a surface at (x,y) coordinatevoid draw_pixel(SDL_Surface *surface, int x, int y, SDL_Color s_color){	//SDL_MapRGB return a color map depending on bpp (definition)	Uint32 color = SDL_MapRGB(surface->format, s_color.r, s_color.g, s_color.b);	//byte per pixel	int bpp = surface->format->BytesPerPixel;	//the selected pixel 	Uint8 *pixel = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;	//here is checked the number of byte used by our surface	switch (bpp)	{		case 1: // 1 byte =>  8-bpp			*pixel = color;		        break;	        case 2: // 2 byte => 16-bpp      			*(Uint16 *)pixel = color;			break;    		case 3: // 3 byte => 24-bpp			if(SDL_BYTEORDER == SDL_BIG_ENDIAN) 			{				pixel[0] = (color >> 16) & 0xff;			        pixel[1] = (color >> 8) & 0xff;				pixel[2] = color & 0xff;			} 			else 			{			        pixel[0] = color & 0xff;				pixel[1] = (color >> 8) & 0xff;				pixel[2] = (color >> 16) & 0xff;			}	      		break;    		case 4: // 4 byte => 32-bpp			*(Uint32 *)pixel = color;      			break;  	}}//this function draws a line of wanted color on a surface from p0 point to p1 pointvoid draw_line(SDL_Surface *surface,point p0, point p1, SDL_Color color){	int i;	int comp;	int d_a,d_b;	int a,b;	int inc;	//the surface is locked	if ( SDL_MUSTLOCK(surface) )		SDL_LockSurface(surface);	//just one point	if(p0.x==p1.x && p0.y==p1.y)		  draw_pixel(surface,p0.x,p0.y,color);	//the line is drawn along horizontal direction	else if(abs(p1.x-p0.x)>=abs(p1.y-p0.y))	{		d_a=p1.x-p0.x;		d_b=p1.y-p0.y;		a=p0.x;		b=p1.x;				//from left to right 		if(p0.x<p1.x)			inc=1;		//from right to left		else			inc=-1;		//this draws also the last pixel		b+=inc;		for(i=a;i!=b;i=i+inc)		{			//y is calculated			comp=(d_b*(i-a))/(d_a)+p0.y;				//calculated pixel is drawn		  	draw_pixel(surface,i,comp,color);		}	}	//the line is drawn along vertical direction	else	{		d_a=p1.y-p0.y;		d_b=p1.x-p0.x;		a=p0.y;		b=p1.y;				//from down to up 		if(p0.y<p1.y)			inc=1;		//from up to down		else			inc=-1;		//this draws also the last pixel		b+=inc;				for(i=a;i!=b;i=i+inc)		{			//x is calculated			comp=(d_b*(i-a))/(d_a)+p0.x;				//calculated pixel is drawn		       	draw_pixel(surface,comp,i,color);		}	}	//the surface is unlocked	if ( SDL_MUSTLOCK(surface) )       		SDL_UnlockSurface(surface);}//this function draws a square of wanted color on a surface having side lenght, //p is the upper left vertex of the square void draw_square(SDL_Surface *surface, point p, int lenght, SDL_Color color){	point temp;	//up side 	if(p.x+lenght<DIM_H)		temp.x=p.x+lenght;	else		temp.x=DIM_H-1;	temp.y=p.y;	draw_line(surface,p,temp,color);		//left side	temp.x=p.x;	if(p.y+lenght<DIM_V)		temp.y=p.y+lenght;	else		temp.y=DIM_V-1;	draw_line(surface,p,temp,color);		//down side 	if(p.y+lenght<DIM_V)		p.y+=lenght;	else		p.y=DIM_V-1;	if(p.x+lenght<DIM_H)		temp.x=p.x+lenght;	else		temp.x=DIM_H-1;	temp.y=p.y;	draw_line(surface,p,temp,color);		//right side	if(p.x+lenght<DIM_H)		p.x+=lenght;	else		p.x=DIM_H-1;	temp.x=p.x;	temp.y=p.y-lenght;	draw_line(surface,p,temp,color);}//this function uses previous draw_square to draw a square of border_color color and then//fill it with fill_color using fill_square functionvoid draw_square(SDL_Surface *surface, SDL_Rect *rect , SDL_Color border_color, SDL_Color fill_color){	SDL_Rect fill_rect = {rect->x + 1,rect->y + 1,rect->w - 1,rect->h - 1};	point r = {rect->x,rect->y};	draw_square(surface,r,rect->w,border_color);	fill_square(surface, &fill_rect, fill_color);}//this function fills a rectangle area with fill_colorvoid fill_square(SDL_Surface *surface, SDL_Rect *rect, SDL_Color fill_color){	//SDL_MapRGB return a color map depending on bpp (definition)	Uint32 color = SDL_MapRGB(surface->format, fill_color.r, fill_color.g, fill_color.b);		SDL_FillRect(surface, rect, color);}//this function colours all cells of a path using different color for the first and the last onevoid colour_path(cell_ind path[], int num_cells, SDL_Surface *surface, SDL_Color border_color, SDL_Color fill_color){	int i; 	SDL_Rect cell;	SDL_Color start = {0xFF, 0xFF, 0x00,0};	SDL_Color end = {0xFF, 0x00, 0xFF,0};	//colour first cell of yellow	cell.y = (path[0].row * CELL_SIDE) + GRIND_Y;	cell.x = (path[0].col * CELL_SIDE) + GRIND_X;	cell.w = CELL_SIDE;	cell.h = CELL_SIDE;	draw_square(surface, &cell , border_color, start);	//colour all others cells but last	for(i = 1; i < num_cells-1; i++)	{		cell.y = (path[i].row * CELL_SIDE) + GRIND_Y;		cell.x = (path[i].col * CELL_SIDE) + GRIND_X;		cell.w = CELL_SIDE;		cell.h = CELL_SIDE;		draw_square(surface, &cell , border_color, fill_color);	}	//colour last cell of fuchsia	cell.y = (path[i].row * CELL_SIDE) + GRIND_Y;	cell.x = (path[i].col * CELL_SIDE) + GRIND_X;	cell.w = CELL_SIDE;	cell.h = CELL_SIDE;	draw_square(surface, &cell , border_color, end);}//this function is used to colour all cells of a path with the same colorvoid decolour_path(cell_ind path[], int num_cells, SDL_Surface *surface, SDL_Color border_color, SDL_Color fill_color){	int i; 	SDL_Rect cell;	for(i = 0; i < num_cells; i++)	{		cell.y = (path[i].row * CELL_SIDE) + GRIND_Y;		cell.x = (path[i].col * CELL_SIDE) + GRIND_X;		cell.w = CELL_SIDE;		cell.h = CELL_SIDE;		draw_square(surface, &cell , border_color, fill_color);	}}