130 lines
4.0 KiB
C++
130 lines
4.0 KiB
C++
/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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//! \file
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#ifndef TNT_FILAMENT_EXPOSURE_H
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#define TNT_FILAMENT_EXPOSURE_H
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#include <utils/compiler.h>
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namespace filament {
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class Camera;
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/**
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* A series of utilities to compute exposure, exposure value at ISO 100 (EV100),
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* luminance and illuminance using a physically-based camera model.
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*/
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namespace Exposure {
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/**
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* Returns the exposure value (EV at ISO 100) of the specified camera.
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*/
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UTILS_PUBLIC
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float ev100(const Camera& camera) noexcept;
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/**
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* Returns the exposure value (EV at ISO 100) of the specified exposure parameters.
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*/
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UTILS_PUBLIC
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float ev100(float aperture, float shutterSpeed, float sensitivity) noexcept;
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/**
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* Returns the exposure value (EV at ISO 100) for the given average luminance (in @f$ \frac{cd}{m^2} @f$).
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*/
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UTILS_PUBLIC
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float ev100FromLuminance(float luminance) noexcept;
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/**
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* Returns the exposure value (EV at ISO 100) for the given illuminance (in lux).
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*/
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UTILS_PUBLIC
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float ev100FromIlluminance(float illuminance) noexcept;
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/**
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* Returns the photometric exposure for the specified camera.
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*/
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UTILS_PUBLIC
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float exposure(const Camera& camera) noexcept;
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/**
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* Returns the photometric exposure for the specified exposure parameters.
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* This function is equivalent to calling `exposure(ev100(aperture, shutterSpeed, sensitivity))`
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* but is slightly faster and offers higher precision.
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*/
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UTILS_PUBLIC
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float exposure(float aperture, float shutterSpeed, float sensitivity) noexcept;
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/**
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* Returns the photometric exposure for the given EV100.
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*/
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UTILS_PUBLIC
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float exposure(float ev100) noexcept;
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/**
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* Returns the incident luminance in @f$ \frac{cd}{m^2} @f$ for the specified camera acting as a spot meter.
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*/
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UTILS_PUBLIC
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float luminance(const Camera& camera) noexcept;
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/**
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* Returns the incident luminance in @f$ \frac{cd}{m^2} @f$ for the specified exposure parameters of
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* a camera acting as a spot meter.
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* This function is equivalent to calling `luminance(ev100(aperture, shutterSpeed, sensitivity))`
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* but is slightly faster and offers higher precision.
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*/
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UTILS_PUBLIC
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float luminance(float aperture, float shutterSpeed, float sensitivity) noexcept;
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/**
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* Converts the specified EV100 to luminance in @f$ \frac{cd}{m^2} @f$.
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* EV100 is not a measure of luminance, but an EV100 can be used to denote a
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* luminance for which a camera would use said EV100 to obtain the nominally
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* correct exposure
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*/
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UTILS_PUBLIC
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float luminance(float ev100) noexcept;
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/**
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* Returns the illuminance in lux for the specified camera acting as an incident light meter.
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*/
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UTILS_PUBLIC
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float illuminance(const Camera& camera) noexcept;
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/**
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* Returns the illuminance in lux for the specified exposure parameters of
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* a camera acting as an incident light meter.
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* This function is equivalent to calling `illuminance(ev100(aperture, shutterSpeed, sensitivity))`
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* but is slightly faster and offers higher precision.
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*/
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UTILS_PUBLIC
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float illuminance(float aperture, float shutterSpeed, float sensitivity) noexcept;
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/**
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* Converts the specified EV100 to illuminance in lux.
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* EV100 is not a measure of illuminance, but an EV100 can be used to denote an
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* illuminance for which a camera would use said EV100 to obtain the nominally
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* correct exposure.
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*/
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UTILS_PUBLIC
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float illuminance(float ev100) noexcept;
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} // namespace exposure
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} // namespace filament
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#endif // TNT_FILAMENT_EXPOSURE_H
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