diff --git a/.clangd b/.clangd
index 9dcba43..4ae1f41 100644
--- a/.clangd
+++ b/.clangd
@@ -1,6 +1,3 @@
-If:
-    OS: Windows
-
 CompileFlags:
     Add:
         --target=x86_64-w64-mingw32
\ No newline at end of file
diff --git a/CMakeLists.txt b/CMakeLists.txt
index c456333..436c9df 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,4 +43,6 @@ elseif(UNIX)
     )
 endif()
 
-
+if (WIN32)
+    add_compile_options(--target=x86_64-w64-mingw32)
+endif()
diff --git a/main.cpp b/main.cpp
index 0762b3b..d3d6730 100644
--- a/main.cpp
+++ b/main.cpp
@@ -58,6 +58,15 @@ public:
             if (heatmapIbo_) {
                 glDeleteBuffers(1, &heatmapIbo_);
             }
+            if (skirtVao_) {
+                glDeleteVertexArrays(1, &skirtVao_);
+            }
+            if (skirtVbo_) {
+                glDeleteBuffers(1, &skirtVbo_);
+            }
+            if (skirtIbo_) {
+                glDeleteBuffers(1, &skirtIbo_);
+            }
             deinit_ = true;
         }
         
@@ -301,6 +310,80 @@ private:
         glBindVertexArray(0);
     }
 
+    void initSkirtGeometry_() {
+        if (skirtIbo_) {
+            glDeleteBuffers(1, &skirtIbo_);
+            skirtIbo_ = 0;
+        }
+        if (skirtVao_) {
+            glDeleteVertexArrays(1, &skirtVao_);
+            skirtVao_ = 0;
+        }
+        if (skirtVbo_) {
+            glDeleteBuffers(1, &skirtVbo_);
+            skirtVbo_ = 0;
+        }
+
+        skirtUVs.clear();
+        skirtNormals.clear();
+        const int cols = std::max(2, heatmapcols_);
+        const int rows = std::max(2, heatmaprows_);
+
+        auto push_border = [&](int c, int r, const glm::vec3& n) {
+            const float u = (cols > 1) ? float(c) / float(cols - 1) : 0.0F;
+            const float v = (rows > 1) ? float(r) / float(rows - 1) : 0.0F;
+            skirtUVs.push_back(glm::vec2(u, v));
+            skirtNormals.push_back(n);
+        };
+
+        for (int c = 0; c < cols; ++c) {
+            push_border(c, 0, glm::vec3(0.0F, -1.0F, 0.0F));
+        }
+        for (int r = 1; r < rows; ++r) {
+            push_border(cols - 1, r, glm::vec3(1.0F, 0.0F, 0.0F));
+        }
+        for (int c = cols -1; c >= 0; --c) {
+            push_border(c, rows - 1, glm::vec3(0.0F, 1.0F, 0.0F));
+        }
+        for (int r = rows - 2; r >= 1; --r) {
+            push_border(0, r, glm::vec3(-1.0F, 0.0F, 0.0F));
+        }
+
+        const int border_count = skirtUVs.size();
+        // TODO: fill
+        // std::vector<float> verts;
+        // verts.assign(border_count * 2 * 8, 0.0F);
+        skirtVertices.assign(border_count * 8 * 2, 0.0F);
+
+        std::vector<unsigned int> idx;
+        idx.reserve(border_count * 6);
+        for (int i = 0; i < border_count; ++i) {
+            unsigned int next = (i + 1) % border_count;
+            const unsigned int top0 = unsigned(i * 2);
+            const unsigned int bot0 = unsigned(i * 2 + 1);
+            const unsigned int top1 = unsigned(next * 2);
+            const unsigned int bot1 = unsigned(next * 2 + 1);
+            idx.push_back(top0);
+            idx.push_back(top1);
+            idx.push_back(bot1);
+
+            idx.push_back(top0);
+            idx.push_back(bot0);
+            idx.push_back(bot1);
+        }
+        skirtIndexCount_ = static_cast<int>(idx.size());
+
+        glGenVertexArrays(1, &skirtVao_);
+        glBindVertexArray(skirtVao_);
+
+        glGenBuffers(1, &skirtVbo_);
+        glBindBuffer(GL_ARRAY_BUFFER, skirtVbo_);
+        glBufferData(GL_ARRAY_BUFFER, skirtVertices.size() * sizeof(float), skirtVertices.data(), GL_STATIC_DRAW);
+
+        glGenBuffers(1, &skirtIbo_);
+        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, skirtIbo_);
+    }
+
     bool initBgProgram() {
         auto vshader = std::make_unique<LOpenGLShader>(LOpenGLShader::ShaderType::Vertex);
         auto fshader = std::make_unique<LOpenGLShader>(LOpenGLShader::ShaderType::Fragment);
@@ -560,6 +643,17 @@ private:
     unsigned int heatmapIbo_ = 0;
     int heatmapIndexCount = 0;
 
+    std::unique_ptr<LOpenGLProgram> skirtProg_;
+    std::string skirtVertShaderPath_;
+    std::string skirtFragShaderPath_;
+    unsigned int skirtVao_ = 0;
+    unsigned int skirtVbo_ = 0;
+    unsigned int skirtIbo_ = 0;
+    std::vector<glm::vec2> skirtUVs;
+    std::vector<glm::vec3> skirtNormals;
+    int skirtIndexCount_ = 0;
+    std::vector<float> skirtVertices;
+
     ViewPort viewport_{800, 600};
     Camera camera_{glm::vec3(0.0F, 0.0F, 2.0F)};
 
diff --git a/shader/skirt.frag b/shader/skirt.frag
index 4226f05..3ec552b 100644
--- a/shader/skirt.frag
+++ b/shader/skirt.frag
@@ -33,5 +33,51 @@ vec3 colorRamp(float t) {
 }
 
 float maxNeighborValue(vec2 uv) {
-    
+    vec2 texelSizeF = 1.0 / uTexelSize;
+    ivec2 texelSizeI = ivec2(max(1.0, floor(uTexelSize +  0.5)));
+    ivec2 maxCoord = texelSizeI - 1;
+
+    vec2 texelF = vec2(clamp(uv * maxCoord, vec2(0.0), vec2(maxCoord)));
+    ivec2 base = ivec2(floor(texelF));
+    ivec2 base10 = min(base + ivec2(1, 0), maxCoord);
+    ivec2 base01 = min(base + ivec2(0, 1), maxCoord);
+    ivec2 base11 = min(base + ivec2(1, 1), maxCoord);
+
+    float v00 = texelFetch(uColorHeigh, base, 0).r;
+    float v10 = texelFetch(uColorHeigh, base10, 0).r;
+    float v01 = texelFetch(uColorHeigh, base01, 0).r;
+    float v11 = texelFetch(uColorHeigh, base11, 0).r;
+
+    return max(max(v00, v10), max(v01, v11));
+}
+
+vec3 colorRampWithZero(float t) {
+    const float zeroW = 0.005;
+    float blend = smoothstep(0.0, zeroW, t);
+    float tRamp = saturate(t - zeroW) / max(1.0 - zeroW, 1e-6);
+    vec3 ramp = colorRamp(tRamp);
+    return mix(uColorZero, ramp, blend);
+}
+
+void main() {
+    vec3 N = normalize(vNormal);
+    vec3 L = normalize(uLightDir);
+    vec3 V = normalize(uCameraPos - vWorldPos);
+    vec3 H = normalize(L + V);
+
+    float diff = saturate(dot(N, L));
+    float spec = pow(saturate(dot(N, H)), 24.0);
+
+    float vC = texture(uHeightTex, vUV).r;
+    bool isZero = abs(vC) <= 1e-6;
+    float t = value01(vC);
+    float m = maxNeighborValue(vUV);
+    float eps = max(1e-4, 0.001 * (uMaxV - uMinV));
+    float force = smoothstep(uMaxV - eps, uMaxV, m);
+    t = max(t, force);
+    vec3 base = isZero ? uColorZero : colorRampWithZero(t);
+
+    vec3 col = base * (0.35 + 0.65 * diff);
+    col += vec3(1.0) * spec * 0.10;
+    FragColor = vec4(clamp(col, 0.0, 1.0), 1.0);
 }
\ No newline at end of file