ai_shader_closure.h

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// Copyright 2021 Autodesk, Inc.  All rights reserved.
//
// Use of this software is subject to the terms of the Autodesk license
// agreement provided at the time of installation or download, or which
// otherwise accompanies this software in either electronic or hard copy form.
 
#pragma once
#include "ai_closure.h"
#include "ai_color.h"
#include "ai_shaderglobals.h"
 
/* BSSRDF random walk versions */
enum class AtRandomWalkVersion
{
   // This is a brute-force Monte Carlo random walk approach to subsurface scattering
   // that produces estimates from a series of simulated interior scattering events.
   v1 = 1,
 
   // This is an improved version of the brute-force Monte Carlo v1, that
   // suffers from less brightening and desaturation at corners. Please note that
   // this change causes light to penetrate more deeply at grazing angles, which
   // can cause an increase in noise and scattering distance.
   v2,
 
   // This version of the random walk SSS was designed for OpenPBR.
   v3
};
 
/* BSSRDF Closures */
AI_API AI_DEVICE AtClosure AiClosureEmpiricalBSSRDF(const AtShaderGlobals* sg, const AtRGB& weight, const AtVector& mfp, const AtRGB& albedo);
 
AI_API AI_DEVICE AtClosure AiClosureRandomWalkBSSRDF(const AtShaderGlobals* sg, const AtRandomWalkVersion& version,
                                                     const AtRGB& weight, const AtVector& mfp, const AtRGB& albedo, float g = 0.0f);
 
AI_API AI_DEVICE void AiClosureBSSRDFSetDirectIndirect(AtClosure closure, float weight_direct, float weight_indirect);
 
/* Emission Closures */
AI_API AI_DEVICE AtClosure AiClosureEmission(const AtShaderGlobals* sg, const AtRGB& weight);
 
 
/* Transparency & Matte Closures */
AI_API AI_DEVICE AtClosure AiClosureTransparent(const AtShaderGlobals* sg, const AtRGB& weight = AI_RGB_WHITE,
                                                const AtClosureList interior_volume = nullptr,
                                                int32_t dielectric_importance = 0,
                                                float dielectric_roughness = 0,
                                                float dielectric_eta = 1,
                                                float transmission_shadow_density = 0.5f);
 
AI_API AI_DEVICE AtClosure AiClosureMatte(const AtShaderGlobals* sg, const AtRGB& weight = AI_RGB_WHITE);
 
/* Background Closure */
AI_API AtClosure AiClosureBackground(const AtShaderGlobals* sg, const AtRGB& weight = AI_RGB_WHITE);
 
/* Volume Closures */
AI_API AI_DEVICE AtClosure AiClosureVolumeAbsorption(const AtShaderGlobals* sg, const AtRGB& weight);
AI_API AI_DEVICE AtClosure AiClosureVolumeEmission(const AtShaderGlobals* sg, const AtRGB& weight);
AI_API AI_DEVICE AtClosure AiClosureVolumeHenyeyGreenstein(const AtShaderGlobals* sg, const AtRGB& absorption, const AtRGB& scattering, const AtRGB& emission, float g = 0.f);
AI_API AI_DEVICE AtClosure AiClosureVolumeDoubleHenyeyGreenstein(const AtShaderGlobals* sg, const AtRGB& absorption, const AtRGB& scattering, const AtRGB& emission, float g = 0.f, float g2=0.f, float w2=0.f);
 
AI_API AI_DEVICE AtClosure AiClosureVolumeMatte(const AtShaderGlobals* sg, const AtRGB& weight);
AI_API AI_DEVICE AtClosure AiClosureVolumeAtmosphere(const AtShaderGlobals* sg, const AtRGB& emission, const AtRGB& transparent, const AtRGB& matte);
 
/*\}*/