pnoise2d_raw_simd4_vec()

fl::simd::simd_u32x4 fl::perlin_s16x16_simd::pnoise2d_raw_simd4_vec ( fl::simd::simd_u32x4 nx_vec, fl::simd::simd_u32x4 ny_vec, const fl::i32 * fade_lut, const fl::u8 * perm )

static

Definition at line 20 of file perlin_s16x16_simd.cpp.hpp.

             {
    // SIMD: Extract integer floor (shift right by FP_BITS)
    fl::simd::simd_u32x4 X_vec = fl::simd::srl_u32_4(nx_vec, FP_BITS);
    fl::simd::simd_u32x4 Y_vec = fl::simd::srl_u32_4(ny_vec, FP_BITS);
 
    // SIMD: Extract fractional part and shift to HP_BITS
    // Convert from Q16.16 to Q8.24 by shifting left 8 bits
    fl::simd::simd_u32x4 mask_fp = fl::simd::set1_u32_4(FP_ONE - 1);
    fl::simd::simd_u32x4 x_frac_vec = fl::simd::and_u32_4(nx_vec, mask_fp);
    fl::simd::simd_u32x4 y_frac_vec = fl::simd::and_u32_4(ny_vec, mask_fp);
 
    // Use the new sll_u32_4 operation for left shift
    x_frac_vec = fl::simd::sll_u32_4(x_frac_vec, 8);
    y_frac_vec = fl::simd::sll_u32_4(y_frac_vec, 8);
 
    // SIMD: Wrap to [0, 255]
    fl::simd::simd_u32x4 mask_255 = fl::simd::set1_u32_4(255);
    X_vec = fl::simd::and_u32_4(X_vec, mask_255);
    Y_vec = fl::simd::and_u32_4(Y_vec, mask_255);
    // ── [end SIMD coordinate arithmetic] ──────────────────────────────────────
 
    // ── [BOUNDARY D+E: SIMD extract → per-lane scalar → SIMD re-pack] ───────
    // Extract coordinates directly from SIMD registers (no intermediate arrays).
    // Each lane does: fade LUT, perm table, grad, lerp — fully self-contained.
    // SSE2 has no integer gather, so scalar random-access is unavoidable.
    constexpr int SHIFT = HP_BITS - fl::s16x16::FRAC_BITS;
    auto lane = [&](int i) -> fl::i32 {
        fl::u32 Xi = fl::simd::extract_u32_4(X_vec, i);
        fl::u32 Yi = fl::simd::extract_u32_4(Y_vec, i);
        fl::i32 xf = static_cast<fl::i32>(fl::simd::extract_u32_4(x_frac_vec, i));
        fl::i32 yf = static_cast<fl::i32>(fl::simd::extract_u32_4(y_frac_vec, i));
 
        fl::i32 u = perlin_s16x16::fade(xf, fade_lut);
        fl::i32 v = perlin_s16x16::fade(yf, fade_lut);
 
        int A  = perm[Xi & 255]       + Yi;
        int AA = perm[A & 255];
        int AB = perm[(A + 1) & 255];
        int B  = perm[(Xi + 1) & 255] + Yi;
        int BA = perm[B & 255];
        int BB = perm[(B + 1) & 255];
 
        fl::i32 g_aa = perlin_s16x16::grad(perm[AA & 255], xf,          yf);
        fl::i32 g_ba = perlin_s16x16::grad(perm[BA & 255], xf - HP_ONE, yf);
        fl::i32 g_ab = perlin_s16x16::grad(perm[AB & 255], xf,          yf - HP_ONE);
        fl::i32 g_bb = perlin_s16x16::grad(perm[BB & 255], xf - HP_ONE, yf - HP_ONE);
        fl::i32 lerp1 = perlin_s16x16::lerp(u, g_aa, g_ba);
        fl::i32 lerp2 = perlin_s16x16::lerp(u, g_ab, g_bb);
        return perlin_s16x16::lerp(v, lerp1, lerp2) >> SHIFT;
    };
    return fl::simd::set_u32_4(
        static_cast<fl::u32>(lane(0)), static_cast<fl::u32>(lane(1)),
        static_cast<fl::u32>(lane(2)), static_cast<fl::u32>(lane(3)));
    // ── [end BOUNDARY D+E] ───────────────────────────────────────────────────
}

References fl::B, fl::perlin_s16x16::fade(), fl::FL_NO_EXCEPT, FP_BITS, FP_ONE, fl::s16x16::FRAC_BITS, fl::perlin_s16x16::grad(), HP_BITS, HP_ONE, and fl::perlin_s16x16::lerp().

Referenced by fl::anonymous_namespace{chasing_spirals.cpp.hpp}::simd4_processChannel().

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