Displacement shaders: moving surface points
After a surface has been tessellated, its surface points can be moved by a displacement shader.
Displacement along normal, not along normal.
TO DO: figure of 5x4 pt grid similar to figure 8.3 of ARM book.
Recalc normals.
RixDisp() ?
Talk about common trick for adding back smoothness? Also, for some surface types a smooth shading normal will be automatically computed for each ray hit.
Displacement bounds
BVH bbox tightening. Not too large: important for ttfp. Not too small: holes.
TO DO: Figure with holes due to too small displacement bound.Testing