Function lerp

src/fl/math/fixed_point/s16x16.h:155–429

#if defined(__riscv) && (__riscv_xlen == 32)
    static FASTLED_FORCE_INLINE s16x16 lerp(s16x16 a, s16x16 b, s16x16 t) {
#else
    static constexpr FASTLED_FORCE_INLINE s16x16 lerp(s16x16 a, s16x16 b, s16x16 t) FL_NOEXCEPT {
#endif
        return a + (b - a) * t;
    }

    static constexpr FASTLED_FORCE_INLINE s16x16 clamp(s16x16 x, s16x16 lo, s16x16 hi) FL_NOEXCEPT {
        return x < lo ? lo : (x > hi ? hi : x);
    }

    static constexpr FASTLED_FORCE_INLINE s16x16 step(s16x16 edge, s16x16 x) FL_NOEXCEPT {
        return x < edge ? s16x16() : s16x16(1.0f);
    }

    static FASTLED_FORCE_INLINE s16x16 smoothstep(s16x16 edge0, s16x16 edge1, s16x16 x) FL_NOEXCEPT {
        constexpr s16x16 zero(0.0f);
        constexpr s16x16 one(1.0f);
        constexpr s16x16 two(2.0f);
        constexpr s16x16 three(3.0f);
        s16x16 t = clamp((x - edge0) / (edge1 - edge0), zero, one);
        return t * t * (three - two * t);
    }

    // ---- Inverse Trigonometry (pure fixed-point) ----------------------------

    static FASTLED_FORCE_INLINE s16x16 atan(s16x16 x) FL_NOEXCEPT {
        constexpr s16x16 one(1.0f);
        constexpr s16x16 pi_over_2(1.5707963f);
        bool neg = x.mValue < 0;
        s16x16 ax = abs(x);
        s16x16 result;
        if (ax <= one) {
            result = atan_unit(ax);
        } else {
            result = pi_over_2 - atan_unit(one / ax);
        }
        return neg ? -result : result;
    }

    static FASTLED_FORCE_INLINE s16x16 atan2(s16x16 y, s16x16 x) FL_NOEXCEPT {
        constexpr s16x16 pi(3.1415926f);
        constexpr s16x16 pi_over_2(1.5707963f);
        if (x.mValue == 0 && y.mValue == 0) return s16x16();
        if (x.mValue == 0) return y.mValue > 0 ? pi_over_2 : -pi_over_2;
        if (y.mValue == 0) return x.mValue > 0 ? s16x16() : pi;
        s16x16 ax = abs(x);
        s16x16 ay = abs(y);
        s16x16 a;
        if (ax >= ay) {
            a = atan_unit(ay / ax);
        } else {
            a = pi_over_2 - atan_unit(ax / ay);
        }
        if (x.mValue < 0) a = pi - a;
        if (y.mValue < 0) a = -a;
        return a;
    }