AllFrequency Precomputed Radiance Transfer for Glossy Objects

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All-Frequency Precomputed Radiance Transfer for
Glossy Objects interactive rendering of shadows,
both sharp and soft, on non-diffuse objects
Xinguo Liu, MSRA Peter-Pike Sloan, DirectX Harry
Shum, MSRA John Snyder MSR
all-frequency, diffuse lighting6x32x32 env.
map transfer1x6144 matrix
all-frequency, glossy lighting6x32x32 env.
map transfer10x6144 matrix
low-frequency, glossy lighting5th order
spherical harmonics (25 coefs) transfer25x25
matrix
PRT Formulation L lighting coefficients
Mp transfer matrix (p surface point)
G(v) view map (v view vector) good accuracy
with m10 10D vector G(v) and 10 rows in matrix
Mp uses BRDF factorization
original
m5, error10
m10, error2.1
PRT Clustering/Compression divide lighting env.
into 16x16 segments use Clustered Principal
Component Analysis on 24 segments (each
2560D) like Vector Quantization but uses a linear
subspace (16D) in each cluster
lighting segment 1
lighting segment 2
lighting segment 3