water.c

water.c

#include<ncurses.h>
#include<malloc.h>
#include<memory.h>
#include<unistd.h>
	typedef unsigned int usecs;
	void usleep(usecs);
//khlor stuff
typedef size_t sizt;
#define ITER(o,n) for(size_t o=0; o<n; o++)
#define ITER2(o,n0,n1) for(size_t o=n0; o<n1; o++)
#define ITER_GRID(x,y,w,h) ITER(y,h){ ITER(x,w){
#define SNAKE(x,y,w) (x+y*w)

#include "water.h"

const char cell_on =   '+';
const char cell_off=   ' ';
const char cell_bound= '_';

typedef unsigned char byte;
//not reentrant nor threadsafe
bool cellrd(void* cells, int x, int y, int w){
	byte c= ((byte*)cells)[SNAKE(x,y,w)/8];
	return (c>>(x%8))&1;
}
void cellwr(void* cells, bool v, int x, int y, int w){
	byte b= 1<<(x%8);
	byte* cp= cells+SNAKE(x,y,w)/8;
	byte c= *cp;
	c= v? c|b : c&~b;
	*cp= c;
}

void water_init(water* wa, int w, int h){
	wa->w= w;
	wa->h= h;
	wa->rd= malloc(w*h/8);
	wa->wr= malloc(w*h/8);
	wa->bd= malloc(w*h/8);
}

void water_simulate_c(water* _, int rand, int frame){
	//automata
	int w= _->w;
	int h= _->h;
	void* rd= _->rd;
	void* wr= _->wr;
	void* bound= _->bd;

	bool r1=   rand    &7;
	bool r2=  (rand>>8)&7;

	char o[8][2]={//kernel
		{ 0, -1},
		//{ 2,0},
		{-1, -1},
		//{ 0, -1},
		{ 4, 0},
		{ r1, 0},
		{ 0, -1},
		//{-2,0},
		{ 1, -1},
		//{ 0, -1},
		{-4, 0},
		{-r2, 0}
	};
	int oi= (frame)%8;
	char ox= o[oi][0];
	char oy= o[oi][1];
	ITER2(y,1,h-1){
	ITER2(x,1,w-1){
		#define m(_v) \
				f(_v##z,x   ,y   )\
				f(_v##n,x-ox,y-oy)\
				f(_v##p,x+ox,y+oy)
			#define f(_v,_x,_y) bool _v= cellrd(rd, _x,_y, w);
				m( )
			#undef f
			#define f(_v,_x,_y) bool _v= cellrd(bound, _x,_y, w);
				m(b)
			#undef f
		#undef m

		if(bp)
			p= true;
		bool v= z?p:n;

		     if(bz)	v= false;
		//else if(bn)	v= p;
		//else if(bp)	v= z;

		cellwr(wr, v, x,y,w);
	}}
	memcpy(rd,wr,w*h/8);
}

#include<signal.h>
bool running= true;
void sigint(int signo){ running= false; }


#define rand(r) ((r)+((r)<<16))^0x73a71731

int main(){
	signal(SIGINT, sigint);
	signal(SIGHUP, sigint);

	//ncurses
	initscr();
	cbreak();
	noecho();
	curs_set(0);
	keypad(stdscr,1);
	timeout(-1);

	WINDOW* win;
	int w,h;
	const int PADW= 2;
	const int PADH= 2;
	w= COLS-PADW*2;
	h= LINES-PADH*2;
	w-= w%8;//byte alignment
	win= newwin(h,w, PADH,PADW);
	water water;
	water_init(&water,w,h);
	{
		//initial state
		void* rd= water.rd;
		void* wr= water.wr;
		void* bd= water.bd;
		ITER_GRID(x,y,w,h){
			//bool b= x/3 == y;//initial volume
			bool b= false;
			b|= x>=w-4 & y==h-1;//emitter
			b|= x== 16 & y==h-1;
			b|= (x==120|x==121) & (y==h-1);
			cellwr(rd,b,x,y,w);
			cellwr(wr,b,x,y,w);

			b= x==0|x==w-1|y==0;
			cellwr(bd,b,x,y,w);
		}}}
	}
	
	//getch();

	int frame= 0;
	int r= 0;

	//loop
	while(running){
		//rendering
		char line[w+1];
			 line[w]=0;//terminator
		void* cells= water.wr;
		void* bd= water.bd;
		ITER(cy,h){
			ITER(cx,w){
				bool c= cellrd(cells,cx,h-cy-1,w);
				bool b= cellrd(bd,cx,h-cy-1,w);
				line[cx]= !!c? cell_on:cell_off;
				if(b)
					line[cx]= cell_bound;
			}
			mvwaddnstr(win, cy,0, line, w);
		}
		refresh();
		wrefresh(win);
		//getch();
		usleep((int)(1000000./30.));
		//water_simulate(&water);
		r= rand(r);
		water_simulate_c(&water, r, frame++);
	}

	delwin(win);
	endwin();
	return 0;
}