// Null Hole

StarBarycenter "Null Hole bc"
{
    RA    0 21 38.47
    Dec    -70 53 10
    Dist    3999.99
}

// Null Hole

Star    "Null Hole A"
{
    ParentBody     "Null Hole bc"
    Class        "X"
    MassSol         2.1

    Orbit
    {
  Period          1.9012852688417e-007
  Eccentricity    0
  Inclination     90
  AscendingNode   0
  ArgOfPericenter 90
  MeanAnomaly     0
  RefPlane       "Ecliptic"
    }
}

Star    "Null Hole B"
{
    ParentBody     "Null Hole bc"
    Class        "X"
    Radius        1
    
    Orbit
    {
  Period          1.9012852688417e-007
  Eccentricity    0
  Inclination     90
  AscendingNode   0
  ArgOfPericenter 0
  MeanAnomaly     0
  RefPlane       "Ecliptic"
    }
}

#version 330 core
#auto_defines

uniform sampler2D   Scene;
uniform vec4        PosScale;   // (BH x, BH y, BH scale x, BH scale y)
uniform vec3        RadDist;    // (BH radius, distance, 2*radius/distance)

#ifdef _VERTEX_

layout(location = 0) in  vec4  VertexPos;
layout(location = 1) in  vec4  VertexTexCoord;
                     out vec2  TexCoord;

void main()
{
    gl_Position = VertexPos;
    TexCoord = VertexTexCoord.xy;
}

#else

                     in  vec2  TexCoord;
layout(location = 0) out vec4  OutColor;

void main()
{
    vec2  texCoord = TexCoord - PosScale.xy;
    float rad = length(texCoord * PosScale.zw);

    if (RadDist.x > 1.0)   // normal black hole
    {
  float distort = max(RadDist.z / (rad * rad), 0.0);
  texCoord = texCoord * (1.0 - distort) + PosScale.xy;
  //texCoord = clamp(texCoord, 0.0, 1.0);
  OutColor = texture(Scene, texCoord);
  OutColor *= clamp((rad * RadDist.y - RadDist.x) / RadDist.x * 100.0, 0.0, 1.0); // antialiased event horizon
    }
    else    // black hole <= (Radius = 1.0)
    {
  float distort = max(RadDist.z / (rad * rad), 0.0);
  texCoord = texCoord * (1.0 + distort) + PosScale.xy;
  //texCoord = clamp(texCoord, 0.0, 1.0);
  OutColor = texture(Scene, texCoord);
  OutColor *= clamp((rad * RadDist.y - RadDist.x) / RadDist.x * 100.0, 1.0, 1.0); // antialiased event horizon
    }
    //if (rad * RadDist.y < sqrt(RadDist.z) * RadDist.y) OutColor.g += 0.2; // check Einstein's radius
}

#endif