This is essentially just the original Minimal D3D11 codebase with 8x MSAA added. However, since MSAA only smooths triangle edges and does not affect textured surface interiors, texturing is removed to isolate and make the effect of MSAA clearer.
In short there are two parts to it: 1) Create and render to an MSAA texture rather than your typical rendertarget/framebuffer (note: the depth buffer must match), and 2) [Resolve](https://gist.github.com/d7samurai/d74299f8bcadcb9cb0686
Basic setup for rendering a fullscreen triangle - as opposed to a fullscreen quad. This is a triangle that extends past the screen boundaries so that it covers it all, with the excess getting clipped away. The use case for this is typically doing a full screen pass for composition or post processing effects etc (though nowadays you might go for a compute shader instead).
Generally a triangle is preferred over a quad because the geometry is simpler (fewer vertices / shader invocations) and it eliminates the quad’s internal diagonal split. Since pixel shading runs in 2×2 pixel units (incidentally also referred to as "quads"), units that straddle the diagonal will do redundant work on pixels that gets masked out and discarded; both triangles pay this cost along the split, each discarding work tha
