basic worley noise algorithm

x11-random/.gitignore

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+bin/*

x11-random/Makefile

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+CC=/usr/bin/gcc
+CFLAGS=-g -Werror -pthread -pedantic -pedantic-errors -fno-fast-math -fno-builtin -m64 -std=iso9899:1999 -I${PWD} -lX11 -lm
+OUT=bin
+OBJ=$(OUT)/obj
+
+
+all:
+	$(CC) $(CFLAGS) worley-noise.c -o $(OUT)/worley-noise
+clean:
+	rm bin/* bin/obj/*
+

x11-random/worley-noise.c

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+#include <stdio.h>
+#include <stdlib.h>
+#include <X11/Xlib.h>
+#include <math.h>
+
+#define WIDTH 1280
+#define HEIGHT 720
+#define SEED 8081
+
+#define POINTS 20
+
+static int seed_offset = 1;
+
+struct point {
+	int x;
+	int y;
+};
+
+
+double dist_p1_p2(int p1x, int p1y, int p2x, int p2y){
+	double pA, pB;
+	pA = p1x - p2x;
+	pB = p1y - p2y;
+
+	return sqrt(pA * pA + pB * pB);
+
+}
+
+void draw_pixel(Display * di, Window wi, GC gc, int x, int y, int color){
+	XSetForeground(di, gc, color);
+	XDrawPoint(di, wi, gc, x, y);
+}
+
+float rand_0_1(){
+	int o0;
+	float o0f, r;
+	srand(SEED+seed_offset++); // define random initial seed
+	o0 = rand();
+	o0f = (float) o0;
+	r = o0f / RAND_MAX;
+	return (r);
+}
+
+double * sort(double * arr){
+	int arr_size = POINTS;
+	int i,j, aux;
+	for (i=0; i<arr_size;i++){
+		for (j=i+1;j<arr_size;j++){
+			if (arr[i] > arr[j]){
+				aux = arr[j];
+				arr[j] = arr[i];
+				arr[i] = aux;
+			}
+		}
+	}
+	
+}
+
+int map (int value, int min, int max, int map_min, int map_max){
+	double R = (double) (map_max - map_min) / (double) (max - min);
+	double y = map_min + (value * R) + R;
+	return (int) y;
+}
+
+void worley_noise(Display * di, Window wi, GC gc){
+	int x, y, i;
+	int c;
+	int noise_space[WIDTH][HEIGHT];
+	double dist[POINTS], sdist[POINTS];
+	struct point p[POINTS];
+
+
+	for (x=0; x<WIDTH; x++){
+		for (y=0;y<HEIGHT; y++){
+			c = (int) (rand_0_1() * 255);
+			c = (c << 16 ) | (c << 8) | c;
+			noise_space[x][y] = c;
+		}
+	}
+	
+	for (i=0; i<POINTS; i++)
+	{
+		p[i].x = (int) (rand_0_1() * WIDTH);
+		p[i].y = (int) (rand_0_1() * HEIGHT);
+	}
+	for (x=0; x<WIDTH; x++){
+		for (y=0;y<HEIGHT; y++){
+			for (i=0;i<POINTS;i++){
+				dist[i] = dist_p1_p2(x, y, p[i].x, p[i].y);
+				sort(dist);
+			}
+			c = map(dist[0], 0, WIDTH/4, 255, 20);
+
+			c = (c << 16 ) | (c << 8) | c;
+			draw_pixel(di, wi, gc, x, y, c);
+		}
+	}
+}
+
+int main(){
+	Display *di = XOpenDisplay(getenv("DISPLAY"));
+	if (di == NULL){
+		fprintf(stderr, "ERROR: No display");
+		exit(EXIT_FAILURE);
+	}
+	int x=0, y=0, width=WIDTH, height=HEIGHT, border_width=1;
+	int sc = DefaultScreen(di);
+	Window ro = DefaultRootWindow(di);
+	Window wi = XCreateSimpleWindow(di,
+					ro,
+					x,
+					y,
+					width,
+					height,
+					border_width,
+					BlackPixel(di, sc),
+					WhitePixel(di, sc));
+
+	XMapWindow(di, wi);
+	XStoreName(di, wi, "Default Window");
+
+	GC gc = XCreateGC(di, ro, 0, NULL);
+
+	XSelectInput(di, wi, KeyPressMask | ExposureMask);
+	XEvent ev;
+	int quit = 0;
+	int z = 50;
+	while (!quit){
+		int a = XNextEvent(di, &ev);
+		if (ev.type == KeyPress) quit == 1;
+		if (ev.type == Expose) {
+			worley_noise(di, wi, gc);
+		}
+	}
+
+	XFreeGC(di, gc);
+	XDestroyWindow(di, wi);
+	XCloseDisplay(di);
+	return (EXIT_SUCCESS);
+
+}
+
+