homework2, shade smooth

Author: sleeplessai

include/OBJ.hpp

@@ -9,4 +9,5 @@ struct OBJ {
 
     void load_obj(std::string path);
     void draw_obj();
+    void draw_obj_smooth();
 };

src/Game.cpp

@@ -115,17 +115,17 @@ void Game::render() {
     model = glm::rotate(glm::mat4(1.0f), glm::radians(motionAngle), motionAxis);
     CHECK_GL(glLoadMatrixf(glm::value_ptr(view * model)));
     glColor3f(1.0f, 0.0f, 0.0f);
-    m_private->ocvLogo.at(0).draw_obj();
+    m_private->ocvLogo.at(0).draw_obj_smooth();
 
     model = glm::rotate(glm::mat4(1.0f), glm::radians(motionAngle), motionAxis);
     CHECK_GL(glLoadMatrixf(glm::value_ptr(view * model)));
     glColor3f(0.0f, 1.0f, 0.0f);
-    m_private->ocvLogo.at(1).draw_obj();
+    m_private->ocvLogo.at(1).draw_obj_smooth();
 
     model = glm::rotate(glm::mat4(1.0f), glm::radians(motionAngle), motionAxis);
     CHECK_GL(glLoadMatrixf(glm::value_ptr(view * model)));
     glColor3f(0.0f, 0.0f, 1.0f);
-    m_private->ocvLogo.at(2).draw_obj();
+    m_private->ocvLogo.at(2).draw_obj_smooth();
 
     motionAngle += motionDelta;
 }

src/OBJ.cpp

@@ -70,3 +70,42 @@ void OBJ::draw_obj() {
 
     CHECK_GL(glEnd());
 }
+
+void OBJ::draw_obj_smooth() {
+    std::vector<glm::vec3> faceNormalBuffer;
+    std::vector<glm::vec3> vertexNormalBuffer(vertices.size());
+    
+    for (auto& face : faces) {
+        auto const& a = vertices.at(face[0]);
+        auto const& b = vertices.at(face[1]);
+        auto const& c = vertices.at(face[2]);
+
+        glm::vec3 fn = compute_normal(a, b, c);
+        faceNormalBuffer.push_back(fn);
+        vertexNormalBuffer[face[0]] += fn;
+        vertexNormalBuffer[face[1]] += fn;
+        vertexNormalBuffer[face[2]] += fn;
+    }
+    for (auto& vn : vertexNormalBuffer) {
+        vn = glm::normalize(vn);
+    }
+
+    glBegin(GL_TRIANGLES);
+    for (auto const& face : faces) {
+        auto const& a = vertices.at(face[0]);
+        auto const& b = vertices.at(face[1]);
+        auto const& c = vertices.at(face[2]);
+        
+        auto const& n1 = vertexNormalBuffer.at(face[0]);
+        auto const& n2 = vertexNormalBuffer.at(face[1]);
+        auto const& n3 = vertexNormalBuffer.at(face[2]);
+
+        glNormal3fv(glm::value_ptr(n1));
+        glVertex3fv(glm::value_ptr(a));
+        glNormal3fv(glm::value_ptr(n2));
+        glVertex3fv(glm::value_ptr(b));
+        glNormal3fv(glm::value_ptr(n3));
+        glVertex3fv(glm::value_ptr(c));
+    }
+    CHECK_GL(glEnd());
+}