Method encode_image

engine/dlib/src/basis/encoder/basisu_backend.cpp:687–1485

TODO: Split this into multiple methods.

		
	// TODO: Split this into multiple methods.
	bool basisu_backend::encode_image()
	{
		basisu_frontend& r = *m_pFront_end;
		const bool is_video = r.get_params().m_tex_type == basist::cBASISTexTypeVideoFrames;

		uint32_t total_used_selector_history_buf = 0;
		uint32_t total_selector_indices_remapped = 0;

		basist::approx_move_to_front selector_history_buf(basist::MAX_SELECTOR_HISTORY_BUF_SIZE);
		histogram selector_history_buf_histogram(basist::MAX_SELECTOR_HISTORY_BUF_SIZE);
		histogram selector_histogram(r.get_total_selector_clusters() + basist::MAX_SELECTOR_HISTORY_BUF_SIZE + 1);
		histogram selector_history_buf_rle_histogram(1 << basist::SELECTOR_HISTORY_BUF_RLE_COUNT_BITS);

		basisu::vector<uint_vec> selector_syms(m_slices.size());

		const uint32_t SELECTOR_HISTORY_BUF_FIRST_SYMBOL_INDEX = r.get_total_selector_clusters();
		const uint32_t SELECTOR_HISTORY_BUF_RLE_SYMBOL_INDEX = SELECTOR_HISTORY_BUF_FIRST_SYMBOL_INDEX + basist::MAX_SELECTOR_HISTORY_BUF_SIZE;

		m_output.m_slice_image_crcs.resize(m_slices.size());

		histogram delta_endpoint_histogram(r.get_total_endpoint_clusters());

		histogram endpoint_pred_histogram(basist::ENDPOINT_PRED_TOTAL_SYMBOLS);
		basisu::vector<uint_vec> endpoint_pred_syms(m_slices.size());

		uint32_t total_endpoint_indices_remapped = 0;

		uint_vec block_endpoint_indices, block_selector_indices;

		interval_timer tm;
		tm.start();

		const int COLOR_DELTA_THRESH = 8;
		const int SEL_DIFF_THRESHOLD = 11;
		
		for (uint32_t slice_index = 0; slice_index < m_slices.size(); slice_index++)
		{
			//const int prev_frame_slice_index = is_video ? find_video_frame(slice_index, -1) : -1;
			//const int next_frame_slice_index = is_video ? find_video_frame(slice_index, 1) : -1;
			const uint32_t first_block_index = m_slices[slice_index].m_first_block_index;
			//const uint32_t width = m_slices[slice_index].m_width;
			//const uint32_t height = m_slices[slice_index].m_height;
			const uint32_t num_blocks_x = m_slices[slice_index].m_num_blocks_x;
			const uint32_t num_blocks_y = m_slices[slice_index].m_num_blocks_y;

			selector_history_buf.reset();

			int selector_history_buf_rle_count = 0;

			int prev_endpoint_pred_sym_bits = -1, endpoint_pred_repeat_count = 0;

			uint32_t prev_endpoint_index = 0;

			vector2D<uint8_t> block_endpoints_are_referenced(num_blocks_x, num_blocks_y);

			for (uint32_t block_y = 0; block_y < num_blocks_y; block_y++)
			{
				for (uint32_t block_x = 0; block_x < num_blocks_x; block_x++)