快速将 RGBA 转换为 ARGB [英] Fast Converting RGBA to ARGB

问题描述

我正在尝试将 rgba 缓冲区转换为 argb，有什么方法可以改进下一个算法，或者有其他更快的方法来执行此类操作吗?考虑到 alpha 值在 argb 缓冲区中一次并不重要，最终应始终为 0xFF.

I am trying to convert a rgba buffer into argb, is there any way to improve the next algorithm, or any other faster way to perform such operation? Taking into account that the alpha value is not important once in the argb buffer, and should always end up as 0xFF.

int y, x, pixel;

for (y = 0; y < height; y++)
{
    for (x = 0; x < width; x++)
    {
     pixel = rgbaBuffer[y * width + x];
     argbBuffer[(height - y - 1) * width + x] = (pixel & 0xff00ff00) | ((pixel << 16) & 0x00ff0000) | ((pixel >> 16) & 0xff);
    }
}

推荐答案

我将只关注交换功能:

typedef unsigned int Color32;

inline Color32 Color32Reverse(Color32 x)
{

    return
    // Source is in format: 0xAARRGGBB
        ((x & 0xFF000000) >> 24) | //______AA
        ((x & 0x00FF0000) >>  8) | //____RR__
        ((x & 0x0000FF00) <<  8) | //__GG____
        ((x & 0x000000FF) << 24);  //BB______
    // Return value is in format:  0xBBGGRRAA
}

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