Unity Mouse Input without Ray/Raycast and Colliders

Question

First of all thank you for your time. I'm quite new in this so I'm struggling a bit. I'm trying to make a drag and release shooter which doesn't really depend on colliders or raycasts but solely depends on mouse delta and camera position. The way I'm trying to have it done is I'm mapping mouse position (x,y) to velocity direction such as new Vector3(mouseX, 0f, mouseY) then rotating it about Y axis to match the visual drag on the screen.

    void OnMouseUp()
{
    releasePos = Input.mousePosition;
    Vector2 m_direction = releasePos - initialPos;
    Vector3 direction = new Vector3(m_direction.x, 0, m_direction.y);
    float userDrag = Mathf.Clamp(direction.magnitude, 0f, maxVelocity);
    direction = Translation(direction);
    direction = Vector3.Normalize(direction);
    rigidbody.velocity = (direction * userDrag) * force;
}

private Vector3 Translation(Vector3 direction)
{
    Vector3 camPos = Camera.main.transform.position;
    camPos.y = 0;
    float angle = Vector3.Angle(new Vector3(0f, 0f, 1f), camPos);
    Quaternion translatedAngle = Quaternion.AngleAxis(angle, Vector3.up);
    direction = translatedAngle * direction;

But as the angle changes it kinda fails to deliver what I'm asking for. Is there a way I can avoid bunch of if, else statements for the angle value or a shorter way of doing this?

Example

Answer 1

OnMouseUp is fundamentally a collider method.

Meaning, the mouse MUST be over the GameObject's collider for the GameObject this code is attached to. If you want to move away from using colliders, then you need to move away from this method.

The generic works-anywhere way of saying "is the mouse button up or down?" is the static methods available in the Input class:

• Input.GetMouseButtonDown() True on the single frame after the mouse button is depressed
• Input.GetMouseButtonUp() True on the single frame after the mouse button is released
• Input.GetMouseButton() True any frame the mouse button is depressed (otherwise false)