I've been trying to implement percentage closer filtering for my shadow mapping as described here Nvidia GPU Gems
When I try to sample my shadow map using a uniform sampler2DShadow and shadow2D or shadow2DProj the GLSL compile fails and gives me the error
shadow2D deprecated after version 120
How would I go about implementing an equivalent solution in GLSL 330+? I'm currently just using a binary texture sample along with Poisson Sampling but the staircase aliasing is pretty bad.