feat(creatures): animate creature walk cycles

Add a Gait component synchronized over the network and procedural animation for model nodes. Load animation parameters from assets/model/creature/pig/animation.json and apply leg swing, body bob, and head motion based on gait. Refactor Gait into its own header for reuse.

assets/model/creature/pig/animation.json

@@ -0,0 +1,33 @@
+{
+  "walk": {
+    "speed": 6.0,
+    "amplitude": 25.0
+  },
+  "run": {
+    "speed": 12.0,
+    "amplitude": 40.0
+  },
+  "body_bob": 0.03,
+  "head": {
+    "node": "Head",
+    "amplitude": 4.0
+  },
+  "legs": [
+    {
+      "node": "Foot_FL",
+      "phase": 0.0
+    },
+    {
+      "node": "Foot_FR",
+      "phase": 3.14159
+    },
+    {
+      "node": "Foot_HL",
+      "phase": 3.14159
+    },
+    {
+      "node": "Foot_HR",
+      "phase": 0.0
+    }
+  ]
+}

include/Cubed/gameplay/client_entity_manager.hpp

@@ -1,5 +1,6 @@
 #pragma once
 #include "Cubed/gameplay/ecs/entity.hpp"
+#include "Cubed/gameplay/gait.hpp"
 #include "glm/ext/vector_float3.hpp"
 #include "world/entity.pb.h"
 
@@ -13,7 +14,7 @@ public:
     enum class Command { CREATE, DESTORY, UPDATE };
 
     ClientEntityManager(ClientWorld& world);
-    void update();
+    void update(float dt);
     void init();
 
     void receive_entity_create(S2CEntityCreate& msg);
@@ -36,6 +37,7 @@ private:
         EntityID id;
         glm::vec3 pos;
         glm::vec3 direction;
+        Gait gait;
     };
 
     using EntityMap = tbb::concurrent_hash_map<EntityID, entt::entity>;

include/Cubed/gameplay/client_player.hpp

@@ -3,7 +3,6 @@
 #include "Cubed/gameplay/ecs/animation.hpp"
 #include "Cubed/gameplay/ecs/identity.hpp"
 #include "Cubed/gameplay/ecs/transform.hpp"
-#include "Cubed/gameplay/player.hpp"
 namespace Cubed {
 
 struct ClientPlayer {

include/Cubed/gameplay/ecs/animation.hpp

@@ -1,6 +1,6 @@
 #pragma once
 
-#include "Cubed/gameplay/player.hpp"
+#include "Cubed/gameplay/gait.hpp"
 namespace Cubed {
 
 struct WalkPose {

include/Cubed/gameplay/gait.hpp

@@ -0,0 +1,21 @@
+#pragma once
+#include <stdexcept>
+#include <utility>
+
+namespace Cubed {
+enum class Gait { STOP = 0, WALK = 1, RUN = 2 };
+constexpr int get_gait_id(Gait gait) { return std::to_underlying(gait); }
+
+inline Gait get_gait_from_id(int id) {
+    switch (id) {
+    case std::to_underlying(Gait::STOP):
+        return Gait::STOP;
+    case std::to_underlying(Gait::WALK):
+        return Gait::WALK;
+    case std::to_underlying(Gait::RUN):
+        return Gait::RUN;
+    default:
+        throw std::runtime_error("Unknown Gait");
+    }
+}
+} // namespace Cubed

include/Cubed/gameplay/local_player.hpp

@@ -11,7 +11,6 @@
 #include "Cubed/gameplay/game_time.hpp"
 #include "Cubed/gameplay/hitbox.hpp"
 #include "Cubed/gameplay/item_stack.hpp"
-#include "Cubed/gameplay/player.hpp"
 #include "Cubed/input/event.hpp"
 #include "Cubed/input/input.hpp"
 

include/Cubed/gameplay/player.hpp

@@ -1,23 +1,7 @@
 #pragma once
 #include "glm/ext/vector_float3.hpp"
 
-#include <stdexcept>
-#include <utility>
 namespace Cubed {
-enum class Gait { STOP = 0, WALK = 1, RUN = 2 };
-constexpr int get_gait_id(Gait gait) { return std::to_underlying(gait); }
 
-inline Gait get_gait_from_id(int id) {
-    switch (id) {
-    case std::to_underlying(Gait::STOP):
-        return Gait::STOP;
-    case std::to_underlying(Gait::WALK):
-        return Gait::WALK;
-    case std::to_underlying(Gait::RUN):
-        return Gait::RUN;
-    default:
-        throw std::runtime_error("Unknown Gait");
-    }
-}
 static constexpr glm::vec3 PLAYER_SIZE{0.6f, 1.8f, 0.6f};
 } // namespace Cubed

include/Cubed/gameplay/server_player.hpp

@@ -1,7 +1,7 @@
 #pragma once
 #include "Cubed/gameplay/chunk_pos.hpp"
+#include "Cubed/gameplay/gait.hpp"
 #include "Cubed/gameplay/game_time.hpp"
-#include "Cubed/gameplay/player.hpp"
 
 #include <absl/container/flat_hash_set.h>
 #include <atomic>

include/Cubed/render/model_manager.hpp

@@ -41,5 +41,6 @@ private:
     IDMap m_id_map;
     NameMap m_name_map;
     Handle load_model(std::string_view model_name);
+    void load_anim_config(ModelNode& node, const std::string& path);
 };
 } // namespace Cubed

include/Cubed/render/model_node.hpp

@@ -9,6 +9,7 @@
 #include <glm/glm.hpp>
 #include <memory>
 #include <string>
+#include <string_view>
 namespace Cubed {
 
 struct Mesh {
@@ -32,11 +33,47 @@ struct Mesh {
                        (void*)offsetof(Vertex3D, nx));
     };
 };
+struct NodeAnimRule {
+    enum class Role { NONE, LEG, HEAD };
+    std::string node;
+    Role role = Role::NONE;
+    float phase = 0.0f;
+};
+
+struct ModelAnimConfig {
+    float walk_speed = 6.0f;
+    float walk_amp = 25.0f;
+    float run_speed = 12.0f;
+    float run_amp = 40.0f;
+    float body_bob = 0.05f;
+    float head_amp = 4.0f;
+    std::vector<NodeAnimRule> nodes;
+
+    const NodeAnimRule* rule_for(std::string_view name) const {
+        for (const auto& r : nodes) {
+            if (r.node == name) {
+                return &r;
+            }
+        }
+        return nullptr;
+    }
+
+    bool has_role(NodeAnimRule::Role role) const {
+        for (const auto& r : nodes) {
+            if (r.role == role) {
+                return true;
+            }
+        }
+        return false;
+    }
+};
 struct ModelNode {
     std::string name;
     glm::mat4 transform{1.0f};
+
     std::vector<Mesh> meshes;
     std::vector<ModelNode> children;
+    ModelAnimConfig anim;
 };
 
 } // namespace Cubed

include/Cubed/render/model_renderer.hpp

@@ -1,5 +1,6 @@
 #pragma once
 
+#include "Cubed/gameplay/ecs/animation.hpp"
 #include "Cubed/gameplay/model.hpp"
 #include "Cubed/render/model_node.hpp"
 #include "Cubed/shader.hpp"
@@ -12,15 +13,18 @@ class ModelRender {
 public:
     ModelRender(Renderer& renderer);
     void render_model(ModelID id, const glm::vec3& pos, float yaw,
-                      Camera& camera);
+                      Camera& camera, const WalkPose& pose);
 
     void shadow_pass(ModelID id, const glm::vec3& pos, float yaw,
-                     Camera& camera);
+                     Camera& camera, const WalkPose& pose);
 
 private:
     Renderer& m_renderer;
     void render_node(const ModelNode& node, const glm::mat4& parent,
-                     const glm::mat4& view, const Shader& shader, bool shadow);
+                     const glm::mat4& view, const Shader& shader, bool shadow,
+                     const WalkPose& pose, const ModelAnimConfig& cfg);
+    glm::mat4 pose_node(const ModelNode& node, const ModelAnimConfig& cfg,
+                        const WalkPose& pose);
     void render_mesh(const Mesh& mesh, bool shadow);
 };
 } // namespace Cubed

src/gameplay/client_entity_manager.cpp

@@ -13,7 +13,19 @@ using namespace google::protobuf;
 
 namespace Cubed {
 ClientEntityManager::ClientEntityManager(ClientWorld& world) : m_world(world) {}
-void ClientEntityManager::update() { handle_task(); }
+void ClientEntityManager::update(float dt) {
+    handle_task();
+
+    auto view = m_registry.view<BaseClientCreature>();
+    for (auto e : view) {
+        auto& c = view.get<BaseClientCreature>(e);
+        if (c.pose.gait == Gait::STOP) {
+            c.pose.walk_time = 0.0f;
+        } else {
+            c.pose.walk_time += dt;
+        }
+    }
+}
 
 void ClientEntityManager::init() {
     m_factories.emplace("cubed:pig", [this](EntityID id) {
@@ -53,7 +65,7 @@ void ClientEntityManager::handle_entity_update(UpdateInfo& info) {
     ASSERT(creature);
     creature->transform.position.value = info.pos;
     creature->transform.direction.value = info.direction;
-
+    creature->pose.gait = info.gait;
     auto r = m_registry.try_get<RenderTransform>(e);
     ASSERT(r);
     r->direction.value =
@@ -79,6 +91,7 @@ void ClientEntityManager::receive_entity_update(S2CEntityUpdate& msg) {
     e.id = msg.id();
     e.pos = Tools::get_net_vec3(msg.pos());
     e.direction = Tools::get_net_vec3(msg.direction());
+    e.gait = get_gait_from_id(msg.gait());
     m_tasks.emplace(Command::UPDATE, std::move(e));
 }
 

src/gameplay/client_world.cpp

@@ -743,7 +743,7 @@ void ClientWorld::send_chat_message(ChatMessage& message) {
 
 void ClientWorld::update(float delta_time) {
     m_player_manager.update(delta_time);
-    m_entity_manager.update();
+    m_entity_manager.update(delta_time);
     {
         std::lock_guard lk(m_delete_vbo_mutex);
         m_pending_delete_vbo.clear();

src/gameplay/server_entity_manager.cpp

@@ -3,6 +3,7 @@
 #include "Cubed/gameplay/creatures/pig.hpp"
 #include "Cubed/gameplay/ecs/identity.hpp"
 #include "Cubed/gameplay/ecs/server_entity.hpp"
+#include "Cubed/gameplay/gait.hpp"
 #include "Cubed/gameplay/hitbox_manager.hpp"
 #include "Cubed/gameplay/server_world.hpp"
 #include "Cubed/gameplay/session.hpp"
@@ -11,6 +12,7 @@
 #include "Cubed/gameplay/systems/wander_ai_system.hpp"
 #include "Cubed/tools/cubed_assert.hpp"
 #include "Cubed/tools/net_utils.hpp"
+
 using namespace google::protobuf;
 
 namespace Cubed {
@@ -88,6 +90,12 @@ void ServerEntityManager::update_send(
 
     Tools::set_net_vec3(p->mutable_direction(),
                         creature.transform.direction.value);
+    const auto& v = creature.velocity.value;
+    if (v.x * v.x + v.z * v.z > 1e-4f) {
+        p->set_gait(get_gait_id(Gait::WALK));
+    } else {
+        p->set_gait(get_gait_id(Gait::STOP));
+    }
 
     for (auto& s : sessions) {
         s->send(make_packet(p));

src/proto/world/entity.proto

@@ -27,4 +27,5 @@ message S2CEntityUpdate {
     uint64 id = 1;
     Vec3 pos = 2;
     Vec3 direction = 3;
+    int32 gait = 4;
 }

src/render/model_manager.cpp

@@ -3,6 +3,12 @@
 #include "Cubed/tools/cubed_assert.hpp"
 #include "Cubed/tools/log.hpp"
 #include "Cubed/tools/name_space.hpp"
+
+#include <filesystem>
+#include <rapidjson/document.h>
+#include <rapidjson/istreamwrapper.h>
+
+namespace fs = std::filesystem;
 namespace Cubed {
 
 ModelManager& ModelManager::instance() {
@@ -80,6 +86,9 @@ ModelManager::Handle ModelManager::load_model(std::string_view model_name) {
                            space[1]);
     }
     auto model = m_loader.load(path);
+    fs::path anim_path = path;
+    anim_path = anim_path.parent_path() / "animation.json";
+    load_anim_config(model, anim_path);
     ModelMap::accessor acc;
     if (m_models.insert(acc, m_next++)) {
         acc->second = std::move(model);
@@ -95,4 +104,50 @@ ModelManager::Handle ModelManager::load_model(std::string_view model_name) {
     return {acc->second, acc->first};
 }
 
+void ModelManager::load_anim_config(ModelNode& node, const std::string& path) {
+    if (!fs::is_regular_file(path)) {
+        return;
+    }
+    std::ifstream s(path);
+    if (!s.is_open()) {
+        return;
+    }
+    rapidjson::IStreamWrapper isw(s);
+    rapidjson::Document doc;
+    doc.ParseStream(isw);
+    if (doc.HasParseError()) {
+        Logger::warn("Can't parse anim config {}", path);
+        return;
+    }
+    ModelAnimConfig cfg;
+    if (doc.HasMember("walk")) {
+        cfg.walk_speed = doc["walk"]["speed"].GetFloat();
+        cfg.walk_amp = doc["walk"]["amplitude"].GetFloat();
+    }
+    if (doc.HasMember("run")) {
+        cfg.run_speed = doc["run"]["speed"].GetFloat();
+        cfg.run_amp = doc["run"]["amplitude"].GetFloat();
+    }
+    if (doc.HasMember("body_bob")) {
+        cfg.body_bob = doc["body_bob"].GetFloat();
+    }
+    if (doc.HasMember("head")) {
+        NodeAnimRule r;
+        r.node = doc["head"]["node"].GetString();
+        r.role = NodeAnimRule::Role::HEAD;
+        cfg.head_amp = doc["head"]["amplitude"].GetFloat();
+        cfg.nodes.push_back(std::move(r));
+    }
+    if (doc.HasMember("legs")) {
+        for (auto& leg : doc["legs"].GetArray()) {
+            NodeAnimRule r;
+            r.node = leg["node"].GetString();
+            r.role = NodeAnimRule::Role::LEG;
+            r.phase = leg["phase"].GetFloat();
+            cfg.nodes.push_back(std::move(r));
+        }
+    }
+    node.anim = std::move(cfg);
+}
+
 } // namespace Cubed

src/render/model_renderer.cpp

@@ -3,37 +3,64 @@
 #include "Cubed/camera.hpp"
 #include "Cubed/render/model_manager.hpp"
 #include "Cubed/render/renderer.hpp"
+
+#include <cmath>
 namespace Cubed {
+
+namespace {
+float swing_angle(const WalkPose& pose, float speed, float amp_deg) {
+    if (pose.gait == Gait::STOP) {
+        return 0.0f;
+    }
+    return glm::sin(pose.walk_time * speed) * glm::radians(amp_deg);
+}
+} // namespace
+
 ModelRender::ModelRender(Renderer& renderer) : m_renderer(renderer) {}
 
 void ModelRender::render_model(ModelID id, const glm::vec3& pos, float yaw,
-                               Camera& camera) {
+                               Camera& camera, const WalkPose& pose) {
     auto& root = ModelManager::model(id).node;
-    glm::mat4 transform = glm::translate(glm::mat4(1.0f), pos) *
+    glm::vec3 bob_pos = pos;
+    if (pose.gait != Gait::STOP &&
+        root.anim.has_role(NodeAnimRule::Role::LEG)) {
+        bob_pos.y += std::abs(glm::sin(pose.walk_time * root.anim.walk_speed)) *
+                     root.anim.body_bob;
+    }
+
+    glm::mat4 transform = glm::translate(glm::mat4(1.0f), bob_pos) *
                           glm::rotate(glm::mat4(1.0f), yaw, {0, 1, 0});
     auto& shader = m_renderer.get_shader("model_shader");
     glm::mat4 view = camera.get_camera_lookat();
     shader.set_loc("proj_matrix", m_renderer.p_mat());
-    render_node(root, transform, view, shader, false);
+    render_node(root, transform, view, shader, false, pose, root.anim);
 }
 
 void ModelRender::shadow_pass(ModelID id, const glm::vec3& pos, float yaw,
-                              Camera& camera) {
+                              Camera& camera, const WalkPose& pose) {
     auto& root = ModelManager::model(id).node;
-    glm::mat4 transform = glm::translate(glm::mat4(1.0f), pos) *
+    glm::vec3 bob_pos = pos;
+    if (pose.gait != Gait::STOP &&
+        root.anim.has_role(NodeAnimRule::Role::LEG)) {
+        bob_pos.y += std::abs(glm::sin(pose.walk_time * root.anim.walk_speed)) *
+                     root.anim.body_bob;
+    }
+
+    glm::mat4 transform = glm::translate(glm::mat4(1.0f), bob_pos) *
                           glm::rotate(glm::mat4(1.0f), yaw, {0, 1, 0});
 
     auto& shader = m_renderer.get_shader("depth_model");
     glm::mat4 view = camera.get_camera_lookat();
 
-    render_node(root, transform, view, shader, true);
+    render_node(root, transform, view, shader, true, pose, root.anim);
 }
 
 void ModelRender::render_node(const ModelNode& node, const glm::mat4& parent,
                               const glm::mat4& view, const Shader& shader,
-                              bool shadow) {
+                              bool shadow, const WalkPose& pose,
+                              const ModelAnimConfig& cfg) {
 
-    glm::mat4 transform = parent * node.transform;
+    glm::mat4 transform = parent * pose_node(node, cfg, pose);
     if (shadow) {
         shader.set_loc("modelMatrix", transform);
     } else {
@@ -48,7 +75,7 @@ void ModelRender::render_node(const ModelNode& node, const glm::mat4& parent,
     }
 
     for (auto& child : node.children) {
-        render_node(child, transform, view, shader, shadow);
+        render_node(child, transform, view, shader, shadow, pose, cfg);
     }
 }
 
@@ -64,4 +91,27 @@ void ModelRender::render_mesh(const Mesh& mesh, bool) {
                    GL_UNSIGNED_INT, 0);
 }
 
+glm::mat4 ModelRender::pose_node(const ModelNode& node,
+                                 const ModelAnimConfig& cfg,
+                                 const WalkPose& pose) {
+    const auto* rule = cfg.rule_for(node.name);
+    if (!rule) {
+        return node.transform;
+    }
+    float angle = 0.0f;
+    if (rule->role == NodeAnimRule::Role::LEG) {
+        float speed = pose.gait == Gait::RUN ? cfg.run_speed : cfg.walk_speed;
+        float amp = pose.gait == Gait::RUN ? cfg.run_amp : cfg.walk_amp;
+
+        angle = swing_angle(pose, speed, amp);
+        angle *= std::cos(rule->phase);
+    } else if (rule->role == NodeAnimRule::Role::HEAD) {
+        angle = glm::sin(pose.walk_time * cfg.walk_speed * 0.5f) *
+                glm::radians(cfg.head_amp);
+    } else {
+        return node.transform;
+    }
+    return glm::rotate(node.transform, angle, glm::vec3(1.0f, 0.0f, 0.0f));
+}
+
 } // namespace Cubed

src/render/world_renderer.cpp

@@ -307,9 +307,9 @@ void WorldRenderer::shadow_entity(ClientWorld& world,
         auto& t = view.get<RenderTransform>(entity);
         float yaw = std::atan2(t.direction.value.x, t.direction.value.z);
 
-        m_renderer.model_renderer().shadow_pass(creature.model,
-                                                t.position.value, yaw,
-                                                world.world_scene().camera());
+        m_renderer.model_renderer().shadow_pass(
+            creature.model, t.position.value, yaw, world.world_scene().camera(),
+            creature.pose);
     }
     m_player_renderer.render(shader, world, true);
 }
@@ -734,9 +734,9 @@ void WorldRenderer::render_entity(ClientWorld& world) {
         }
         auto& t = view.get<RenderTransform>(entity);
         float yaw = std::atan2(t.direction.value.x, t.direction.value.z);
-        m_renderer.model_renderer().render_model(creature.model,
-                                                 t.position.value, yaw,
-                                                 world.world_scene().camera());
+        m_renderer.model_renderer().render_model(
+            creature.model, t.position.value, yaw, world.world_scene().camera(),
+            creature.pose);
     }
 
     m_player_renderer.render(shader, world, false);