Do you mean a bounding rectangle? That exists on a lot of GPUs, where you draw a triangle and the entire bounding box surrounding the triangle is covered. Howev

Do you mean a bounding rectangle? That exists on a lot of GPUs, where you draw a triangle and the entire bounding box surrounding the triangle is covered. However, the details differ greatly between different GPUs, meaning it's hard to standardize. Full-screen triangles are just fine.