From bd8b0a9ba1bdd68b915fed75f1e901851b340efd Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Fri, 11 Nov 2022 17:02:58 +0100
Subject: Extracted random spawning mechanism to a dedicated class

---
 battles/CMakeLists.txt        |  1 +
 battles/src/Battle.cpp        | 26 ++++++++++++++++++++++----
 battles/src/RandomSpawner.cpp | 38 ++++++++++++++++++++++++++++++++++++++
 battles/src/RandomSpawner.h   | 28 ++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+), 4 deletions(-)
 create mode 100644 battles/src/RandomSpawner.cpp
 create mode 100644 battles/src/RandomSpawner.h

diff --git a/battles/CMakeLists.txt b/battles/CMakeLists.txt
index 44a6de0..15e9042 100644
--- a/battles/CMakeLists.txt
+++ b/battles/CMakeLists.txt
@@ -2,6 +2,7 @@ project(battles)
 add_library(
 	${PROJECT_NAME}
 	src/Battle.cpp
+	src/RandomSpawner.cpp
 	src/scenarios.cpp
 )
 target_include_directories(
diff --git a/battles/src/Battle.cpp b/battles/src/Battle.cpp
index 99ed076..a28cdc6 100644
--- a/battles/src/Battle.cpp
+++ b/battles/src/Battle.cpp
@@ -9,6 +9,8 @@
 #include <kurator/battles/Scenario.h>
 #include <kurator/universe/ShipType.h>
 
+#include "RandomSpawner.h"
+
 
 namespace kurator
 {
@@ -16,6 +18,9 @@ namespace battles
 {
 
 
+int total_teams_in(const Scenario& scenario);
+
+
 class BaseBattle : public Battle
 {
 public:
@@ -24,18 +29,19 @@ public:
 	void update(float dt) override;
 private:
 	entt::registry _registry;
+	RandomSpawner spawner;
 };
 
 
-BaseBattle::BaseBattle(const Scenario& scenario)
+BaseBattle::BaseBattle(const Scenario& scenario) :
+	_registry {},
+	spawner {total_teams_in(scenario), 2.5, 0.1}
 {
-	std::random_device dev;
-	std::uniform_real_distribution<> pos{-2.5, 2.5};
 	for (const auto& ship : scenario.ships) {
 		const auto entity = _registry.create();
 		_registry.emplace<universe::ShipType>(entity, ship.type);
 		_registry.emplace<Team>(entity, ship.team);
-		_registry.emplace<Transform>(entity, Point{pos(dev), pos(dev)}, Point{0.0, 0.0});
+		_registry.emplace<Transform>(entity, spawner.get(ship.team));
 	}
 }
 
@@ -63,5 +69,17 @@ prepare(const Scenario& scenario)
 }
 
 
+int
+total_teams_in(const Scenario& scenario)
+{
+	int last_team = 0;
+	for (const auto& ship : scenario.ships) {
+		if (ship.team > last_team)
+			last_team = ship.team;
+	}
+	return last_team + 1;
+}
+
+
 }  // namespace battles
 }  // namespace kurator
diff --git a/battles/src/RandomSpawner.cpp b/battles/src/RandomSpawner.cpp
new file mode 100644
index 0000000..a81a18c
--- /dev/null
+++ b/battles/src/RandomSpawner.cpp
@@ -0,0 +1,38 @@
+#include "RandomSpawner.h"
+
+#include <cmath>
+
+#include <kurator/battles/components.h>
+#include <kurator/battles/Point.h>
+
+
+namespace kurator
+{
+namespace battles
+{
+
+
+RandomSpawner::RandomSpawner(const int total_teams, const double distance, const double variation) :
+	angle_step {2.0 * M_PI / total_teams},
+	device {},
+	distribution_d {distance - distance * variation, distance + distance * variation},
+	distribution_a {-variation * M_PI, variation * M_PI}
+{
+}
+
+
+Transform
+RandomSpawner::get(const int team)
+{
+	const double distance = distribution_d(device);
+	const double angle = angle_step * team + distribution_a(device);
+	const Point position {
+		distance * std::cos(angle),
+		distance * std::sin(angle),
+	};
+	return {position, {}};
+}
+
+
+}  // namespace battles
+}  // namespace kurator
diff --git a/battles/src/RandomSpawner.h b/battles/src/RandomSpawner.h
new file mode 100644
index 0000000..7505ae8
--- /dev/null
+++ b/battles/src/RandomSpawner.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include <random>
+
+#include <kurator/battles/components.h>
+
+
+namespace kurator
+{
+namespace battles
+{
+
+
+class RandomSpawner
+{
+public:
+	RandomSpawner(int total_teams, double distance, double variation);
+	Transform get(int team);
+private:
+	const double angle_step;
+	std::random_device device;
+	std::uniform_real_distribution<double> distribution_d;
+	std::uniform_real_distribution<double> distribution_a;
+};
+
+
+}  // namespace battles
+}  // namespace kurator
-- 
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