refactor: transparent render (#14)

* fix(renderer): defer uniform location retrieval and add view matrix in outline rendering

* refactor(gameplay): encapsulate per-type vertex data into VertexData struct

* feat(rendering): separate transparent blocks into discard and blend modes

* feat(renderer): implement order-independent transparency

* fix(shaders): reduce alpha discard threshold to 0.8

CMakeLists.txt

@@ -123,6 +123,7 @@ add_executable(${PROJECT_NAME}
     src/gameplay/river_worm.cpp
     src/gameplay/river_path.cpp
     src/block.cpp
+    src/gameplay/vertex_data.cpp
 )
 
 if(CMAKE_BUILD_TYPE STREQUAL "Debug")

assets/data/block/air.toml

@@ -1,5 +1,7 @@
 id = 0
+is_blend = false
 is_cross_plane = false
+is_discard = true
 is_gas = true
 is_liquid = false
 is_passable = true

assets/data/block/dirt.toml

@@ -1,5 +1,7 @@
 id = 2
+is_blend = false
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/grass.toml

@@ -1,5 +1,7 @@
 id = 9
+is_blend = false
 is_cross_plane = true
+is_discard = true
 is_gas = false
 is_liquid = false
 is_passable = true

assets/data/block/grass_block.toml

@@ -1,5 +1,7 @@
 id = 1
+is_blend = false
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/leaf.toml

@@ -1,5 +1,7 @@
 id = 6
+is_blend = false
 is_cross_plane = false
+is_discard = true
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/log.toml

@@ -1,5 +1,7 @@
 id = 5
+is_blend = false
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/sand.toml

@@ -1,5 +1,7 @@
 id = 4
+is_blend = false
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/snowy_grass_block.toml

@@ -1,5 +1,7 @@
 id = 8
+is_blend = false
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/stone.toml

@@ -1,5 +1,7 @@
 id = 3
+is_blend = false
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = false
 is_passable = false

assets/data/block/template.toml

@@ -5,3 +5,5 @@ is_gas = false
 is_passable = false
 is_cross_plane = false
 is_transparent = false
+is_discard = false
+is_blend = false

assets/data/block/water.toml

@@ -1,5 +1,7 @@
 id = 7
+is_blend = true
 is_cross_plane = false
+is_discard = false
 is_gas = false
 is_liquid = true
 is_passable = true

assets/shaders/block_accumulation_f_shader.glsl

@@ -0,0 +1,28 @@
+#version 460
+
+layout (location = 0) out vec4 accum;
+layout (location = 1) out float reveal;
+
+in vec2 tc;
+flat in int tex_layer;
+in float v_depth;
+layout (binding = 0) uniform sampler2DArray samp;
+
+float weight(float z, float a) {
+    float intermediate = 0.03 / (1e-5 + pow(z / 200.0, 4.0));
+    
+    return a * clamp(intermediate, 1e-2, 3e2);
+}
+
+void main() {
+    vec4 color = texture(samp, vec3(tc, tex_layer));
+    float alpha = color.a;
+    if (alpha < 1e-4) discard;
+
+
+    float w = weight(v_depth, alpha);
+
+    accum = vec4(color.rgb * alpha * w, alpha * w);
+
+    reveal = alpha;
+}

assets/shaders/block_accumulation_v_shader.glsl

@@ -0,0 +1,21 @@
+#version 460
+
+layout (location = 0) in vec3 pos;
+layout (location = 1) in vec2 texCoord;
+layout (location = 2) in float layer;
+out vec2 tc;
+flat out int tex_layer;
+out float v_depth;
+
+uniform mat4 mv_matrix;
+uniform mat4 proj_matrix;
+
+
+
+void main(void) {
+    vec4 view_pos = mv_matrix * vec4(pos, 1.0);
+    gl_Position = proj_matrix * view_pos;
+    tc = texCoord;
+    tex_layer = int(layer);
+    v_depth = -view_pos.z;
+}

assets/shaders/block_composite_f_shader.glsl

@@ -0,0 +1,19 @@
+#version 460
+
+uniform sampler2D u_accumTex;
+uniform sampler2D u_revealTex;
+in vec2 TexCoord;
+out vec4 FragColor;
+
+void main() {
+    vec4 a = texture(u_accumTex, TexCoord);
+    float r = texture(u_revealTex, TexCoord).r;
+
+    if (a.a < 1e-4) discard;
+
+    vec3 color = a.rgb / max(a.a, 1e-5);
+    float transmittance = r;
+    float opacity = 1.0 - transmittance;
+
+    FragColor = vec4(color * opacity, opacity);
+}

assets/shaders/block_composite_v_shader.glsl

@@ -0,0 +1,11 @@
+#version 460
+
+layout (location = 0) in vec2 pos;
+layout (location = 1) in vec2 texCoord;
+
+out vec2 TexCoord;
+
+void main() {
+    gl_Position = vec4(pos.x, pos.y, 0.0, 1.0);
+    TexCoord = texCoord;
+}

assets/shaders/block_f_shader.glsl

@@ -8,7 +8,7 @@ layout (binding = 0) uniform sampler2DArray samp;
 
 void main(void) {
     color = texture(samp, vec3(tc, tex_layer));
-    if (color.a < 0.1) {
+    if (color.a < 0.8) {
         discard;
     }
     //color = varyingColor;

include/Cubed/gameplay/block.hpp

@@ -47,11 +47,16 @@ struct BlockData {
     bool is_passable = false;
     bool is_cross_plane = false;
     bool is_transparent = false;
+
+    bool is_discard = false;
+    bool is_blend = false;
+
     BlockData(BlockType b_id, std::string_view b_name, bool liquid,
-              bool passable, bool cross_plane, bool transparent, bool gas)
+              bool passable, bool cross_plane, bool transparent, bool gas,
+              bool discard, bool blend)
         : name(b_name), id(b_id), is_liquid(liquid), is_gas(gas),
           is_passable(passable), is_cross_plane(cross_plane),
-          is_transparent(transparent) {}
+          is_transparent(transparent), is_discard(discard), is_blend(blend) {}
 };
 
 class BlockManager {
@@ -69,6 +74,10 @@ public:
     static bool is_cross_plane(BlockType id);
     static bool is_transparent(BlockType id);
     static bool is_passable(BlockType id);
+
+    static bool is_discard(BlockType id);
+    static bool is_blend(BlockType id);
+
     static BlockType cross_plane_index(BlockType id);
 
 private:

include/Cubed/gameplay/chunk.hpp

@@ -4,7 +4,7 @@
 #include "Cubed/gameplay/block.hpp"
 #include "Cubed/gameplay/chunk_generator.hpp"
 #include "Cubed/gameplay/chunk_pos.hpp"
-#include "Cubed/primitive_data.hpp"
+#include "Cubed/gameplay/vertex_data.hpp"
 
 #include <atomic>
 #include <mutex>
@@ -17,13 +17,10 @@ private:
     static constexpr int SIZE_X = CHUNK_SIZE;
     static constexpr int SIZE_Y = WORLD_SIZE_Y;
     static constexpr int SIZE_Z = CHUNK_SIZE;
-
+    static constexpr int VERTEX_DATA_SUM = 4;
     std::atomic<bool> m_dirty{false};
     std::atomic<bool> m_need_upload{true};
     std::atomic<bool> m_is_on_gen_vertex_data{false};
-    std::atomic<size_t> m_normal_vertices_sum = 0;
-    std::atomic<size_t> m_cross_vertices_sum = 0;
-    std::atomic<size_t> m_transparent_vertices_sum = 0;
     std::atomic<BiomeType> m_biome = BiomeType::PLAIN;
     std::mutex m_vertexs_data_mutex;
 
@@ -34,12 +31,14 @@ private:
     HeightMapArray m_heightmap;
     // the index is a array of block id
     std::vector<BlockType> m_blocks;
-    GLuint m_normal_vbo = 0;
+
-    GLuint m_cross_plane_vbo = 0;
+    /*
-    GLuint m_transparent_normal_vbo = 0;
+    0 - normal
-    std::vector<Vertex> m_normal_vertices;
+    1 - cross_plane
-    std::vector<Vertex> m_cross_plane_vertices;
+    2 - normal_discard
-    std::vector<Vertex> m_transparent_normal_vertices;
+    3 - transparent and blend
+    */
+    std::vector<VertexData> m_vertex_data;
     float frequency = 0.01f;
     float height = 80;
     unsigned m_seed = 0;
@@ -47,9 +46,10 @@ private:
     BiomeConditions m_conditions;
 
     void clear_dirty();
-    void gen_normal_vertices(
+    void gen_vertices(
         const std::array<const std::vector<BlockType>*, 4>& neighbor_block);
-    void gen_cross_plane_vertices();
+    void gen_cross_plane_vertices(int world_x, int world_y, int world_z,
+                                  BlockType id);
 
 public:
     Chunk(World& world, ChunkPos chunk_pos);
@@ -107,8 +107,11 @@ public:
     GLuint get_cross_vbo() const;
     size_t get_cross_vertices_sum() const;
 
-    GLuint get_transparent_vbo() const;
+    GLuint get_normal_discard_vbo() const;
-    size_t get_transparent_vertices_sum() const;
+    size_t get_normal_discard_vertices_sum() const;
+
+    GLuint get_normal_blend_vbo() const;
+    size_t get_normal_blend_vertices_sum() const;
 
     bool is_dirty() const;
     void mark_dirty();

include/Cubed/gameplay/vertex_data.hpp

@@ -0,0 +1,24 @@
+#pragma once
+#include "Cubed/primitive_data.hpp"
+
+#include <atomic>
+#include <glad/glad.h>
+#include <vector>
+namespace Cubed {
+class World;
+struct VertexData {
+    std::vector<Vertex> m_vertices;
+    GLuint m_vbo = 0;
+    std::atomic<std::size_t> m_sum{0};
+    World& m_world;
+    VertexData(World& world);
+    ~VertexData();
+    VertexData(const VertexData&) = delete;
+    VertexData(VertexData&&) noexcept;
+    VertexData& operator=(const VertexData&) = delete;
+    VertexData& operator=(VertexData&&) noexcept;
+
+    void upload();
+    void update_sum();
+};
+} // namespace Cubed

include/Cubed/gameplay/world.hpp

@@ -19,8 +19,10 @@ struct ChunkRenderSnapshot {
     size_t normal_vertices_count;
     GLuint cross_vbo;
     size_t cross_vertices_count;
-    GLuint transparent_vbo;
+    GLuint normal_discard_vbo;
-    size_t transparent_vertices_count;
+    size_t normal_discard_vertices_count;
+    GLuint normal_blend_vbo;
+    size_t normal_blend_vertices_count;
     glm::vec3 center;
     glm::vec3 half_extents;
 };
@@ -90,9 +92,6 @@ public:
 
     Player& get_player(const std::string& name);
     void init_world();
-    bool is_aabb_in_frustum(const glm::vec3& center,
-                            const glm::vec3& half_extents);
-
     int get_block(const glm::ivec3& block_pos) const;
     bool is_solid(const glm::ivec3& block_pos) const;
     bool can_pass_block(const glm::ivec3& block_pos) const;
@@ -100,9 +99,6 @@ public:
     static ChunkPos chunk_pos(int world_x, int world_z);
 
     void need_gen();
-    void render(const glm::mat4& mvp_matrix,
-                const TextureManager& texture_manager,
-                const glm::vec3& camera_pos);
 
     void set_block(const glm::ivec3& pos, unsigned id);
     void update(float delta_time);
@@ -121,6 +117,8 @@ public:
 
     CaveCarver& cave_carcer();
     RiverWorm& river_worm();
+    std::vector<glm::vec4>& planes();
+    std::vector<ChunkRenderSnapshot>& render_snapshots();
 };
 
 } // namespace Cubed

include/Cubed/renderer.hpp

@@ -15,7 +15,7 @@ class World;
 class DevPanel;
 class Renderer {
 public:
-    constexpr static int NUM_VAO = 6;
+    constexpr static int NUM_VAO = 7;
 
     Renderer(const Camera& camera, World& world,
              const TextureManager& texture_manager, DevPanel& dev_panel);
@@ -40,6 +40,9 @@ private:
 
     float m_delta_time = 0.0f;
 
+    float m_width = 0.0f;
+    float m_height = 0.0f;
+
     glm::mat4 m_p_mat, m_v_mat, m_m_mat, m_mv_mat, m_mvp_mat;
 
     GLuint m_mv_loc = 0;
@@ -55,6 +58,10 @@ private:
     GLuint m_screen_texture = 0;
     GLuint m_depth_render_buffer = 0;
 
+    GLuint m_oit_fbo = 0;
+    GLuint m_accum_texture = 0;
+    GLuint m_reveal_texture = 0;
+    GLuint m_oit_depth_render_buffer = 0;
     GLuint m_quad_vbo = 0;
 
     glm::mat4 m_ui_proj;

include/Cubed/tools/math_tools.hpp

@@ -9,6 +9,9 @@ void extract_frustum_planes(const glm::mat4& mvp_matrix,
                             std::vector<glm::vec4>& planes);
 
 float smootherstep(float edge0, float edge1, float x);
+bool is_aabb_in_frustum(const glm::vec3& center, const glm::vec3& half_extents,
+                        const std::vector<glm::vec4>& planes);
+
 } // namespace Math
 
 } // namespace Cubed

src/block.cpp

@@ -90,6 +90,21 @@ bool BlockManager::is_passable(BlockType id) {
     return m_datas[id].is_passable;
 }
 
+bool BlockManager::is_discard(BlockType id) {
+    if (id >= sums()) {
+        Logger::error("Id {}, is Over The Max Id", id, sums() - 1);
+        return m_datas[0].is_discard;
+    }
+    return m_datas[id].is_discard;
+}
+bool BlockManager::is_blend(BlockType id) {
+    if (id >= sums()) {
+        Logger::error("Id {}, is Over The Max Id", id, sums() - 1);
+        return m_datas[0].is_blend;
+    }
+    return m_datas[id].is_blend;
+}
+
 void BlockManager::init() {
     fs::path data_path{block_data_dir};
 
@@ -125,8 +140,11 @@ void BlockManager::init() {
         auto is_cross_plane = safe_get_value(block, "is_cross_plane", false);
         auto is_transparent = safe_get_value(block, "is_transparent", false);
         auto is_gas = safe_get_value(block, "is_gas", false);
+        auto is_discard = safe_get_value(block, "is_discard", false);
+        auto is_blend = safe_get_value(block, "is_blend", false);
         m_datas.emplace_back(*id, *name, *is_liquid, *is_passable,
-                             *is_cross_plane, *is_transparent, *is_gas);
+                             *is_cross_plane, *is_transparent, *is_gas,
+                             *is_discard, *is_blend);
     }
     std::sort(
         m_datas.begin(), m_datas.end(),

src/gameplay/chunk.cpp

@@ -9,65 +9,36 @@
 namespace Cubed {
 
 Chunk::Chunk(World& world, ChunkPos chunk_pos)
-    : m_chunk_pos(chunk_pos), m_world(world) {}
+    : m_chunk_pos(chunk_pos), m_world(world) {
-
+    for (int i = 0; i < VERTEX_DATA_SUM; i++) {
-Chunk::~Chunk() {
+        m_vertex_data.emplace_back(m_world);
-    if (m_normal_vbo != 0) {
-        m_world.push_delete_vbo(m_normal_vbo);
-    }
-    if (m_cross_plane_vbo != 0) {
-        m_world.push_delete_vbo(m_cross_plane_vbo);
-    }
-    if (m_transparent_normal_vbo != 0) {
-        m_world.push_delete_vbo(m_transparent_normal_vbo);
     }
 }
 
+Chunk::~Chunk() {}
+
 Chunk::Chunk(Chunk&& other) noexcept
     : m_dirty(other.is_dirty()), m_need_upload(other.m_need_upload.load()),
       m_is_on_gen_vertex_data(other.m_is_on_gen_vertex_data.load()),
-      m_normal_vertices_sum(other.m_normal_vertices_sum.load()),
-      m_cross_vertices_sum(other.m_cross_vertices_sum.load()),
-      m_transparent_vertices_sum(other.m_transparent_vertices_sum.load()),
       m_biome(other.m_biome.load()), m_chunk_pos(std::move(other.m_chunk_pos)),
       m_world(other.m_world), m_heightmap(std::move(other.m_heightmap)),
-      m_blocks(std::move(other.m_blocks)), m_normal_vbo(other.m_normal_vbo),
+      m_blocks(std::move(other.m_blocks)),
-      m_cross_plane_vbo(other.m_cross_plane_vbo),
+      m_vertex_data(std::move(other.m_vertex_data)), m_seed(other.m_seed),
-      m_transparent_normal_vbo(other.m_transparent_normal_vbo),
+      m_conditions(other.m_conditions) {}
-      m_normal_vertices(std::move(other.m_normal_vertices)),
-      m_cross_plane_vertices(std::move(other.m_cross_plane_vertices)),
-      m_transparent_normal_vertices(
-          std::move(other.m_transparent_normal_vertices)),
-      m_seed(other.m_seed), m_conditions(other.m_conditions) {
-    other.m_normal_vbo = 0;
-    other.m_cross_plane_vbo = 0;
-    other.m_transparent_normal_vbo = 0;
-}
 
 Chunk& Chunk::operator=(Chunk&& other) noexcept {
     // Logger::info("other Chunk pos {} {} in Chunk& Chunk::operator=(Chunk&&
     // other) this {}", other.m_chunk_pos.x, other.m_chunk_pos.z,
     // static_cast<const void*>(&other));
-    m_normal_vbo = other.m_normal_vbo;
+
-    other.m_normal_vbo = 0;
-    m_cross_plane_vbo = other.m_cross_plane_vbo;
-    m_transparent_normal_vbo = other.m_transparent_normal_vbo;
-    other.m_transparent_normal_vbo = 0;
-    other.m_cross_plane_vbo = 0;
     m_chunk_pos = std::move(other.m_chunk_pos);
     m_heightmap = std::move(other.m_heightmap);
     m_blocks = std::move(other.m_blocks);
     m_dirty = other.is_dirty();
-    m_normal_vertices = std::move(other.m_normal_vertices);
+    m_vertex_data = std::move(other.m_vertex_data);
-    m_cross_plane_vertices = std::move(other.m_cross_plane_vertices);
-    m_transparent_normal_vertices =
-        std::move(other.m_transparent_normal_vertices);
     m_biome = other.m_biome.load();
     m_is_on_gen_vertex_data = other.m_is_on_gen_vertex_data.load();
     m_need_upload = other.m_need_upload.load();
-    m_normal_vertices_sum = other.m_normal_vertices_sum.load();
-    m_cross_vertices_sum = other.m_cross_vertices_sum.load();
-    m_transparent_vertices_sum = other.m_transparent_vertices_sum.load();
     m_seed = other.m_seed;
     m_conditions = other.m_conditions;
     return *this;
@@ -139,29 +110,41 @@ void Chunk::gen_vertex_data(
     }
     m_is_on_gen_vertex_data = true;
     std::lock_guard lk(m_vertexs_data_mutex);
-    gen_normal_vertices(neighbor_block);
+
-    gen_cross_plane_vertices();
+    for (auto& data : m_vertex_data) {
+        data.m_vertices.clear();
+    }
+
+    gen_vertices(neighbor_block);
+    for (auto& data : m_vertex_data) {
+        data.update_sum();
+    }
     m_need_upload = true;
     m_is_on_gen_vertex_data = false;
 }
 
-GLuint Chunk::get_normal_vbo() const { return m_normal_vbo; }
+GLuint Chunk::get_normal_vbo() const { return m_vertex_data[0].m_vbo; }
 
 size_t Chunk::get_normal_vertices_sum() const {
-    if (m_normal_vertices_sum == 0) {
+    if (m_vertex_data[0].m_sum == 0) {
         Logger::warn("m_normal_vertices_sum is 0");
     }
-    return m_normal_vertices_sum.load();
+    return m_vertex_data[0].m_sum.load();
 }
 
-GLuint Chunk::get_cross_vbo() const { return m_cross_plane_vbo; }
+GLuint Chunk::get_cross_vbo() const { return m_vertex_data[1].m_vbo; }
 size_t Chunk::get_cross_vertices_sum() const {
-    return m_cross_vertices_sum.load();
+    return m_vertex_data[1].m_sum.load();
 }
 
-GLuint Chunk::get_transparent_vbo() const { return m_transparent_normal_vbo; }
+GLuint Chunk::get_normal_discard_vbo() const { return m_vertex_data[2].m_vbo; }
-size_t Chunk::get_transparent_vertices_sum() const {
+size_t Chunk::get_normal_discard_vertices_sum() const {
-    return m_transparent_vertices_sum.load();
+    return m_vertex_data[2].m_sum.load();
+}
+
+GLuint Chunk::get_normal_blend_vbo() const { return m_vertex_data[3].m_vbo; }
+size_t Chunk::get_normal_blend_vertices_sum() const {
+    return m_vertex_data[3].m_sum.load();
 }
 
 void Chunk::gen_phase_one() {
@@ -235,33 +218,12 @@ void Chunk::upload_to_gpu() {
 
     ASSERT(is_need_upload());
 
-    if (m_normal_vbo == 0) {
+    std::lock_guard lk(m_vertexs_data_mutex);
-        glGenBuffers(1, &m_normal_vbo);
+
+    for (auto& data : m_vertex_data) {
+        data.upload();
     }
 
-    std::lock_guard lk(m_vertexs_data_mutex);
-    glBindBuffer(GL_ARRAY_BUFFER, m_normal_vbo);
-    glBufferData(GL_ARRAY_BUFFER, m_normal_vertices.size() * sizeof(Vertex),
-                 m_normal_vertices.data(), GL_DYNAMIC_DRAW);
-    glBindBuffer(GL_ARRAY_BUFFER, 0);
-    if (m_cross_plane_vertices.size() != 0) {
-        if (m_cross_plane_vbo == 0) {
-            glGenBuffers(1, &m_cross_plane_vbo);
-        }
-        glBindBuffer(GL_ARRAY_BUFFER, m_cross_plane_vbo);
-        glBufferData(GL_ARRAY_BUFFER,
-                     m_cross_plane_vertices.size() * sizeof(Vertex),
-                     m_cross_plane_vertices.data(), GL_DYNAMIC_DRAW);
-    }
-    if (m_transparent_normal_vertices.size() != 0) {
-        if (m_transparent_normal_vbo == 0) {
-            glGenBuffers(1, &m_transparent_normal_vbo);
-        }
-        glBindBuffer(GL_ARRAY_BUFFER, m_transparent_normal_vbo);
-        glBufferData(GL_ARRAY_BUFFER,
-                     m_transparent_normal_vertices.size() * sizeof(Vertex),
-                     m_transparent_normal_vertices.data(), GL_DYNAMIC_DRAW);
-    }
     // after fininshed it, can use
     clear_dirty();
     m_need_upload = false;
@@ -300,10 +262,8 @@ unsigned Chunk::seed() const {
 
 BiomeConditions& Chunk::conditions() { return m_conditions; }
 
-void Chunk::gen_normal_vertices(
+void Chunk::gen_vertices(
     const std::array<const std::vector<BlockType>*, 4>& neighbor_block) {
-    m_normal_vertices.clear();
-    m_transparent_normal_vertices.clear();
     static const glm::ivec3 DIR[6] = {{0, 0, 1},  {1, 0, 0}, {0, 0, -1},
                                       {-1, 0, 0}, {0, 1, 0}, {0, -1, 0}};
 
@@ -399,6 +359,10 @@ void Chunk::gen_normal_vertices(
                     if (neighbor_culled) {
                         continue;
                     }
+                    if (BlockManager::is_cross_plane(cur_id)) {
+                        gen_cross_plane_vertices(world_x, world_y, world_z,
+                                                 cur_id);
+                    }
                     for (int i = 0; i < 6; i++) {
                         Vertex vex = {
                             VERTICES_POS[face][i][0] + (float)world_x * 1.0f,
@@ -410,55 +374,57 @@ void Chunk::gen_normal_vertices(
 
                         };
                         if (BlockManager::is_transparent(cur_id)) {
-                            m_transparent_normal_vertices.emplace_back(vex);
+                            if (BlockManager::is_discard(cur_id) &&
+                                BlockManager::is_blend(cur_id)) {
+                                Logger::warn(
+                                    "Block id {} is both discard and blend is "
+                                    "must only one can true !!!",
+                                    cur_id);
+                            }
+                            if (BlockManager::is_discard(cur_id)) {
+                                m_vertex_data[2].m_vertices.emplace_back(vex);
+                            } else if (BlockManager::is_blend(cur_id)) {
+                                m_vertex_data[3].m_vertices.emplace_back(vex);
+                            } else {
+                                Logger::warn("Id {} is transparent but not "
+                                             "discard or blend",
+                                             cur_id);
+                                m_vertex_data[3].m_vertices.emplace_back(vex);
+                            }
+
                         } else {
-                            m_normal_vertices.emplace_back(vex);
+                            m_vertex_data[0].m_vertices.emplace_back(vex);
                         }
                     }
                 }
             }
         }
     }
-    m_normal_vertices_sum = m_normal_vertices.size();
-    m_transparent_vertices_sum = m_transparent_normal_vertices.size();
 }
-void Chunk::gen_cross_plane_vertices() {
+void Chunk::gen_cross_plane_vertices(int world_x, int world_y, int world_z,
+                                     BlockType id) {
 
-    m_cross_plane_vertices.clear();
+    if (!BlockManager::is_cross_plane(id)) {
+        Logger::warn("Block {} {} {} id {} is not cross plane", world_x,
+                     world_y, world_z, id);
+        return;
+    }
+    for (int face = 0; face < 2; face++) {
+        for (int i = 0; i < 6; i++) {
+            Vertex vex = {
+                CROSS_VERTICES_POS[face][i][0] + (float)world_x * 1.0f,
+                CROSS_VERTICES_POS[face][i][1] + (float)world_y * 1.0f,
+                CROSS_VERTICES_POS[face][i][2] + (float)world_z * 1.0f,
+                CROSS_TEX_COORDS[face][i][0],
+                CROSS_TEX_COORDS[face][i][1],
+                static_cast<float>(BlockManager::cross_plane_index(id))
 
-    for (int x = 0; x < SIZE_X; x++) {
+            };
-        for (int y = 0; y < SIZE_Y; y++) {
+            m_vertex_data[1].m_vertices.emplace_back(vex);
-            for (int z = 0; z < SIZE_Z; z++) {
-                int world_x = x + m_chunk_pos.x * CHUNK_SIZE;
-                int world_z = z + m_chunk_pos.z * CHUNK_SIZE;
-                int world_y = y;
-                int id = m_blocks[index(x, y, z)];
-
-                if (!BlockManager::is_cross_plane(id)) {
-                    continue;
-                }
-                for (int face = 0; face < 2; face++) {
-                    for (int i = 0; i < 6; i++) {
-                        Vertex vex = {CROSS_VERTICES_POS[face][i][0] +
-                                          (float)world_x * 1.0f,
-                                      CROSS_VERTICES_POS[face][i][1] +
-                                          (float)world_y * 1.0f,
-                                      CROSS_VERTICES_POS[face][i][2] +
-                                          (float)world_z * 1.0f,
-                                      CROSS_TEX_COORDS[face][i][0],
-                                      CROSS_TEX_COORDS[face][i][1],
-                                      static_cast<float>(
-                                          BlockManager::cross_plane_index(id))
-
-                        };
-                        m_cross_plane_vertices.emplace_back(vex);
-                    }
-                }
-            }
         }
     }
-    m_cross_vertices_sum = m_cross_plane_vertices.size();
-    // Logger::info("Cross Sum {}", m_cross_vertices_sum.load());
 }
 
+// Logger::info("Cross Sum {}", m_cross_vertices_sum.load());
+
 } // namespace Cubed

src/gameplay/vertex_data.cpp

@@ -0,0 +1,39 @@
+#include "Cubed/gameplay/vertex_data.hpp"
+
+#include "Cubed/gameplay/world.hpp"
+
+namespace Cubed {
+VertexData::VertexData(World& world) : m_world(world) {}
+VertexData::~VertexData() {
+    if (m_vbo != 0) {
+        m_world.push_delete_vbo(m_vbo);
+    }
+}
+VertexData::VertexData(VertexData&& o) noexcept
+    : m_vertices(std::move(o.m_vertices)), m_vbo(o.m_vbo),
+      m_sum(o.m_sum.load()), m_world(o.m_world) {
+    o.m_vbo = 0;
+    o.m_sum = 0;
+}
+VertexData& VertexData::operator=(VertexData&& o) noexcept {
+    m_vbo = o.m_vbo;
+    o.m_vbo = 0;
+    m_sum = o.m_sum.load();
+    o.m_sum = 0;
+    m_vertices = std::move(o.m_vertices);
+    return *this;
+}
+void VertexData::upload() {
+    if (m_vertices.size() == 0) {
+        return;
+    }
+    if (m_vbo == 0) {
+        glGenBuffers(1, &m_vbo);
+    }
+    glBindBuffer(GL_ARRAY_BUFFER, m_vbo);
+    glBufferData(GL_ARRAY_BUFFER, m_vertices.size() * sizeof(Vertex),
+                 m_vertices.data(), GL_DYNAMIC_DRAW);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+}
+void VertexData::update_sum() { m_sum = m_vertices.size(); }
+} // namespace Cubed

src/gameplay/world.cpp

@@ -1,12 +1,9 @@
 #include "Cubed/gameplay/world.hpp"
 
 #include "Cubed/config.hpp"
-#include "Cubed/debug_collector.hpp"
 #include "Cubed/gameplay/player.hpp"
-#include "Cubed/texture_manager.hpp"
 #include "Cubed/tools/cubed_assert.hpp"
 #include "Cubed/tools/cubed_hash.hpp"
-#include "Cubed/tools/math_tools.hpp"
 
 namespace Cubed {
 
@@ -291,115 +288,6 @@ void World::init_chunks() {
     }
 }
 */
-void World::render(const glm::mat4& mvp_matrix,
-                   const TextureManager& texture_manager,
-                   const glm::vec3& camera_pos) {
-    Math::extract_frustum_planes(mvp_matrix, m_planes);
-    int rendered_sum = 0;
-    for (const auto& snapshot : m_render_snapshots) {
-
-        if (is_aabb_in_frustum(snapshot.center, snapshot.half_extents)) {
-            glBindTexture(GL_TEXTURE_2D_ARRAY,
-                          texture_manager.get_texture_array());
-            glBindBuffer(GL_ARRAY_BUFFER, snapshot.normal_vbo);
-            glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                                  (void*)0);
-            glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                                  (void*)offsetof(Vertex, s));
-            glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                                  (void*)offsetof(Vertex, layer));
-
-            glEnableVertexAttribArray(0);
-            glEnableVertexAttribArray(1);
-            glEnableVertexAttribArray(2);
-
-            glDrawArrays(GL_TRIANGLES, 0, snapshot.normal_vertices_count);
-            glBindBuffer(GL_ARRAY_BUFFER, 0);
-
-            rendered_sum++;
-        }
-    }
-    glDepthMask(GL_FALSE);
-
-    struct SortableSnapshot {
-        const ChunkRenderSnapshot* snapshot;
-        float distance;
-    };
-
-    std::vector<SortableSnapshot> cross_list;
-    std::vector<SortableSnapshot> transparent_list;
-
-    for (const auto& snapshot : m_render_snapshots) {
-
-        if (!is_aabb_in_frustum(snapshot.center, snapshot.half_extents)) {
-            continue;
-        }
-
-        float dist = glm::distance(camera_pos, snapshot.center);
-        glm::vec2 camera_pos_xz{camera_pos.x, camera_pos.z};
-        if (snapshot.cross_vertices_count != 0) {
-            glm::vec2 center_xz{snapshot.center.x, snapshot.center.z};
-            float dist2d = glm::distance(camera_pos_xz, center_xz);
-            if (dist2d <= CROSS_PLANE_DISTANCE * 16) {
-                cross_list.push_back({&snapshot, dist});
-            }
-        }
-        if (snapshot.transparent_vertices_count != 0) {
-            transparent_list.push_back({&snapshot, dist});
-        }
-    }
-    std::sort(transparent_list.begin(), transparent_list.end(),
-              [](const SortableSnapshot& a, const SortableSnapshot& b) {
-                  return a.distance > b.distance;
-              });
-    std::sort(cross_list.begin(), cross_list.end(),
-              [](const SortableSnapshot& a, const SortableSnapshot& b) {
-                  return a.distance > b.distance;
-              });
-
-    for (const auto& item : cross_list) {
-        const auto& snapshot = *item.snapshot;
-        glBindTexture(GL_TEXTURE_2D_ARRAY,
-                      texture_manager.get_cross_plane_array());
-        glBindBuffer(GL_ARRAY_BUFFER, snapshot.cross_vbo);
-        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                              (void*)0);
-        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                              (void*)offsetof(Vertex, s));
-        glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                              (void*)offsetof(Vertex, layer));
-
-        glEnableVertexAttribArray(0);
-        glEnableVertexAttribArray(1);
-        glEnableVertexAttribArray(2);
-
-        glDrawArrays(GL_TRIANGLES, 0, snapshot.cross_vertices_count);
-        glBindBuffer(GL_ARRAY_BUFFER, 0);
-    }
-
-    for (const auto& item : transparent_list) {
-        const auto& snapshot = *item.snapshot;
-        glBindTexture(GL_TEXTURE_2D_ARRAY, texture_manager.get_texture_array());
-        glBindBuffer(GL_ARRAY_BUFFER, snapshot.transparent_vbo);
-        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                              (void*)0);
-        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                              (void*)offsetof(Vertex, s));
-        glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
-                              (void*)offsetof(Vertex, layer));
-
-        glEnableVertexAttribArray(0);
-        glEnableVertexAttribArray(1);
-        glEnableVertexAttribArray(2);
-
-        glDrawArrays(GL_TRIANGLES, 0, snapshot.transparent_vertices_count);
-        glBindBuffer(GL_ARRAY_BUFFER, 0);
-    }
-
-    glDepthMask(GL_TRUE);
-    DebugCollector::get().report(
-        "rendered_chunk", "Rendered Chunk: " + std::to_string(rendered_sum));
-}
 
 ChunkPos World::chunk_pos(int world_x, int world_z) {
     int chunk_x, chunk_z;
@@ -774,21 +662,6 @@ void World::need_gen() {
     m_gen_cv.notify_one();
 }
 
-bool World::is_aabb_in_frustum(const glm::vec3& center,
-                               const glm::vec3& half_extents) {
-    for (const auto& plane : m_planes) {
-        // distance
-        float d = glm::dot(glm::vec3(plane), center) + plane.w;
-        float r = half_extents.x * std::abs(plane.x) +
-                  half_extents.y * std::abs(plane.y) +
-                  half_extents.z * std::abs(plane.z);
-        if (d + r < 0) {
-            return false;
-        }
-    }
-    return true;
-}
-
 int World::get_block(const glm::ivec3& block_pos) const {
     auto [chunk_x, chunk_z] = chunk_pos(block_pos.x, block_pos.z);
     std::lock_guard lk(m_chunks_mutex);
@@ -966,8 +839,10 @@ void World::update(float delta_time) {
                 m_render_snapshots.push_back(
                     {chunk.get_normal_vbo(), chunk.get_normal_vertices_sum(),
                      chunk.get_cross_vbo(), chunk.get_cross_vertices_sum(),
-                     chunk.get_transparent_vbo(),
+                     chunk.get_normal_discard_vbo(),
-                     chunk.get_transparent_vertices_sum(),
+                     chunk.get_normal_discard_vertices_sum(),
+                     chunk.get_normal_blend_vbo(),
+                     chunk.get_normal_blend_vertices_sum(),
                      glm::vec3(static_cast<float>(pos.x * CHUNK_SIZE) +
                                    static_cast<float>(CHUNK_SIZE / 2),
                                static_cast<float>(WORLD_SIZE_Y / 2),
@@ -1024,4 +899,8 @@ void World::rendering_distance(int rendering_distance) {
 
 CaveCarver& World::cave_carcer() { return m_cave_carcer; }
 RiverWorm& World::river_worm() { return m_river_worm; }
+std::vector<glm::vec4>& World::planes() { return m_planes; }
+std::vector<ChunkRenderSnapshot>& World::render_snapshots() {
+    return m_render_snapshots;
+};
 } // namespace Cubed

src/renderer.cpp

@@ -12,6 +12,7 @@
 #include "Cubed/tools/cubed_hash.hpp"
 #include "Cubed/tools/font.hpp"
 #include "Cubed/tools/log.hpp"
+#include "Cubed/tools/math_tools.hpp"
 #include "Cubed/tools/shader_tools.hpp"
 
 #include <GLFW/glfw3.h>
@@ -36,6 +37,11 @@ Renderer::~Renderer() {
     glDeleteFramebuffers(1, &m_fbo);
     glDeleteTextures(1, &m_screen_texture);
     glDeleteRenderbuffers(1, &m_depth_render_buffer);
+
+    glDeleteFramebuffers(1, &m_oit_fbo);
+    glDeleteTextures(1, &m_accum_texture);
+    glDeleteTextures(1, &m_reveal_texture);
+    glDeleteRenderbuffers(1, &m_oit_depth_render_buffer);
 }
 
 void Renderer::hot_reload() {
@@ -52,7 +58,7 @@ void Renderer::init() {
     Logger::info("Renderer: {}",
                  reinterpret_cast<const char*>(glGetString(GL_RENDERER)));
 
-    Shader world_shader{"world", "shaders/block_v_shader.glsl",
+    Shader world_shader{"normal_block", "shaders/block_v_shader.glsl",
                         "shaders/block_f_shader.glsl"};
     Shader outline_shader{"outline", "shaders/outline_v_shader.glsl",
                           "shaders/outline_f_shader.glsl"};
@@ -65,7 +71,11 @@ void Renderer::init() {
     Shader under_water_shader{"under_water",
                               "shaders/under_water_v_shader.glsl",
                               "shaders/under_water_f_shader.glsl"};
-
+    Shader accum_shader{"accum", "shaders/block_accumulation_v_shader.glsl",
+                        "shaders/block_accumulation_f_shader.glsl"};
+    Shader composite_block_shader{"composite",
+                                  "shaders/block_composite_v_shader.glsl",
+                                  "shaders/block_composite_f_shader.glsl"};
     m_shaders.insert({world_shader.hash(), std::move(world_shader)});
     m_shaders.insert({outline_shader.hash(), std::move(outline_shader)});
     m_shaders.insert({sky_shdaer.hash(), std::move(sky_shdaer)});
@@ -73,7 +83,9 @@ void Renderer::init() {
     m_shaders.insert({text_shdaer.hash(), std::move(text_shdaer)});
     m_shaders.insert(
         {under_water_shader.hash(), std::move(under_water_shader)});
-
+    m_shaders.insert({accum_shader.hash(), std::move(accum_shader)});
+    m_shaders.insert(
+        {composite_block_shader.hash(), std::move(composite_block_shader)});
     glEnable(GL_DEPTH_TEST);
     glDepthFunc(GL_LEQUAL);
 
@@ -182,15 +194,19 @@ void Renderer::render_outline() {
     const auto& shader = get_shader("outline");
     shader.use();
 
-    m_mv_loc = shader.loc("mv_matrix");
-    m_proj_loc = shader.loc("proj_matrix");
-
     const auto& block_pos = m_world.get_look_block_pos("TestPlayer");
 
     if (block_pos != std::nullopt) {
+
+        m_mv_loc = shader.loc("mv_matrix");
+        m_proj_loc = shader.loc("proj_matrix");
+
         m_m_mat =
             glm::translate(glm::mat4(1.0f), glm::vec3(block_pos.value().pos));
+
+        m_v_mat = m_camera.get_camera_lookat();
         m_mv_mat = m_v_mat * m_m_mat;
+
         glUniformMatrix4fv(m_mv_loc, 1, GL_FALSE, glm::value_ptr(m_mv_mat));
         glUniformMatrix4fv(m_proj_loc, 1, GL_FALSE, glm::value_ptr(m_p_mat));
 
@@ -235,7 +251,8 @@ void Renderer::render_sky() {
 void Renderer::render_text() {
     const auto& shader = get_shader("text");
     shader.use();
-
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     glDisable(GL_DEPTH_TEST);
     m_proj_loc = shader.loc("projection");
 
@@ -254,7 +271,8 @@ void Renderer::render_ui() {
     shader.use();
 
     glDisable(GL_DEPTH_TEST);
-
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     m_mv_loc = shader.loc("m_matrix");
     m_proj_loc = shader.loc("proj_matrix");
 
@@ -330,6 +348,9 @@ void Renderer::updata_framebuffer(int width, int height) {
     if (m_fbo == 0) {
         glGenFramebuffers(1, &m_fbo);
     }
+    if (m_oit_fbo == 0) {
+        glGenFramebuffers(1, &m_oit_fbo);
+    }
     glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
 
     glDeleteTextures(1, &m_screen_texture);
@@ -357,14 +378,51 @@ void Renderer::updata_framebuffer(int width, int height) {
         Logger::info("Frame Buffer Complete!");
     }
     glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+    glBindFramebuffer(GL_FRAMEBUFFER, m_oit_fbo);
+    glDeleteTextures(1, &m_accum_texture);
+    glDeleteTextures(1, &m_reveal_texture);
+    glDeleteRenderbuffers(1, &m_oit_depth_render_buffer);
+    glGenTextures(1, &m_accum_texture);
+    glBindTexture(GL_TEXTURE_2D, m_accum_texture);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F, width, height, 0, GL_RGBA,
+                 GL_HALF_FLOAT, NULL);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                           m_accum_texture, 0);
+    glGenTextures(1, &m_reveal_texture);
+    glBindTexture(GL_TEXTURE_2D, m_reveal_texture);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_R16F, width, height, 0, GL_RED,
+                 GL_HALF_FLOAT, NULL);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
+                           m_reveal_texture, 0);
+    glGenRenderbuffers(1, &m_oit_depth_render_buffer);
+    glBindRenderbuffer(GL_RENDERBUFFER, m_oit_depth_render_buffer);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
+    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
+                              GL_RENDERBUFFER, m_oit_depth_render_buffer);
+    GLenum draw_buffer[] = {GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1};
+    glDrawBuffers(2, draw_buffer);
+    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
+        Logger::error("FBO incomplete after resize!");
+    } else {
+        Logger::info("Frame Buffer Complete!");
+    }
+    glBindFramebuffer(GL_FRAMEBUFFER, 0);
+
+    m_width = width;
+    m_height = height;
 }
 
 void Renderer::render_world() {
-    const auto& shader = get_shader("world");
+    const auto& normal_block_shader = get_shader("normal_block");
-    shader.use();
+    normal_block_shader.use();
 
-    m_mv_loc = shader.loc("mv_matrix");
+    m_mv_loc = normal_block_shader.loc("mv_matrix");
-    m_proj_loc = shader.loc("proj_matrix");
+    m_proj_loc = normal_block_shader.loc("proj_matrix");
     glActiveTexture(GL_TEXTURE0);
 
     m_m_mat = glm::translate(glm::mat4(1.0f), glm::vec3(0.0f, 0.0f, 0.0f));
@@ -373,7 +431,174 @@ void Renderer::render_world() {
     glUniformMatrix4fv(m_mv_loc, 1, GL_FALSE, glm::value_ptr(m_mv_mat));
     glUniformMatrix4fv(m_proj_loc, 1, GL_FALSE, glm::value_ptr(m_p_mat));
     m_mvp_mat = m_p_mat * m_mv_mat;
-    m_world.render(m_mvp_mat, m_texture_manager, m_camera.get_camera_pos());
+
+    auto& camera_pos = m_camera.get_camera_pos();
+    auto& m_planes = m_world.planes();
+    auto& m_render_snapshots = m_world.render_snapshots();
+
+    Math::extract_frustum_planes(m_mvp_mat, m_planes);
+
+    int rendered_sum = 0;
+
+    for (const auto& snapshot : m_render_snapshots) {
+
+        if (Math::is_aabb_in_frustum(snapshot.center, snapshot.half_extents,
+                                     m_planes)) {
+            glBindTexture(GL_TEXTURE_2D_ARRAY,
+                          m_texture_manager.get_texture_array());
+            glBindBuffer(GL_ARRAY_BUFFER, snapshot.normal_vbo);
+            glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)0);
+            glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)offsetof(Vertex, s));
+            glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)offsetof(Vertex, layer));
+
+            glEnableVertexAttribArray(0);
+            glEnableVertexAttribArray(1);
+            glEnableVertexAttribArray(2);
+
+            glDrawArrays(GL_TRIANGLES, 0, snapshot.normal_vertices_count);
+            glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+            rendered_sum++;
+        }
+    }
+    // cross_plane and discard
+
+    for (const auto& snapshot : m_render_snapshots) {
+        if (!Math::is_aabb_in_frustum(snapshot.center, snapshot.half_extents,
+                                      m_planes)) {
+            continue;
+        }
+        glm::vec2 camera_pos_xz{camera_pos.x, camera_pos.z};
+        if (snapshot.cross_vertices_count != 0) {
+            glm::vec2 center_xz{snapshot.center.x, snapshot.center.z};
+            float dist2d = glm::distance(camera_pos_xz, center_xz);
+            if (dist2d <= CROSS_PLANE_DISTANCE * 16) {
+                glBindTexture(GL_TEXTURE_2D_ARRAY,
+                              m_texture_manager.get_cross_plane_array());
+                glBindBuffer(GL_ARRAY_BUFFER, snapshot.cross_vbo);
+                glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                      (void*)0);
+                glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                      (void*)offsetof(Vertex, s));
+                glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                      (void*)offsetof(Vertex, layer));
+
+                glEnableVertexAttribArray(0);
+                glEnableVertexAttribArray(1);
+                glEnableVertexAttribArray(2);
+
+                glDrawArrays(GL_TRIANGLES, 0, snapshot.cross_vertices_count);
+                glBindBuffer(GL_ARRAY_BUFFER, 0);
+            }
+        }
+        if (snapshot.normal_discard_vertices_count != 0) {
+            glBindTexture(GL_TEXTURE_2D_ARRAY,
+                          m_texture_manager.get_texture_array());
+            glBindBuffer(GL_ARRAY_BUFFER, snapshot.normal_discard_vbo);
+            glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)0);
+            glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)offsetof(Vertex, s));
+            glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)offsetof(Vertex, layer));
+
+            glEnableVertexAttribArray(0);
+            glEnableVertexAttribArray(1);
+            glEnableVertexAttribArray(2);
+
+            glDrawArrays(GL_TRIANGLES, 0,
+                         snapshot.normal_discard_vertices_count);
+            glBindBuffer(GL_ARRAY_BUFFER, 0);
+        }
+    }
+
+    // copy depth buffer
+
+    glBindFramebuffer(GL_READ_FRAMEBUFFER, m_fbo);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_oit_fbo);
+    glBlitFramebuffer(0, 0, m_width, m_height, 0, 0, m_width, m_height,
+                      GL_DEPTH_BUFFER_BIT, GL_NEAREST);
+    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_oit_fbo);
+
+    // pass one accumulate
+    auto& accum_shader = get_shader("accum");
+    accum_shader.use();
+    GLint mv_loc = accum_shader.loc("mv_matrix");
+    GLint proj_loc = accum_shader.loc("proj_matrix");
+    glUniformMatrix4fv(mv_loc, 1, GL_FALSE, glm::value_ptr(m_mv_mat));
+    glUniformMatrix4fv(proj_loc, 1, GL_FALSE, glm::value_ptr(m_p_mat));
+    glBindFramebuffer(GL_FRAMEBUFFER, m_oit_fbo);
+    glClearBufferfv(GL_COLOR, 0, glm::value_ptr(glm::vec4(0.0f)));
+    float one = 1.0f;
+    glClearBufferfv(GL_COLOR, 1, &one);
+
+    glEnable(GL_DEPTH_TEST);
+    glDepthMask(GL_FALSE);
+
+    glEnable(GL_BLEND);
+    glBlendFunci(0, GL_ONE, GL_ONE);
+
+    glBlendFunci(1, GL_ZERO, GL_ONE_MINUS_SRC_COLOR);
+    for (const auto& snapshot : m_render_snapshots) {
+        if (!Math::is_aabb_in_frustum(snapshot.center, snapshot.half_extents,
+                                      m_planes)) {
+            continue;
+        }
+
+        if (snapshot.normal_blend_vertices_count != 0) {
+            glBindTexture(GL_TEXTURE_2D_ARRAY,
+                          m_texture_manager.get_texture_array());
+            glBindBuffer(GL_ARRAY_BUFFER, snapshot.normal_blend_vbo);
+            glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)0);
+            glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)offsetof(Vertex, s));
+            glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, sizeof(Vertex),
+                                  (void*)offsetof(Vertex, layer));
+
+            glEnableVertexAttribArray(0);
+            glEnableVertexAttribArray(1);
+            glEnableVertexAttribArray(2);
+
+            glDrawArrays(GL_TRIANGLES, 0, snapshot.normal_blend_vertices_count);
+            glBindBuffer(GL_ARRAY_BUFFER, 0);
+        }
+    }
+    auto& composite_shader = get_shader("composite");
+    glDisable(GL_BLEND);
+    composite_shader.use();
+    glUniform1i(composite_shader.loc("u_accumTex"), 0);
+    glUniform1i(composite_shader.loc("u_revealTex"), 1);
+    glDisable(GL_DEPTH_TEST);
+    glDepthMask(GL_TRUE);
+    glEnable(GL_BLEND);
+    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+
+    glBindVertexArray(m_vao[6]);
+
+    glBindBuffer(GL_ARRAY_BUFFER, m_quad_vbo);
+
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float),
+                          (void*)0);
+    glEnableVertexAttribArray(1);
+    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(float),
+                          (void*)(2 * sizeof(float)));
+
+    glActiveTexture(GL_TEXTURE0);
+    glBindTexture(GL_TEXTURE_2D, m_accum_texture);
+    glActiveTexture(GL_TEXTURE1);
+    glBindTexture(GL_TEXTURE_2D, m_reveal_texture);
+
+    glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+    glDrawArrays(GL_TRIANGLES, 0, 6);
+    glBindVertexArray(0);
+
+    DebugCollector::get().report(
+        "rendered_chunk", "Rendered Chunk: " + std::to_string(rendered_sum));
 }
 
 void Renderer::render_dev_panel() {

src/tools/math_tools.cpp

@@ -45,6 +45,21 @@ float smootherstep(float edge0, float edge1, float x) {
     return x * x * x * (x * (6.0f * x - 15.0f) + 10.0f);
 }
 
+bool is_aabb_in_frustum(const glm::vec3& center, const glm::vec3& half_extents,
+                        const std::vector<glm::vec4>& planes) {
+    for (const auto& plane : planes) {
+        // distance
+        float d = glm::dot(glm::vec3(plane), center) + plane.w;
+        float r = half_extents.x * std::abs(plane.x) +
+                  half_extents.y * std::abs(plane.y) +
+                  half_extents.z * std::abs(plane.z);
+        if (d + r < 0) {
+            return false;
+        }
+    }
+    return true;
+}
+
 } // namespace Math
 
 } // namespace Cubed