Spherize hydra
From Adobe Labs
[edit]
Spherize source code
/*****************************************************************************
*
* Author: Joa Ebert
* http://blog.je2050.de
* Contact: j -at- je2050.de
*
*****************************************************************************/
kernel Spherize
<
nameSpace: "popforge::ImageProcessing";
vendor: "Joa Ebert";
version: 1;
description: "Applies spherical displacement map to an image.";
>
{
parameter float refractionIndex
<
minValue: 0.0;
maxValue: 1.0;
defaultValue: 1.0 / 1.8;
description: "Refraction index of the sphere.";
>;
parameter float radius
<
minValue: 1.0;
maxValue: 2880.0;
defaultValue: 64.0;
description: "Radius of the sphere.";
>;
parameter float2 center
<
minValue: float2(0.0);
maxValue: float2(2880.0);
defaultValue: float2(200.0);
description: "Center of the sphere.";
>;
void evaluatePixel(in image4 source, out pixel4 result)
{
float2 coord = outCoord();
float2 dist = coord - center;
float radius2 = radius * radius;
float r2 = dist.x * dist.x + dist.y * dist.y; //maybe there is a function for this? remember its not |dist|
// check if we actually want to displace or not
if ( r2 > 0.0 && r2 < radius2 )
{
// distance from radius
float z2 = radius2 - r2;
float z = sqrt(z2);
// refraction
float xa = asin( dist.x / sqrt( dist.x * dist.x + z2 ) );
float xb = xa - xa * refractionIndex;
float ya = asin( dist.y / sqrt( dist.y * dist.y + z2 ) );
float yb = ya - ya * refractionIndex;
// displace by refraction
coord.x -= z * tan( xb );
coord.y -= z * tan( yb );
}
// sample with interpolation
result = sampleLinear(source,coord);
}
}
