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#include <stdio.h>
#include <math.h>
#include "tectonics.h"
struct centroid_t {
double x, y;
int updates;
};
static int closest_point(struct world_t *world, double x, double y)
{
double dist = 1e9;
int closest = -1;
for (int i=0; i<world->n_points; i++) {
struct point_t *pt = world->points + i;
double d = distance(x, y, pt->x, pt->y);
if (d <= dist) {
dist = d;
closest = i;
}
}
return closest;
}
static void relax_points(struct world_t *world, int iterations)
{
struct centroid_t *centroid =
malloc(sizeof(struct centroid_t) * world->n_points);
for (int i=0; i<world->n_points; i++) {
struct point_t *pt = world->points + i;
struct centroid_t *c = centroid + i;
c->x = pt->x;
c->y = pt->y;
c->updates = 1;
}
for (int i=0; i<iterations; i++) {
printf("%02f%%\n", 100*((double)i+1)/iterations);
double x = rand01();
double y = rand01();
int closest = closest_point(world, x, y);
int t = centroid[closest].updates;
centroid[closest].x = (t*centroid[closest].x + x)/(t+1);
centroid[closest].y = (t*centroid[closest].y + y)/(t+1);
centroid[closest].updates += 1;
}
for (int i=0; i<world->n_points; i++) {
struct point_t *pt = world->points + i;
struct centroid_t *c = centroid + i;
pt->x = c->x;
pt->y = c->y;
}
}
void create_world(struct world_t *world, int n_points)
{
world->n_points = n_points;
world->points = malloc(sizeof(struct point_t) * n_points);
if (world->points == NULL) {
fprintf(stderr,
"ERROR: failed to allocate %d points\n",
n_points);
return;
}
struct point_t center = { 0.5, 0.5 };
world->tree = new_node(center, 0.5);
for (int i=0; i<n_points; i++) {
struct point_t *pt = world->points + i;
pt->x = rand01();
pt->y = rand01();
insert(&(world->tree), world->points, i);
}
}
void free_world(struct world_t *world)
{
free(world->points);
}
void render_world(cairo_t *cr, struct world_t *world)
{
int width, height;
get_cairo_size(cr, &width, &height);
double r = ((double)width) / (100*sqrt(world->n_points));
cairo_set_source_rgba(cr, 1, 0, 0, 1);
for (int i=0; i<world->n_points; i++) {
struct point_t *pt = world->points + i;
double xc = pt->x * width;
double yc = pt->y * height;
cairo_arc(cr, xc, yc, r, 0, 2*M_PI);
cairo_stroke(cr);
}
draw_quadtree(cr, &(world->tree));
}
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