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// Copyright 2009 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
#pragma once
#include "DGEnum.h"
#include "rkcommon/math/vec.ih"
OSPRAY_BEGIN_ISPC_NAMESPACE
struct Material;
struct Renderer;
/* differential geometry information that gives more detailed
information on the actual geometry that a ray has hit */
struct DifferentialGeometry
{
vec3f P; // world space location of the hit-point, includes epsilon offset
// towards front side
vec3f lP; // local instance space location of the hit-point
vec3f Ng; // geometry normal if DG_NG was set, possibly not
// normalized/facefordwarded if DG_NORMALIZE and/or DG_FACEFORWARD
// weren't specified
vec3f Ns; // shading normal if DG_NS was set, possibly not
// normalized/facefordwarded if DG_NORMALIZE and/or DG_FACEFORWARD
// weren't specified
vec3f dPds; // tangent, the partial derivative of the hit-point wrt. tc s
vec3f dPdt; // bi-tangent, the partial derivative of the hit-point wrt. tc t
vec2f st; // texture coordinates if DG_TEXCOORD was set
vec4f color; // interpolated vertex color (rgba) if DG_COLOR was set; defaults
// to vec4f(1.f) if queried but not present in geometry
int32 primID; // hit primitive (-1 if no hit), e.g. for Ptex
float areaPDF; // for geometryLights
float epsilon; // adaptive epsilon, isotropic in object-space
Material *material; // pointer to hit-point's material
const Renderer *uniform renderer; // pointer to renderer being used
unsigned int objID; // user definable model id (0xffff none)
unsigned int instID; // user definable instance id (0xffff none)
float pixelFootprint; // 1:1 mapping between pixels and texels
};
// assumed precision of intersection routines
#define ulpEpsilon 0x1.0fp-21f
inline float calcEpsilon(const vec3f &P, float t)
{
return reduce_max(make_vec4f(abs(P), t)) * ulpEpsilon;
}
inline float calcEpsilon(const vec3f &P, const vec3f &dir, float t)
{
// convert ray-space t to object-/world-space using max(dir) instead of
// costly length; the error is at most sqrt(3)~1.7, quite acceptable for eps
return calcEpsilon(P, reduce_max(abs(dir)) * t);
}
OSPRAY_END_ISPC_NAMESPACE
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