gl-rocket/glm/gtc/color_space.inl

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2021-01-02 17:01:54 +01:00
/// @ref gtc_color_space
namespace glm{
namespace detail
{
template<length_t L, typename T, qualifier Q>
struct compute_rgbToSrgb
{
GLM_FUNC_QUALIFIER static vec<L, T, Q> call(vec<L, T, Q> const& ColorRGB, T GammaCorrection)
{
vec<L, T, Q> const ClampedColor(clamp(ColorRGB, static_cast<T>(0), static_cast<T>(1)));
return mix(
pow(ClampedColor, vec<L, T, Q>(GammaCorrection)) * static_cast<T>(1.055) - static_cast<T>(0.055),
ClampedColor * static_cast<T>(12.92),
lessThan(ClampedColor, vec<L, T, Q>(static_cast<T>(0.0031308))));
}
};
template<typename T, qualifier Q>
struct compute_rgbToSrgb<4, T, Q>
{
GLM_FUNC_QUALIFIER static vec<4, T, Q> call(vec<4, T, Q> const& ColorRGB, T GammaCorrection)
{
return vec<4, T, Q>(compute_rgbToSrgb<3, T, Q>::call(vec<3, T, Q>(ColorRGB), GammaCorrection), ColorRGB.w);
}
};
template<length_t L, typename T, qualifier Q>
struct compute_srgbToRgb
{
GLM_FUNC_QUALIFIER static vec<L, T, Q> call(vec<L, T, Q> const& ColorSRGB, T Gamma)
{
return mix(
pow((ColorSRGB + static_cast<T>(0.055)) * static_cast<T>(0.94786729857819905213270142180095), vec<L, T, Q>(Gamma)),
ColorSRGB * static_cast<T>(0.07739938080495356037151702786378),
lessThanEqual(ColorSRGB, vec<L, T, Q>(static_cast<T>(0.04045))));
}
};
template<typename T, qualifier Q>
struct compute_srgbToRgb<4, T, Q>
{
GLM_FUNC_QUALIFIER static vec<4, T, Q> call(vec<4, T, Q> const& ColorSRGB, T Gamma)
{
return vec<4, T, Q>(compute_srgbToRgb<3, T, Q>::call(vec<3, T, Q>(ColorSRGB), Gamma), ColorSRGB.w);
}
};
}//namespace detail
template<length_t L, typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<L, T, Q> convertLinearToSRGB(vec<L, T, Q> const& ColorLinear)
{
return detail::compute_rgbToSrgb<L, T, Q>::call(ColorLinear, static_cast<T>(0.41666));
}
// Based on Ian Taylor http://chilliant.blogspot.fr/2012/08/srgb-approximations-for-hlsl.html
template<>
GLM_FUNC_QUALIFIER vec<3, float, lowp> convertLinearToSRGB(vec<3, float, lowp> const& ColorLinear)
{
vec<3, float, lowp> S1 = sqrt(ColorLinear);
vec<3, float, lowp> S2 = sqrt(S1);
vec<3, float, lowp> S3 = sqrt(S2);
return 0.662002687f * S1 + 0.684122060f * S2 - 0.323583601f * S3 - 0.0225411470f * ColorLinear;
}
template<length_t L, typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<L, T, Q> convertLinearToSRGB(vec<L, T, Q> const& ColorLinear, T Gamma)
{
return detail::compute_rgbToSrgb<L, T, Q>::call(ColorLinear, static_cast<T>(1) / Gamma);
}
template<length_t L, typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<L, T, Q> convertSRGBToLinear(vec<L, T, Q> const& ColorSRGB)
{
return detail::compute_srgbToRgb<L, T, Q>::call(ColorSRGB, static_cast<T>(2.4));
}
template<length_t L, typename T, qualifier Q>
GLM_FUNC_QUALIFIER vec<L, T, Q> convertSRGBToLinear(vec<L, T, Q> const& ColorSRGB, T Gamma)
{
return detail::compute_srgbToRgb<L, T, Q>::call(ColorSRGB, Gamma);
}
}//namespace glm