astcenc_ideal_endpoints_and_weights.cpp

// SPDX-License-Identifier: Apache-2.0
// ----------------------------------------------------------------------------
// Copyright 2011-2024 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 for computing color endpoints and texel weights.
 */

#include <cassert>

#include "astcenc_internal.h"
#include "astcenc_vecmathlib.h"

/**
 * @brief Compute the infilled weight for N texel indices in a decimated grid.
 *
 * @param di        The weight grid decimation to use.
 * @param weights   The decimated weight values to use.
 * @param index     The first texel index to interpolate.
 *
 * @return The interpolated weight for the given set of SIMD_WIDTH texels.
 */
static vfloat bilinear_infill_vla(
	const decimation_info& di,
	const float* weights,
	unsigned int index
) { … }

/**
 * @brief Compute the infilled weight for N texel indices in a decimated grid.
 *
 * This is specialized version which computes only two weights per texel for
 * encodings that are only decimated in a single axis.
 *
 * @param di        The weight grid decimation to use.
 * @param weights   The decimated weight values to use.
 * @param index     The first texel index to interpolate.
 *
 * @return The interpolated weight for the given set of SIMD_WIDTH texels.
 */
static vfloat bilinear_infill_vla_2(
	const decimation_info& di,
	const float* weights,
	unsigned int index
) { … }

/**
 * @brief Compute the ideal endpoints and weights for 1 color component.
 *
 * @param      blk         The image block color data to compress.
 * @param      pi          The partition info for the current trial.
 * @param[out] ei          The computed ideal endpoints and weights.
 * @param      component   The color component to compute.
 */
static void compute_ideal_colors_and_weights_1_comp(
	const image_block& blk,
	const partition_info& pi,
	endpoints_and_weights& ei,
	unsigned int component
) { … }

/**
 * @brief Compute the ideal endpoints and weights for 2 color components.
 *
 * @param      blk          The image block color data to compress.
 * @param      pi           The partition info for the current trial.
 * @param[out] ei           The computed ideal endpoints and weights.
 * @param      component1   The first color component to compute.
 * @param      component2   The second color component to compute.
 */
static void compute_ideal_colors_and_weights_2_comp(
	const image_block& blk,
	const partition_info& pi,
	endpoints_and_weights& ei,
	int component1,
	int component2
) { … }

/**
 * @brief Compute the ideal endpoints and weights for 3 color components.
 *
 * @param      blk                 The image block color data to compress.
 * @param      pi                  The partition info for the current trial.
 * @param[out] ei                  The computed ideal endpoints and weights.
 * @param      omitted_component   The color component excluded from the calculation.
 */
static void compute_ideal_colors_and_weights_3_comp(
	const image_block& blk,
	const partition_info& pi,
	endpoints_and_weights& ei,
	unsigned int omitted_component
) { … }

/**
 * @brief Compute the ideal endpoints and weights for 4 color components.
 *
 * @param      blk   The image block color data to compress.
 * @param      pi    The partition info for the current trial.
 * @param[out] ei    The computed ideal endpoints and weights.
 */
static void compute_ideal_colors_and_weights_4_comp(
	const image_block& blk,
	const partition_info& pi,
	endpoints_and_weights& ei
) { … }

/* See header for documentation. */
void compute_ideal_colors_and_weights_1plane(
	const image_block& blk,
	const partition_info& pi,
	endpoints_and_weights& ei
) { … }

/* See header for documentation. */
void compute_ideal_colors_and_weights_2planes(
	const block_size_descriptor& bsd,
	const image_block& blk,
	unsigned int plane2_component,
	endpoints_and_weights& ei1,
	endpoints_and_weights& ei2
) { … }

/* See header for documentation. */
float compute_error_of_weight_set_1plane(
	const endpoints_and_weights& eai,
	const decimation_info& di,
	const float* dec_weight_quant_uvalue
) { … }

/* See header for documentation. */
float compute_error_of_weight_set_2planes(
	const endpoints_and_weights& eai1,
	const endpoints_and_weights& eai2,
	const decimation_info& di,
	const float* dec_weight_quant_uvalue_plane1,
	const float* dec_weight_quant_uvalue_plane2
) { … }

/* See header for documentation. */
void compute_ideal_weights_for_decimation(
	const endpoints_and_weights& ei,
	const decimation_info& di,
	float* dec_weight_ideal_value
) { … }

/* See header for documentation. */
void compute_quantized_weights_for_decimation(
	const decimation_info& di,
	float low_bound,
	float high_bound,
	const float* dec_weight_ideal_value,
	float* weight_set_out,
	uint8_t* quantized_weight_set,
	quant_method quant_level
) { … }

/**
 * @brief Compute the RGB + offset for a HDR endpoint mode #7.
 *
 * Since the matrix needed has a regular structure we can simplify the inverse calculation. This
 * gives us ~24 multiplications vs. 96 for a generic inverse.
 *
 *  mat[0] = vfloat4(rgba_ws.x,      0.0f,      0.0f, wght_ws.x);
 *  mat[1] = vfloat4(     0.0f, rgba_ws.y,      0.0f, wght_ws.y);
 *  mat[2] = vfloat4(     0.0f,      0.0f, rgba_ws.z, wght_ws.z);
 *  mat[3] = vfloat4(wght_ws.x, wght_ws.y, wght_ws.z,      psum);
 *  mat = invert(mat);
 *
 * @param rgba_weight_sum     Sum of partition component error weights.
 * @param weight_weight_sum   Sum of partition component error weights * texel weight.
 * @param rgbq_sum            Sum of partition component error weights * texel weight * color data.
 * @param psum                Sum of RGB color weights * texel weight^2.
 */
static inline vfloat4 compute_rgbo_vector(
	vfloat4 rgba_weight_sum,
	vfloat4 weight_weight_sum,
	vfloat4 rgbq_sum,
	float psum
) { … }

/* See header for documentation. */
void recompute_ideal_colors_1plane(
	const image_block& blk,
	const partition_info& pi,
	const decimation_info& di,
	const uint8_t* dec_weights_uquant,
	endpoints& ep,
	vfloat4 rgbs_vectors[BLOCK_MAX_PARTITIONS],
	vfloat4 rgbo_vectors[BLOCK_MAX_PARTITIONS]
) { … }

/* See header for documentation. */
void recompute_ideal_colors_2planes(
	const image_block& blk,
	const block_size_descriptor& bsd,
	const decimation_info& di,
	const uint8_t* dec_weights_uquant_plane1,
	const uint8_t* dec_weights_uquant_plane2,
	endpoints& ep,
	vfloat4& rgbs_vector,
	vfloat4& rgbo_vector,
	int plane2_component
) { … }

#endif
godot/thirdparty/astcenc/astcenc_ideal_endpoints_and_weights.cpp
