Function color_diff

engine/dlib/src/basis/encoder/basisu_uastc_enc.cpp:2639–2645

	}

	static inline uint64_t color_diff(const ycbcr& a, const ycbcr& b)
	{
		const int y_delta = a.m_y - b.m_y;
		const int cb_delta = a.m_cb - b.m_cb;
		const int cr_delta = a.m_cr - b.m_cr;
		return ((int64_t)y_delta * y_delta * 4) + ((int64_t)cr_delta * cr_delta) + ((int64_t)cb_delta * cb_delta);
	}

	static inline int gray_distance2(const color_rgba& c, int r, int g, int b)
	{