我试图创建一个图像文件,如下所示:

uint8_t raw_r[pixel_width][pixel_height];
uint8_t raw_g[pixel_width][pixel_height];
uint8_t raw_b[pixel_width][pixel_height];
uint8_t blue(uint32_t x, uint32_t y)
{
    return (rand()%2)? (x+y)%rand() : ((x*y%1024)%rand())%2 ? (x-y)%rand() : rand();
}
uint8_t green(uint32_t x, uint32_t y)
{
    return (rand()%2)? (x-y)%rand() : ((x*y%1024)%rand())%2 ? (x+y)%rand() : rand();
}
uint8_t red(uint32_t x, uint32_t y)
{
    return (rand()%2)? (y-x)%rand() : ((x*y%1024)%rand())%2 ? (x+y)%rand() : rand();
}

for (y=0; y<pixel_height; ++y)
{
    for (x=0; x<pixel_width; ++x)
    {
        raw_b[x][y]=blue(x, y);
        raw_g[x][y]=green(x, y);
        raw_r[x][y]=red(x, y);
    }
}

我希望随机得到一些东西(白噪声).但是,输出很有意思:

你知道原因吗？

编辑

现在,很明显它与之无关rand().

也试试这段代码: …

想要打印 uint32 十六进制。尝试过“PRIx32”，对我来说看起来很糟糕：

967407c0 23 4481d55f ffffff52 de3cd140
2fc aa7363cf fffff40d 563270c0 2b86

所以...尝试了这个。肮脏但有效：

 /*******************************************************************************
 Print a digit in hex.
 *******************************************************************************/
 void mpal_digit_t_print_hex(
     mpal_digit_t * input)
 {
     uint8_t p_1, p_2, p_3, p_4, p_5, p_6, p_7, p_8;

     p_1 = (uint8_t)(((*input) << 0) >> 28);
     p_2 = (uint8_t)(((*input) << 4) >> 28);
     p_3 = (uint8_t)(((*input) << 8) >> 28);
     p_4 = (uint8_t)(((*input) << 12) >> 28);
     p_5 = (uint8_t)(((*input) << 16) >> 28);
     p_6 = (uint8_t)(((*input) << 20) >> 28);
     p_7 = …