reorganize vertex and face class

Author: ZzzhHe

include/face.hpp

@@ -0,0 +1,51 @@
+#pragma once
+
+#include "vertex.hpp"
+#include "material.hpp" 
+
+#include <array>
+
+namespace simple_renderer {
+
+class Face {
+public:
+    // Default constructor
+    Face() = default;
+    // Copy constructor
+    Face(const Face& face) = default;
+    Face& operator=(const Face& face) = default;
+    // Move constructor
+    Face(Face&& face) = default;
+    Face& operator=(Face&& face) = default;
+    // Destructor
+    ~Face() = default;
+
+    explicit Face(const Vertex& v0, const Vertex& v1, const Vertex& v2, Material material)
+        : vertices_{v0, v1, v2}, material_(std::move(material)) {
+        calculateNormal();
+    }
+
+    void transform(const glm::mat4 &tran) {
+        vertices_[0].transform(tran);
+        vertices_[1].transform(tran);
+        vertices_[2].transform(tran);
+    }
+
+    const std::array<Vertex, 3>& vertices() const { return vertices_; }
+    const Vertex& vertex(size_t index) const { return vertices_[index]; }
+    const glm::vec3& normal() const { return normal_; }
+    const Material& material() const { return material_; }
+
+private:
+    std::array<Vertex, 3> vertices_;
+    glm::vec3 normal_;
+    Material material_;
+
+    void calculateNormal() {
+        glm::vec3 edge1 = glm::vec3(vertices_[1].position()) - glm::vec3(vertices_[0].position());
+        glm::vec3 edge2 = glm::vec3(vertices_[2].position()) - glm::vec3(vertices_[0].position());
+        normal_ = glm::normalize(glm::cross(edge1, edge2));
+    }
+};
+
+}