Very small <100LOC Raylib program to visualize a node tree

raylib_visualize_nodes.c

#include <stdbool.h>
#include <raylib.h>

struct Node {
	const char *name;
	int prev;
	Vector2 ui_pos;
};

typedef struct Node Node;

int main(void)
{
	InitWindow(1280, 720, "Raylib: Visualize Nodes");
	SetTargetFPS(60);

	Node nodes[256] = {0};
	int nodes_top = 1;

	nodes[nodes_top++] = (Node) {
		.name = "foo",
		.prev = 0,
		.ui_pos = { 200, 200 }
	};

	nodes[nodes_top++] = (Node) {
		.name = "bar",
		.prev = 1,
		.ui_pos = { 500, 200 }
	};

	nodes[nodes_top++] = (Node) {
		.name = "baz",
		.prev = 1,
		.ui_pos = { 500, 500 }
	};

	int dragging_node = 0;

	const int node_width = 200;
	const int node_height = 200;

	while(!WindowShouldClose()) {
		BeginDrawing();

		ClearBackground(RAYWHITE);

		for(int i = 1; i < nodes_top; ++i) {
			Node *n = &nodes[i];

			if(!dragging_node && IsMouseButtonDown(0)) {
				Vector2 pos = GetMousePosition();
				if(CheckCollisionPointRec(pos, (Rectangle){ n->ui_pos.x, n->ui_pos.y, node_width, node_height })) {
					dragging_node = i;
				}
			}

			if(dragging_node == i) {
				Vector2 mouse_delta = GetMouseDelta();
				n->ui_pos.x += mouse_delta.x;
				n->ui_pos.y += mouse_delta.y;
			
				if(IsMouseButtonUp(0)) {
					dragging_node = false;
				}
			}

			DrawRectangle(n->ui_pos.x, n->ui_pos.y, node_width, node_height, SKYBLUE);
			
			if(n->name) {
				DrawText(n->name, n->ui_pos.x, n->ui_pos.y - 25, 20, DARKGRAY);
			}

			DrawCircle(n->ui_pos.x, n->ui_pos.y + 25, 14, RED);
			DrawCircle(n->ui_pos.x + node_width, n->ui_pos.y + 25, 14, RED);

			if(n->prev) {
				Node *prev = &nodes[n->prev];

				Vector2 a = { prev->ui_pos.x + node_width, prev->ui_pos.y + 25 };
				Vector2 b = { n->ui_pos.x, n->ui_pos.y + 25 };
				DrawLineEx(a, b, 4.0f, DARKGRAY);
			}
		}

		EndDrawing();
	}

	CloseWindow();

	return 0;
}