// SPDX-License-Identifier: Apache-2.0 // ---------------------------------------------------------------------------- // Copyright 2011-2023 Arm Limited // // Licensed under the Apache License, Version 2.0 (the "License"); you may not // use this file except in compliance with the License. You may obtain a copy // of the License at: // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the // License for the specific language governing permissions and limitations // under the License. // ---------------------------------------------------------------------------- #if !defined(ASTCENC_DECOMPRESS_ONLY) /** * @brief Functions to compress a symbolic block. */ #include "astcenc_internal.h" #include "astcenc_diagnostic_trace.h" #include <cassert> /** * @brief Merge two planes of endpoints into a single vector. * * @param ep_plane1 The endpoints for plane 1. * @param ep_plane2 The endpoints for plane 2. * @param component_plane2 The color component for plane 2. * @param[out] result The merged output. */ static void merge_endpoints( const endpoints& ep_plane1, const endpoints& ep_plane2, unsigned int component_plane2, endpoints& result ) { unsigned int partition_count = ep_plane1.partition_count; assert(partition_count == 1); vmask4 sep_mask = vint4::lane_id() == vint4(component_plane2); result.partition_count = partition_count; result.endpt0[0] = select(ep_plane1.endpt0[0], ep_plane2.endpt0[0], sep_mask); result.endpt1[0] = select(ep_plane1.endpt1[0], ep_plane2.endpt1[0], sep_mask); } /** * @brief Attempt to improve weights given a chosen configuration. * * Given a fixed weight grid decimation and weight value quantization, iterate over all weights (per * partition and per plane) and attempt to improve image quality by moving each weight up by one or * down by one quantization step. * * This is a specialized function which only supports operating on undecimated weight grids, * therefore primarily improving the performance of 4x4 and 5x5 blocks where grid decimation * is needed less often. * * @param decode_mode The decode mode (LDR, HDR). * @param bsd The block size information. * @param blk The image block color data to compress. * @param[out] scb The symbolic compressed block output. */ static bool realign_weights_undecimated( astcenc_profile decode_mode, const block_size_descriptor& bsd, const image_block& blk, symbolic_compressed_block& scb ) { // Get the partition descriptor unsigned int partition_count = scb.partition_count; const auto& pi = bsd.get_partition_info(partition_count, scb.partition_index); // Get the quantization table const block_mode& bm = bsd.get_block_mode(scb.block_mode); unsigned int weight_quant_level = bm.quant_mode; const quant_and_transfer_table& qat = quant_and_xfer_tables[weight_quant_level]; unsigned int max_plane = bm.is_dual_plane; int plane2_component = scb.plane2_component; vmask4 plane_mask = vint4::lane_id() == vint4(plane2_component); // Decode the color endpoints bool rgb_hdr; bool alpha_hdr; vint4 endpnt0[BLOCK_MAX_PARTITIONS]; vint4 endpnt1[BLOCK_MAX_PARTITIONS]; vfloat4 endpnt0f[BLOCK_MAX_PARTITIONS]; vfloat4 offset[BLOCK_MAX_PARTITIONS]; promise(partition_count > 0); for (unsigned int pa_idx = 0; pa_idx < partition_count; pa_idx++) { unpack_color_endpoints(decode_mode, scb.color_formats[pa_idx], scb.color_values[pa_idx], rgb_hdr, alpha_hdr, endpnt0[pa_idx], endpnt1[pa_idx]); } uint8_t* dec_weights_uquant = scb.weights; bool adjustments = false; // For each plane and partition ... for (unsigned int pl_idx = 0; pl_idx <= max_plane; pl_idx++) { for (unsigned int pa_idx = 0; pa_idx < partition_count; pa_idx++) { // Compute the endpoint delta for all components in current plane vint4 epd = endpnt1[pa_idx] - endpnt0[pa_idx]; epd = select(epd, vint4::zero(), plane_mask); endpnt0f[pa_idx] = int_to_float(endpnt0[pa_idx]); offset[pa_idx] = int_to_float(epd) * (1.0f / 64.0f); } // For each weight compute previous, current, and next errors promise(bsd.texel_count > 0); for (unsigned int texel = 0; texel < bsd.texel_count; texel++) { int uqw = dec_weights_uquant[texel]; uint32_t prev_and_next = qat.prev_next_values[uqw]; int uqw_down = prev_and_next & 0xFF; int uqw_up = (prev_and_next >> 8) & 0xFF; // Interpolate the colors to create the diffs float weight_base = static_cast<float>(uqw); float weight_down = static_cast<float>(uqw_down - uqw); float weight_up = static_cast<float>(uqw_up - uqw); unsigned int partition = pi.partition_of_texel[texel]; vfloat4 color_offset = offset[partition]; vfloat4 color_base = endpnt0f[partition]; vfloat4 color = color_base + color_offset * weight_base; vfloat4 orig_color = blk.texel(texel); vfloat4 error_weight = blk.channel_weight; vfloat4 color_diff = color - orig_color; vfloat4 color_diff_down = color_diff + color_offset * weight_down; vfloat4 color_diff_up = color_diff + color_offset * weight_up; float error_base = dot_s(color_diff * color_diff, error_weight); float error_down = dot_s(color_diff_down * color_diff_down, error_weight); float error_up = dot_s(color_diff_up * color_diff_up, error_weight); // Check if the prev or next error is better, and if so use it if ((error_up < error_base) && (error_up < error_down) && (uqw < 64)) { dec_weights_uquant[texel] = static_cast<uint8_t>(uqw_up); adjustments = true; } else if ((error_down < error_base) && (uqw > 0)) { dec_weights_uquant[texel] = static_cast<uint8_t>(uqw_down); adjustments = true; } } // Prepare iteration for plane 2 dec_weights_uquant += WEIGHTS_PLANE2_OFFSET; plane_mask = ~plane_mask; } return adjustments; } /** * @brief Attempt to improve weights given a chosen configuration. * * Given a fixed weight grid decimation and weight value quantization, iterate over all weights (per * partition and per plane) and attempt to improve image quality by moving each weight up by one or * down by one quantization step. * * @param decode_mode The decode mode (LDR, HDR). * @param bsd The block size information. * @param blk The image block color data to compress. * @param[out] scb The symbolic compressed block output. */ static bool realign_weights_decimated( astcenc_profile decode_mode, const block_size_descriptor& bsd, const image_block& blk, symbolic_compressed_block& scb ) { // Get the partition descriptor unsigned int partition_count = scb.partition_count; const auto& pi = bsd.get_partition_info(partition_count, scb.partition_index); // Get the quantization table const block_mode& bm = bsd.get_block_mode(scb.block_mode); unsigned int weight_quant_level = bm.quant_mode; const quant_and_transfer_table& qat = quant_and_xfer_tables[weight_quant_level]; // Get the decimation table const decimation_info& di = bsd.get_decimation_info(bm.decimation_mode); unsigned int weight_count = di.weight_count; assert(weight_count != bsd.texel_count); unsigned int max_plane = bm.is_dual_plane; int plane2_component = scb.plane2_component; vmask4 plane_mask = vint4::lane_id() == vint4(plane2_component); // Decode the color endpoints bool rgb_hdr; bool alpha_hdr; vint4 endpnt0[BLOCK_MAX_PARTITIONS]; vint4 endpnt1[BLOCK_MAX_PARTITIONS]; vfloat4 endpnt0f[BLOCK_MAX_PARTITIONS]; vfloat4 offset[BLOCK_MAX_PARTITIONS]; promise(partition_count > 0); promise(weight_count > 0); for (unsigned int pa_idx = 0; pa_idx < partition_count; pa_idx++) { unpack_color_endpoints(decode_mode, scb.color_formats[pa_idx], scb.color_values[pa_idx], rgb_hdr, alpha_hdr, endpnt0[pa_idx], endpnt1[pa_idx]); } uint8_t* dec_weights_uquant = scb.weights; bool adjustments = false; // For each plane and partition ... for (unsigned int pl_idx = 0; pl_idx <= max_plane; pl_idx++) { for (unsigned int pa_idx = 0; pa_idx < partition_count; pa_idx++) { // Compute the endpoint delta for all components in current plane vint4 epd = endpnt1[pa_idx] - endpnt0[pa_idx]; epd = select(epd, vint4::zero(), plane_mask); endpnt0f[pa_idx] = int_to_float(endpnt0[pa_idx]); offset[pa_idx] = int_to_float(epd) * (1.0f / 64.0f); } // Create an unquantized weight grid for this decimation level alignas(ASTCENC_VECALIGN) float uq_weightsf[BLOCK_MAX_WEIGHTS]; for (unsigned int we_idx = 0; we_idx < weight_count; we_idx += ASTCENC_SIMD_WIDTH) { vint unquant_value(dec_weights_uquant + we_idx); vfloat unquant_valuef = int_to_float(unquant_value); storea(unquant_valuef, uq_weightsf + we_idx); } // For each weight compute previous, current, and next errors for (unsigned int we_idx = 0; we_idx < weight_count; we_idx++) { int uqw = dec_weights_uquant[we_idx]; uint32_t prev_and_next = qat.prev_next_values[uqw]; float uqw_base = uq_weightsf[we_idx]; float uqw_down = static_cast<float>(prev_and_next & 0xFF); float uqw_up = static_cast<float>((prev_and_next >> 8) & 0xFF); float uqw_diff_down = uqw_down - uqw_base; float uqw_diff_up = uqw_up - uqw_base; vfloat4 error_basev = vfloat4::zero(); vfloat4 error_downv = vfloat4::zero(); vfloat4 error_upv = vfloat4::zero(); // Interpolate the colors to create the diffs unsigned int texels_to_evaluate = di.weight_texel_count[we_idx]; promise(texels_to_evaluate > 0); for (unsigned int te_idx = 0; te_idx < texels_to_evaluate; te_idx++) { unsigned int texel = di.weight_texels_tr[te_idx][we_idx]; float tw_base = di.texel_contrib_for_weight[te_idx][we_idx]; float weight_base = (uq_weightsf[di.texel_weights_tr[0][texel]] * di.texel_weight_contribs_float_tr[0][texel] + uq_weightsf[di.texel_weights_tr[1][texel]] * di.texel_weight_contribs_float_tr[1][texel]) + (uq_weightsf[di.texel_weights_tr[2][texel]] * di.texel_weight_contribs_float_tr[2][texel] + uq_weightsf[di.texel_weights_tr[3][texel]] * di.texel_weight_contribs_float_tr[3][texel]); // Ideally this is integer rounded, but IQ gain it isn't worth the overhead // float weight = astc::flt_rd(weight_base + 0.5f); // float weight_down = astc::flt_rd(weight_base + 0.5f + uqw_diff_down * tw_base) - weight; // float weight_up = astc::flt_rd(weight_base + 0.5f + uqw_diff_up * tw_base) - weight; float weight_down = weight_base + uqw_diff_down * tw_base - weight_base; float weight_up = weight_base + uqw_diff_up * tw_base - weight_base; unsigned int partition = pi.partition_of_texel[texel]; vfloat4 color_offset = offset[partition]; vfloat4 color_base = endpnt0f[partition]; vfloat4 color = color_base + color_offset * weight_base; vfloat4 orig_color = blk.texel(texel); vfloat4 color_diff = color - orig_color; vfloat4 color_down_diff = color_diff + color_offset * weight_down; vfloat4 color_up_diff = color_diff + color_offset * weight_up; error_basev += color_diff * color_diff; error_downv += color_down_diff * color_down_diff; error_upv += color_up_diff * color_up_diff; } vfloat4 error_weight = blk.channel_weight; float error_base = hadd_s(error_basev * error_weight); float error_down = hadd_s(error_downv * error_weight); float error_up = hadd_s(error_upv * error_weight); // Check if the prev or next error is better, and if so use it if ((error_up < error_base) && (error_up < error_down) && (uqw < 64)) { uq_weightsf[we_idx] = uqw_up; dec_weights_uquant[we_idx] = static_cast<uint8_t>(uqw_up); adjustments = true; } else if ((error_down < error_base) && (uqw > 0)) { uq_weightsf[we_idx] = uqw_down; dec_weights_uquant[we_idx] = static_cast<uint8_t>(uqw_down); adjustments = true; } } // Prepare iteration for plane 2 dec_weights_uquant += WEIGHTS_PLANE2_OFFSET; plane_mask = ~plane_mask; } return adjustments; } /** * @brief Compress a block using a chosen partitioning and 1 plane of weights. * * @param config The compressor configuration. * @param bsd The block size information. * @param blk The image block color data to compress. * @param only_always True if we only use "always" percentile block modes. * @param tune_errorval_threshold The error value threshold. * @param partition_count The partition count. * @param partition_index The partition index if @c partition_count is 2-4. * @param[out] scb The symbolic compressed block output. * @param[out] tmpbuf The quantized weights for plane 1. */ static float compress_symbolic_block_for_partition_1plane( const astcenc_config& config, const block_size_descriptor& bsd, const image_block& blk, bool only_always, float tune_errorval_threshold, unsigned int partition_count, unsigned int partition_index, symbolic_compressed_block& scb, compression_working_buffers& tmpbuf, int quant_limit ) { promise(partition_count > 0); promise(config.tune_candidate_limit > 0); promise(config.tune_refinement_limit > 0); int max_weight_quant = astc::min(static_cast<int>(QUANT_32), quant_limit); auto compute_difference = &compute_symbolic_block_difference_1plane; if ((partition_count == 1) && !(config.flags & ASTCENC_FLG_MAP_RGBM)) { compute_difference = &compute_symbolic_block_difference_1plane_1partition; } const auto& pi = bsd.get_partition_info(partition_count, partition_index); // Compute ideal weights and endpoint colors, with no quantization or decimation endpoints_and_weights& ei = tmpbuf.ei1; compute_ideal_colors_and_weights_1plane(blk, pi, ei); // Compute ideal weights and endpoint colors for every decimation float* dec_weights_ideal = tmpbuf.dec_weights_ideal; uint8_t* dec_weights_uquant = tmpbuf.dec_weights_uquant; // For each decimation mode, compute an ideal set of weights with no quantization unsigned int max_decimation_modes = only_always ? bsd.decimation_mode_count_always : bsd.decimation_mode_count_selected; promise(max_decimation_modes > 0); for (unsigned int i = 0; i < max_decimation_modes; i++) { const auto& dm = bsd.get_decimation_mode(i); if (!dm.is_ref_1plane(static_cast<quant_method>(max_weight_quant))) { continue; } const auto& di = bsd.get_decimation_info(i); compute_ideal_weights_for_decimation( ei, di, dec_weights_ideal + i * BLOCK_MAX_WEIGHTS); } // Compute maximum colors for the endpoints and ideal weights, then for each endpoint and ideal // weight pair, compute the smallest weight that will result in a color value greater than 1 vfloat4 min_ep(10.0f); for (unsigned int i = 0; i < partition_count; i++) { vfloat4 ep = (vfloat4(1.0f) - ei.ep.endpt0[i]) / (ei.ep.endpt1[i] - ei.ep.endpt0[i]); vmask4 use_ep = (ep > vfloat4(0.5f)) & (ep < min_ep); min_ep = select(min_ep, ep, use_ep); } float min_wt_cutoff = hmin_s(min_ep); // For each mode, use the angular method to compute a shift compute_angular_endpoints_1plane( only_always, bsd, dec_weights_ideal, max_weight_quant, tmpbuf); float* weight_low_value = tmpbuf.weight_low_value1; float* weight_high_value = tmpbuf.weight_high_value1; int8_t* qwt_bitcounts = tmpbuf.qwt_bitcounts; float* qwt_errors = tmpbuf.qwt_errors; // For each mode (which specifies a decimation and a quantization): // * Compute number of bits needed for the quantized weights // * Generate an optimized set of quantized weights // * Compute quantization errors for the mode static const int8_t free_bits_for_partition_count[4] { 115 - 4, 111 - 4 - PARTITION_INDEX_BITS, 108 - 4 - PARTITION_INDEX_BITS, 105 - 4 - PARTITION_INDEX_BITS }; unsigned int max_block_modes = only_always ? bsd.block_mode_count_1plane_always : bsd.block_mode_count_1plane_selected; promise(max_block_modes > 0); for (unsigned int i = 0; i < max_block_modes; i++) { const block_mode& bm = bsd.block_modes[i]; if (bm.quant_mode > max_weight_quant) { qwt_errors[i] = 1e38f; continue; } assert(!bm.is_dual_plane); int bitcount = free_bits_for_partition_count[partition_count - 1] - bm.weight_bits; if (bitcount <= 0) { qwt_errors[i] = 1e38f; continue; } if (weight_high_value[i] > 1.02f * min_wt_cutoff) { weight_high_value[i] = 1.0f; } int decimation_mode = bm.decimation_mode; const auto& di = bsd.get_decimation_info(decimation_mode); qwt_bitcounts[i] = static_cast<int8_t>(bitcount); alignas(ASTCENC_VECALIGN) float dec_weights_uquantf[BLOCK_MAX_WEIGHTS]; // Generate the optimized set of weights for the weight mode compute_quantized_weights_for_decimation( di, weight_low_value[i], weight_high_value[i], dec_weights_ideal + BLOCK_MAX_WEIGHTS * decimation_mode, dec_weights_uquantf, dec_weights_uquant + BLOCK_MAX_WEIGHTS * i, bm.get_weight_quant_mode()); // Compute weight quantization errors for the block mode qwt_errors[i] = compute_error_of_weight_set_1plane( ei, di, dec_weights_uquantf); } // Decide the optimal combination of color endpoint encodings and weight encodings uint8_t partition_format_specifiers[TUNE_MAX_TRIAL_CANDIDATES][BLOCK_MAX_PARTITIONS]; int block_mode_index[TUNE_MAX_TRIAL_CANDIDATES]; quant_method color_quant_level[TUNE_MAX_TRIAL_CANDIDATES]; quant_method color_quant_level_mod[TUNE_MAX_TRIAL_CANDIDATES]; unsigned int candidate_count = compute_ideal_endpoint_formats( pi, blk, ei.ep, qwt_bitcounts, qwt_errors, config.tune_candidate_limit, 0, max_block_modes, partition_format_specifiers, block_mode_index, color_quant_level, color_quant_level_mod, tmpbuf); // Iterate over the N believed-to-be-best modes to find out which one is actually best float best_errorval_in_mode = ERROR_CALC_DEFAULT; float best_errorval_in_scb = scb.errorval; for (unsigned int i = 0; i < candidate_count; i++) { TRACE_NODE(node0, "candidate"); const int bm_packed_index = block_mode_index[i]; assert(bm_packed_index >= 0 && bm_packed_index < static_cast<int>(bsd.block_mode_count_1plane_selected)); const block_mode& qw_bm = bsd.block_modes[bm_packed_index]; int decimation_mode = qw_bm.decimation_mode; const auto& di = bsd.get_decimation_info(decimation_mode); promise(di.weight_count > 0); trace_add_data("weight_x", di.weight_x); trace_add_data("weight_y", di.weight_y); trace_add_data("weight_z", di.weight_z); trace_add_data("weight_quant", qw_bm.quant_mode); // Recompute the ideal color endpoints before storing them vfloat4 rgbs_colors[BLOCK_MAX_PARTITIONS]; vfloat4 rgbo_colors[BLOCK_MAX_PARTITIONS]; symbolic_compressed_block workscb; endpoints workep = ei.ep; uint8_t* u8_weight_src = dec_weights_uquant + BLOCK_MAX_WEIGHTS * bm_packed_index; for (unsigned int j = 0; j < di.weight_count; j++) { workscb.weights[j] = u8_weight_src[j]; } for (unsigned int l = 0; l < config.tune_refinement_limit; l++) { recompute_ideal_colors_1plane( blk, pi, di, workscb.weights, workep, rgbs_colors, rgbo_colors); // Quantize the chosen color, tracking if worth trying the mod value bool all_same = color_quant_level[i] != color_quant_level_mod[i]; for (unsigned int j = 0; j < partition_count; j++) { workscb.color_formats[j] = pack_color_endpoints( workep.endpt0[j], workep.endpt1[j], rgbs_colors[j], rgbo_colors[j], partition_format_specifiers[i][j], workscb.color_values[j], color_quant_level[i]); all_same = all_same && workscb.color_formats[j] == workscb.color_formats[0]; } // If all the color endpoint modes are the same, we get a few more bits to store colors; // let's see if we can take advantage of this: requantize all the colors and see if the // endpoint modes remain the same. workscb.color_formats_matched = 0; if (partition_count >= 2 && all_same) { uint8_t colorvals[BLOCK_MAX_PARTITIONS][8]; uint8_t color_formats_mod[BLOCK_MAX_PARTITIONS] { 0 }; bool all_same_mod = true; for (unsigned int j = 0; j < partition_count; j++) { color_formats_mod[j] = pack_color_endpoints( workep.endpt0[j], workep.endpt1[j], rgbs_colors[j], rgbo_colors[j], partition_format_specifiers[i][j], colorvals[j], color_quant_level_mod[i]); // Early out as soon as it's no longer possible to use mod if (color_formats_mod[j] != color_formats_mod[0]) { all_same_mod = false; break; } } if (all_same_mod) { workscb.color_formats_matched = 1; for (unsigned int j = 0; j < BLOCK_MAX_PARTITIONS; j++) { for (unsigned int k = 0; k < 8; k++) { workscb.color_values[j][k] = colorvals[j][k]; } workscb.color_formats[j] = color_formats_mod[j]; } } } // Store header fields workscb.partition_count = static_cast<uint8_t>(partition_count); workscb.partition_index = static_cast<uint16_t>(partition_index); workscb.plane2_component = -1; workscb.quant_mode = workscb.color_formats_matched ? color_quant_level_mod[i] : color_quant_level[i]; workscb.block_mode = qw_bm.mode_index; workscb.block_type = SYM_BTYPE_NONCONST; // Pre-realign test if (l == 0) { float errorval = compute_difference(config, bsd, workscb, blk); if (errorval == -ERROR_CALC_DEFAULT) { errorval = -errorval; workscb.block_type = SYM_BTYPE_ERROR; } trace_add_data("error_prerealign", errorval); best_errorval_in_mode = astc::min(errorval, best_errorval_in_mode); // Average refinement improvement is 3.5% per iteration (allow 4.5%), but the first // iteration can help more so we give it a extra 8% leeway. Use this knowledge to // drive a heuristic to skip blocks that are unlikely to catch up with the best // block we have already. unsigned int iters_remaining = config.tune_refinement_limit - l; float threshold = (0.045f * static_cast<float>(iters_remaining)) + 1.08f; if (errorval > (threshold * best_errorval_in_scb)) { break; } if (errorval < best_errorval_in_scb) { best_errorval_in_scb = errorval; workscb.errorval = errorval; scb = workscb; if (errorval < tune_errorval_threshold) { // Skip remaining candidates - this is "good enough" i = candidate_count; break; } } } bool adjustments; if (di.weight_count != bsd.texel_count) { adjustments = realign_weights_decimated( config.profile, bsd, blk, workscb); } else { adjustments = realign_weights_undecimated( config.profile, bsd, blk, workscb); } // Post-realign test float errorval = compute_difference(config, bsd, workscb, blk); if (errorval == -ERROR_CALC_DEFAULT) { errorval = -errorval; workscb.block_type = SYM_BTYPE_ERROR; } trace_add_data("error_postrealign", errorval); best_errorval_in_mode = astc::min(errorval, best_errorval_in_mode); // Average refinement improvement is 3.5% per iteration, so skip blocks that are // unlikely to catch up with the best block we have already. Assume a 4.5% per step to // give benefit of the doubt ... unsigned int iters_remaining = config.tune_refinement_limit - 1 - l; float threshold = (0.045f * static_cast<float>(iters_remaining)) + 1.0f; if (errorval > (threshold * best_errorval_in_scb)) { break; } if (errorval < best_errorval_in_scb) { best_errorval_in_scb = errorval; workscb.errorval = errorval; scb = workscb; if (errorval < tune_errorval_threshold) { // Skip remaining candidates - this is "good enough" i = candidate_count; break; } } if (!adjustments) { break; } } } return best_errorval_in_mode; } /** * @brief Compress a block using a chosen partitioning and 2 planes of weights. * * @param config The compressor configuration. * @param bsd The block size information. * @param blk The image block color data to compress. * @param tune_errorval_threshold The error value threshold. * @param plane2_component The component index for the second plane of weights. * @param[out] scb The symbolic compressed block output. * @param[out] tmpbuf The quantized weights for plane 1. */ static float compress_symbolic_block_for_partition_2planes( const astcenc_config& config, const block_size_descriptor& bsd, const image_block& blk, float tune_errorval_threshold, unsigned int plane2_component, symbolic_compressed_block& scb, compression_working_buffers& tmpbuf, int quant_limit ) { promise(config.tune_candidate_limit > 0); promise(config.tune_refinement_limit > 0); promise(bsd.decimation_mode_count_selected > 0); int max_weight_quant = astc::min(static_cast<int>(QUANT_32), quant_limit); // Compute ideal weights and endpoint colors, with no quantization or decimation endpoints_and_weights& ei1 = tmpbuf.ei1; endpoints_and_weights& ei2 = tmpbuf.ei2; compute_ideal_colors_and_weights_2planes(bsd, blk, plane2_component, ei1, ei2); // Compute ideal weights and endpoint colors for every decimation float* dec_weights_ideal = tmpbuf.dec_weights_ideal; uint8_t* dec_weights_uquant = tmpbuf.dec_weights_uquant; // For each decimation mode, compute an ideal set of weights with no quantization for (unsigned int i = 0; i < bsd.decimation_mode_count_selected; i++) { const auto& dm = bsd.get_decimation_mode(i); if (!dm.is_ref_2plane(static_cast<quant_method>(max_weight_quant))) { continue; } const auto& di = bsd.get_decimation_info(i); compute_ideal_weights_for_decimation( ei1, di, dec_weights_ideal + i * BLOCK_MAX_WEIGHTS); compute_ideal_weights_for_decimation( ei2, di, dec_weights_ideal + i * BLOCK_MAX_WEIGHTS + WEIGHTS_PLANE2_OFFSET); } // Compute maximum colors for the endpoints and ideal weights, then for each endpoint and ideal // weight pair, compute the smallest weight that will result in a color value greater than 1 vfloat4 min_ep1(10.0f); vfloat4 min_ep2(10.0f); vfloat4 ep1 = (vfloat4(1.0f) - ei1.ep.endpt0[0]) / (ei1.ep.endpt1[0] - ei1.ep.endpt0[0]); vmask4 use_ep1 = (ep1 > vfloat4(0.5f)) & (ep1 < min_ep1); min_ep1 = select(min_ep1, ep1, use_ep1); vfloat4 ep2 = (vfloat4(1.0f) - ei2.ep.endpt0[0]) / (ei2.ep.endpt1[0] - ei2.ep.endpt0[0]); vmask4 use_ep2 = (ep2 > vfloat4(0.5f)) & (ep2 < min_ep2); min_ep2 = select(min_ep2, ep2, use_ep2); vfloat4 err_max(ERROR_CALC_DEFAULT); vmask4 err_mask = vint4::lane_id() == vint4(plane2_component); // Set the plane2 component to max error in ep1 min_ep1 = select(min_ep1, err_max, err_mask); float min_wt_cutoff1 = hmin_s(min_ep1); // Set the minwt2 to the plane2 component min in ep2 float min_wt_cutoff2 = hmin_s(select(err_max, min_ep2, err_mask)); compute_angular_endpoints_2planes( bsd, dec_weights_ideal, max_weight_quant, tmpbuf); // For each mode (which specifies a decimation and a quantization): // * Compute number of bits needed for the quantized weights // * Generate an optimized set of quantized weights // * Compute quantization errors for the mode float* weight_low_value1 = tmpbuf.weight_low_value1; float* weight_high_value1 = tmpbuf.weight_high_value1; float* weight_low_value2 = tmpbuf.weight_low_value2; float* weight_high_value2 = tmpbuf.weight_high_value2; int8_t* qwt_bitcounts = tmpbuf.qwt_bitcounts; float* qwt_errors = tmpbuf.qwt_errors; unsigned int start_2plane = bsd.block_mode_count_1plane_selected; unsigned int end_2plane = bsd.block_mode_count_1plane_2plane_selected; for (unsigned int i = start_2plane; i < end_2plane; i++) { const block_mode& bm = bsd.block_modes[i]; assert(bm.is_dual_plane); if (bm.quant_mode > max_weight_quant) { qwt_errors[i] = 1e38f; continue; } qwt_bitcounts[i] = static_cast<int8_t>(109 - bm.weight_bits); if (weight_high_value1[i] > 1.02f * min_wt_cutoff1) { weight_high_value1[i] = 1.0f; } if (weight_high_value2[i] > 1.02f * min_wt_cutoff2) { weight_high_value2[i] = 1.0f; } unsigned int decimation_mode = bm.decimation_mode; const auto& di = bsd.get_decimation_info(decimation_mode); alignas(ASTCENC_VECALIGN) float dec_weights_uquantf[BLOCK_MAX_WEIGHTS]; // Generate the optimized set of weights for the mode compute_quantized_weights_for_decimation( di, weight_low_value1[i], weight_high_value1[i], dec_weights_ideal + BLOCK_MAX_WEIGHTS * decimation_mode, dec_weights_uquantf, dec_weights_uquant + BLOCK_MAX_WEIGHTS * i, bm.get_weight_quant_mode()); compute_quantized_weights_for_decimation( di, weight_low_value2[i], weight_high_value2[i], dec_weights_ideal + BLOCK_MAX_WEIGHTS * decimation_mode + WEIGHTS_PLANE2_OFFSET, dec_weights_uquantf + WEIGHTS_PLANE2_OFFSET, dec_weights_uquant + BLOCK_MAX_WEIGHTS * i + WEIGHTS_PLANE2_OFFSET, bm.get_weight_quant_mode()); // Compute weight quantization errors for the block mode qwt_errors[i] = compute_error_of_weight_set_2planes( ei1, ei2, di, dec_weights_uquantf, dec_weights_uquantf + WEIGHTS_PLANE2_OFFSET); } // Decide the optimal combination of color endpoint encodings and weight encodings uint8_t partition_format_specifiers[TUNE_MAX_TRIAL_CANDIDATES][BLOCK_MAX_PARTITIONS]; int block_mode_index[TUNE_MAX_TRIAL_CANDIDATES]; quant_method color_quant_level[TUNE_MAX_TRIAL_CANDIDATES]; quant_method color_quant_level_mod[TUNE_MAX_TRIAL_CANDIDATES]; endpoints epm; merge_endpoints(ei1.ep, ei2.ep, plane2_component, epm); const auto& pi = bsd.get_partition_info(1, 0); unsigned int candidate_count = compute_ideal_endpoint_formats( pi, blk, epm, qwt_bitcounts, qwt_errors, config.tune_candidate_limit, bsd.block_mode_count_1plane_selected, bsd.block_mode_count_1plane_2plane_selected, partition_format_specifiers, block_mode_index, color_quant_level, color_quant_level_mod, tmpbuf); // Iterate over the N believed-to-be-best modes to find out which one is actually best float best_errorval_in_mode = ERROR_CALC_DEFAULT; float best_errorval_in_scb = scb.errorval; for (unsigned int i = 0; i < candidate_count; i++) { TRACE_NODE(node0, "candidate"); const int bm_packed_index = block_mode_index[i]; assert(bm_packed_index >= static_cast<int>(bsd.block_mode_count_1plane_selected) && bm_packed_index < static_cast<int>(bsd.block_mode_count_1plane_2plane_selected)); const block_mode& qw_bm = bsd.block_modes[bm_packed_index]; int decimation_mode = qw_bm.decimation_mode; const auto& di = bsd.get_decimation_info(decimation_mode); promise(di.weight_count > 0); trace_add_data("weight_x", di.weight_x); trace_add_data("weight_y", di.weight_y); trace_add_data("weight_z", di.weight_z); trace_add_data("weight_quant", qw_bm.quant_mode); vfloat4 rgbs_color; vfloat4 rgbo_color; symbolic_compressed_block workscb; endpoints workep = epm; uint8_t* u8_weight1_src = dec_weights_uquant + BLOCK_MAX_WEIGHTS * bm_packed_index; uint8_t* u8_weight2_src = dec_weights_uquant + BLOCK_MAX_WEIGHTS * bm_packed_index + WEIGHTS_PLANE2_OFFSET; for (int j = 0; j < di.weight_count; j++) { workscb.weights[j] = u8_weight1_src[j]; workscb.weights[j + WEIGHTS_PLANE2_OFFSET] = u8_weight2_src[j]; } for (unsigned int l = 0; l < config.tune_refinement_limit; l++) { recompute_ideal_colors_2planes( blk, bsd, di, workscb.weights, workscb.weights + WEIGHTS_PLANE2_OFFSET, workep, rgbs_color, rgbo_color, plane2_component); // Quantize the chosen color workscb.color_formats[0] = pack_color_endpoints( workep.endpt0[0], workep.endpt1[0], rgbs_color, rgbo_color, partition_format_specifiers[i][0], workscb.color_values[0], color_quant_level[i]); // Store header fields workscb.partition_count = 1; workscb.partition_index = 0; workscb.quant_mode = color_quant_level[i]; workscb.color_formats_matched = 0; workscb.block_mode = qw_bm.mode_index; workscb.plane2_component = static_cast<int8_t>(plane2_component); workscb.block_type = SYM_BTYPE_NONCONST; // Pre-realign test if (l == 0) { float errorval = compute_symbolic_block_difference_2plane(config, bsd, workscb, blk); if (errorval == -ERROR_CALC_DEFAULT) { errorval = -errorval; workscb.block_type = SYM_BTYPE_ERROR; } trace_add_data("error_prerealign", errorval); best_errorval_in_mode = astc::min(errorval, best_errorval_in_mode); // Average refinement improvement is 3.5% per iteration (allow 4.5%), but the first // iteration can help more so we give it a extra 8% leeway. Use this knowledge to // drive a heuristic to skip blocks that are unlikely to catch up with the best // block we have already. unsigned int iters_remaining = config.tune_refinement_limit - l; float threshold = (0.045f * static_cast<float>(iters_remaining)) + 1.08f; if (errorval > (threshold * best_errorval_in_scb)) { break; } if (errorval < best_errorval_in_scb) { best_errorval_in_scb = errorval; workscb.errorval = errorval; scb = workscb; if (errorval < tune_errorval_threshold) { // Skip remaining candidates - this is "good enough" i = candidate_count; break; } } } // Perform a final pass over the weights to try to improve them. bool adjustments; if (di.weight_count != bsd.texel_count) { adjustments = realign_weights_decimated( config.profile, bsd, blk, workscb); } else { adjustments = realign_weights_undecimated( config.profile, bsd, blk, workscb); } // Post-realign test float errorval = compute_symbolic_block_difference_2plane(config, bsd, workscb, blk); if (errorval == -ERROR_CALC_DEFAULT) { errorval = -errorval; workscb.block_type = SYM_BTYPE_ERROR; } trace_add_data("error_postrealign", errorval); best_errorval_in_mode = astc::min(errorval, best_errorval_in_mode); // Average refinement improvement is 3.5% per iteration, so skip blocks that are // unlikely to catch up with the best block we have already. Assume a 4.5% per step to // give benefit of the doubt ... unsigned int iters_remaining = config.tune_refinement_limit - 1 - l; float threshold = (0.045f * static_cast<float>(iters_remaining)) + 1.0f; if (errorval > (threshold * best_errorval_in_scb)) { break; } if (errorval < best_errorval_in_scb) { best_errorval_in_scb = errorval; workscb.errorval = errorval; scb = workscb; if (errorval < tune_errorval_threshold) { // Skip remaining candidates - this is "good enough" i = candidate_count; break; } } if (!adjustments) { break; } } } return best_errorval_in_mode; } /** * @brief Determine the lowest cross-channel correlation factor. * * @param texels_per_block The number of texels in a block. * @param blk The image block color data to compress. * * @return Return the lowest correlation factor. */ static float prepare_block_statistics( int texels_per_block, const image_block& blk ) { // Compute covariance matrix, as a collection of 10 scalars that form the upper-triangular row // of the matrix. The matrix is symmetric, so this is all we need for this use case. float rs = 0.0f; float gs = 0.0f; float bs = 0.0f; float as = 0.0f; float rr_var = 0.0f; float gg_var = 0.0f; float bb_var = 0.0f; float aa_var = 0.0f; float rg_cov = 0.0f; float rb_cov = 0.0f; float ra_cov = 0.0f; float gb_cov = 0.0f; float ga_cov = 0.0f; float ba_cov = 0.0f; float weight_sum = 0.0f; promise(texels_per_block > 0); for (int i = 0; i < texels_per_block; i++) { float weight = hadd_s(blk.channel_weight) / 4.0f; assert(weight >= 0.0f); weight_sum += weight; float r = blk.data_r[i]; float g = blk.data_g[i]; float b = blk.data_b[i]; float a = blk.data_a[i]; float rw = r * weight; rs += rw; rr_var += r * rw; rg_cov += g * rw; rb_cov += b * rw; ra_cov += a * rw; float gw = g * weight; gs += gw; gg_var += g * gw; gb_cov += b * gw; ga_cov += a * gw; float bw = b * weight; bs += bw; bb_var += b * bw; ba_cov += a * bw; float aw = a * weight; as += aw; aa_var += a * aw; } float rpt = 1.0f / astc::max(weight_sum, 1e-7f); rr_var -= rs * (rs * rpt); rg_cov -= gs * (rs * rpt); rb_cov -= bs * (rs * rpt); ra_cov -= as * (rs * rpt); gg_var -= gs * (gs * rpt); gb_cov -= bs * (gs * rpt); ga_cov -= as * (gs * rpt); bb_var -= bs * (bs * rpt); ba_cov -= as * (bs * rpt); aa_var -= as * (as * rpt); // These will give a NaN if a channel is constant - these are fixed up in the next step rg_cov *= astc::rsqrt(rr_var * gg_var); rb_cov *= astc::rsqrt(rr_var * bb_var); ra_cov *= astc::rsqrt(rr_var * aa_var); gb_cov *= astc::rsqrt(gg_var * bb_var); ga_cov *= astc::rsqrt(gg_var * aa_var); ba_cov *= astc::rsqrt(bb_var * aa_var); if (astc::isnan(rg_cov)) rg_cov = 1.0f; if (astc::isnan(rb_cov)) rb_cov = 1.0f; if (astc::isnan(ra_cov)) ra_cov = 1.0f; if (astc::isnan(gb_cov)) gb_cov = 1.0f; if (astc::isnan(ga_cov)) ga_cov = 1.0f; if (astc::isnan(ba_cov)) ba_cov = 1.0f; float lowest_correlation = astc::min(fabsf(rg_cov), fabsf(rb_cov)); lowest_correlation = astc::min(lowest_correlation, fabsf(ra_cov)); lowest_correlation = astc::min(lowest_correlation, fabsf(gb_cov)); lowest_correlation = astc::min(lowest_correlation, fabsf(ga_cov)); lowest_correlation = astc::min(lowest_correlation, fabsf(ba_cov)); // Diagnostic trace points trace_add_data("min_r", blk.data_min.lane<0>()); trace_add_data("max_r", blk.data_max.lane<0>()); trace_add_data("min_g", blk.data_min.lane<1>()); trace_add_data("max_g", blk.data_max.lane<1>()); trace_add_data("min_b", blk.data_min.lane<2>()); trace_add_data("max_b", blk.data_max.lane<2>()); trace_add_data("min_a", blk.data_min.lane<3>()); trace_add_data("max_a", blk.data_max.lane<3>()); trace_add_data("cov_rg", fabsf(rg_cov)); trace_add_data("cov_rb", fabsf(rb_cov)); trace_add_data("cov_ra", fabsf(ra_cov)); trace_add_data("cov_gb", fabsf(gb_cov)); trace_add_data("cov_ga", fabsf(ga_cov)); trace_add_data("cov_ba", fabsf(ba_cov)); return lowest_correlation; } /* See header for documentation. */ void compress_block( const astcenc_contexti& ctx, const image_block& blk, physical_compressed_block& pcb, compression_working_buffers& tmpbuf) { astcenc_profile decode_mode = ctx.config.profile; symbolic_compressed_block scb; const block_size_descriptor& bsd = *ctx.bsd; float lowest_correl; TRACE_NODE(node0, "block"); trace_add_data("pos_x", blk.xpos); trace_add_data("pos_y", blk.ypos); trace_add_data("pos_z", blk.zpos); // Set stricter block targets for luminance data as we have more bits to play with bool block_is_l = blk.is_luminance(); float block_is_l_scale = block_is_l ? 1.0f / 1.5f : 1.0f; // Set slightly stricter block targets for lumalpha data as we have more bits to play with bool block_is_la = blk.is_luminancealpha(); float block_is_la_scale = block_is_la ? 1.0f / 1.05f : 1.0f; bool block_skip_two_plane = false; int max_partitions = ctx.config.tune_partition_count_limit; unsigned int requested_partition_indices[3] { ctx.config.tune_2partition_index_limit, ctx.config.tune_3partition_index_limit, ctx.config.tune_4partition_index_limit }; unsigned int requested_partition_trials[3] { ctx.config.tune_2partitioning_candidate_limit, ctx.config.tune_3partitioning_candidate_limit, ctx.config.tune_4partitioning_candidate_limit }; #if defined(ASTCENC_DIAGNOSTICS) // Do this early in diagnostic builds so we can dump uniform metrics // for every block. Do it later in release builds to avoid redundant work! float error_weight_sum = hadd_s(blk.channel_weight) * bsd.texel_count; float error_threshold = ctx.config.tune_db_limit * error_weight_sum * block_is_l_scale * block_is_la_scale; lowest_correl = prepare_block_statistics(bsd.texel_count, blk); trace_add_data("lowest_correl", lowest_correl); trace_add_data("tune_error_threshold", error_threshold); #endif // Detected a constant-color block if (all(blk.data_min == blk.data_max)) { TRACE_NODE(node1, "pass"); trace_add_data("partition_count", 0); trace_add_data("plane_count", 1); scb.partition_count = 0; // Encode as FP16 if using HDR if ((decode_mode == ASTCENC_PRF_HDR) || (decode_mode == ASTCENC_PRF_HDR_RGB_LDR_A)) { scb.block_type = SYM_BTYPE_CONST_F16; vint4 color_f16 = float_to_float16(blk.origin_texel); store(color_f16, scb.constant_color); } // Encode as UNORM16 if NOT using HDR else { scb.block_type = SYM_BTYPE_CONST_U16; vfloat4 color_f32 = clamp(0.0f, 1.0f, blk.origin_texel) * 65535.0f; vint4 color_u16 = float_to_int_rtn(color_f32); store(color_u16, scb.constant_color); } trace_add_data("exit", "quality hit"); symbolic_to_physical(bsd, scb, pcb); return; } #if !defined(ASTCENC_DIAGNOSTICS) float error_weight_sum = hadd_s(blk.channel_weight) * bsd.texel_count; float error_threshold = ctx.config.tune_db_limit * error_weight_sum * block_is_l_scale * block_is_la_scale; #endif // Set SCB and mode errors to a very high error value scb.errorval = ERROR_CALC_DEFAULT; scb.block_type = SYM_BTYPE_ERROR; float best_errorvals_for_pcount[BLOCK_MAX_PARTITIONS] { ERROR_CALC_DEFAULT, ERROR_CALC_DEFAULT, ERROR_CALC_DEFAULT, ERROR_CALC_DEFAULT }; float exit_thresholds_for_pcount[BLOCK_MAX_PARTITIONS] { 0.0f, ctx.config.tune_2partition_early_out_limit_factor, ctx.config.tune_3partition_early_out_limit_factor, 0.0f }; // Trial using 1 plane of weights and 1 partition. // Most of the time we test it twice, first with a mode cutoff of 0 and then with the specified // mode cutoff. This causes an early-out that speeds up encoding of easy blocks. However, this // optimization is disabled for 4x4 and 5x4 blocks where it nearly always slows down the // compression and slightly reduces image quality. float errorval_mult[2] { 1.0f / ctx.config.tune_mse_overshoot, 1.0f }; static const float errorval_overshoot = 1.0f / ctx.config.tune_mse_overshoot; // Only enable MODE0 fast path (trial 0) if 2D, and more than 25 texels int start_trial = 1; if ((bsd.texel_count >= TUNE_MIN_TEXELS_MODE0_FASTPATH) && (bsd.zdim == 1)) { start_trial = 0; } int quant_limit = QUANT_32; for (int i = start_trial; i < 2; i++) { TRACE_NODE(node1, "pass"); trace_add_data("partition_count", 1); trace_add_data("plane_count", 1); trace_add_data("search_mode", i); float errorval = compress_symbolic_block_for_partition_1plane( ctx.config, bsd, blk, i == 0, error_threshold * errorval_mult[i] * errorval_overshoot, 1, 0, scb, tmpbuf, QUANT_32); // Record the quant level so we can use the filter later searches const auto& bm = bsd.get_block_mode(scb.block_mode); quant_limit = bm.get_weight_quant_mode(); best_errorvals_for_pcount[0] = astc::min(best_errorvals_for_pcount[0], errorval); if (errorval < (error_threshold * errorval_mult[i])) { trace_add_data("exit", "quality hit"); goto END_OF_TESTS; } } #if !defined(ASTCENC_DIAGNOSTICS) lowest_correl = prepare_block_statistics(bsd.texel_count, blk); #endif block_skip_two_plane = lowest_correl > ctx.config.tune_2plane_early_out_limit_correlation; // Test the four possible 1-partition, 2-planes modes. Do this in reverse, as // alpha is the most likely to be non-correlated if it is present in the data. for (int i = BLOCK_MAX_COMPONENTS - 1; i >= 0; i--) { TRACE_NODE(node1, "pass"); trace_add_data("partition_count", 1); trace_add_data("plane_count", 2); trace_add_data("plane_component", i); if (block_skip_two_plane) { trace_add_data("skip", "tune_2plane_early_out_limit_correlation"); continue; } if (blk.grayscale && i != 3) { trace_add_data("skip", "grayscale block"); continue; } if (blk.is_constant_channel(i)) { trace_add_data("skip", "constant component"); continue; } float errorval = compress_symbolic_block_for_partition_2planes( ctx.config, bsd, blk, error_threshold * errorval_overshoot, i, scb, tmpbuf, quant_limit); // If attempting two planes is much worse than the best one plane result // then further two plane searches are unlikely to help so move on ... if (errorval > (best_errorvals_for_pcount[0] * 1.85f)) { break; } if (errorval < error_threshold) { trace_add_data("exit", "quality hit"); goto END_OF_TESTS; } } // Find best blocks for 2, 3 and 4 partitions for (int partition_count = 2; partition_count <= max_partitions; partition_count++) { unsigned int partition_indices[TUNE_MAX_PARTITIONING_CANDIDATES]; unsigned int requested_indices = requested_partition_indices[partition_count - 2]; unsigned int requested_trials = requested_partition_trials[partition_count - 2]; requested_trials = astc::min(requested_trials, requested_indices); unsigned int actual_trials = find_best_partition_candidates( bsd, blk, partition_count, requested_indices, partition_indices, requested_trials); float best_error_in_prev = best_errorvals_for_pcount[partition_count - 2]; for (unsigned int i = 0; i < actual_trials; i++) { TRACE_NODE(node1, "pass"); trace_add_data("partition_count", partition_count); trace_add_data("partition_index", partition_indices[i]); trace_add_data("plane_count", 1); trace_add_data("search_mode", i); float errorval = compress_symbolic_block_for_partition_1plane( ctx.config, bsd, blk, false, error_threshold * errorval_overshoot, partition_count, partition_indices[i], scb, tmpbuf, quant_limit); best_errorvals_for_pcount[partition_count - 1] = astc::min(best_errorvals_for_pcount[partition_count - 1], errorval); // If using N partitions doesn't improve much over using N-1 partitions then skip trying // N+1. Error can dramatically improve if the data is correlated or non-correlated and // aligns with a partitioning that suits that encoding, so for this inner loop check add // a large error scale because the "other" trial could be a lot better. float best_error = best_errorvals_for_pcount[partition_count - 1]; float best_error_scale = exit_thresholds_for_pcount[partition_count - 1] * 1.85f; if (best_error > (best_error_in_prev * best_error_scale)) { trace_add_data("skip", "tune_partition_early_out_limit_factor"); goto END_OF_TESTS; } if (errorval < error_threshold) { trace_add_data("exit", "quality hit"); goto END_OF_TESTS; } } // If using N partitions doesn't improve much over using N-1 partitions then skip trying N+1 float best_error = best_errorvals_for_pcount[partition_count - 1]; float best_error_scale = exit_thresholds_for_pcount[partition_count - 1]; if (best_error > (best_error_in_prev * best_error_scale)) { trace_add_data("skip", "tune_partition_early_out_limit_factor"); goto END_OF_TESTS; } } trace_add_data("exit", "quality not hit"); END_OF_TESTS: // If we still have an error block then convert to something we can encode // TODO: Do something more sensible here, such as average color block if (scb.block_type == SYM_BTYPE_ERROR) { #if defined(ASTCENC_DIAGNOSTICS) static bool printed_once = false; if (!printed_once) { printed_once = true; printf("WARN: At least one block failed to find a valid encoding.\n" " Try increasing compression quality settings.\n\n"); } #endif scb.block_type = SYM_BTYPE_CONST_U16; vfloat4 color_f32 = clamp(0.0f, 1.0f, blk.origin_texel) * 65535.0f; vint4 color_u16 = float_to_int_rtn(color_f32); store(color_u16, scb.constant_color); } // Compress to a physical block symbolic_to_physical(bsd, scb, pcb); } #endif