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justhomework/OpenGL/hello/include/camera.h

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2023-05-25 08:55:12 +00:00
#ifndef CAMERA_H
#define CAMERA_H
#include "glad/glad.h"
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <iostream>
#include <vector>
// Defines several possible options for camera movement. Used as abstraction to
// stay away from window-system specific input methods
enum Camera_Movement { FORWARD, BACKWARD, LEFT, RIGHT };
// Default camera values
const float YAW = -90.0f;
const float PITCH = 0.0f;
const float SPEED = 2.5f;
const float SENSITIVITY = 0.1f;
const float ZOOM = 45.0f;
// An abstract camera class that processes input and calculates the
// corresponding Euler Angles, Vectors and Matrices for use in OpenGL
class Camera {
public:
// camera Attributes
glm::vec3 Position;
glm::vec3 Front;
glm::vec3 Up;
glm::vec3 Right;
glm::vec3 WorldUp;
// euler Angles
float Yaw;
float Pitch;
// camera options
float MovementSpeed;
float MouseSensitivity;
float Zoom;
bool firstMouse;
float lastX, lastY;
// constructor with vectors
Camera(float X, float Y, glm::vec3 position = glm::vec3(0.0f, 0.0f, 0.0f),
glm::vec3 up = glm::vec3(0.0f, 1.0f, 0.0f), float yaw = YAW,
float pitch = PITCH)
: Front(glm::vec3(0.0f, 0.0f, -1.0f)), MovementSpeed(SPEED),
MouseSensitivity(SENSITIVITY), Zoom(ZOOM) {
lastX = X;
lastY = Y;
Position = position;
WorldUp = up;
Yaw = yaw;
Pitch = pitch;
updateCameraVectors();
}
// constructor with scalar values
Camera(float posX, float posY, float posZ, float upX, float upY, float upZ,
float yaw, float pitch)
: Front(glm::vec3(0.0f, 0.0f, -1.0f)), MovementSpeed(SPEED),
MouseSensitivity(SENSITIVITY), Zoom(ZOOM) {
Position = glm::vec3(posX, posY, posZ);
WorldUp = glm::vec3(upX, upY, upZ);
Yaw = yaw;
Pitch = pitch;
updateCameraVectors();
}
// returns the view matrix calculated using Euler Angles and the LookAt Matrix
glm::mat4 GetViewMatrix() {
return glm::lookAt(Position, Position + Front, Up);
}
// 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)
void ProcessKeyboard(Camera_Movement direction, float deltaTime) {
float velocity = MovementSpeed * deltaTime;
if (direction == FORWARD)
Position += Front * velocity;
if (direction == BACKWARD)
Position -= Front * velocity;
if (direction == LEFT)
Position -= Right * velocity;
if (direction == RIGHT)
Position += Right * velocity;
}
// processes input received from a mouse input system. Expects the offset
// value in both the x and y direction.
void ProcessMouseMovement(float xpos, float ypos,
GLboolean constrainPitch = true) {
if (firstMouse) {
lastX = xpos;
lastY = ypos;
firstMouse = false;
}
float xoffset = xpos - lastX;
float yoffset = lastY - ypos;
lastX = xpos;
lastY = ypos;
xoffset *= MouseSensitivity;
yoffset *= MouseSensitivity;
Yaw += xoffset;
Pitch += yoffset;
// make sure that when pitch is out of bounds, screen doesn't get flipped
if (constrainPitch) {
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
void ProcessMouseScroll(float yoffset) {
Zoom -= (float)yoffset;
if (Zoom < 1.0f)
Zoom = 1.0f;
if (Zoom > 45.0f)
Zoom = 45.0f;
}
private:
// calculates the front vector from the Camera's (updated) Euler Angles
void updateCameraVectors() {
// 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);
// also re-calculate the Right and Up vector
Right = glm::normalize(glm::cross(
Front, WorldUp)); // normalize the vectors, because their length gets
// closer to 0 the more you look up or down which
// results in slower movement.
Up = glm::normalize(glm::cross(Right, Front));
}
};
#endif