raylib_camera.rs

use raylib::prelude::*;

pub fn update_camera(rl: &RaylibHandle, camera: &mut Camera3D, mouse_delta: Vector2) {
    let speed = 5.0;
    let sensivity = 0.003;

    {
        // Rotate
        camera.target = (camera.target - camera.position).rotate_by(Quaternion::from_axis_angle(
            camera.up,
            -mouse_delta.x * sensivity,
        )) + camera.position;

        let forward = camera.target - camera.position;
        let right = forward.cross(camera.up);
        let max_angle_up = (-mouse_delta.y * sensivity)
            .min(
                Quaternion::from_vec3_pair(camera.up, forward)
                    .to_axis_angle()
                    .1,
            )
            .max(
                Quaternion::from_vec3_pair(-camera.up, forward)
                    .to_axis_angle()
                    .1
                    * -1.0,
            );
        camera.target =
            forward.rotate_by(Quaternion::from_axis_angle(right, max_angle_up)) + camera.position;
    }

    {
        // Move
        let mut forward = camera.target - camera.position;
        forward.y = 0.0;
        forward.normalize();
        let right = forward.cross(camera.up);

        let mut motion = Vector3::zero();
        motion += forward
            * (rl.is_key_down(KeyboardKey::KEY_W) as i32
                - rl.is_key_down(KeyboardKey::KEY_S) as i32) as f32;
        motion += right
            * (rl.is_key_down(KeyboardKey::KEY_D) as i32
                - rl.is_key_down(KeyboardKey::KEY_A) as i32) as f32;
        motion += camera.up
            * (rl.is_key_down(KeyboardKey::KEY_SPACE) as i32
                - rl.is_key_down(KeyboardKey::KEY_LEFT_SHIFT) as i32) as f32;

        motion *= rl.get_frame_time() * speed;

        camera.position += motion;
        camera.target += motion;
    }
}