glfwTerminate(); return0; } // process all input: query GLFW whether relevant keys are pressed/released this // frame and react accordingly // ----------------------- voidprocessInput(GLFWwindow* window){ if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) glfwSetWindowShouldClose(window, true); }
// glfw: whenever the window size changed (by OS or user resize) this callback // function executes // ---------------------- voidframebuffer_size_callback(GLFWwindow* window, int width, int height){ // make sure the viewport matches the new window dimensions; note that width // and height will be significantly larger than specified on retina // displays. glViewport(0, 0, width, height); }
int width, height, nrComponents; unsignedchar* data = stbi_load(path, &width, &height, &nrComponents, 0); if (data) { GLenum format = {}; if (nrComponents == 1) format = GL_RED; elseif (nrComponents == 3) format = GL_RGB; elseif (nrComponents == 4) format = GL_RGBA;
glBindTexture(GL_TEXTURE_2D, textureID); glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data); glGenerateMipmap(GL_TEXTURE_2D);
// An abstract camera class that processes input and calculates the // corresponding Euler Angles, Vectors and Matrices for use in OpenGL classCamera { public: // 摄像机属性 glm::vec3 Position; // 摄像机位置向量 glm::vec3 Front; // 方向向量，摄像机指向的目标的方向 glm::vec3 Up; // 上向量，也即y轴正方向，叉乘方向向量可得右向量 glm::vec3 Right; // 右向量，摄像机空间x轴的正方向 glm::vec3 WorldUp; // 上向量 // 有了三个互相垂直的轴，外加一个平移向量，即可创建一个矩阵，可以用这个矩阵乘以任何向量来将其变换到那个空间
// returns the view matrix calculated using Euler Angles and the LookAt // Matrix glm::mat4 GetViewMatrix()// 生成观察矩阵 { // return glm::lookAt(Position, Position + Front, Up); // // // lookat函数只需要一个位置，一个目标，和一个上向量，它会自己创建一个观察矩阵，此观察矩阵点乘空间中的物体，即可将物体变换到此观察空间中
// ------------ 以下为自己的lookat： // 1. Position = known // 2. Calculate cameraDirection glm::vec3 zaxis = glm::normalize(-Front); // 3. Get positive right axis vector glm::vec3 xaxis = glm::normalize(glm::cross(glm::normalize(WorldUp), zaxis)); // 4. Calculate camera up vector glm::vec3 yaxis = glm::cross(zaxis, xaxis);
// Create translation and rotation matrix // In glm we access elements as mat[col][row] due to column-major layout glm::mat4 translation = glm::mat4(1.0f); // Identity matrix by default translation[3][0] = -Position.x; // Third column, first row translation[3][1] = -Position.y; translation[3][2] = -Position.z; glm::mat4 rotation = glm::mat4(1.0f); rotation[0][0] = xaxis.x; // First column, first row rotation[1][0] = xaxis.y; rotation[2][0] = xaxis.z; rotation[0][1] = yaxis.x; // First column, second row rotation[1][1] = yaxis.y; rotation[2][1] = yaxis.z; rotation[0][2] = zaxis.x; // First column, third row rotation[1][2] = zaxis.y; rotation[2][2] = zaxis.z; return rotation * translation; }
// processes input received from any keyboard-like input system. Accepts // input parameter in the form of camera defined ENUM (to abstract it from // windowing systems) voidProcessKeyboard(Camera_Movement direction, float deltaTime){ float velocity = MovementSpeed * deltaTime; // 设定速度 // 根据方向调整方向向量 if (direction == FORWARD) Position += Front * velocity; if (direction == BACKWARD) Position -= Front * velocity; if (direction == LEFT) Position -= Right * velocity; if (direction == RIGHT) Position += Right * velocity; if (direction == UP) Position.y += velocity; if (direction == DOWN) Position.y -= velocity; // Position.y = 0.0f; // 确保不会偏离xz平面
// Setting faster if (direction == FASTER_FORWARD) Position += Front * (velocity * 10); if (direction == FASTER_BACKWARD) Position -= Front * (velocity * 10); if (direction == FASTER_LEFT) Position -= Right * (velocity * 10); if (direction == FASTER_RIGHT) Position += Right * (velocity * 10); }
// processes input received from a mouse input system. Expects the offset // value in both the x and y direction. voidProcessMouseMovement(float xoffset, float yoffset, GLboolean constrainPitch = true){ xoffset *= MouseSensitivity; // x方向的鼠标偏离 yoffset *= MouseSensitivity; // y方向的鼠标偏离
Yaw += xoffset; // 偏航 Pitch += yoffset; // 仰角
if (constrainPitch) // 确保仰角足够大时屏幕不会被翻转 { if (Pitch > 89.0f) Pitch = 89.0f; if (Pitch < -89.0f) Pitch = -89.0f; }
// update Front, Right and Up Vectors using the updated Euler angles updateCameraVectors(); }
// processes input received from a mouse scroll-wheel event. Only requires // input on the vertical wheel-axis voidProcessMouseScroll(float yoffset)// 处理缩放 { Zoom -= (float)yoffset; if (Zoom < 1.0f) Zoom = 1.0f; if (Zoom > 45.0f) Zoom = 45.0f; }
private: // 从更新后的相机的欧拉角计算方向向量 voidupdateCameraVectors(){ // calculate the new Front vector 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)); Front = glm::normalize(front); // 同时重新计算了右向量和上向量 Right = glm::normalize(glm::cross(Front, WorldUp)); // 将向量归一化，因为你向上或向下看的次数越多，它们的长度就越接近0，这会导致移动速度变慢。 Up = glm::normalize(glm::cross(Right, Front)); } }; #endif
