UE4 球面均匀采样原理及代码

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