PCSX2's Hardware Renderer has gained support for AA1!

AA1 is the PS2's name for antialiasing, which works by adding partially transparent pixels to the edges of lines and triangles to give a softer edge.

AA1 was originally been implemented in SW renderer for a while (this just adds it to HW).

It is implemented by using the vertex shader to generate new polygons for the edge pixels of lines/triangles.

Do note that enabling AA1 may significantly increase system requirements!