diff --git a/common/gl_enum.hh b/common/gl_enum.hh
index d528f72..9b4d3b5 100644
--- a/common/gl_enum.hh
+++ b/common/gl_enum.hh
@@ -182,6 +182,31 @@ inline bool HasStencil(InternalFormat fmt) noexcept {
 }
 
 
+enum class TestFunc {
+  Never,
+  Always,
+  Equal,
+  NotEqual,
+  Less,
+  LessOrEqual,
+  Greater,
+  GreaterOrEqual,
+};
+template <>
+struct EnumMeta<TestFunc> {
+  static inline const std::unordered_map<TestFunc, GLenum> glmap = {
+    {TestFunc::Never,          GL_NEVER},
+    {TestFunc::Always,         GL_ALWAYS},
+    {TestFunc::Equal,          GL_EQUAL},
+    {TestFunc::NotEqual,       GL_NOTEQUAL},
+    {TestFunc::Less,           GL_LESS},
+    {TestFunc::LessOrEqual,    GL_LEQUAL},
+    {TestFunc::Greater,        GL_GREATER},
+    {TestFunc::GreaterOrEqual, GL_GEQUAL},
+  };
+};
+
+
 enum class BufferTarget {
   Array,
   ElementArray,
@@ -280,31 +305,6 @@ struct EnumMeta<DrawMode> {
   };
 };
 
-
-enum class FramebufferSlot {
-  Color0,
-  Color1,
-  Color2,
-  Color3,
-  Color4,
-  Color5,
-  Color6,
-  Color7,
-};
-template <>
-struct EnumMeta<FramebufferSlot> {
-  static inline const std::unordered_map<FramebufferSlot, GLenum> glmap = {
-    {FramebufferSlot::Color0, GL_COLOR_ATTACHMENT0},
-    {FramebufferSlot::Color1, GL_COLOR_ATTACHMENT0+1},
-    {FramebufferSlot::Color2, GL_COLOR_ATTACHMENT0+2},
-    {FramebufferSlot::Color3, GL_COLOR_ATTACHMENT0+3},
-    {FramebufferSlot::Color4, GL_COLOR_ATTACHMENT0+4},
-    {FramebufferSlot::Color5, GL_COLOR_ATTACHMENT0+5},
-    {FramebufferSlot::Color6, GL_COLOR_ATTACHMENT0+6},
-    {FramebufferSlot::Color7, GL_COLOR_ATTACHMENT0+7},
-  };
-};
-
 }  // namespace nf7::gl
 
 
@@ -312,6 +312,8 @@ namespace yas::detail {
 
 NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::NumericType);
 NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::ColorComp);
+NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::InternalFormat);
+NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::TestFunc);
 
 NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::BufferTarget);
 NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::BufferUsage);
@@ -322,6 +324,4 @@ NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::ShaderType);
 
 NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::DrawMode);
 
-NF7_YAS_DEFINE_ENUM_SERIALIZER(nf7::gl::FramebufferSlot);
-
 }  // namespace yas::detail
diff --git a/common/gl_obj.cc b/common/gl_obj.cc
index d040da2..4c237ed 100644
--- a/common/gl_obj.cc
+++ b/common/gl_obj.cc
@@ -186,6 +186,19 @@ nf7::Future<std::shared_ptr<Obj<Obj_ProgramMeta>>> Obj_ProgramMeta::Create(
   return pro.future();
 }
 
+void Obj_ProgramMeta::ApplyState() const noexcept {
+  if (depth) {
+    glEnable(GL_DEPTH_TEST);
+    glDepthRange(depth->near, depth->far);
+    glDepthFunc(gl::ToEnum(depth->func));
+  }
+}
+void Obj_ProgramMeta::RevertState() const noexcept {
+  if (depth) {
+    glDisable(GL_DEPTH_TEST);
+  }
+}
+
 
 nf7::Future<std::shared_ptr<Obj<Obj_VertexArrayMeta>>> Obj_VertexArrayMeta::Create(
     const std::shared_ptr<nf7::Context>& ctx) const noexcept
diff --git a/common/gl_obj.hh b/common/gl_obj.hh
index 097f226..681f311 100644
--- a/common/gl_obj.hh
+++ b/common/gl_obj.hh
@@ -113,6 +113,13 @@ struct Obj_ProgramMeta final {
  public:
   struct Param { };
 
+  struct Depth {
+    float near = 0, far = 1;
+    gl::TestFunc func = gl::TestFunc::Less;
+
+    void serialize(auto& ar) { ar(near, far, func); }
+  };
+
   static void Delete(GLuint id) noexcept {
     glDeleteProgram(id);
   }
@@ -121,6 +128,11 @@ struct Obj_ProgramMeta final {
   nf7::Future<std::shared_ptr<Obj<Obj_ProgramMeta>>> Create(
       const std::shared_ptr<nf7::Context>& ctx,
       const std::vector<nf7::File::Id>&    shaders) noexcept;
+
+  void ApplyState() const noexcept;
+  void RevertState() const noexcept;
+
+  std::optional<Depth> depth;
 };
 using Program = Obj<Obj_ProgramMeta>;
 using ProgramFactory = AsyncFactory<nf7::Mutex::Resource<std::shared_ptr<Program>>>;
diff --git a/file/gl_obj.cc b/file/gl_obj.cc
index c4cd618..8ae2ab9 100644
--- a/file/gl_obj.cc
+++ b/file/gl_obj.cc
@@ -730,7 +730,7 @@ struct Program {
   Program& operator=(Program&&) = default;
 
   void serialize(auto& ar) {
-    ar(shaders_);
+    ar(shaders_, depth_);
   }
 
   std::string Stringify() noexcept {
@@ -742,6 +742,18 @@ struct Program {
       st << shader.Stringify();
     }
     st << YAML::EndSeq;
+
+    if (depth_) {
+      st << YAML::Key << "depth";
+      st << YAML::BeginMap;
+      st << YAML::Key   << "near";
+      st << YAML::Value << depth_->near;
+      st << YAML::Key   << "far";
+      st << YAML::Value << depth_->far;
+      st << YAML::Key   << "func";
+      st << YAML::Value << std::string {magic_enum::enum_name(depth_->func)};
+      st << YAML::EndMap;
+    }
     st << YAML::EndMap;
     return std::string {st.c_str(), st.size()};
   }
@@ -749,16 +761,25 @@ struct Program {
   try {
     const auto yaml = YAML::Load(v);
 
-    std::vector<nf7::File::Path> shaders;
+    Program ret;
     for (const auto& shader : yaml["shaders"]) {
-      shaders.push_back(
+      ret.shaders_.push_back(
           nf7::File::Path::Parse(shader.as<std::string>()));
     }
-    if (shaders.size() == 0) {
+    if (ret.shaders_.size() == 0) {
       throw nf7::Exception {"no shader is attached"};
     }
 
-    shaders_ = std::move(shaders);
+    if (const auto& yaml_depth = yaml["depth"]) {
+      depth_.emplace(Product::Meta::Depth {
+        .near = yaml_depth["near"].as<float>(),
+        .far  = yaml_depth["far"].as<float>(),
+        .func = magic_enum::enum_cast<gl::TestFunc>(
+            yaml_depth["func"].as<std::string>()).value(),
+      });
+    }
+
+    *this = std::move(ret);
   } catch (YAML::Exception& e) {
     throw nf7::Exception {std::string {"YAML error: "}+e.what()};
   }
@@ -802,6 +823,9 @@ struct Program {
         throw nf7::Exception {"negative size viewport"};
       }
 
+      gl::Program::Meta config = (**p.obj).meta();
+      // TODO: override configurations
+
       // this will be triggered when all preparation done
       nf7::AggregatePromise apro {p.la};
 
@@ -903,12 +927,14 @@ struct Program {
         }
 
         // draw
+        config.ApplyState();
         if (vao->meta().index) {
           const auto numtype = gl::ToEnum(vao->meta().index->numtype);
           glDrawElementsInstanced(mode, count, numtype, nullptr, inst);
         } else {
           glDrawArraysInstanced(mode, 0, count, inst);
         }
+        config.RevertState();
         const auto status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
 
         // unbind all
@@ -934,7 +960,8 @@ struct Program {
   }
 
  private:
-  std::vector<nf7::File::Path> shaders_;
+  std::vector<nf7::File::Path>        shaders_;
+  std::optional<Product::Meta::Depth> depth_ = {{}};
 
 
   static void SetUniform(GLuint prog, const char* name, const nf7::Value& v) {