Hello! I have a quaternion that stores the orientation of my camera and what I would like to do is set the pitch, yaw and roll of the quaternion relative to the world.
What I mean my that is imagine 4 walls around you with an arrow on each wall pointing to the world up. What I want to do is no matter what the pitch, yaw and roll of the quaternion, if I'm looking at any of the arrows (any yaw) but with a little roll (so the arrow will point anywhere but up). If I use the setRoll function and pass 0*, the camera should see the arrow pointing up. If I pass 90* to the setRoll function, no matter how many times I call the function it should set the camera's rotation to 90* so the arrow will point to the left.
Here is my full camera class below. The only code that really matters are the setPitch, setYaw and setRoll functions.
Camera.hpp
#ifndef CAMERA_HPP
#define CAMERA_HPP
// GLAD
#include <glad/glad.h>
// GLM
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include <glm/gtc/quaternion.hpp>
class QuaternionCamera
{
public:
QuaternionCamera(glm::vec3 position, float zNear, float zFar);
QuaternionCamera(glm::vec3 position, glm::quat orientation, float zNear, float zFar);
QuaternionCamera(glm::vec3 position, glm::vec3 orientation, float zNear, float zFar);
// Set the position in world coords
void setPosition(glm::vec3 position);
// Set the orientation relative to the world
void setOrientation(glm::quat orientation);
// Set the orientation relative to the world
void setOrientation(glm::vec3 orientation);
// Set the pitch relative to the world
void setPitch(float amount);
// Set the yaw relative to the world
void setYaw(float amount);
// Set the roll relative to the world
void setRoll(float amount);
// Set the camera's near plane
void setZNear(float zNear);
// Set the camera's far plane
void setZFar(float zFar);
// Move the camera relative to it's current location
void move(glm::vec3 movement);
// Move the camera relative to it's current location on the world axis
void moveAxis(glm::vec3 translation);
// Rotate the camera relative to it's current location
void rotate(glm::quat rotation);
// Rotate the camera relative to it's current location
void rotate(glm::vec3 rotation);
// Pitch the camera relative to it's current location
void pitch(float amount);
// Yaw the camera relative to it's current location
void yaw(float amount);
// Roll the camera relative to it's current location
void roll(float amount);
// Get the camera's position in world coords
glm::vec3 getPosition() const;
// Get the camera's direction relative to the world
glm::vec3 getDirection() const;
// Get the camera's right vector
glm::vec3 getRight() const;
// Get the camera's up vector
glm::vec3 getUp() const;
// Get the camera's rotation relative to the world
glm::quat getOrientation() const;
// Get the camera's near plane
float getZNear() const;
// Get the camera's far plane
float getZFar() const;
// Get the camera's view matrix
glm::mat4 getViewMatrix() const;
// Get the camera's projection matrix
glm::mat4 getProjectionMatrix() const;
// Get the camera's view projection matrix
glm::mat4 getViewProjectionMatrix() const;
protected:
// updateProjectionMatrix is virtual because it will be defined in the two derived camera classes.
// This is because the camera class does not know if we want a perspective or orthographic viewport.
// So because the viewport is defined in a derived class, and because we change the projection matrix
// in the base camera class (zNear and zFar), we need a way to get an updated projection matrix!
virtual void updateProjectionMatrix() = 0;
void updateViewProjectionMatrix();
float zNear;
float zFar;
glm::mat4 projectionMatrix;
glm::mat4 viewProjectionMatrix;
private:
void updateCameraVectors();
void updateViewMatrix();
glm::mat4 viewMatrix;
glm::vec3 position;
glm::quat orientation;
glm::vec3 direction; // Camera Direction / Camera View Facing
glm::vec3 right;
glm::vec3 up;
};
#endif
Camera.cpp
QuaternionCamera::QuaternionCamera(glm::vec3 position, float zNear, float zFar)
{
this->position = position;
this->orientation = glm::quat(1.0f, 0.0f, 0.0f, 0.0f); // glm::quat constructor is (w, x, y, z) but it is stored as (x, y, z, w)
right = glm::vec3( 1, 0, 0);
up = glm::vec3( 0, 1, 0);
direction = glm::vec3( 0, 0, -1);
this->zNear = zNear;
this->zFar = zFar;
updateViewMatrix();
updateViewProjectionMatrix();
}
QuaternionCamera::QuaternionCamera(glm::vec3 position, glm::quat orientation, float zNear, float zFar)
{
this->position = position;
this->orientation = orientation;
right = glm::vec3( 1, 0, 0);
up = glm::vec3( 0, 1, 0);
direction = glm::vec3( 0, 0, -1);
this->zNear = zNear;
this->zFar = zFar;
updateViewMatrix();
updateViewProjectionMatrix();
}
QuaternionCamera::QuaternionCamera(glm::vec3 position, glm::vec3 orientation, float zNear, float zFar)
{
this->position = position;
this->orientation = glm::quat(glm::vec3(glm::radians(orientation.x), glm::radians(orientation.y), glm::radians(orientation.z)));
right = glm::vec3( 1, 0, 0);
up = glm::vec3( 0, 1, 0);
direction = glm::vec3( 0, 0, -1);
this->zNear = zNear;
this->zFar = zFar;
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::setPosition(glm::vec3 position)
{
this->position = position;
}
void QuaternionCamera::setOrientation(glm::quat orientation)
{
this->orientation = orientation;
}
void QuaternionCamera::setOrientation(glm::vec3 orientation)
{
glm::quat orientationQuat = glm::quat(orientation);
this->orientation = orientationQuat;
}
void QuaternionCamera::setPitch(float amount)
{
// TODO:
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::setYaw(float amount)
{
// TODO:
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::setRoll(float amount)
{
// TODO:
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::setZNear(float zNear)
{
this->zNear = zNear;
updateProjectionMatrix();
}
void QuaternionCamera::setZFar(float zFar)
{
this->zFar = zFar;
updateProjectionMatrix();
}
void QuaternionCamera::move(glm::vec3 movement)
{
position += (orientation * glm::vec3(1, 0, 0)) * movement.x + (orientation * glm::vec3(0, 1, 0)) * movement.y + (orientation * glm::vec3(0, 0, -1)) * movement.z;
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::moveAxis(glm::vec3 translation)
{
position += translation;
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::rotate(glm::quat rotation)
{
orientation *= rotation;
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::rotate(glm::vec3 rotation)
{
glm::quat rotationQuat = glm::quat(rotation);
orientation *= rotationQuat;
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::pitch(float amount)
{
glm::quat rotation = glm::angleAxis(glm::radians(amount), glm::vec3(1, 0, 0));
orientation *= rotation;
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::yaw(float amount)
{
glm::quat rotation = glm::angleAxis(glm::radians(-amount), glm::vec3(0, 1, 0));
orientation *= rotation;
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
void QuaternionCamera::roll(float amount)
{
glm::quat rotation = glm::angleAxis(glm::radians(amount), glm::vec3(0, 0, -1));
orientation *= rotation;
updateCameraVectors();
updateViewMatrix();
updateViewProjectionMatrix();
}
glm::vec3 QuaternionCamera::getPosition() const
{
return position;
}
glm::vec3 QuaternionCamera::getDirection() const
{
return direction;
}
glm::vec3 QuaternionCamera::getRight() const
{
return right;
}
glm::vec3 QuaternionCamera::getUp() const
{
return up;
}
glm::quat QuaternionCamera::getOrientation() const
{
return orientation;
}
float QuaternionCamera::getZNear() const
{
return zNear;
}
float QuaternionCamera::getZFar() const
{
return zFar;
}
glm::mat4 QuaternionCamera::getViewMatrix() const
{
return viewMatrix;
}
glm::mat4 QuaternionCamera::getProjectionMatrix() const
{
return projectionMatrix;
}
glm::mat4 QuaternionCamera::getViewProjectionMatrix() const
{
return viewProjectionMatrix;
}
void QuaternionCamera::updateViewProjectionMatrix()
{
viewProjectionMatrix = getProjectionMatrix() * getViewMatrix();
}
void QuaternionCamera::updateCameraVectors()
{
right = glm::normalize(orientation * glm::vec3(1, 0, 0));
up = glm::normalize(orientation * glm::vec3(0, 1, 0));
direction = glm::normalize(orientation * glm::vec3(0, 0, -1));
if (glm::dot(up, glm::cross(right, direction)) < 0)
{
up *= -1;
}
}
void QuaternionCamera::updateViewMatrix()
{
viewMatrix = glm::lookAt(position, position + direction, up/*glm::cross(right, direction)*/);
}
PerspectiveCamera::PerspectiveCamera(glm::vec3 position, float fov, float aspectRatio, float zNear, float zFar) : QuaternionCamera(position, zNear, zFar)
{
this->fov = fov;
this->aspectRatio = aspectRatio;
updateProjectionMatrix();
}
PerspectiveCamera::PerspectiveCamera(glm::vec3 position, glm::quat rotation, float fov, float aspectRatio, float zNear, float zFar) : QuaternionCamera(position, rotation, zNear, zFar)
{
this->fov = fov;
this->aspectRatio = aspectRatio;
updateProjectionMatrix();
}
PerspectiveCamera::PerspectiveCamera(glm::vec3 position, glm::vec3 rotation, float fov, float aspectRatio, float zNear, float zFar) : QuaternionCamera(position, rotation, zNear, zFar)
{
this->fov = fov;
this->aspectRatio = aspectRatio;
updateProjectionMatrix();
}
void PerspectiveCamera::setFOV(float fov)
{
this->fov = fov;
updateProjectionMatrix();
}
void PerspectiveCamera::setAspectRatio(float aspectRatio)
{
this->aspectRatio = aspectRatio;
updateProjectionMatrix();
}
void PerspectiveCamera::setAspectRatio(float width, float height)
{
this->aspectRatio = height / width;
updateProjectionMatrix();
}
float PerspectiveCamera::getFOV() const
{
return fov;
}
float PerspectiveCamera::getAspectRatio() const
{
return aspectRatio;
}
void PerspectiveCamera::updateProjectionMatrix()
{
projectionMatrix = glm::perspective(glm::radians(fov), aspectRatio, zNear, zFar);
}
In general, changing the pitch, yaw, or roll will change all the components of a quaternion. So I would just transform the quaternion into euler angles, set the appropriate angle, and transform that back into the quaternion. Something like this:
glm::vec3 eulerAngles = glm::eulerAngles(orientation);
eulerAngles.x = amount; // .y for yaw, .z for roll
orientation = glm::quat(eulerAngles);