thorvg/src/renderer/sw_engine/tvgSwRasterNeon.h

/*
 * Copyright (c) 2021 - 2023 the ThorVG project. All rights reserved.

 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:

 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifdef THORVG_NEON_VECTOR_SUPPORT

#include <arm_neon.h>

static inline uint8x8_t ALPHA_BLEND(uint8x8_t c, uint8x8_t a)
{
    uint16x8_t t = vmull_u8(c, a);
    return vshrn_n_u16(t, 8);
}


static void neonRasterPixel32(uint32_t *dst, uint32_t val, uint32_t offset, int32_t len)
{
    uint32_t iterations = len / 4;
    uint32_t neonFilled = iterations * 4;

    dst += offset;
    uint32x4_t vectorVal = {val, val, val, val};

    for (uint32_t i = 0; i < iterations; ++i) {
        vst1q_u32(dst, vectorVal);
        dst += 4;
    }

    int32_t leftovers = len - neonFilled;
    while (leftovers--) *dst++ = val;
}


static bool neonRasterTranslucentRle(SwSurface* surface, const SwRleData* rle, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
{
    if (surface->channelSize != sizeof(uint32_t)) {
        TVGERR("SW_ENGINE", "Unsupported Channel Size = %d", surface->channelSize);
        return false;
    }

    auto color = surface->blender.join(r, g, b, a);
    auto span = rle->spans;
    uint32_t src;
    uint8x8_t *vDst = nullptr;
    uint16_t align;

    for (uint32_t i = 0; i < rle->size; ++i) {
        if (span->coverage < 255) src = ALPHA_BLEND(color, span->coverage);
        else src = color;

        auto dst = &surface->buf32[span->y * surface->stride + span->x];
        auto ialpha = IALPHA(src);

        if ((((uint32_t) dst) & 0x7) != 0) {
            //fill not aligned byte
            *dst = src + ALPHA_BLEND(*dst, ialpha);
            vDst = (uint8x8_t*)(dst + 1);
            align = 1;
        } else {
            vDst = (uint8x8_t*) dst;
            align = 0;
        }

        uint8x8_t vSrc = (uint8x8_t) vdup_n_u32(src);
        uint8x8_t vIalpha = vdup_n_u8((uint8_t) ialpha);

        for (uint32_t x = 0; x < (span->len - align) / 2; ++x)
            vDst[x] = vadd_u8(vSrc, ALPHA_BLEND(vDst[x], vIalpha));

        auto leftovers = (span->len - align) % 2;
        if (leftovers > 0) dst[span->len - 1] = src + ALPHA_BLEND(dst[span->len - 1], ialpha);

        ++span;
    }
    return true;
}


static bool neonRasterTranslucentRect(SwSurface* surface, const SwBBox& region, uint8_t r, uint8_t g, uint8_t b, uint8_t a)
{
    if (surface->channelSize != sizeof(uint32_t)) {
        TVGERR("SW_ENGINE", "Unsupported Channel Size = %d", surface->channelSize);
        return false;
    }

    auto color = surface->blender.join(r, g, b, a);
    auto buffer = surface->buf32 + (region.min.y * surface->stride) + region.min.x;
    auto h = static_cast<uint32_t>(region.max.y - region.min.y);
    auto w = static_cast<uint32_t>(region.max.x - region.min.x);
    auto ialpha = 255 - a;

    auto vColor = vdup_n_u32(color);
    auto vIalpha = vdup_n_u8((uint8_t) ialpha);

    uint8x8_t* vDst = nullptr;
    uint32_t align;

    for (uint32_t y = 0; y < h; ++y) {
        auto dst = &buffer[y * surface->stride];

        if ((((uint32_t) dst) & 0x7) != 0) {
            //fill not aligned byte
            *dst = color + ALPHA_BLEND(*dst, ialpha);
            vDst = (uint8x8_t*) (dst + 1);
            align = 1;
        } else {
            vDst = (uint8x8_t*) dst;
            align = 0;
        }

        for (uint32_t x = 0; x <  (w - align) / 2; ++x)
            vDst[x] = vadd_u8((uint8x8_t)vColor, ALPHA_BLEND(vDst[x], vIalpha));

        auto leftovers = (w - align) % 2;
        if (leftovers > 0) dst[w - 1] = color + ALPHA_BLEND(dst[w - 1], ialpha);
    }
    return true;
}

#endif