ive used the picking UV method before
Slow depends on how you use it. if you have 200 characters to pick every frame.. yeah. But you can even get clever on that and pick one character per frame, and you shouldnt be able to notice any latency in shading. Or you may just update characters in view, or within a given range to camera ect. cycling them one char per frame.
If you wanted to take the time to make a hybrid of an array and UV picking minus the readpixel you would have the best of speed and accuracy. Just make your array the same size as your lightmap (this is IF you have one world lightmap)
Slow depends on how you use it. if you have 200 characters to pick every frame.. yeah. But you can even get clever on that and pick one character per frame, and you shouldnt be able to notice any latency in shading. Or you may just update characters in view, or within a given range to camera ect. cycling them one char per frame.
If you wanted to take the time to make a hybrid of an array and UV picking minus the readpixel you would have the best of speed and accuracy. Just make your array the same size as your lightmap (this is IF you have one world lightmap)