* @brief Integer-exponent 10^n via table lookup; falls back to std::pow if out of band. */
| 91 | * @brief Integer-exponent 10^n via table lookup; falls back to std::pow if out of band. |
| 92 | */ |
| 93 | static inline double fastPow10(double exponent) noexcept |
| 94 | { |
| 95 | static constexpr double kTable[] = { |
| 96 | 1e-15, 1e-14, 1e-13, 1e-12, 1e-11, 1e-10, 1e-9, 1e-8, 1e-7, 1e-6, 1e-5, |
| 97 | 1e-4, 1e-3, 1e-2, 1e-1, 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, |
| 98 | 1e7, 1e8, 1e9, 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, |
| 99 | }; |
| 100 | const int idx = static_cast<int>(exponent) + 15; |
| 101 | if (idx < 0 || idx >= static_cast<int>(sizeof(kTable) / sizeof(kTable[0]))) [[unlikely]] |
| 102 | return std::pow(10.0, exponent); |
| 103 | |
| 104 | return kTable[idx]; |
| 105 | } |
| 106 | |
| 107 | /** |
| 108 | * @brief Linearly interpolates a color from per-channel LUT arrays of length n. |