//Author : Vrej Melkonian
//Date : Friday, June 25, 2004
//
//Fragment Shader, GLSL 1.00
//Derived from ARBfp1.0 with filename f_depthmap.txt
//

//The Render Target should be a floating point texture
void main()
{
//Calculate depth
vec4 len;
len.x = dot ( gl_TexCoord [0], gl_TexCoord [0]);
len = vec4 (len.x, len.x, len.x, len.x);

len.w = inversesqrt (len.w);
len *= len.w;

//The range of len is not limited to [0..1]
//We need floating point Render Target!!!
gl_FragColor = len;
}