A WebGPU helper class implementing a viewport clear operation. When rendering to a texture,
the whole surface can be cleared using loadOp, but if only a viewport needs to be cleared, or if
it needs to be cleared later during the rendering, this need to be achieved by rendering a quad.
This class renders a full-screen quad, and expects the viewport / scissor to be set up to clip
it to only required area.
A WebGPU helper class implementing a viewport clear operation. When rendering to a texture, the whole surface can be cleared using loadOp, but if only a viewport needs to be cleared, or if it needs to be cleared later during the rendering, this need to be achieved by rendering a quad. This class renders a full-screen quad, and expects the viewport / scissor to be set up to clip it to only required area.