I'm making a 3D RTS, and I want to see if a tile is in the window or not. I have been told to multiply the MVP matrix by the vector position (im using the center position) of the tiles, and I am to somehow get some value between -1 and 1 to see if it is in view.
I am confused how I get a value like this from a vec4. Also when I multiply by the position, do I just put 0.0 for the w component?
My view frustum is extremely simple. The tiles will always be within the near and far planes, it's always guaranteed a single tile will not fill the screen etc. I'm looking for fast, but asking people and searching google has not yielded a demonstration of the vec4*mat4 approach.
Help is appreciated/