blender/intern/cycles/kernel/shaders/stdcycles.h
Mikhail 21bc1a99ba Cycles: optimize ensure_valid_reflection(), reduces render time by about 1%
This is an implementation that is about 1.5-2.1 times faster. It gives a result
that is on average 6° different from the old implementation. The difference is
because normals (Ng, N, N') are not selected to be coplanar, but instead
reflection R is lifted the least amount and the N' is computed as a bisector.

Differential Revision: https://developer.blender.org/D10084
2021-03-15 18:01:57 +01:00

114 lines
5.2 KiB
C

/////////////////////////////////////////////////////////////////////////////
// Copyright (c) 2009-2010 Sony Pictures Imageworks Inc., et al. All Rights Reserved.
//
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// modification, are permitted provided that the following conditions are
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// * Redistributions of source code must retain the above copyright
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// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
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/////////////////////////////////////////////////////////////////////////////
#ifndef CCL_STDCYCLESOSL_H
#define CCL_STDCYCLESOSL_H
#include "stdosl.h"
// Declaration of built-in functions and closures, stdosl.h does not make
// these available so we have to redefine them.
#define BUILTIN [[int builtin = 1]]
#define BUILTIN_DERIV [[ int builtin = 1, int deriv = 1 ]]
closure color diffuse_ramp(normal N, color colors[8]) BUILTIN;
closure color phong_ramp(normal N, float exponent, color colors[8]) BUILTIN;
closure color diffuse_toon(normal N, float size, float smooth) BUILTIN;
closure color glossy_toon(normal N, float size, float smooth) BUILTIN;
closure color microfacet_ggx(normal N, float ag) BUILTIN;
closure color microfacet_ggx_aniso(normal N, vector T, float ax, float ay) BUILTIN;
closure color microfacet_ggx_refraction(normal N, float ag, float eta) BUILTIN;
closure color microfacet_multi_ggx(normal N, float ag, color C) BUILTIN;
closure color microfacet_multi_ggx_aniso(normal N, vector T, float ax, float ay, color C) BUILTIN;
closure color microfacet_multi_ggx_glass(normal N, float ag, float eta, color C) BUILTIN;
closure color microfacet_ggx_fresnel(normal N, float ag, float eta, color C, color Cspec0) BUILTIN;
closure color microfacet_ggx_aniso_fresnel(
normal N, vector T, float ax, float ay, float eta, color C, color Cspec0) BUILTIN;
closure color
microfacet_multi_ggx_fresnel(normal N, float ag, float eta, color C, color Cspec0) BUILTIN;
closure color microfacet_multi_ggx_aniso_fresnel(
normal N, vector T, float ax, float ay, float eta, color C, color Cspec0) BUILTIN;
closure color
microfacet_multi_ggx_glass_fresnel(normal N, float ag, float eta, color C, color Cspec0) BUILTIN;
closure color microfacet_beckmann(normal N, float ab) BUILTIN;
closure color microfacet_beckmann_aniso(normal N, vector T, float ax, float ay) BUILTIN;
closure color microfacet_beckmann_refraction(normal N, float ab, float eta) BUILTIN;
closure color ashikhmin_shirley(normal N, vector T, float ax, float ay) BUILTIN;
closure color ashikhmin_velvet(normal N, float sigma) BUILTIN;
closure color ambient_occlusion() BUILTIN;
closure color principled_diffuse(normal N, float roughness) BUILTIN;
closure color principled_sheen(normal N) BUILTIN;
closure color principled_clearcoat(normal N, float clearcoat, float clearcoat_roughness) BUILTIN;
// BSSRDF
closure color bssrdf(string method, normal N, vector radius, color albedo) BUILTIN;
// Hair
closure color
hair_reflection(normal N, float roughnessu, float roughnessv, vector T, float offset) BUILTIN;
closure color
hair_transmission(normal N, float roughnessu, float roughnessv, vector T, float offset) BUILTIN;
closure color principled_hair(normal N,
color sigma,
float roughnessu,
float roughnessv,
float coat,
float alpha,
float eta) BUILTIN;
// Volume
closure color henyey_greenstein(float g) BUILTIN;
closure color absorption() BUILTIN;
normal ensure_valid_reflection(normal Ng, normal I, normal N)
{
/* The implementation here mirrors the one in kernel_montecarlo.h,
* check there for an explanation of the algorithm. */
vector R;
float NI = dot(N, I);
float NgR, threshold;
if (NI > 0) {
R = (2 * NI) * N - I;
NgR = dot(Ng, R);
threshold = min(0.9 * dot(Ng, I), 0.01);
if (NgR >= threshold) {
return N;
}
}
else {
R = -I;
NgR = dot(Ng, R);
threshold = 0.01;
}
R = R + Ng * (threshold - NgR);
return normalize(I * length(R) + R * length(I));
}
#endif /* CCL_STDOSL_H */