The graphics device used to draw the quad.
The destination render target. If undefined, target is the frame buffer.
The shader used for rendering the quad. Vertex shader should contain
attribute vec2 vertex_position.
Optionalrect: Vec4
The viewport rectangle of the quad, in pixels. Defaults to fullscreen:
[0, 0, target.width, target.height].
OptionalscissorRect: Vec4
The scissor rectangle of the quad, in pixels. Defaults to fullscreen:
[0, 0, target.width, target.height].
Draws a screen-space quad using a specific shader.