FirstOpenGL

一个很偶然的机会让我遇到了OpenGL 了解到了图形学，GPU编程，并产生了极大的兴趣，遂开始学习。 希望以后能创作出有意思的东西

仓库目录

1. OpenGL
           这个工程里是我第一次接触OpenGL建立的学习工程，教程来自B站 最好的OpenGL教程之一
   课程来自国外，视频里是用英文进行讲解，但是吐字准确，一般都听得懂。 课程也比较简单清晰易懂，跟着学下来没遇到特别的难点。
   帮助我跨过了前期配置OpenGL的巨量问题，画出了人生的第一个三角形。目前学至p22

2. LearnOpenGL
           这个工程是我后续接触的到的另一个学习教程，教程来自 LearnOpenGL CN。目前是我主要的学习课程，了解到了很多更细更广的知识。

   1. FirstOpenGL项目
              这个项目对应教程中的入门篇
      参考的网上资料有 矩阵旋转 视点矩阵推导lookAt
      在入门篇的摄像机小节里，对教程的鼠标移动做了小修改

      1. 原文全局变量

         bool firstMouse = true;
         float yaw   = -90.0f;	// yaw is initialized to -90.0 degrees since a yaw of 0.0 results in a direction vector pointing to the right so we initially rotate a bit to the left.
         float pitch =  0.0f;
         float lastX =  800.0f / 2.0;
         float lastY =  600.0 / 2.0;
         float fov   =  45.0f;
         

      2. 原文鼠标相应函数

         void mouse_callback(GLFWwindow* window, double xpos, double ypos)
         {
         	if (firstMouse)
         	{
         		lastX = xpos;
         		lastY = ypos;
         		firstMouse = false;
         	}
         
         	float xoffset = xpos - lastX;
         	float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
         	lastX = xpos;
         	lastY = ypos;
         
         	float sensitivity = 0.1f; // change this value to your liking
         	xoffset *= sensitivity;
         	yoffset *= sensitivity;
         
         	yaw += xoffset;
         	pitch += yoffset;
         
         	// make sure that when pitch is out of bounds, screen doesn't get flipped
         	if (pitch > 89.0f)
         		pitch = 89.0f;
         	if (pitch < -89.0f)
         		pitch = -89.0f;
         
         	glm::vec3 front;
         	front.x = cos(glm::radians(yaw)) * cos(glm::radians(pitch));
         	front.y = sin(glm::radians(pitch));
         	front.z = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
         	cameraFront = glm::normalize(front);
         }
         

      3. 我的全局变量

         float yaw = 0.0f;//偏航角  摄像机初始在正X轴 -90度之后就在正Z轴上了
         float pitch = 0.0f;//俯仰角
         float lastX = 800.0f / 2.0;
         float lastY = 600.0f / 2.0;
         float fov = 45.0f;
         bool firstMove = true;
         

      4. 我的鼠标相应函数

         void mouse_callback(GLFWwindow* window, double xpos, double ypos)
         {
         	if (firstMove)
         	{
         		lastX = xpos;
         		lastY = ypos;
         		firstMove = false;
         	}
         
         	float xoffset = xpos - lastX;//鼠标左移 xpos变小 视角要左转(相机逆时针 yaw变大)
         	float yoffset = lastY - ypos;//鼠标上移 ypos变小 视角要上仰(相机从下面往上看 ZOY平面是个顺时针移动 pitch变小)
         	lastX = xpos;
         	lastY = ypos;
         
         	float sensitivity = 0.1f;
         	xoffset *= sensitivity;
         	yoffset *= sensitivity;
         
         	yaw += xoffset;
         	pitch += yoffset;
         
         	if (pitch > 89.0f)
         		pitch = 89.0f;
         	if (pitch < -89.0f)
         		pitch = -89.0f;
         
         	glm::vec3 front(1.0f);
         	front.x = sin(glm::radians(yaw)) * cos(glm::radians(pitch));
         	front.y = sin(glm::radians(pitch));
         	front.z = -cos(glm::radians(yaw)) * cos(glm::radians(pitch));
         	cameraFront = glm::normalize(front);
         
         }
         

   2. Chapter2
              这个项目对应教程中的光照篇