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我有以下JNI方法，我想将其转换为 Android RenderScript，因为这会使我的项目更易于管理。

这是JNI方法：

static void applyRGBCurve(int width, int height, int *pixels, int *rgb) {
    int R[256];
    int G[256];
    int B[256];

    // It seems that they extract the RGB components here
    // to build up a lookup table
    // so, we end up with lookup table for the RED component, GREEN component, BLUE component of each pixel
    for (int i = 0; i < 256; i++) {
        R[i] = (rgb[i] << 16) & 0x00FF0000;
        G[i] = (rgb[i] << 8) & 0x0000FF00;
        B[i] = rgb[i] & 0x000000FF;
    }

    for (int i = 0; i < width * height; i++) {
        // using the lookup tables, they construct each pixel
        pixels[i] =
                (0xFF000000 & pixels[i]) | (R[(pixels[i] >> 16) & 0xFF]) | (G[(pixels[i] >> 8) & 0xFF]) | (B[pixels[i] & 0xFF]);
    }
}

我是新手RenderScript。所以我很感谢任何帮助。

这是我尝试过的：

#pragma version(1)
#pragma rs java_package_name(com.example.imageprocessinginkotlin)
#pragma rs_fp_relaxed

int rgb[256];
uint32_t R[256];
uint32_t G[256];
uint32_t B[256];

void prepareChannels(){

    for (int i = 0; i < 256; i++) {
        // HERE I did not know how to apply shift operations in Renderscript
        R[i] = rgb[i] & 0xFF;           
        G[i] = rgb[i] & 0xFF;
        B[i] = rgb[i] & 0xFF;
    }
}

uchar4 RS_KERNEL applyRGBCurve(uchar4 in){

    uchar4 out;

    out.a = in.a;
    out.r = R[in.r];
    out.g = G[in.g];
    out.b = B[in.b];

    return out;
}

从 Java 端看，它看起来像这样：

val rs = RenderScript.create(activity)
allocationIn = Allocation.createFromBitmap(rs, bitmap)
allocationOut = Allocation.createFromBitmap(rs, bitmap)

script = ScriptC_tonecurve(rs)

script.set_rgb(item.rgb.toIntArray())
script.invoke_prepareChannels()
script.forEach_applyRGBCurve(allocationIn, allocationOut)
allocationOut.copyTo(bitmap)
binding.imageView.setImageBitmap(bitmap)

我的Renderscript代码是否等同于 JNI 方法？我会说不是因为缺少移位操作（与 JNI 方法相比）。

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