Direct3D HLSL Programming using RenderMonkey IDE

Making Butterly Wings
Iridescent
Iridescence Sample is a view-dependent Scale gradient and map bias based effect gradient on the map computed index to make index
iridescence change quicker across the wings
// Compute index into the iridescence gradient map, which
// consists of N*V coefficient
float fGradientIndex = dot( vNormal, View) *
iridescence_speed_scale + iridescence_speed_bias;
// Load the iridescence value from the gradient map:
float4 iridescence = tex1D( gradientMap, fGradientIndex );
Resulting iridescence image:
Game Developer Conference, San Jose, CA, March 7 th 2003