parallax mapping
http://sunandblackcat.com/tipFullView.php?topicid=28
http://www.cnblogs.com/jim-game-dev/p/5410529.html
let’s review the algorithm parallax mapping. in the picture above.
we look at the point T0. we get the view vector V, we extend v to the blue part.
we split the depth from 0.0 to 1.0 to 8 parts. the height between two lines is 0.125.
1. T0D’=0.75 and T0D =0 as 0.75>0 go on.
2. T1C’=0.625 and T1C = 0.125 as 0.625>0.125 go on.
3. T2B’=0.375 and T2B=0.25 as 0.375>0.25 go on
4. T3A’~0.2 and T3A=0.375 as 0.2<0.375 stop.
now we find the T3 is the final result. this is the algorithm says.
we then use the texture coordinate of T3 to sample color for T0.