diff options
| -rw-r--r-- | intern/cycles/kernel/closure/bsdf.h | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/intern/cycles/kernel/closure/bsdf.h b/intern/cycles/kernel/closure/bsdf.h index 5e26f90a878..c83e97d94c2 100644 --- a/intern/cycles/kernel/closure/bsdf.h +++ b/intern/cycles/kernel/closure/bsdf.h @@ -73,6 +73,28 @@ ccl_device_inline float bsdf_get_roughness_squared(const ShaderClosure *sc) return bsdf_get_specular_roughness_squared(sc); } +/* An additional term to smooth illumination on grazing angles when using bump mapping. + * Based on "Taming the Shadow Terminator" by Matt Jen-Yuan Chiang, + * Yining Karl Li and Brent Burley. */ +ccl_device_inline float bump_shadowing_term(float3 Ng, float3 N, float3 I) +{ + float g = safe_divide(dot(Ng, I), dot(N, I) * dot(Ng, N)); + + /* If the incoming light is on the unshadowed side, return full brightness. */ + if (g >= 1.0f) { + return 1.0f; + } + + /* If the incoming light points away from the surface, return black. */ + if (g < 0.0f) { + return 0.0f; + } + + /* Return smoothed value to avoid discontinuity at perpendicular angle. */ + float g2 = sqr(g); + return -g2 * g + g2 + g; +} + ccl_device_inline int bsdf_sample(KernelGlobals *kg, ShaderData *sd, const ShaderClosure *sc, @@ -424,6 +446,11 @@ ccl_device_inline int bsdf_sample(KernelGlobals *kg, } } } + else if (label & LABEL_DIFFUSE) { + if (sc->N != sd->N) { + *eval *= bump_shadowing_term((label & LABEL_TRANSMIT) ? -sd->N : sd->N, sc->N, *omega_in); + } + } return label; } @@ -535,6 +562,9 @@ ccl_device_inline eval = make_float3(0.0f, 0.0f, 0.0f); break; } + if (CLOSURE_IS_BSDF_DIFFUSE(sc->type)) { + eval *= bump_shadowing_term(sd->N, sc->N, omega_in); + } } else { switch (sc->type) { @@ -621,6 +651,9 @@ ccl_device_inline eval = make_float3(0.0f, 0.0f, 0.0f); break; } + if (CLOSURE_IS_BSDF_DIFFUSE(sc->type)) { + eval *= bump_shadowing_term(-sd->N, sc->N, omega_in); + } } return eval; |