123 lines
3 KiB
C
123 lines
3 KiB
C
#include <raylib.h>
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#include <stddef.h>
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#include <stdlib.h>
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typedef struct Node {
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Rectangle bounds;
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Vector2 entities[4];
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int entity_count;
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struct Node* children[4];
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} Node;
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Node* create_node(Rectangle bounds) {
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Node* n = calloc(1, sizeof(Node));
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n->bounds = bounds;
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return n;
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}
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void split_node(Node* n) {
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Rectangle b = n->bounds;
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Vector2 half = (Vector2){ b.width / 2.0f, b.height / 2.0f };
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n->children[0] = create_node((Rectangle){ b.x, b.y, half.x, half.y });
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n->children[1] = create_node((Rectangle){ b.x + half.x, b.y, half.x, half.y });
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n->children[2] = create_node((Rectangle){ b.x, b.y + half.y, half.x, half.y });
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n->children[3] = create_node((Rectangle){ b.x + half.x, b.y + half.y, half.x, half.y });
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}
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int inside(Node* n, Vector2 p) {
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return p.x > n->bounds.x && p.x < n->bounds.x + n->bounds.width &&
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p.y > n->bounds.y && p.y < n->bounds.y + n->bounds.height;
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}
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int is_leaf(Node* n) {
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return
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n->children[0] == NULL &&
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n->children[1] == NULL &&
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n->children[2] == NULL &&
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n->children[3] == NULL;
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}
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void add(Node* n, Vector2 p) {
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if(n->entity_count >= 4) {
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if(is_leaf(n)) {
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split_node(n);
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}
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int added = 0;
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for(int i = 0; i < 4; i++) {
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if(inside(n->children[i], p)) {
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add(n->children[i], p);
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added = 1;
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break;
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}
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}
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if(!added) {
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add(n->children[0], p);
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}
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} else {
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n->entities[n->entity_count++] = p;
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}
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}
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void draw(Vector2 p, Color c) {
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DrawCircleV(p, 5.0f, c);
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}
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void visualize(Node* n) {
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//DrawRectangleLinesEx(n->bounds, 1.0f, RED);
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if(!is_leaf(n)) {
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visualize(n->children[0]);
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visualize(n->children[1]);
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visualize(n->children[2]);
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visualize(n->children[3]);
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}
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Vector2 m_pos = GetMousePosition();
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if(inside(n, m_pos)) {
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//DrawRectangleLinesEx(n->bounds, 1.0f, BLUE);
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for(int i = 0; i < n->entity_count; i++) {
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if(CheckCollisionCircles(m_pos, 1.0f, n->entities[i], 5.0f)) {
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draw(n->entities[i], GREEN);
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} else {
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draw(n->entities[i], WHITE);
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}
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}
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} else {
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for(int i = 0; i < n->entity_count; i++) {
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draw(n->entities[i], WHITE);
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}
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}
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}
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int main() {
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const int width = 800;
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const int height = 600;
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InitWindow(width, height, "quadtree");
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Node* root = create_node((Rectangle){ 0.0f, 0.0f, width, height });
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for(int i = 0; i < 5000; i++) {
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add(root, (Vector2){ GetRandomValue(0, width), GetRandomValue(0, height) });
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}
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while(!WindowShouldClose()) {
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/*if(IsMouseButtonPressed(MOUSE_LEFT_BUTTON)) {
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add(root, GetMousePosition());
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}*/
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BeginDrawing();
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{
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ClearBackground(BLACK);
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visualize(root);
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DrawFPS(10, 10);
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}
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EndDrawing();
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}
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CloseWindow();
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}
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