// camera view matrix
void Library::Camera::CalculateVeiw()
{
    DirectX::XMVECTOR R = DirectX::XMLoadFloat3(&m_right);
    DirectX::XMVECTOR U = DirectX::XMLoadFloat3(&m_up);
    DirectX::XMVECTOR L = DirectX::XMLoadFloat3(&m_look);
    DirectX::XMVECTOR P = DirectX::XMLoadFloat3(&m_position);

    // Keep camera's axes orthogonal to each other and of unit length.
    L = DirectX::XMVector3Normalize(L);
    U = DirectX::XMVector3Normalize(DirectX::XMVector3Cross(L, R));

    // U, L already ortho-normal, so no need to normalize cross product.
    R = DirectX::XMVector3Cross(U, L);

    DirectX::XMMATRIX V = DirectX::XMMatrixLookToRH(P, L, U);
    DirectX::XMStoreFloat4x4(&m_view, V);

    DirectX::XMStoreFloat3(&m_position, P);
    DirectX::XMStoreFloat3(&m_up, U);
    DirectX::XMStoreFloat3(&m_look, L);
    DirectX::XMStoreFloat3(&m_right, R);
}


// light view matrix
void ShadowMap::SetLightSource(const LightSource * light)
{
    for (unsigned int i = 0; i < MAX_LIGHT_SOURCES; i++)
    {
        if (!light[i].Type)
            continue;

        m_lightSource[i] = light[i];

        DirectX::XMVECTOR pos;
        DirectX::XMVECTOR dir = DirectX::XMVector4Normalize((DirectX::XMLoadFloat4(&(m_lightSource[i].LightDir))));
        pos = DirectX::XMLoadFloat4(&(m_lightSource[i].LightPos));

        DirectX::XMMATRIX V = DirectX::XMMatrixLookToRH(pos, dir, DirectX::XMVectorSet(0.0f, 1.0f, 0.0f, 0.f));
        DirectX::XMStoreFloat4x4(&(m_lightView[i]), V);
    }
}