SPHERE Function

Defines a spherical object that can be used by the RENDER function.

Usage

result = SPHERE( )

Parameters

None.

Returned Value

result—A structure that defines an ellipsoidal object.

Keywords

Color—A 256-element double-precision floating-point vector containing the color (intensity) coefficients of the object. (Default: Color(*)=1.0) .

Decal—A 2D array of bytes whose elements correspond to indices into the arrays of material properties. .

Kamb—A 256-element double-precision floating-point vector containing the ambient (flat shaded) coefficients. (Default: Kamb(*)=0.0) .

Kdiff—A 256-element double-precision floating-point vector containing the diffuse reflectance coefficients. (Default: Kdiff(*)=1.0) .

Ktran—A 256-element double-precision floating-point vector containing the specular transmission coefficients. (Default: Ktran(*)=0.0) .

Transform—A 4-by-4 double-precision floating-point array containing the local transformation matrix whose default is the identity matrix. .

Discussion

A SPHERE is used by the RENDER function to render ellipsoid objects, such as for spherical inverse mapping or molecular modeling (atoms). It is centered at the origin, with a radius of 0.5.

You can alter its diameter and orientation with the Transform keyword.

Example

ds = 6

; Create a 6-by-6 checkerboard image.

checks = BYTARR(ds, ds)

checks(*) = 255

FOR x=0L, ds - 1 DO $

   FOR y=0L, ds - 1 DO $

      IF ((x mod 2) EQ (y mod 2)) THEN $

         checks(x, y) = 128

; Set checks to be full and one-half intensity.

two = FLTARR(256)

two(128) = 0.5 & two(255) = 1.0

s = SPHERE(Decal=checks, Color=two)

TV, RENDER(s)