This is a guest post from my friend Łukasz Izdebski Ph.D.
Today I want to share with you a trick which my collage from previews work mentioned to me a long time ago. It's about alpha tested (also known as cutout) materials. This technique which I want to share with you consists of two neat tricks that can improve the quality of alpha tested (cutout) materials.
Alpha test is an old technique used in computer graphics. The idea behind it is very simple. In a very basic form, a material (shader) of a rendered object can discard processed pixels based on the alpha channel of RGBA texture. When shaded pixel’s final alpha value is less than this threshold value (threshold value is constant for the instance of the material and a typical value is 50%), it is clipped (discarded) and will not land in the shaders output framebuffer. These types of materials are commonly used to render vegetation, fences, impostors/billboards, etc.
Alpha tested materials have some, I will say a little issue. It can be noticed when rendered object (with this material) is far away from the camera. Let the following video below be an example of this issue.