OpenGL 画高斯随机函数

const float CFFTOceanShader::_getGaussianRandomFloat() const
{
    float u1 = rand() / (float)RAND_MAX;
    float u2 = rand() / (float)RAND_MAX;
    if (u1 < 1e-6f)
        u1 = 1e-6f;
    return sqrtf(-2.0f * logf(u1)) * cosf(2.0f * D3DX_PI * u2);
}