Program Listing for File Camera.cpp

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#include "scene/Camera.hpp"

#include <GLFW/glfw3.h>

Camera::Camera()
  :

    position(glm::vec3(0.0f, 100.0f, -80.0f)), front(glm::vec3(0.0f, 0.0f, -1.f)),
    world_up(glm::vec3(0.0f, 1.0f, 0.0f)), right(glm::normalize(glm::cross(front, world_up))),
    up(glm::normalize(glm::cross(right, front))), yaw(80.f), pitch(-40.0f), movement_speed(200.f), turn_speed(0.25f),
    near_plane(0.1f), far_plane(4000.f), fov(45.f)

{}

void Camera::key_control(bool *keys, float delta_time)
{
    float velocity = movement_speed * delta_time;

    if (keys[GLFW_KEY_W]) { position += front * velocity; }

    if (keys[GLFW_KEY_D]) { position += right * velocity; }

    if (keys[GLFW_KEY_A]) { position += -right * velocity; }

    if (keys[GLFW_KEY_S]) { position += -front * velocity; }

    if (keys[GLFW_KEY_Q]) { yaw += -velocity; }

    if (keys[GLFW_KEY_E]) { yaw += velocity; }
}

void Camera::mouse_control(float x_change, float y_change)
{
    // here we only want to support views 90 degrees to each side
    // again choose turn speed well in respect to its ordinal scale
    x_change *= turn_speed;
    y_change *= turn_speed;

    yaw += x_change;
    pitch += y_change;

    if (pitch > 89.0f) { pitch = 89.0f; }

    if (pitch < -89.0f) { pitch = -89.0f; }

    // by changing the rotations you need to update all parameters
    // for we retrieve them later for further calculations!
    update();
}

void Camera::set_near_plane(float near_plane) { this->near_plane = near_plane; }

void Camera::set_far_plane(float far_plane) { this->far_plane = far_plane; }

void Camera::set_fov(float fov) { this->fov = fov; }

void Camera::set_camera_position(glm::vec3 new_camera_position) { this->position = new_camera_position; }

glm::mat4 Camera::calculate_viewmatrix()
{
    // very necessary for further calc
    return glm::lookAt(position, position + front, up);
}

Camera::~Camera() {}

void Camera::update()
{
    // https://learnopengl.com/Getting-started/Camera?fbclid=IwAR1WEr4jt6IyWC52s_WKYHtaFoeug37pG5YqbDPifgn5F1UXPbUjWbJWiqQ
    //  thats a bit tricky; have a look to link above if there a questions :)
    //  but simple geometrical analysis
    //  consider yaw you are turnig to the side; pich as you move the head forward
    //  and back; roll rotations around z-axis will make you dizzy :)) notice that
    //  to roll will not chnge my front vector
    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);

    // retrieve the right vector with some world_up
    right = glm::normalize(glm::cross(front, world_up));

    // but this means the up vector must again be calculated with right vector
    // calculated!!!
    up = glm::normalize(glm::cross(right, front));
}