refactor: river (#10)

* fix: correct snowy grass block texture

* refactor: river generation

* fix: water placement error due to interpolation

* perf: improve river naturalness

* feat: add river tab item

* fix: path truncation

CMakeLists.txt

@@ -120,6 +120,8 @@ add_executable(${PROJECT_NAME}
     src/gameplay/cave_carver.cpp
     src/gameplay/cave_path.cpp
     src/gameplay/builders/snowy_plain_builder.cpp
+    src/gameplay/river_worm.cpp
+    src/gameplay/river_path.cpp
 )
 
 if(CMAKE_BUILD_TYPE STREQUAL "Debug")

include/Cubed/dev_panel.hpp

@@ -47,6 +47,7 @@ private:
     void show_about_table_bar();
     void show_biome_table_bar();
     void show_cave_table_bar();
+    void show_river_table_bar();
     void show_settings_tab_item();
     void show_world_tab_item();
     void show_player_tab_item();

include/Cubed/gameplay/builders/biome_builder.hpp

@@ -12,6 +12,5 @@ public:
 
 protected:
     void build_bottom();
-    void fill_water();
 };
 } // namespace Cubed

include/Cubed/gameplay/cave_carver.hpp

@@ -4,10 +4,10 @@ namespace Cubed {
 class CaveCarver {
 public:
     CaveCarver();
-    std::unordered_map<int, CavePath>& paths();
+    std::unordered_map<unsigned, CavePath>& paths();
     void init(unsigned world_seed);
     void reload(unsigned world_seed);
-    void add_path(const glm::vec3& pos);
+    void add_path(const glm::vec3& pos, unsigned chunk_seed);
     void try_to_add_path(const ChunkPos& pos, unsigned chunk_seed);
     void cleanup_finished_caves();
 
@@ -15,7 +15,7 @@ public:
     float& cave_probability();
 
 private:
-    std::unordered_map<int, CavePath> m_paths;
+    std::unordered_map<unsigned, CavePath> m_paths;
     unsigned m_seed = 0;
     int m_sum = 0;
     Random m_random;

include/Cubed/gameplay/cave_path.hpp

@@ -1,47 +1,13 @@
 #pragma once
 
 #include "Cubed/gameplay/chunk_pos.hpp"
+#include "Cubed/gameplay/path_point.hpp"
 #include "Cubed/tools/cubed_random.hpp"
 
 #include <glm/glm.hpp>
 #include <unordered_set>
 namespace Cubed {
 
-struct PathPoint {
-    glm::vec3 pos;
-    glm::vec3 tangent{0.0f, 0.0f, 1.0f};
-    float rad_xz;
-    float rad_y;
-    PathPoint(const glm::vec3& p, float rx, float ry)
-        : pos(p), rad_xz(rx), rad_y(ry) {}
-    bool contains(const glm::vec3& other_pos) const {
-        glm::vec3 to_point = other_pos - pos;
-
-        glm::vec3 world_up(0.0f, 1.0f, 0.0f);
-
-        glm::vec3 right = glm::normalize(glm::cross(tangent, world_up));
-
-        if (glm::length(right) < 0.001f) {
-            glm::vec3 alt_up(1.0f, 0.0f, 0.0f);
-            right = glm::normalize(glm::cross(tangent, alt_up));
-        }
-
-        glm::vec3 up = glm::normalize(glm::cross(right, tangent));
-
-        float horizontal_dist = glm::dot(to_point, right);
-        float vertical_dist = glm::dot(to_point, up);
-
-        float a = rad_xz;
-        float b = rad_y;
-        if (a <= 0.0f || b <= 0.0f)
-            return false;
-
-        float check = (horizontal_dist * horizontal_dist) / (a * a) +
-                      (vertical_dist * vertical_dist) / (b * b);
-        return check <= 1.0f;
-    }
-};
-
 class CavePath {
 public:
     CavePath(unsigned int world_seed, int path_id, const glm::vec3& start_pos);

include/Cubed/gameplay/chunk_generator.hpp

@@ -46,6 +46,7 @@ public:
     Random& random();
     const std::array<BiomeType, 8>& neighbor_biome() const;
     void generate_cave();
+    void generate_river();
 
 private:
     static inline std::atomic<bool> is_init{false};

include/Cubed/gameplay/path_point.hpp

@@ -0,0 +1,36 @@
+#pragma once
+#include <glm/glm.hpp>
+struct PathPoint {
+    glm::vec3 pos;
+    glm::vec3 tangent{0.0f, 0.0f, 1.0f};
+    float rad_xz;
+    float rad_y;
+    PathPoint(const glm::vec3& p, float rx, float ry)
+        : pos(p), rad_xz(rx), rad_y(ry) {}
+    bool contains(const glm::vec3& other_pos) const {
+        glm::vec3 to_point = other_pos - pos;
+
+        glm::vec3 world_up(0.0f, 1.0f, 0.0f);
+
+        glm::vec3 right = glm::normalize(glm::cross(tangent, world_up));
+
+        if (glm::length(right) < 0.001f) {
+            glm::vec3 alt_up(1.0f, 0.0f, 0.0f);
+            right = glm::normalize(glm::cross(tangent, alt_up));
+        }
+
+        glm::vec3 up = glm::normalize(glm::cross(right, tangent));
+
+        float horizontal_dist = glm::dot(to_point, right);
+        float vertical_dist = glm::dot(to_point, up);
+
+        float a = rad_xz;
+        float b = rad_y;
+        if (a <= 0.0f || b <= 0.0f)
+            return false;
+
+        float check = (horizontal_dist * horizontal_dist) / (a * a) +
+                      (vertical_dist * vertical_dist) / (b * b);
+        return check <= 1.0f;
+    }
+};

include/Cubed/gameplay/river.path.hpp

@@ -0,0 +1,52 @@
+#pragma once
+
+#include "Cubed/gameplay/chunk_pos.hpp"
+#include "Cubed/gameplay/path_point.hpp"
+#include "Cubed/tools/cubed_random.hpp"
+
+#include <glm/glm.hpp>
+#include <unordered_set>
+
+namespace Cubed {
+class RiverPath {
+
+public:
+    RiverPath(unsigned int world_seed, int path_id, const glm::vec3& start_pos);
+    const std::vector<PathPoint>& points() const;
+    void clear_chunk(const ChunkPos& pos);
+    bool is_finished() const;
+
+    static float& radius_xz_min();
+    static float& radius_xz_max();
+    static float& radius_y_min();
+    static float& radius_y_max();
+    static float& delta_angle_min();
+    static float& delta_angle_max();
+    static int& step_min();
+    static int& step_max();
+
+private:
+    static inline float m_radius_xz_min = 5.0f;
+    static inline float m_radius_xz_max = 10.0f;
+    static inline float m_radius_y_min = 4.0f;
+    static inline float m_radius_y_max = 8.0f;
+    static inline float m_delta_angle_min = -3.0f;
+    static inline float m_delta_angle_max = 3.0f;
+    static inline int m_step_min = 150;
+    static inline int m_step_max = 400;
+
+    int m_path_id = 0;
+    unsigned int m_seed = 0;
+    float m_yaw = 0.0f;
+    float m_pitch = 0.0f;
+    int m_step = 0;
+    float m_step_len = 1.0f;
+    PathPoint m_start_path_point{{0.0f, 0.0f, 0.0f}, 0.0f, 0.0f};
+    Random m_random;
+
+    std::vector<PathPoint> m_points;
+    std::unordered_set<ChunkPos, ChunkPos::Hash> m_pending_chunks;
+    void collect_path_points();
+    void precompute_chunk_coverage();
+};
+} // namespace Cubed

include/Cubed/gameplay/river_worm.hpp

@@ -0,0 +1,31 @@
+#pragma once
+#include "Cubed/gameplay/chunk_pos.hpp"
+#include "Cubed/gameplay/river.path.hpp"
+#include "Cubed/tools/cubed_random.hpp"
+
+#include <glm/glm.hpp>
+#include <unordered_map>
+namespace Cubed {
+
+class RiverWorm {
+public:
+    RiverWorm();
+    std::unordered_map<unsigned, RiverPath>& paths();
+    void init(unsigned world_seed);
+    void reload(unsigned world_seed);
+    void add_path(const glm::vec3& pos, unsigned chunk_seed);
+    void try_to_add_path(const ChunkPos& pos, unsigned chunk_seed);
+    void cleanup_finished_rivers();
+
+    int river_sum() const;
+    float& river_probability();
+
+private:
+    std::unordered_map<unsigned, RiverPath> m_paths;
+    unsigned m_seed = 0;
+    int m_sum = 0;
+    Random m_random;
+    float m_probability = 0.01f;
+};
+
+}; // namespace Cubed

include/Cubed/gameplay/world.hpp

@@ -2,6 +2,7 @@
 #include "Cubed/AABB.hpp"
 #include "Cubed/gameplay/cave_carver.hpp"
 #include "Cubed/gameplay/chunk.hpp"
+#include "Cubed/gameplay/river_worm.hpp"
 
 #include <atomic>
 #include <condition_variable>
@@ -56,19 +57,19 @@ private:
     std::vector<std::pair<ChunkPos, Chunk>> m_new_chunk_queue;
 
     CaveCarver m_cave_carcer;
-
+    RiverWorm m_river_worm;
     void init_chunks();
 
     void gen_chunks_internal();
     void sync_player_pos(glm::vec3& player_pos);
-    void compute_required_chunks(ChunkPosSet& required_chunks);
+    void compute_required_chunks(ChunkPosSet& required_chunks,
+                                 ChunkHashMap& temp_neighbor);
     void sync_and_collect_missing_chunks(std::vector<ChunkPos>&,
                                          const ChunkPosSet&);
     void
     build_neighbor_context_for_new_chunks(ConstChunkMap& new_chunks_neighbor,
                                           ChunkPtrUpdateList& affected_neighbor,
-                                          const ChunkUpdateList& new_chunks,
+                                          const ChunkUpdateList& new_chunks);
-                                          ChunkHashMap& temp_neighbor);
     void build_neighbor_context_for_affected_neighbors(ChunkPtrUpdateList&,
                                                        ConstChunkMap&);
 
@@ -112,6 +113,7 @@ public:
     void stop_gen_thread();
 
     CaveCarver& cave_carcer();
+    RiverWorm& river_worm();
 };
 
 } // namespace Cubed

src/dev_panel.cpp

@@ -34,16 +34,16 @@ constexpr int AMPLITUDE_MAX = 80;
 constexpr float TREE_FREQ_MIM = 0.001f;
 constexpr float TREE_FREQ_MAX = 0.3f;
 
-constexpr float CAVE_PROBABILITY_MIN = 0.005f;
+constexpr float PATH_PROBABILITY_MIN = 0.005f;
-constexpr float CAVE_PROBABILITY_MAX = 0.1f;
+constexpr float PATH_PROBABILITY_MAX = 0.1f;
 constexpr float RADIUS_XZ_MIN = 1.0f;
 constexpr float RADIUS_XZ_MAX = 50.0f;
 constexpr float RADIUS_Y_MIN = 1.0f;
 constexpr float RADIUS_Y_MAX = 50.0f;
 constexpr float DELTA_ANGLE_MIN = -30.0f;
 constexpr float DELTA_ANGLE_MAX = 30.0f;
-constexpr int CAVE_STEP_MIN = 1;
+constexpr int PATH_STEP_MIN = 1;
-constexpr int CAVE_STEP_MAX = 1000;
+constexpr int PATH_STEP_MAX = 1000;
 
 static int filter_unsigned(ImGuiInputTextCallbackData* data) {
     if (data->EventFlag == ImGuiInputTextFlags_CallbackCharFilter) {
@@ -269,7 +269,7 @@ void DevPanel::show_cave_table_bar() {
 
     ImGui::Text("Total Cave Sum %d", cave_carcer.cave_sum());
     ImGui::SliderFloat("Cave Probability", &cave_carcer.cave_probability(),
-                       CAVE_PROBABILITY_MIN, CAVE_PROBABILITY_MAX);
+                       PATH_PROBABILITY_MIN, PATH_PROBABILITY_MAX);
     ImGui::SliderFloat("Radius XZ Min", &CavePath::radius_xz_min(),
                        RADIUS_XZ_MIN, RADIUS_XZ_MAX);
     ImGui::SliderFloat("Radius XZ Max", &CavePath::radius_xz_max(),
@@ -282,10 +282,34 @@ void DevPanel::show_cave_table_bar() {
                        DELTA_ANGLE_MIN, 0.0f);
     ImGui::SliderFloat("Delta Angle Max", &CavePath::delta_angle_max(), 0.0f,
                        DELTA_ANGLE_MAX);
-    ImGui::SliderInt("Step Min", &CavePath::step_min(), CAVE_STEP_MIN,
+    ImGui::SliderInt("Step Min", &CavePath::step_min(), PATH_STEP_MIN,
-                     CAVE_STEP_MAX);
+                     PATH_STEP_MAX);
-    ImGui::SliderInt("Step Max", &CavePath::step_max(), CAVE_STEP_MIN,
+    ImGui::SliderInt("Step Max", &CavePath::step_max(), PATH_STEP_MIN,
-                     CAVE_STEP_MAX);
+                     PATH_STEP_MAX);
+}
+
+void DevPanel::show_river_table_bar() {
+    auto& river_wrom = m_app.world().river_worm();
+
+    ImGui::Text("Total River Sum %d", river_wrom.river_sum());
+    ImGui::SliderFloat("River Probability", &river_wrom.river_probability(),
+                       PATH_PROBABILITY_MIN, PATH_PROBABILITY_MAX);
+    ImGui::SliderFloat("Radius XZ Min##river", &RiverPath::radius_xz_min(),
+                       RADIUS_XZ_MIN, RADIUS_XZ_MAX);
+    ImGui::SliderFloat("Radius XZ Max##river", &RiverPath::radius_xz_max(),
+                       RADIUS_XZ_MIN, RADIUS_XZ_MAX);
+    ImGui::SliderFloat("Radius Y Min##river", &RiverPath::radius_y_min(),
+                       RADIUS_Y_MIN, RADIUS_Y_MAX);
+    ImGui::SliderFloat("Radius Y Max##river", &RiverPath::radius_y_max(),
+                       RADIUS_Y_MIN, RADIUS_Y_MAX);
+    ImGui::SliderFloat("Delta Angle Min##river", &RiverPath::delta_angle_min(),
+                       DELTA_ANGLE_MIN, 0.0f);
+    ImGui::SliderFloat("Delta Angle Max##river", &RiverPath::delta_angle_max(),
+                       0.0f, DELTA_ANGLE_MAX);
+    ImGui::SliderInt("Step Min##river", &RiverPath::step_min(), PATH_STEP_MIN,
+                     PATH_STEP_MAX);
+    ImGui::SliderInt("Step Max##river", &RiverPath::step_max(), PATH_STEP_MIN,
+                     PATH_STEP_MAX);
 }
 
 void DevPanel::show_settings_tab_item() {
@@ -438,6 +462,10 @@ void DevPanel::show_world_tab_item() {
                 show_cave_table_bar();
                 ImGui::EndTabItem();
             }
+            if (ImGui::BeginTabItem("River")) {
+                show_river_table_bar();
+                ImGui::EndTabItem();
+            }
             if (ImGui::BeginTabItem("Biome")) {
                 show_biome_table_bar();
                 ImGui::EndTabItem();

src/gameplay/builders/biome_builder.cpp

@@ -15,27 +15,5 @@ void BiomeBuilder::build_bottom() {
         }
     }
 }
-void BiomeBuilder::fill_water() {
+
-    ChunkGenerator& chunk_generator = get_chunk_generator();
-    Chunk& chunk = chunk_generator.chunk();
-    auto& m_blocks = chunk.blocks();
-    auto& neighbor = chunk_generator.neighbor_biome();
-    auto& heightmap = chunk.heightmap();
-    for (int i = 0; i < 8; i++) {
-        if (neighbor[i] == BiomeType::RIVER) {
-            for (int x = 0; x < SIZE_X; x++) {
-                for (int z = 0; z < SIZE_Z; z++) {
-                    if (heightmap[x][z] >= SEA_LEVEL) {
-                        continue;
-                    }
-                    int height = heightmap[x][z];
-                    for (int y = height; y < SEA_LEVEL; y++) {
-                        m_blocks[Chunk::index(x, y, z)] = 7;
-                    }
-                }
-            }
-            return;
-        }
-    }
-}
 } // namespace Cubed

src/gameplay/builders/desert_builder.cpp

@@ -29,7 +29,7 @@ void DesertBuilder::build_blocks() {
     }
 }
 
-void DesertBuilder::build_vegetation() { fill_water(); }
+void DesertBuilder::build_vegetation() {}
 
 ChunkGenerator& DesertBuilder::get_chunk_generator() {
     return m_chunk_generator;

src/gameplay/builders/forest_builder.cpp

@@ -52,7 +52,6 @@ void ForestBuilder::build_vegetation() {
             }
         }
     }
-    fill_water();
 }
 
 ChunkGenerator& ForestBuilder::get_chunk_generator() {

src/gameplay/builders/mountain_builder.cpp

@@ -25,7 +25,7 @@ void MountainBuilder::build_blocks() {
     }
 }
 
-void MountainBuilder::build_vegetation() { fill_water(); }
+void MountainBuilder::build_vegetation() {}
 
 ChunkGenerator& MountainBuilder::get_chunk_generator() {
     return m_chunk_generator;

src/gameplay/builders/plain_builder.cpp

@@ -29,7 +29,7 @@ void PlainBuilder::build_blocks() {
     }
 }
 
-void PlainBuilder::build_vegetation() { fill_water(); }
+void PlainBuilder::build_vegetation() {}
 
 ChunkGenerator& PlainBuilder::get_chunk_generator() {
     return m_chunk_generator;

src/gameplay/builders/river_builder.cpp

@@ -1,6 +1,5 @@
 #include "Cubed/gameplay/builders/river_builder.hpp"
 
-#include "Cubed/gameplay/chunk.hpp"
 #include "Cubed/gameplay/chunk_generator.hpp"
 namespace Cubed {
 RiverBuilder::RiverBuilder(ChunkGenerator& chunk_generator)
@@ -12,6 +11,7 @@ void RiverBuilder::build_biome() {
 };
 
 void RiverBuilder::build_blocks() {
+    /*
     auto& m_chunk = m_chunk_generator.chunk();
     auto& m_blocks = m_chunk.blocks();
     auto& m_heightmap = m_chunk.heightmap();
@@ -33,9 +33,11 @@ void RiverBuilder::build_blocks() {
             }
         }
     }
+        */
 }
 
 void RiverBuilder::build_vegetation() {
+    /*
     auto& m_chunk = m_chunk_generator.chunk();
     auto& m_blocks = m_chunk.blocks();
     auto& m_heightmap = m_chunk.heightmap();
@@ -50,6 +52,7 @@ void RiverBuilder::build_vegetation() {
             }
         }
     }
+        */
 }
 
 ChunkGenerator& RiverBuilder::get_chunk_generator() {

src/gameplay/builders/snowy_plain_builder.cpp

@@ -29,7 +29,7 @@ void SnowyPlainBuilder::build_blocks() {
     }
 }
 
-void SnowyPlainBuilder::build_vegetation() { fill_water(); }
+void SnowyPlainBuilder::build_vegetation() {}
 
 ChunkGenerator& SnowyPlainBuilder::get_chunk_generator() {
     return m_chunk_generator;

src/gameplay/cave_carver.cpp

@@ -5,7 +5,7 @@
 namespace Cubed {
 CaveCarver::CaveCarver() {}
 
-std::unordered_map<int, CavePath>& CaveCarver::paths() { return m_paths; }
+std::unordered_map<unsigned, CavePath>& CaveCarver::paths() { return m_paths; }
 
 void CaveCarver::init(unsigned world_seed) {
     m_seed = world_seed;
@@ -19,13 +19,17 @@ void CaveCarver::reload(unsigned world_seed) {
     init(world_seed);
 }
 
-void CaveCarver::add_path(const glm::vec3& pos) {
+void CaveCarver::add_path(const glm::vec3& pos, unsigned chunk_seed) {
-    m_paths.emplace(m_sum, CavePath{m_seed, m_sum, pos});
+    m_paths.emplace(chunk_seed, CavePath{m_seed, m_sum, pos});
     m_sum++;
 }
 
 void CaveCarver::try_to_add_path(const ChunkPos& chunk_pos,
                                  unsigned chunk_seed) {
+    auto it = m_paths.find(chunk_seed);
+    if (it != m_paths.end()) {
+        return;
+    }
     Random random{chunk_seed};
     if (random.random_bool(static_cast<double>(m_cave_probability))) {
         const int CHUNK_MIN_X = chunk_pos.x * CHUNK_SIZE;
@@ -38,7 +42,7 @@ void CaveCarver::try_to_add_path(const ChunkPos& chunk_pos,
         int x = random.random_int(CHUNK_MIN_X, CHUNK_MAX_X);
         int y = random.random_int(CHUNK_MIN_Y + 1, max_y);
         int z = random.random_int(CHUNK_MIN_Z, CHUNK_MAX_Z);
-        add_path(glm::vec3{x, y, z});
+        add_path(glm::vec3{x, y, z}, chunk_seed);
     }
 }
 

src/gameplay/chunk.cpp

@@ -151,7 +151,7 @@ void Chunk::gen_vertex_data(
                         auto is_cull =
                             [&](const std::vector<BlockType>* chunk_blocks) {
                                 if (chunk_blocks == nullptr) {
-                                    return false;
+                                    return true;
                                 }
                                 int x, y, z;
                                 y = world_ny;
@@ -294,6 +294,7 @@ void Chunk::gen_phase_six(
     }
     m_generator->blend_surface_blocks_borders(neighbor_block);
     m_generator->generate_cave();
+    m_generator->generate_river();
 }
 
 void Chunk::gen_phase_seven() {

src/gameplay/chunk_generator.cpp

@@ -539,11 +539,17 @@ void ChunkGenerator::blend_surface_blocks_borders(
             // Update the top block if the type changed
             if (final_type != type_self) {
                 // top block
-                if (m_chunk.biome() == BiomeType::RIVER && final_type == 1) {
+                if (final_type == 7 && top_y > SEA_LEVEL) {
-                    final_type = 2;
+                    if (type_self == 7) {
+                        m_blocks[Chunk::index(x, top_y, z)] = 0;
+                    } else {
+                        m_blocks[Chunk::index(x, top_y, z)] = type_self;
                     }
 
+                } else {
                     m_blocks[Chunk::index(x, top_y, z)] = final_type;
+                }
+
                 // bottom block
                 unsigned fill_type = 2;
                 if (final_type == 1) {
@@ -552,11 +558,15 @@ void ChunkGenerator::blend_surface_blocks_borders(
                     fill_type = 4;
                 }
                 for (int y = top_y - 5; y < top_y; y++) {
+                    if (fill_type == 7 && y > SEA_LEVEL) {
+                        m_blocks[Chunk::index(x, y, z)] = 0;
+                    } else {
                         m_blocks[Chunk::index(x, y, z)] = fill_type;
                     }
                 }
             }
         }
+    }
 }
 
 void ChunkGenerator::generate_vegetation() {
@@ -650,6 +660,76 @@ void ChunkGenerator::generate_cave() {
     }
 }
 
+void ChunkGenerator::generate_river() {
+
+    auto& river_worm = m_chunk.world().river_worm();
+    auto& paths = river_worm.paths();
+    const auto& chunk_pos = m_chunk.chunk_pos();
+    auto& blocks = m_chunk.blocks();
+    const int CHUNK_MIN_X = chunk_pos.x * CHUNK_SIZE;
+    const int CHUNK_MIN_Z = chunk_pos.z * CHUNK_SIZE;
+    const int CHUNK_MAX_X = CHUNK_MIN_X + SIZE_X - 1;
+    const int CHUNK_MAX_Z = CHUNK_MIN_Z + SIZE_Z - 1;
+    const int CHUNK_MIN_Y = 0;
+    const int CHUNK_MAX_Y = SIZE_Y - 1;
+
+    bool is_river = false;
+
+    for (auto& [id, path] : paths) {
+        for (const auto& point : path.points()) {
+            if (m_chunk.biome() == BiomeType::DESERT) {
+                path.clear_chunk(chunk_pos);
+                continue;
+            }
+            const glm::vec3& center = point.pos;
+            float rad_xz = point.rad_xz;
+            float rad_y = point.rad_y;
+
+            int min_x = static_cast<int>(std::floor(center.x - rad_xz));
+            int max_x = static_cast<int>(std::floor(center.x + rad_xz));
+            int min_z = static_cast<int>(std::floor(center.z - rad_xz));
+            int max_z = static_cast<int>(std::floor(center.z + rad_xz));
+            int min_y = static_cast<int>(std::floor(center.y - rad_y));
+            int max_y = static_cast<int>(std::floor(center.y + rad_y));
+
+            min_x = std::max(min_x, CHUNK_MIN_X);
+            max_x = std::min(max_x, CHUNK_MAX_X);
+            min_z = std::max(min_z, CHUNK_MIN_Z);
+            max_z = std::min(max_z, CHUNK_MAX_Z);
+            min_y = std::max(min_y, CHUNK_MIN_Y);
+            max_y = std::min(max_y, CHUNK_MAX_Y);
+
+            for (int wx = min_x; wx <= max_x; ++wx) {
+                int x = wx - CHUNK_MIN_X;
+                for (int wz = min_z; wz <= max_z; ++wz) {
+                    int z = wz - CHUNK_MIN_Z;
+                    for (int wy = min_y; wy <= max_y; ++wy) {
+                        int y = wy;
+                        glm::vec3 pos(static_cast<float>(wx),
+                                      static_cast<float>(wy),
+                                      static_cast<float>(wz));
+                        if (point.contains(pos)) {
+                            if (y > SEA_LEVEL) {
+                                blocks[Chunk::index(x, y, z)] = 0;
+                                continue;
+                            }
+                            is_river = true;
+                            if (blocks[Chunk::index(x, y, z)] == 0) {
+                                continue;
+                            }
+                            blocks[Chunk::index(x, y, z)] = 7;
+                        }
+                    }
+                }
+            }
+        }
+        path.clear_chunk(chunk_pos);
+    }
+    if (is_river) {
+        m_chunk.biome(RIVER);
+    }
+}
+
 Chunk& ChunkGenerator::chunk() { return m_chunk; }
 
 Random& ChunkGenerator::random() { return m_random; }

src/gameplay/river_path.cpp

@@ -0,0 +1,93 @@
+#include "Cubed/constants.hpp"
+#include "Cubed/gameplay/river.path.hpp"
+#include "Cubed/tools/cubed_hash.hpp"
+#include "Cubed/tools/math_tools.hpp"
+
+#include <algorithm>
+namespace Cubed {
+RiverPath::RiverPath(unsigned int world_seed, int path_id,
+                     const glm::vec3& start_pos) {
+    m_path_id = path_id;
+    m_seed = HASH::combine_32(world_seed, path_id);
+    m_random.init(m_seed);
+    m_yaw = m_random.random_float(0.0f, 360.0f);
+    m_pitch = 0.0f;
+    m_start_path_point.pos = start_pos;
+    m_start_path_point.rad_xz =
+        m_random.random_float(m_radius_xz_min, m_radius_xz_max);
+    m_start_path_point.rad_y =
+        m_random.random_float(m_radius_y_min, m_radius_y_max);
+    m_step = m_random.random_int(m_step_min, m_step_max);
+    m_points.reserve(m_step + 1);
+    m_points.push_back(m_start_path_point);
+    collect_path_points();
+    precompute_chunk_coverage();
+}
+
+void RiverPath::collect_path_points() {
+    for (int i = 0; i < m_step; i++) {
+
+        m_yaw = std::fmod(m_yaw, 360.0f);
+        if (m_yaw < 0.0f)
+            m_yaw += 360.0f;
+
+        float dx = std::cos(glm::radians(m_pitch)) *
+                   std::sin(glm::radians(m_yaw)) * m_step_len;
+        float dy = std::sin(glm::radians(m_pitch)) * m_step_len;
+        float dz = std::cos(glm::radians(m_pitch)) *
+                   std::cos(glm::radians(m_yaw)) * m_step_len;
+
+        m_points[i].tangent = glm::normalize(glm::vec3{dx, dy, dz});
+
+        float t = Math::smootherstep(0, m_step - 1, i);
+
+        float drad_xz = m_start_path_point.rad_xz * (1.0f - t);
+        float drad_y = m_start_path_point.rad_y * (1.0f - t);
+        drad_xz = std::max(drad_xz, 4.0f);
+        drad_y = std::max(drad_y, 4.0f);
+        m_points.emplace_back(m_points[i].pos + glm::vec3{dx, dy, dz}, drad_xz,
+                              drad_y);
+
+        m_yaw += m_random.random_float(m_delta_angle_min, m_delta_angle_max);
+    }
+    auto n = m_points.size();
+    if (n >= 2) {
+        m_points[n - 1].tangent = m_points[n - 2].tangent;
+    }
+}
+
+void RiverPath::precompute_chunk_coverage() {
+    for (const auto& point : m_points) {
+        float rad = point.rad_xz;
+        const glm::vec3& center = point.pos;
+
+        int min_cx =
+            static_cast<int>(std::floor((center.x - rad) / CHUNK_SIZE));
+        int max_cx =
+            static_cast<int>(std::floor((center.x + rad) / CHUNK_SIZE));
+        int min_cz =
+            static_cast<int>(std::floor((center.z - rad) / CHUNK_SIZE));
+        int max_cz =
+            static_cast<int>(std::floor((center.z + rad) / CHUNK_SIZE));
+
+        for (int cx = min_cx; cx <= max_cx; ++cx)
+            for (int cz = min_cz; cz <= max_cz; ++cz)
+                m_pending_chunks.insert({cx, cz});
+    }
+}
+
+void RiverPath::clear_chunk(const ChunkPos& pos) {
+    m_pending_chunks.erase(pos);
+}
+const std::vector<PathPoint>& RiverPath::points() const { return m_points; }
+bool RiverPath::is_finished() const { return m_pending_chunks.empty(); }
+
+float& RiverPath::radius_xz_min() { return m_radius_xz_min; }
+float& RiverPath::radius_xz_max() { return m_radius_xz_max; }
+float& RiverPath::radius_y_min() { return m_radius_y_min; }
+float& RiverPath::radius_y_max() { return m_radius_y_max; }
+float& RiverPath::delta_angle_min() { return m_delta_angle_min; }
+float& RiverPath::delta_angle_max() { return m_delta_angle_max; }
+int& RiverPath::step_min() { return m_step_min; }
+int& RiverPath::step_max() { return m_step_max; }
+} // namespace Cubed

src/gameplay/river_worm.cpp

@@ -0,0 +1,53 @@
+#include "Cubed/gameplay/river_worm.hpp"
+
+#include "Cubed/constants.hpp"
+
+namespace Cubed {
+RiverWorm::RiverWorm() {}
+
+std::unordered_map<unsigned, RiverPath>& RiverWorm::paths() { return m_paths; }
+
+void RiverWorm::init(unsigned world_seed) {
+    m_seed = world_seed;
+    m_sum = 0;
+    m_random.init(m_seed);
+}
+
+void RiverWorm::reload(unsigned world_seed) {
+    m_seed = world_seed;
+    m_paths.clear();
+    init(world_seed);
+}
+
+void RiverWorm::add_path(const glm::vec3& pos, unsigned chunk_seed) {
+    m_paths.emplace(chunk_seed, RiverPath{m_seed, m_sum, pos});
+    m_sum++;
+}
+
+void RiverWorm::try_to_add_path(const ChunkPos& chunk_pos,
+                                unsigned chunk_seed) {
+    auto it = m_paths.find(chunk_seed);
+    if (it != m_paths.end()) {
+        return;
+    }
+    Random random{chunk_seed};
+    if (random.random_bool(static_cast<double>(m_probability))) {
+        const int CHUNK_MIN_X = chunk_pos.x * CHUNK_SIZE;
+        const int CHUNK_MIN_Z = chunk_pos.z * CHUNK_SIZE;
+        const int CHUNK_MAX_X = CHUNK_MIN_X + SIZE_X - 1;
+        const int CHUNK_MAX_Z = CHUNK_MIN_Z + SIZE_Z - 1;
+        int x = random.random_int(CHUNK_MIN_X, CHUNK_MAX_X);
+        int y = SEA_LEVEL + 2;
+        int z = random.random_int(CHUNK_MIN_Z, CHUNK_MAX_Z);
+        add_path(glm::vec3{x, y, z}, chunk_seed);
+    }
+}
+
+void RiverWorm::cleanup_finished_rivers() {
+    std::erase_if(m_paths,
+                  [](const auto& kv) { return kv.second.is_finished(); });
+}
+
+int RiverWorm::river_sum() const { return m_sum; }
+float& RiverWorm::river_probability() { return m_probability; }
+} // namespace Cubed

src/gameplay/world.cpp

@@ -64,6 +64,7 @@ Player& World::get_player(const std::string& name) {
 
 void World::init_world() {
     m_cave_carcer.init(ChunkGenerator::seed());
+    m_river_worm.init(ChunkGenerator::seed());
     m_chunks.reserve(MAX_DISTANCE * MAX_DISTANCE * 4);
     auto t1 = std::chrono::system_clock::now();
 
@@ -339,15 +340,17 @@ void World::gen_chunks_internal() {
     m_chunk_gen_fraction = 0.0f;
     m_chunk_gen_finished = false;
     ChunkPosSet required_chunks;
-    compute_required_chunks(required_chunks);
+    ChunkHashMap temp_neighbor;
+    compute_required_chunks(required_chunks, temp_neighbor);
 
     ASSERT_MSG(!required_chunks.empty(), "required chunks is empty!!");
 
     std::vector<ChunkPos> need_gen_chunks_pos;
+
     sync_and_collect_missing_chunks(need_gen_chunks_pos, required_chunks);
 
     Logger::info("New Gen Chunks Sum: {}", need_gen_chunks_pos.size());
-
+    Logger::info("Temp Chunks sum {}", temp_neighbor.size());
     if (need_gen_chunks_pos.empty()) {
         m_could_gen = true;
         m_chunk_gen_fraction = 1.0f;
@@ -364,26 +367,27 @@ void World::gen_chunks_internal() {
     ConstChunkMap new_chunks_neighbor;
     //  affected neighbor
     ChunkPtrUpdateList affected_neighbor;
-    ChunkHashMap temp_neighbor;
 
-    build_neighbor_context_for_new_chunks(
+    build_neighbor_context_for_new_chunks(new_chunks_neighbor,
-        new_chunks_neighbor, affected_neighbor, new_chunks, temp_neighbor);
+                                          affected_neighbor, new_chunks);
 
-    // Logger::info("Temp neighbor sum {}", temp_neighbor.size());
     //  build new chunk, but the neighbor in m_chunks also need to re-build
 
     for (auto& [pos, chunk] : new_chunks) {
         chunk.gen_phase_one();
         m_cave_carcer.try_to_add_path(pos, chunk.seed());
+        m_river_worm.try_to_add_path(pos, chunk.seed());
+    }
+    // precompute path to ensure the continuity of the path
+    for (auto& [pos, chunk] : temp_neighbor) {
+        chunk.gen_phase_one();
+        m_cave_carcer.try_to_add_path(pos, chunk.seed());
+        m_river_worm.try_to_add_path(pos, chunk.seed());
     }
-
-    // for (auto& [pos, chunk] : temp_neighbor) {
-    //     chunk.gen_phase_one();
-    //     m_cave_carcer.try_to_add_path(pos, chunk.seed());
-    // }
 
     m_chunk_gen_fraction = 0.2f;
 
+    /*
     std::array<const Chunk*, 8> neighbor_chunks;
     for (auto& [pos, chunks] : new_chunks) {
         for (int i = 0; i < 8; i++) {
@@ -391,13 +395,14 @@ void World::gen_chunks_internal() {
             auto it = new_chunks_neighbor.find(neighbor_pos);
             if (it == new_chunks_neighbor.end()) {
                 neighbor_chunks[i] = nullptr;
-                ASSERT_MSG(false, "Cant Find Neighbot");
+                // ASSERT_MSG(false, "Cant Find Neighbot");
                 continue;
             }
             neighbor_chunks[i] = it->second;
         }
         chunks.gen_phase_two(neighbor_chunks);
     }
+    */
 
     /*
     for (auto& [pos, chunks] : temp_neighbor) {
@@ -545,6 +550,7 @@ void World::gen_chunks_internal() {
         }
     }
     m_cave_carcer.cleanup_finished_caves();
+    m_river_worm.cleanup_finished_rivers();
     m_chunk_gen_fraction = 1.0f;
     m_chunk_gen_finished = true;
 }
@@ -554,7 +560,8 @@ void World::sync_player_pos(glm::vec3& player_pos) {
     player_pos = m_gen_player_pos;
 }
 
-void World::compute_required_chunks(ChunkPosSet& required_chunks) {
+void World::compute_required_chunks(ChunkPosSet& required_chunks,
+                                    ChunkHashMap& temp_neighbor) {
     glm::vec3 player_pos;
     sync_player_pos(player_pos);
 
@@ -569,6 +576,18 @@ void World::compute_required_chunks(ChunkPosSet& required_chunks) {
             required_chunks.emplace(u, v);
         }
     }
+    int max_path_len = std::max(CavePath::step_max(), RiverPath::step_max());
+    half = std::ceil(static_cast<float>(max_path_len) / CHUNK_SIZE) * 2;
+    for (int u = chunk_x - half; u <= chunk_x + half; ++u) {
+        for (int v = chunk_z - half; v <= chunk_z + half; ++v) {
+            ChunkPos pos{u, v};
+            auto it = required_chunks.find(pos);
+            if (it != required_chunks.end()) {
+                continue;
+            }
+            temp_neighbor.emplace(pos, Chunk(*this, pos));
+        }
+    }
 }
 
 void World::sync_and_collect_missing_chunks(
@@ -593,7 +612,7 @@ void World::sync_and_collect_missing_chunks(
 
 void World::build_neighbor_context_for_new_chunks(
     ConstChunkMap& new_chunks_neighbor, ChunkPtrUpdateList& affected_neighbor,
-    const ChunkUpdateList& new_chunks, ChunkHashMap& temp_neighbor) {
+    const ChunkUpdateList& new_chunks) {
     {
         std::lock_guard lk(m_chunks_mutex);
         for (auto& [pos, chunk] : new_chunks) {
@@ -602,8 +621,6 @@ void World::build_neighbor_context_for_new_chunks(
                 if (it != m_chunks.end()) {
                     new_chunks_neighbor.insert({it->first, &(it->second)});
                     affected_neighbor.push_back({it->first, &(it->second)});
-                } else {
-                    temp_neighbor.emplace(pos + dir, Chunk(*this, pos + dir));
                 }
             }
         }
@@ -611,9 +628,6 @@ void World::build_neighbor_context_for_new_chunks(
     for (auto& [pos, chunk] : new_chunks) {
         new_chunks_neighbor.insert({pos, &chunk});
     }
-    for (auto& [pos, chunk] : temp_neighbor) {
-        new_chunks_neighbor.insert({pos, &chunk});
-    }
 }
 
 void World::build_neighbor_context_for_affected_neighbors(
@@ -860,6 +874,7 @@ void World::rebuild_world() {
     m_is_rebuilding = true;
     stop_gen_thread();
     m_cave_carcer.reload(ChunkGenerator::seed());
+    m_river_worm.reload(ChunkGenerator::seed());
     {
         std::scoped_lock lk(m_chunks_mutex, m_new_chunk_queue_mutex);
         m_chunks.clear();
@@ -882,5 +897,5 @@ void World::rendering_distance(int rendering_distance) {
 }
 
 CaveCarver& World::cave_carcer() { return m_cave_carcer; }
-
+RiverWorm& World::river_worm() { return m_river_worm; }
 } // namespace Cubed