pub struct Camera {
    pub eye: cgmath::Point3<f32>,
    pub target: cgmath::Point3<f32>,
    pub up: cgmath::Vector3<f32>,
    pub aspect: f32,
    pub fovy: f32,
    pub znear: f32,
    pub zfar: f32,
}

impl Camera {
    fn build_view_projection_matrix(&self) -> cgmath::Matrix4<f32> {
        let view = cgmath::Matrix4::look_at_rh(self.eye, self.target, self.up);

        let proj = cgmath::perspective(cgmath::Deg(self.fovy), self.aspect, self.znear, self.zfar);

        OPENGL_TO_WGPU_MATRIX * proj * view
    }

    pub fn update_aspect(&mut self, aspect: f32) {
        self.aspect = aspect;
    }
}

pub const OPENGL_TO_WGPU_MATRIX: cgmath::Matrix4<f32> = cgmath::Matrix4::new(
    1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.5, 0.5, 0.0, 0.0, 0.0, 1.0,
);

unsafe impl bytemuck::Pod for CameraUniform {}
unsafe impl bytemuck::Zeroable for CameraUniform {}

#[repr(C)]
#[derive(Debug, Copy, Clone)]
pub struct CameraUniform {
    view_proj: cgmath::Matrix4<f32>,
}
impl Default for CameraUniform {
    fn default() -> CameraUniform {
        use cgmath::SquareMatrix;
        Self {
            view_proj: cgmath::Matrix4::identity(),
        }
    }
}
impl CameraUniform {
    pub fn update_view_proj(&mut self, camera: &Camera) {
        self.view_proj = camera.build_view_projection_matrix();
    }
}