From 701dd6b120e7e5116ea8ee37795facb4db05fc64 Mon Sep 17 00:00:00 2001
From: Persson-dev <sim16.prib@gmail.com>
Date: Thu, 1 Jan 2026 22:19:55 +0100
Subject: [PATCH] add basic entity movement

---
 src/td/game/World.cpp                   | 14 ++++++-
 src/td/simulation/CommandApply.cpp      |  7 +++-
 src/td/simulation/system/EntityMove.cpp | 52 ++++++++++++++++++++++++-
 3 files changed, 70 insertions(+), 3 deletions(-)

diff --git a/src/td/game/World.cpp b/src/td/game/World.cpp
index cb5a935..4b0d444 100644
--- a/src/td/game/World.cpp
+++ b/src/td/game/World.cpp
@@ -1,7 +1,10 @@
+#include <cassert>
+#include <td/Maths.h>
 #include <td/game/World.h>
+#include <td/game/WorldTypes.h>
 
-#include <td/simulation/WorldTicker.h>
 #include <td/protocol/packet/PacketSerialize.h>
+#include <td/simulation/WorldTicker.h>
 
 namespace td {
 namespace game {
@@ -89,5 +92,14 @@ void World::ResetSnapshots(std::shared_ptr<sim::WorldSnapshot>& a_Current, std::
 	m_NextState = a_Next;
 }
 
+TilePtr World::GetTile(std::int32_t x, std::int32_t y) const {
+	ChunkCoord coords{static_cast<std::int16_t>(x / Chunk::ChunkWidth), static_cast<std::int16_t>(y / Chunk::ChunkHeight)};
+	auto it = m_Chunks.find(coords);
+	assert(it != m_Chunks.end());
+	auto chunk = it->second;
+	Vec2i inchunkCoords{x % Chunk::ChunkWidth, y % Chunk::ChunkHeight};
+	return GetTilePtr(chunk->GetTileIndex(inchunkCoords.y * Chunk::ChunkWidth + inchunkCoords.x));
+}
+
 }  // namespace game
 }  // namespace td
diff --git a/src/td/simulation/CommandApply.cpp b/src/td/simulation/CommandApply.cpp
index 8e17aef..ae6e234 100644
--- a/src/td/simulation/CommandApply.cpp
+++ b/src/td/simulation/CommandApply.cpp
@@ -1,3 +1,4 @@
+#include <td/Types.h>
 #include <td/simulation/CommandApply.h>
 
 namespace td {
@@ -6,7 +7,7 @@ namespace sim {
 CommandApply::CommandApply(const game::World& a_World, WorldSnapshot& a_Snapshot) : m_World(a_World), m_Snapshot(a_Snapshot) {}
 
 void CommandApply::Handle(const protocol::commands::EndCommand& a_End) {
-	(void) m_World;
+	(void)m_World;
 }
 
 void CommandApply::Handle(const protocol::commands::PlaceTowerCommand& a_PlaceTower) {
@@ -24,6 +25,10 @@ void CommandApply::Handle(const protocol::commands::PlayerJoinCommand& a_PlayerJ
 void CommandApply::Handle(const protocol::commands::SpawnTroopCommand& a_SpawnTroop) {
 	auto zombie = std::make_shared<game::Zombie>();
 	zombie->m_Position = a_SpawnTroop->m_Position;
+
+	// TODO: make it spawn dependant
+	zombie->m_Direction = Direction::PositiveY;
+
 	m_Snapshot.m_Mobs.push_back(zombie);
 }
 
diff --git a/src/td/simulation/system/EntityMove.cpp b/src/td/simulation/system/EntityMove.cpp
index 798a6f8..b597831 100644
--- a/src/td/simulation/system/EntityMove.cpp
+++ b/src/td/simulation/system/EntityMove.cpp
@@ -1,11 +1,61 @@
+#include <td/Maths.h>
+#include <td/Types.h>
+#include <td/game/WorldTypes.h>
 #include <td/simulation/system/EntityMove.h>
 
+#include <td/game/World.h>
+
 namespace td {
 namespace sim {
 
+static Vec2i GetUnitDirection(Direction a_Direction) {
+	switch (a_Direction) {
+		case Direction::PositiveX:
+			return {1, 0};
+		case Direction::NegativeX:
+			return {-1, 0};
+		case Direction::PositiveY:
+			return {0, 1};
+		case Direction::NegativeY:
+			return {0, -1};
+	}
+	return {0, 0};
+}
+
+class DirectionTileVisitor : public game::TileHandler {
+  private:
+	Direction m_Direction;
+
+  public:
+	DirectionTileVisitor() {}
+
+	virtual void Handle(const game::EmptyTile& a_Tile) override {}
+
+	virtual void Handle(const game::TowerTile& a_Tile) override {}
+
+	virtual void Handle(const game::DecorationTile& a_Tile) override {}
+
+	virtual void Handle(const game::WalkableTile& a_Tile) override {
+		m_Direction = a_Tile->m_Direction;
+	}
+
+	const Direction GetDirection() {
+		return m_Direction;
+	}
+};
+
 void EntityMove::Tick(const game::World& a_World, WorldSnapshot& a_State, FpFloat a_Delta) {
 	for (auto& mob : a_State.m_Mobs) {
-		mob->m_Position.x += a_Delta;
+		auto tile = a_World.GetTile(static_cast<std::int32_t>(mob->m_Position.x), static_cast<std::int32_t>(mob->m_Position.y));
+		Direction direction = mob->m_Direction;
+		if (tile) {
+			DirectionTileVisitor visitor;
+			tile->Dispatch(visitor);
+			direction = visitor.GetDirection();
+		}
+		auto directVector = GetUnitDirection(direction);
+		mob->m_Position.x += directVector.x * a_Delta;
+		mob->m_Position.y += directVector.y * a_Delta;
 	}
 }