OpenGL 4 Shading Language Cookbook - Third Edition

How it works...

The findOffset function determines the texture coordinate to use when shading. We pass in the vector toward the viewer (we negate the direction to move away from the eye), and the function returns the texture coordinate. It also returns the value of the height at that location via the output parameter height. The first line determines the number of discrete height levels (nSteps). We pick a number between 10 and 60 by interpolating using the value of the z coordinate of the view vector. If the z coordinate is small, then the view vector is close to vertical with respect to the height levels. When the view vector is close to vertical, we can use fewer steps because the ray travels a shorter relative horizontal distance between ...