#include <libps.h>
#include "fractal.h"

void Segment(u_char map[MAP_SIZE][MAP_SIZE], int x1, int y1, int x2, int y2);
void NewHeight(u_char map[MAP_SIZE][MAP_SIZE], int x,int y, int a,int b, int c,int d);

void GenerateMap(u_char map[MAP_SIZE][MAP_SIZE], int seed) {
	int i, j, k, a, b, c, d;
	u_char map2[MAP_SIZE][MAP_SIZE];
	srand(seed);
	for (j=0; j<MAP_SIZE; j++) {
		for (i=0; i<MAP_SIZE; i++)
			map[i][j] = 0;
	}
	map[0][0] = rand() & 127;
	Segment(map, 0, 0, MAP_SIZE, MAP_SIZE);
	
	
	for (k=0; k<2; k++) {
		for (j=0; j<MAP_SIZE; j++) {
			for (i=0; i<MAP_SIZE; i++) {
				a = (i-1) % MAP_SIZE;
				b = (i+1) % MAP_SIZE;
				c = (j-1) % MAP_SIZE;
				d = (j+1) % MAP_SIZE;
				map2[i][j] = (map[i][j] + map[b][j] + map[a][j] + map[i][d]
			+ map[i][c] + map[b][d] + map[a][d] + map[b][c] + map[a][c])/9;
				}
		}
		for (j=0; j<MAP_SIZE; j++) {
			for (i=0; i<MAP_SIZE; i++)
				map[i][j] = map2[i][j];
		}
	}
}

void Segment(u_char map[MAP_SIZE][MAP_SIZE], int x1, int y1, int x2, int y2) {
	int col;
	int xm = (x1+x2)>>1;
	int ym = (y1+y2)>>1;
	
	//All this is working out the height of the landscape at each point
	if ((x2-x1)<2 && (y2-y1)<2)
		return;
	
		NewHeight(map, xm, y1, x1, y1, x2, y1);
		NewHeight(map, x2, ym, x2, y1, x2, y2);
		NewHeight(map, xm, y2, x1, y2, x2, y2);
		NewHeight(map, x1, ym, x1, y1, x1, y2);

	col = (map[x1][y1] + map[x2%MAP_SIZE][y1] + map[x1][y2%MAP_SIZE] + map[x2%MAP_SIZE][y2%MAP_SIZE])>>2;
	if (map[xm][ym]==0)
		map[xm][ym] = col;
	
	Segment(map, x1,y1,xm,ym);
	Segment(map, xm,y1,x2,ym);
	Segment(map, x1,ym,xm,y2);
	Segment(map, xm,ym,x2,y2);
}


void NewHeight(u_char map[MAP_SIZE][MAP_SIZE], int x,int y, int a,int b, int c,int d) {
	int col = (Abs(a-c) + Abs(b-d))<<6;
	
	if (map[x%MAP_SIZE][y%MAP_SIZE] != 0)
		return;

	if (col<2)
		col = 2;
	
	a = a % MAP_SIZE;
	b = b % MAP_SIZE;
	c = c % MAP_SIZE;
	d = d % MAP_SIZE;
	
	col = (rand() % col)-(col>>1);
	col = col + ((map[a][b] + map[c][d] + 1)>>1);
	
	if (col<1)
		col = 1;
	if (col>255)
		col = 255;
	
	map[x%MAP_SIZE][y%MAP_SIZE] = col;
}