diff --git a/src/GLObjects/GLObject.cpp b/src/GLObjects/GLObject.cpp
index fe9e7d5..5b1217e 100644
--- a/src/GLObjects/GLObject.cpp
+++ b/src/GLObjects/GLObject.cpp
@@ -25,7 +25,7 @@ void GLObject::create() {
 	glBindBuffer(GL_ARRAY_BUFFER, _vertexVbo);
 	glBufferData(GL_ARRAY_BUFFER, _vertexCount*sizeof(Vertex), nullptr, GL_STREAM_DRAW);
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _indexVbo);
-	glBufferData(GL_ELEMENT_ARRAY_BUFFER, _indexCount*sizeof(GLuint), _indices.get(), GL_STATIC_DRAW);
+	glBufferData(GL_ELEMENT_ARRAY_BUFFER, _indexCount*sizeof(GLuint), _indices.get(), GL_STREAM_DRAW);
 
 	_trianglesCount = _indexCount*sizeof(GLuint)/sizeof(GLuint);
 
diff --git a/src/GLObjects/Mesh.cpp b/src/GLObjects/Mesh.cpp
index 50d0c6b..d0cbb0f 100644
--- a/src/GLObjects/Mesh.cpp
+++ b/src/GLObjects/Mesh.cpp
@@ -4,8 +4,8 @@
 #include <iostream>
 
 Mesh::Mesh(ShaderProgram* shader, std::size_t size) : GLObject(shader), _size(size), _xs(size), _ys(size), _normals(2*size*size) {
-	_vertexCount = (_size + 1)*(_size + 1);
-	_indexCount = _vertexCount;
+	_vertexCount = _size*_size;
+	_indexCount = (_size - 1)*(_size - 1)*6;
 	_vertices = std::make_unique<Vertex[]>(_vertexCount);
 	_indices = std::make_unique<GLuint[]>(_indexCount);
 }
@@ -16,8 +16,8 @@ Mesh::~Mesh() {
 
 void Mesh::generateVertices() const {
     for(std::size_t j = 0; j < _size; ++j) {
-        for (std::size_t i = 0; i <= _size; ++i) {
-            size_t idx = j*(_size - 1) + i;
+        for (std::size_t i = 0; i < _size; ++i) {
+            size_t idx = j*_size + i;
             _vertices[idx].x = (float)i/_size - 0.5f;
             _vertices[idx].y = (float)j/_size - 0.5f;
             _vertices[idx].z = 0.f;
@@ -28,45 +28,50 @@ void Mesh::generateVertices() const {
     }
 }
 
+inline size_t Mesh::normalIndex(size_t x, size_t y) {
+    return  2*(x + y*_size);
+}
+
 void Mesh::updateVertices() const {
     for(std::size_t j = 0; j < _size; ++j) {
-        for(std::size_t i = 0; i <= _size; ++i) {
-            std::size_t idx = j*(_size - 1) + i;
+        for(std::size_t i = 0; i < _size; ++i) {
+            std::size_t idx = j*_size + i;
             _vertices[idx].z = heightMap(i, j);
         }
     }
 
     // 1. Calc normals for all triangles
-//    _normals.clear();
-//    for(std::size_t j = 0; j < _size; ++j) {
-//        for(std::size_t i = 0; i <= _size; ++i) {
-//            float x = _xs[i], x2 = _xs[i + 1];
-//            float y = _ys[j], y2 = _ys[j + 1];
-//
-//            glm::vec3 p1(x, y, _vertices[j*(_size - 1) + i].z);
-//            glm::vec3 p2(x2, y, _vertices[j*(_size - 1) + i + 1].z);
-//            glm::vec3 p3(x, y2, _vertices[(j + 1)*(_size - 1) + i].z);
-//            glm::vec3 p4(x2, y2, _vertices[(j + 1)*(_size - 1) + i + 1].z);
-//
-//            glm::vec3 v1 = p1 - p3;
-//            glm::vec3 v2 = p2 - p3;
-//            glm::vec3 v3 = p4 - p3;
-//
-//            glm::vec3 norm1 = glm::cross(v2, v1);
-//            glm::vec3 norm2 = glm::cross(v3, v2);
-//
-//            _normals.emplace_back(norm1);
-//            _normals.emplace_back(norm2);
-//        }
-//    }
+    _normals.clear();
+    for(std::size_t j = 0; j < _size; ++j) {
+        for(std::size_t i = 0; i < _size; ++i) {
+            float x = _xs[i], x2 = _xs[i + 1];
+            float y = _ys[j], y2 = _ys[j + 1];
+
+            glm::vec3 p1(x, y, _vertices[j*(_size - 1) + i].z);
+            glm::vec3 p2(x2, y, _vertices[j*(_size - 1) + i + 1].z);
+            glm::vec3 p3(x, y2, _vertices[(j + 1)*(_size - 1) + i].z);
+            glm::vec3 p4(x2, y2, _vertices[(j + 1)*(_size - 1) + i + 1].z);
+
+            glm::vec3 v1 = p1 - p3;
+            glm::vec3 v2 = p2 - p3;
+            glm::vec3 v3 = p4 - p3;
+
+            glm::vec3 norm1 = glm::cross(v2, v1);
+            glm::vec3 norm2 = glm::cross(v3, v2);
+
+            _normals.emplace_back(norm1);
+            _normals.emplace_back(norm2);
+        }
+    }
 
     // 2. Calc normals for all vertices based on precalculated normals for triangles
     //    Normal of vertex is an average of normals of adjacent triangles
-//    for(std::size_t j = 0; j < _size; ++j) {
-//        for (std::size_t i = 0; i <= _size; ++i) {
-//
-//        }
-//    }
+    for(std::size_t j = 0; j < _size; ++j) {
+        for (std::size_t i = 0; i < _size; ++i) {
+            size_t idx1 = normalIndex(i - 1, j - 1);
+            size_t idx2 = normalIndex(i - 1, j);
+        }
+    }
 }
 
 void Mesh::generateIndices() const {
diff --git a/src/GLObjects/Mesh.h b/src/GLObjects/Mesh.h
index 87dd11a..7f2c2a0 100644
--- a/src/GLObjects/Mesh.h
+++ b/src/GLObjects/Mesh.h
@@ -24,6 +24,9 @@ public:
 	Mesh(ShaderProgram* shader, std::size_t size);
 	virtual ~Mesh();
 
+private:
+    size_t normalIndex(size_t x, size_t y);
+
 protected:
 	void generateVertices() const override final;
     void updateVertices() const override final;