5.1.13 Height-Field

The syntax of a height field object is:

HEIGHT_FIELD:
  height_field { HF_IMAGE [HF_MODIFIERS] }

HF_IMAGE:
  FUNCTION_IMAGE | [HF_TYPE] FILE_NAME

HF_TYPE:
  gif | tga | pot | png | pgm | ppm | jpeg | tiff | sys

HF_MODIFIERS:
  [hierarchy [BOOL]] & [smooth [BOOL]] & [water_level FLOAT] 
    & [OBJECT_MODIFIERS]

See also:

• [pov:6.5.1.5]Height Field
• [pov:3.6.2]Height Field Object
• www.f-lohmueller.de/.../povheigh1e.htm

This is given by the set of points $\langle X,Y,Z\rangle$ with $0\leq X\leq 1$ and $0\leq Z\leq 1$, where $Y$ is at most the value of the (interpolate) pixel in the given image of dimension $\operatorname{WIDTH}*\operatorname{HEIGHT}$ at the scaled point in column $X*\operatorname{WIDTH}$ and row $Y*\operatorname{HEIGHT}$.