89 lines
3.2 KiB
C++
89 lines
3.2 KiB
C++
// Copyright 2009-2021 Intel Corporation
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// SPDX-License-Identifier: Apache-2.0
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#include "light.h"
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#include <sampling.hpp>
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#include <math/linearspace3.h>
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namespace embree {
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struct DirectionalLight {
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Light super; //!< inherited light fields
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LinearSpace3fa frame; //!< coordinate frame, with vz == direction *towards* the light source
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Vec3fa radiance; //!< RGB color and intensity of light
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float cosAngle;
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//!< Angular limit of the cone light in an easier to use form: cosine of the half angle in radians
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float pdf; //!< Probability to sample a direction to the light
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};
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// for very small cones treat as singular light, because float precision is not good enough
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#define COS_ANGLE_MAX 0.99999988f
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// Implementation
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//////////////////////////////////////////////////////////////////////////////
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Light_SampleRes DirectionalLight_sample(const Light* super,
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const Sample& dg,
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const Vec2f& s) {
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const DirectionalLight* self = (DirectionalLight *) super;
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Light_SampleRes res;
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res.dir = self->frame.vz;
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res.dist = inf;
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res.pdf = self->pdf;
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if (self->cosAngle < COS_ANGLE_MAX)
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res.dir = self->frame * uniformSampleCone(self->cosAngle, s);
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res.weight = self->radiance; // *pdf/pdf cancel
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return res;
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}
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Light_EvalRes DirectionalLight_eval(const Light* super,
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const Sample&,
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const Vec3fa& dir) {
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DirectionalLight* self = (DirectionalLight *) super;
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Light_EvalRes res;
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res.dist = inf;
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if (self->cosAngle < COS_ANGLE_MAX && dot(self->frame.vz, dir) > self->cosAngle) {
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res.value = self->radiance * self->pdf;
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res.pdf = self->pdf;
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} else {
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res.value = Vec3fa(0.f);
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res.pdf = 0.f;
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}
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return res;
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}
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// Exports (called from C++)
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//////////////////////////////////////////////////////////////////////////////
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//! Set the parameters of an ispc-side DirectionalLight object
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extern "C" void DirectionalLight_set(void* super,
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const Vec3fa& direction,
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const Vec3fa& radiance,
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float cosAngle) {
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DirectionalLight* self = (DirectionalLight *) super;
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self->frame = frame(direction);
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self->radiance = radiance;
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self->cosAngle = cosAngle;
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self->pdf = cosAngle < COS_ANGLE_MAX ? uniformSampleConePDF(cosAngle) : inf;
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}
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//! Create an ispc-side DirectionalLight object
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extern "C" void* DirectionalLight_create() {
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DirectionalLight* self = (DirectionalLight *) alignedUSMMalloc(sizeof(DirectionalLight), 16);
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Light_Constructor(&self->super);
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//self->super.sample = GET_FUNCTION_POINTER(DirectionalLight_sample);
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//self->super.eval = GET_FUNCTION_POINTER(DirectionalLight_eval);
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self->super.type = LIGHT_DIRECTIONAL;
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DirectionalLight_set(self, Vec3fa(0.f, 0.f, 1.f), Vec3fa(1.f), 1.f);
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return self;
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}
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} // namespace embree
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