MonteCarlo.ush
float4 UniformSampleSphere( float2 E )
{
float Phi = 2 * PI * E.x;
float CosTheta = 1 - 2 * E.y;
float SinTheta = sqrt( 1 - CosTheta * CosTheta );
float3 H;
H.x = SinTheta * cos( Phi );
H.y = SinTheta * sin( Phi );
H.z = CosTheta;
float PDF = 1.0 / (4 * PI);
return float4( H, PDF );
}
图片转自:均匀采样球 ue4 - 知乎