godot/thirdparty/astcenc/astcenc_block_sizes.cpp

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// 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.
// ----------------------------------------------------------------------------
/**
* @brief Functions to generate block size descriptor and decimation tables.
*/
#include "astcenc_internal.h"
/**
* @brief Decode the properties of an encoded 2D block mode.
*
* @param block_mode The encoded block mode.
* @param[out] x_weights The number of weights in the X dimension.
* @param[out] y_weights The number of weights in the Y dimension.
* @param[out] is_dual_plane True if this block mode has two weight planes.
* @param[out] quant_mode The quantization level for the weights.
* @param[out] weight_bits The storage bit count for the weights.
*
* @return Returns true if a valid mode, false otherwise.
*/
static bool decode_block_mode_2d(
unsigned int block_mode,
unsigned int& x_weights,
unsigned int& y_weights,
bool& is_dual_plane,
unsigned int& quant_mode,
unsigned int& weight_bits
) {
unsigned int base_quant_mode = (block_mode >> 4) & 1;
unsigned int H = (block_mode >> 9) & 1;
unsigned int D = (block_mode >> 10) & 1;
unsigned int A = (block_mode >> 5) & 0x3;
x_weights = 0;
y_weights = 0;
if ((block_mode & 3) != 0)
{
base_quant_mode |= (block_mode & 3) << 1;
unsigned int B = (block_mode >> 7) & 3;
switch ((block_mode >> 2) & 3)
{
case 0:
x_weights = B + 4;
y_weights = A + 2;
break;
case 1:
x_weights = B + 8;
y_weights = A + 2;
break;
case 2:
x_weights = A + 2;
y_weights = B + 8;
break;
case 3:
B &= 1;
if (block_mode & 0x100)
{
x_weights = B + 2;
y_weights = A + 2;
}
else
{
x_weights = A + 2;
y_weights = B + 6;
}
break;
}
}
else
{
base_quant_mode |= ((block_mode >> 2) & 3) << 1;
if (((block_mode >> 2) & 3) == 0)
{
return false;
}
unsigned int B = (block_mode >> 9) & 3;
switch ((block_mode >> 7) & 3)
{
case 0:
x_weights = 12;
y_weights = A + 2;
break;
case 1:
x_weights = A + 2;
y_weights = 12;
break;
case 2:
x_weights = A + 6;
y_weights = B + 6;
D = 0;
H = 0;
break;
case 3:
switch ((block_mode >> 5) & 3)
{
case 0:
x_weights = 6;
y_weights = 10;
break;
case 1:
x_weights = 10;
y_weights = 6;
break;
case 2:
case 3:
return false;
}
break;
}
}
unsigned int weight_count = x_weights * y_weights * (D + 1);
quant_mode = (base_quant_mode - 2) + 6 * H;
is_dual_plane = D != 0;
weight_bits = get_ise_sequence_bitcount(weight_count, static_cast<quant_method>(quant_mode));
return (weight_count <= BLOCK_MAX_WEIGHTS &&
weight_bits >= BLOCK_MIN_WEIGHT_BITS &&
weight_bits <= BLOCK_MAX_WEIGHT_BITS);
}
/**
* @brief Decode the properties of an encoded 3D block mode.
*
* @param block_mode The encoded block mode.
* @param[out] x_weights The number of weights in the X dimension.
* @param[out] y_weights The number of weights in the Y dimension.
* @param[out] z_weights The number of weights in the Z dimension.
* @param[out] is_dual_plane True if this block mode has two weight planes.
* @param[out] quant_mode The quantization level for the weights.
* @param[out] weight_bits The storage bit count for the weights.
*
* @return Returns true if a valid mode, false otherwise.
*/
static bool decode_block_mode_3d(
unsigned int block_mode,
unsigned int& x_weights,
unsigned int& y_weights,
unsigned int& z_weights,
bool& is_dual_plane,
unsigned int& quant_mode,
unsigned int& weight_bits
) {
unsigned int base_quant_mode = (block_mode >> 4) & 1;
unsigned int H = (block_mode >> 9) & 1;
unsigned int D = (block_mode >> 10) & 1;
unsigned int A = (block_mode >> 5) & 0x3;
x_weights = 0;
y_weights = 0;
z_weights = 0;
if ((block_mode & 3) != 0)
{
base_quant_mode |= (block_mode & 3) << 1;
unsigned int B = (block_mode >> 7) & 3;
unsigned int C = (block_mode >> 2) & 0x3;
x_weights = A + 2;
y_weights = B + 2;
z_weights = C + 2;
}
else
{
base_quant_mode |= ((block_mode >> 2) & 3) << 1;
if (((block_mode >> 2) & 3) == 0)
{
return false;
}
int B = (block_mode >> 9) & 3;
if (((block_mode >> 7) & 3) != 3)
{
D = 0;
H = 0;
}
switch ((block_mode >> 7) & 3)
{
case 0:
x_weights = 6;
y_weights = B + 2;
z_weights = A + 2;
break;
case 1:
x_weights = A + 2;
y_weights = 6;
z_weights = B + 2;
break;
case 2:
x_weights = A + 2;
y_weights = B + 2;
z_weights = 6;
break;
case 3:
x_weights = 2;
y_weights = 2;
z_weights = 2;
switch ((block_mode >> 5) & 3)
{
case 0:
x_weights = 6;
break;
case 1:
y_weights = 6;
break;
case 2:
z_weights = 6;
break;
case 3:
return false;
}
break;
}
}
unsigned int weight_count = x_weights * y_weights * z_weights * (D + 1);
quant_mode = (base_quant_mode - 2) + 6 * H;
is_dual_plane = D != 0;
weight_bits = get_ise_sequence_bitcount(weight_count, static_cast<quant_method>(quant_mode));
return (weight_count <= BLOCK_MAX_WEIGHTS &&
weight_bits >= BLOCK_MIN_WEIGHT_BITS &&
weight_bits <= BLOCK_MAX_WEIGHT_BITS);
}
/**
* @brief Create a 2D decimation entry for a block-size and weight-decimation pair.
*
* @param x_texels The number of texels in the X dimension.
* @param y_texels The number of texels in the Y dimension.
* @param x_weights The number of weights in the X dimension.
* @param y_weights The number of weights in the Y dimension.
* @param[out] di The decimation info structure to populate.
* @param[out] wb The decimation table init scratch working buffers.
*/
static void init_decimation_info_2d(
unsigned int x_texels,
unsigned int y_texels,
unsigned int x_weights,
unsigned int y_weights,
decimation_info& di,
dt_init_working_buffers& wb
) {
unsigned int texels_per_block = x_texels * y_texels;
unsigned int weights_per_block = x_weights * y_weights;
uint8_t max_texel_count_of_weight = 0;
promise(weights_per_block > 0);
promise(texels_per_block > 0);
promise(x_texels > 0);
promise(y_texels > 0);
for (unsigned int i = 0; i < weights_per_block; i++)
{
wb.texel_count_of_weight[i] = 0;
}
for (unsigned int i = 0; i < texels_per_block; i++)
{
wb.weight_count_of_texel[i] = 0;
}
for (unsigned int y = 0; y < y_texels; y++)
{
for (unsigned int x = 0; x < x_texels; x++)
{
unsigned int texel = y * x_texels + x;
unsigned int x_weight = (((1024 + x_texels / 2) / (x_texels - 1)) * x * (x_weights - 1) + 32) >> 6;
unsigned int y_weight = (((1024 + y_texels / 2) / (y_texels - 1)) * y * (y_weights - 1) + 32) >> 6;
unsigned int x_weight_frac = x_weight & 0xF;
unsigned int y_weight_frac = y_weight & 0xF;
unsigned int x_weight_int = x_weight >> 4;
unsigned int y_weight_int = y_weight >> 4;
unsigned int qweight[4];
qweight[0] = x_weight_int + y_weight_int * x_weights;
qweight[1] = qweight[0] + 1;
qweight[2] = qweight[0] + x_weights;
qweight[3] = qweight[2] + 1;
// Truncated-precision bilinear interpolation
unsigned int prod = x_weight_frac * y_weight_frac;
unsigned int weight[4];
weight[3] = (prod + 8) >> 4;
weight[1] = x_weight_frac - weight[3];
weight[2] = y_weight_frac - weight[3];
weight[0] = 16 - x_weight_frac - y_weight_frac + weight[3];
for (unsigned int i = 0; i < 4; i++)
{
if (weight[i] != 0)
{
wb.grid_weights_of_texel[texel][wb.weight_count_of_texel[texel]] = static_cast<uint8_t>(qweight[i]);
wb.weights_of_texel[texel][wb.weight_count_of_texel[texel]] = static_cast<uint8_t>(weight[i]);
wb.weight_count_of_texel[texel]++;
wb.texels_of_weight[qweight[i]][wb.texel_count_of_weight[qweight[i]]] = static_cast<uint8_t>(texel);
wb.texel_weights_of_weight[qweight[i]][wb.texel_count_of_weight[qweight[i]]] = static_cast<uint8_t>(weight[i]);
wb.texel_count_of_weight[qweight[i]]++;
max_texel_count_of_weight = astc::max(max_texel_count_of_weight, wb.texel_count_of_weight[qweight[i]]);
}
}
}
}
uint8_t max_texel_weight_count = 0;
for (unsigned int i = 0; i < texels_per_block; i++)
{
di.texel_weight_count[i] = wb.weight_count_of_texel[i];
max_texel_weight_count = astc::max(max_texel_weight_count, di.texel_weight_count[i]);
for (unsigned int j = 0; j < wb.weight_count_of_texel[i]; j++)
{
di.texel_weight_contribs_int_tr[j][i] = wb.weights_of_texel[i][j];
di.texel_weight_contribs_float_tr[j][i] = static_cast<float>(wb.weights_of_texel[i][j]) * (1.0f / WEIGHTS_TEXEL_SUM);
di.texel_weights_tr[j][i] = wb.grid_weights_of_texel[i][j];
}
// Init all 4 entries so we can rely on zeros for vectorization
for (unsigned int j = wb.weight_count_of_texel[i]; j < 4; j++)
{
di.texel_weight_contribs_int_tr[j][i] = 0;
di.texel_weight_contribs_float_tr[j][i] = 0.0f;
di.texel_weights_tr[j][i] = 0;
}
}
di.max_texel_weight_count = max_texel_weight_count;
for (unsigned int i = 0; i < weights_per_block; i++)
{
unsigned int texel_count_wt = wb.texel_count_of_weight[i];
di.weight_texel_count[i] = static_cast<uint8_t>(texel_count_wt);
for (unsigned int j = 0; j < texel_count_wt; j++)
{
uint8_t texel = wb.texels_of_weight[i][j];
// Create transposed versions of these for better vectorization
di.weight_texels_tr[j][i] = texel;
di.weights_texel_contribs_tr[j][i] = static_cast<float>(wb.texel_weights_of_weight[i][j]);
// Store the per-texel contribution of this weight for each texel it contributes to
di.texel_contrib_for_weight[j][i] = 0.0f;
for (unsigned int k = 0; k < 4; k++)
{
uint8_t dttw = di.texel_weights_tr[k][texel];
float dttwf = di.texel_weight_contribs_float_tr[k][texel];
if (dttw == i && dttwf != 0.0f)
{
di.texel_contrib_for_weight[j][i] = di.texel_weight_contribs_float_tr[k][texel];
break;
}
}
}
// Initialize array tail so we can over-fetch with SIMD later to avoid loop tails
// Match last texel in active lane in SIMD group, for better gathers
uint8_t last_texel = di.weight_texels_tr[texel_count_wt - 1][i];
for (unsigned int j = texel_count_wt; j < max_texel_count_of_weight; j++)
{
di.weight_texels_tr[j][i] = last_texel;
di.weights_texel_contribs_tr[j][i] = 0.0f;
}
}
// Initialize array tail so we can over-fetch with SIMD later to avoid loop tails
unsigned int texels_per_block_simd = round_up_to_simd_multiple_vla(texels_per_block);
for (unsigned int i = texels_per_block; i < texels_per_block_simd; i++)
{
di.texel_weight_count[i] = 0;
for (unsigned int j = 0; j < 4; j++)
{
di.texel_weight_contribs_float_tr[j][i] = 0;
di.texel_weights_tr[j][i] = 0;
di.texel_weight_contribs_int_tr[j][i] = 0;
}
}
// Initialize array tail so we can over-fetch with SIMD later to avoid loop tails
// Match last texel in active lane in SIMD group, for better gathers
unsigned int last_texel_count_wt = wb.texel_count_of_weight[weights_per_block - 1];
uint8_t last_texel = di.weight_texels_tr[last_texel_count_wt - 1][weights_per_block - 1];
unsigned int weights_per_block_simd = round_up_to_simd_multiple_vla(weights_per_block);
for (unsigned int i = weights_per_block; i < weights_per_block_simd; i++)
{
di.weight_texel_count[i] = 0;
for (unsigned int j = 0; j < max_texel_count_of_weight; j++)
{
di.weight_texels_tr[j][i] = last_texel;
di.weights_texel_contribs_tr[j][i] = 0.0f;
}
}
di.texel_count = static_cast<uint8_t>(texels_per_block);
di.weight_count = static_cast<uint8_t>(weights_per_block);
di.weight_x = static_cast<uint8_t>(x_weights);
di.weight_y = static_cast<uint8_t>(y_weights);
di.weight_z = 1;
}
/**
* @brief Create a 3D decimation entry for a block-size and weight-decimation pair.
*
* @param x_texels The number of texels in the X dimension.
* @param y_texels The number of texels in the Y dimension.
* @param z_texels The number of texels in the Z dimension.
* @param x_weights The number of weights in the X dimension.
* @param y_weights The number of weights in the Y dimension.
* @param z_weights The number of weights in the Z dimension.
* @param[out] di The decimation info structure to populate.
@param[out] wb The decimation table init scratch working buffers.
*/
static void init_decimation_info_3d(
unsigned int x_texels,
unsigned int y_texels,
unsigned int z_texels,
unsigned int x_weights,
unsigned int y_weights,
unsigned int z_weights,
decimation_info& di,
dt_init_working_buffers& wb
) {
unsigned int texels_per_block = x_texels * y_texels * z_texels;
unsigned int weights_per_block = x_weights * y_weights * z_weights;
uint8_t max_texel_count_of_weight = 0;
promise(weights_per_block > 0);
promise(texels_per_block > 0);
for (unsigned int i = 0; i < weights_per_block; i++)
{
wb.texel_count_of_weight[i] = 0;
}
for (unsigned int i = 0; i < texels_per_block; i++)
{
wb.weight_count_of_texel[i] = 0;
}
for (unsigned int z = 0; z < z_texels; z++)
{
for (unsigned int y = 0; y < y_texels; y++)
{
for (unsigned int x = 0; x < x_texels; x++)
{
int texel = (z * y_texels + y) * x_texels + x;
int x_weight = (((1024 + x_texels / 2) / (x_texels - 1)) * x * (x_weights - 1) + 32) >> 6;
int y_weight = (((1024 + y_texels / 2) / (y_texels - 1)) * y * (y_weights - 1) + 32) >> 6;
int z_weight = (((1024 + z_texels / 2) / (z_texels - 1)) * z * (z_weights - 1) + 32) >> 6;
int x_weight_frac = x_weight & 0xF;
int y_weight_frac = y_weight & 0xF;
int z_weight_frac = z_weight & 0xF;
int x_weight_int = x_weight >> 4;
int y_weight_int = y_weight >> 4;
int z_weight_int = z_weight >> 4;
int qweight[4];
int weight[4];
qweight[0] = (z_weight_int * y_weights + y_weight_int) * x_weights + x_weight_int;
qweight[3] = ((z_weight_int + 1) * y_weights + (y_weight_int + 1)) * x_weights + (x_weight_int + 1);
// simplex interpolation
int fs = x_weight_frac;
int ft = y_weight_frac;
int fp = z_weight_frac;
int cas = ((fs > ft) << 2) + ((ft > fp) << 1) + ((fs > fp));
int N = x_weights;
int NM = x_weights * y_weights;
int s1, s2, w0, w1, w2, w3;
switch (cas)
{
case 7:
s1 = 1;
s2 = N;
w0 = 16 - fs;
w1 = fs - ft;
w2 = ft - fp;
w3 = fp;
break;
case 3:
s1 = N;
s2 = 1;
w0 = 16 - ft;
w1 = ft - fs;
w2 = fs - fp;
w3 = fp;
break;
case 5:
s1 = 1;
s2 = NM;
w0 = 16 - fs;
w1 = fs - fp;
w2 = fp - ft;
w3 = ft;
break;
case 4:
s1 = NM;
s2 = 1;
w0 = 16 - fp;
w1 = fp - fs;
w2 = fs - ft;
w3 = ft;
break;
case 2:
s1 = N;
s2 = NM;
w0 = 16 - ft;
w1 = ft - fp;
w2 = fp - fs;
w3 = fs;
break;
case 0:
s1 = NM;
s2 = N;
w0 = 16 - fp;
w1 = fp - ft;
w2 = ft - fs;
w3 = fs;
break;
default:
s1 = NM;
s2 = N;
w0 = 16 - fp;
w1 = fp - ft;
w2 = ft - fs;
w3 = fs;
break;
}
qweight[1] = qweight[0] + s1;
qweight[2] = qweight[1] + s2;
weight[0] = w0;
weight[1] = w1;
weight[2] = w2;
weight[3] = w3;
for (unsigned int i = 0; i < 4; i++)
{
if (weight[i] != 0)
{
wb.grid_weights_of_texel[texel][wb.weight_count_of_texel[texel]] = static_cast<uint8_t>(qweight[i]);
wb.weights_of_texel[texel][wb.weight_count_of_texel[texel]] = static_cast<uint8_t>(weight[i]);
wb.weight_count_of_texel[texel]++;
wb.texels_of_weight[qweight[i]][wb.texel_count_of_weight[qweight[i]]] = static_cast<uint8_t>(texel);
wb.texel_weights_of_weight[qweight[i]][wb.texel_count_of_weight[qweight[i]]] = static_cast<uint8_t>(weight[i]);
wb.texel_count_of_weight[qweight[i]]++;
max_texel_count_of_weight = astc::max(max_texel_count_of_weight, wb.texel_count_of_weight[qweight[i]]);
}
}
}
}
}
uint8_t max_texel_weight_count = 0;
for (unsigned int i = 0; i < texels_per_block; i++)
{
di.texel_weight_count[i] = wb.weight_count_of_texel[i];
max_texel_weight_count = astc::max(max_texel_weight_count, di.texel_weight_count[i]);
// Init all 4 entries so we can rely on zeros for vectorization
for (unsigned int j = 0; j < 4; j++)
{
di.texel_weight_contribs_int_tr[j][i] = 0;
di.texel_weight_contribs_float_tr[j][i] = 0.0f;
di.texel_weights_tr[j][i] = 0;
}
for (unsigned int j = 0; j < wb.weight_count_of_texel[i]; j++)
{
di.texel_weight_contribs_int_tr[j][i] = wb.weights_of_texel[i][j];
di.texel_weight_contribs_float_tr[j][i] = static_cast<float>(wb.weights_of_texel[i][j]) * (1.0f / WEIGHTS_TEXEL_SUM);
di.texel_weights_tr[j][i] = wb.grid_weights_of_texel[i][j];
}
}
di.max_texel_weight_count = max_texel_weight_count;
for (unsigned int i = 0; i < weights_per_block; i++)
{
unsigned int texel_count_wt = wb.texel_count_of_weight[i];
di.weight_texel_count[i] = static_cast<uint8_t>(texel_count_wt);
for (unsigned int j = 0; j < texel_count_wt; j++)
{
unsigned int texel = wb.texels_of_weight[i][j];
// Create transposed versions of these for better vectorization
di.weight_texels_tr[j][i] = static_cast<uint8_t>(texel);
di.weights_texel_contribs_tr[j][i] = static_cast<float>(wb.texel_weights_of_weight[i][j]);
// Store the per-texel contribution of this weight for each texel it contributes to
di.texel_contrib_for_weight[j][i] = 0.0f;
for (unsigned int k = 0; k < 4; k++)
{
uint8_t dttw = di.texel_weights_tr[k][texel];
float dttwf = di.texel_weight_contribs_float_tr[k][texel];
if (dttw == i && dttwf != 0.0f)
{
di.texel_contrib_for_weight[j][i] = di.texel_weight_contribs_float_tr[k][texel];
break;
}
}
}
// Initialize array tail so we can over-fetch with SIMD later to avoid loop tails
// Match last texel in active lane in SIMD group, for better gathers
uint8_t last_texel = di.weight_texels_tr[texel_count_wt - 1][i];
for (unsigned int j = texel_count_wt; j < max_texel_count_of_weight; j++)
{
di.weight_texels_tr[j][i] = last_texel;
di.weights_texel_contribs_tr[j][i] = 0.0f;
}
}
// Initialize array tail so we can over-fetch with SIMD later to avoid loop tails
unsigned int texels_per_block_simd = round_up_to_simd_multiple_vla(texels_per_block);
for (unsigned int i = texels_per_block; i < texels_per_block_simd; i++)
{
di.texel_weight_count[i] = 0;
for (unsigned int j = 0; j < 4; j++)
{
di.texel_weight_contribs_float_tr[j][i] = 0;
di.texel_weights_tr[j][i] = 0;
di.texel_weight_contribs_int_tr[j][i] = 0;
}
}
// Initialize array tail so we can over-fetch with SIMD later to avoid loop tails
// Match last texel in active lane in SIMD group, for better gathers
int last_texel_count_wt = wb.texel_count_of_weight[weights_per_block - 1];
uint8_t last_texel = di.weight_texels_tr[last_texel_count_wt - 1][weights_per_block - 1];
unsigned int weights_per_block_simd = round_up_to_simd_multiple_vla(weights_per_block);
for (unsigned int i = weights_per_block; i < weights_per_block_simd; i++)
{
di.weight_texel_count[i] = 0;
for (int j = 0; j < max_texel_count_of_weight; j++)
{
di.weight_texels_tr[j][i] = last_texel;
di.weights_texel_contribs_tr[j][i] = 0.0f;
}
}
di.texel_count = static_cast<uint8_t>(texels_per_block);
di.weight_count = static_cast<uint8_t>(weights_per_block);
di.weight_x = static_cast<uint8_t>(x_weights);
di.weight_y = static_cast<uint8_t>(y_weights);
di.weight_z = static_cast<uint8_t>(z_weights);
}
/**
* @brief Assign the texels to use for kmeans clustering.
*
* The max limit is @c BLOCK_MAX_KMEANS_TEXELS; above this a random selection is used.
* The @c bsd.texel_count is an input and must be populated beforehand.
*
* @param[in,out] bsd The block size descriptor to populate.
*/
static void assign_kmeans_texels(
block_size_descriptor& bsd
) {
// Use all texels for kmeans on a small block
if (bsd.texel_count <= BLOCK_MAX_KMEANS_TEXELS)
{
for (uint8_t i = 0; i < bsd.texel_count; i++)
{
bsd.kmeans_texels[i] = i;
}
return;
}
// Select a random subset of BLOCK_MAX_KMEANS_TEXELS for kmeans on a large block
uint64_t rng_state[2];
astc::rand_init(rng_state);
// Initialize array used for tracking used indices
bool seen[BLOCK_MAX_TEXELS];
for (uint8_t i = 0; i < bsd.texel_count; i++)
{
seen[i] = false;
}
// Assign 64 random indices, retrying if we see repeats
unsigned int arr_elements_set = 0;
while (arr_elements_set < BLOCK_MAX_KMEANS_TEXELS)
{
uint8_t texel = static_cast<uint8_t>(astc::rand(rng_state));
texel = texel % bsd.texel_count;
if (!seen[texel])
{
bsd.kmeans_texels[arr_elements_set++] = texel;
seen[texel] = true;
}
}
}
/**
* @brief Allocate a single 2D decimation table entry.
*
* @param x_texels The number of texels in the X dimension.
* @param y_texels The number of texels in the Y dimension.
* @param x_weights The number of weights in the X dimension.
* @param y_weights The number of weights in the Y dimension.
* @param bsd The block size descriptor we are populating.
* @param wb The decimation table init scratch working buffers.
* @param index The packed array index to populate.
*/
static void construct_dt_entry_2d(
unsigned int x_texels,
unsigned int y_texels,
unsigned int x_weights,
unsigned int y_weights,
block_size_descriptor& bsd,
dt_init_working_buffers& wb,
unsigned int index
) {
unsigned int weight_count = x_weights * y_weights;
assert(weight_count <= BLOCK_MAX_WEIGHTS);
bool try_2planes = (2 * weight_count) <= BLOCK_MAX_WEIGHTS;
decimation_info& di = bsd.decimation_tables[index];
init_decimation_info_2d(x_texels, y_texels, x_weights, y_weights, di, wb);
int maxprec_1plane = -1;
int maxprec_2planes = -1;
for (int i = 0; i < 12; i++)
{
unsigned int bits_1plane = get_ise_sequence_bitcount(weight_count, static_cast<quant_method>(i));
if (bits_1plane >= BLOCK_MIN_WEIGHT_BITS && bits_1plane <= BLOCK_MAX_WEIGHT_BITS)
{
maxprec_1plane = i;
}
if (try_2planes)
{
unsigned int bits_2planes = get_ise_sequence_bitcount(2 * weight_count, static_cast<quant_method>(i));
if (bits_2planes >= BLOCK_MIN_WEIGHT_BITS && bits_2planes <= BLOCK_MAX_WEIGHT_BITS)
{
maxprec_2planes = i;
}
}
}
// At least one of the two should be valid ...
assert(maxprec_1plane >= 0 || maxprec_2planes >= 0);
bsd.decimation_modes[index].maxprec_1plane = static_cast<int8_t>(maxprec_1plane);
bsd.decimation_modes[index].maxprec_2planes = static_cast<int8_t>(maxprec_2planes);
bsd.decimation_modes[index].refprec_1plane = 0;
bsd.decimation_modes[index].refprec_2planes = 0;
}
/**
* @brief Allocate block modes and decimation tables for a single 2D block size.
*
* @param x_texels The number of texels in the X dimension.
* @param y_texels The number of texels in the Y dimension.
* @param can_omit_modes Can we discard modes that astcenc won't use, even if legal?
* @param mode_cutoff Percentile cutoff in range [0,1]. Low values more likely to be used.
* @param[out] bsd The block size descriptor to populate.
*/
static void construct_block_size_descriptor_2d(
unsigned int x_texels,
unsigned int y_texels,
bool can_omit_modes,
float mode_cutoff,
block_size_descriptor& bsd
) {
// Store a remap table for storing packed decimation modes.
// Indexing uses [Y * 16 + X] and max size for each axis is 12.
static const unsigned int MAX_DMI = 12 * 16 + 12;
int decimation_mode_index[MAX_DMI];
dt_init_working_buffers* wb = new dt_init_working_buffers;
bsd.xdim = static_cast<uint8_t>(x_texels);
bsd.ydim = static_cast<uint8_t>(y_texels);
bsd.zdim = 1;
bsd.texel_count = static_cast<uint8_t>(x_texels * y_texels);
for (unsigned int i = 0; i < MAX_DMI; i++)
{
decimation_mode_index[i] = -1;
}
// Gather all the decimation grids that can be used with the current block
#if !defined(ASTCENC_DECOMPRESS_ONLY)
const float *percentiles = get_2d_percentile_table(x_texels, y_texels);
float always_cutoff = 0.0f;
#else
// Unused in decompress-only builds
(void)can_omit_modes;
(void)mode_cutoff;
#endif
// Construct the list of block formats referencing the decimation tables
unsigned int packed_bm_idx = 0;
unsigned int packed_dm_idx = 0;
// Trackers
unsigned int bm_counts[4] { 0 };
unsigned int dm_counts[4] { 0 };
// Clear the list to a known-bad value
for (unsigned int i = 0; i < WEIGHTS_MAX_BLOCK_MODES; i++)
{
bsd.block_mode_packed_index[i] = BLOCK_BAD_BLOCK_MODE;
}
// Iterate four times to build a usefully ordered list:
// - Pass 0 - keep selected single plane "always" block modes
// - Pass 1 - keep selected single plane "non-always" block modes
// - Pass 2 - keep select dual plane block modes
// - Pass 3 - keep everything else that's legal
unsigned int limit = can_omit_modes ? 3 : 4;
for (unsigned int j = 0; j < limit; j ++)
{
for (unsigned int i = 0; i < WEIGHTS_MAX_BLOCK_MODES; i++)
{
// Skip modes we've already included in a previous pass
if (bsd.block_mode_packed_index[i] != BLOCK_BAD_BLOCK_MODE)
{
continue;
}
// Decode parameters
unsigned int x_weights;
unsigned int y_weights;
bool is_dual_plane;
unsigned int quant_mode;
unsigned int weight_bits;
bool valid = decode_block_mode_2d(i, x_weights, y_weights, is_dual_plane, quant_mode, weight_bits);
// Always skip invalid encodings for the current block size
if (!valid || (x_weights > x_texels) || (y_weights > y_texels))
{
continue;
}
// Selectively skip dual plane encodings
if (((j <= 1) && is_dual_plane) || (j == 2 && !is_dual_plane))
{
continue;
}
// Always skip encodings we can't physically encode based on
// generic encoding bit availability
if (is_dual_plane)
{
// This is the only check we need as only support 1 partition
if ((109 - weight_bits) <= 0)
{
continue;
}
}
else
{
// This is conservative - fewer bits may be available for > 1 partition
if ((111 - weight_bits) <= 0)
{
continue;
}
}
// Selectively skip encodings based on percentile
bool percentile_hit = false;
#if !defined(ASTCENC_DECOMPRESS_ONLY)
if (j == 0)
{
percentile_hit = percentiles[i] <= always_cutoff;
}
else
{
percentile_hit = percentiles[i] <= mode_cutoff;
}
#endif
if (j != 3 && !percentile_hit)
{
continue;
}
// Allocate and initialize the decimation table entry if we've not used it yet
int decimation_mode = decimation_mode_index[y_weights * 16 + x_weights];
if (decimation_mode < 0)
{
construct_dt_entry_2d(x_texels, y_texels, x_weights, y_weights, bsd, *wb, packed_dm_idx);
decimation_mode_index[y_weights * 16 + x_weights] = packed_dm_idx;
decimation_mode = packed_dm_idx;
dm_counts[j]++;
packed_dm_idx++;
}
auto& bm = bsd.block_modes[packed_bm_idx];
bm.decimation_mode = static_cast<uint8_t>(decimation_mode);
bm.quant_mode = static_cast<uint8_t>(quant_mode);
bm.is_dual_plane = static_cast<uint8_t>(is_dual_plane);
bm.weight_bits = static_cast<uint8_t>(weight_bits);
bm.mode_index = static_cast<uint16_t>(i);
auto& dm = bsd.decimation_modes[decimation_mode];
if (is_dual_plane)
{
dm.set_ref_2plane(bm.get_weight_quant_mode());
}
else
{
dm.set_ref_1plane(bm.get_weight_quant_mode());
}
bsd.block_mode_packed_index[i] = static_cast<uint16_t>(packed_bm_idx);
packed_bm_idx++;
bm_counts[j]++;
}
}
bsd.block_mode_count_1plane_always = bm_counts[0];
bsd.block_mode_count_1plane_selected = bm_counts[0] + bm_counts[1];
bsd.block_mode_count_1plane_2plane_selected = bm_counts[0] + bm_counts[1] + bm_counts[2];
bsd.block_mode_count_all = bm_counts[0] + bm_counts[1] + bm_counts[2] + bm_counts[3];
bsd.decimation_mode_count_always = dm_counts[0];
bsd.decimation_mode_count_selected = dm_counts[0] + dm_counts[1] + dm_counts[2];
bsd.decimation_mode_count_all = dm_counts[0] + dm_counts[1] + dm_counts[2] + dm_counts[3];
#if !defined(ASTCENC_DECOMPRESS_ONLY)
assert(bsd.block_mode_count_1plane_always > 0);
assert(bsd.decimation_mode_count_always > 0);
delete[] percentiles;
#endif
// Ensure the end of the array contains valid data (should never get read)
for (unsigned int i = bsd.decimation_mode_count_all; i < WEIGHTS_MAX_DECIMATION_MODES; i++)
{
bsd.decimation_modes[i].maxprec_1plane = -1;
bsd.decimation_modes[i].maxprec_2planes = -1;
bsd.decimation_modes[i].refprec_1plane = 0;
bsd.decimation_modes[i].refprec_2planes = 0;
}
// Determine the texels to use for kmeans clustering.
assign_kmeans_texels(bsd);
delete wb;
}
/**
* @brief Allocate block modes and decimation tables for a single 3D block size.
*
* TODO: This function doesn't include all of the heuristics that we use for 2D block sizes such as
* the percentile mode cutoffs. If 3D becomes more widely used we should look at this.
*
* @param x_texels The number of texels in the X dimension.
* @param y_texels The number of texels in the Y dimension.
* @param z_texels The number of texels in the Z dimension.
* @param[out] bsd The block size descriptor to populate.
*/
static void construct_block_size_descriptor_3d(
unsigned int x_texels,
unsigned int y_texels,
unsigned int z_texels,
block_size_descriptor& bsd
) {
// Store a remap table for storing packed decimation modes.
// Indexing uses [Z * 64 + Y * 8 + X] and max size for each axis is 6.
static constexpr unsigned int MAX_DMI = 6 * 64 + 6 * 8 + 6;
int decimation_mode_index[MAX_DMI];
unsigned int decimation_mode_count = 0;
dt_init_working_buffers* wb = new dt_init_working_buffers;
bsd.xdim = static_cast<uint8_t>(x_texels);
bsd.ydim = static_cast<uint8_t>(y_texels);
bsd.zdim = static_cast<uint8_t>(z_texels);
bsd.texel_count = static_cast<uint8_t>(x_texels * y_texels * z_texels);
for (unsigned int i = 0; i < MAX_DMI; i++)
{
decimation_mode_index[i] = -1;
}
// gather all the infill-modes that can be used with the current block size
for (unsigned int x_weights = 2; x_weights <= x_texels; x_weights++)
{
for (unsigned int y_weights = 2; y_weights <= y_texels; y_weights++)
{
for (unsigned int z_weights = 2; z_weights <= z_texels; z_weights++)
{
unsigned int weight_count = x_weights * y_weights * z_weights;
if (weight_count > BLOCK_MAX_WEIGHTS)
{
continue;
}
decimation_info& di = bsd.decimation_tables[decimation_mode_count];
decimation_mode_index[z_weights * 64 + y_weights * 8 + x_weights] = decimation_mode_count;
init_decimation_info_3d(x_texels, y_texels, z_texels, x_weights, y_weights, z_weights, di, *wb);
int maxprec_1plane = -1;
int maxprec_2planes = -1;
for (unsigned int i = 0; i < 12; i++)
{
unsigned int bits_1plane = get_ise_sequence_bitcount(weight_count, static_cast<quant_method>(i));
if (bits_1plane >= BLOCK_MIN_WEIGHT_BITS && bits_1plane <= BLOCK_MAX_WEIGHT_BITS)
{
maxprec_1plane = i;
}
unsigned int bits_2planes = get_ise_sequence_bitcount(2 * weight_count, static_cast<quant_method>(i));
if (bits_2planes >= BLOCK_MIN_WEIGHT_BITS && bits_2planes <= BLOCK_MAX_WEIGHT_BITS)
{
maxprec_2planes = i;
}
}
if ((2 * weight_count) > BLOCK_MAX_WEIGHTS)
{
maxprec_2planes = -1;
}
bsd.decimation_modes[decimation_mode_count].maxprec_1plane = static_cast<int8_t>(maxprec_1plane);
bsd.decimation_modes[decimation_mode_count].maxprec_2planes = static_cast<int8_t>(maxprec_2planes);
bsd.decimation_modes[decimation_mode_count].refprec_1plane = maxprec_1plane == -1 ? 0 : 0xFFFF;
bsd.decimation_modes[decimation_mode_count].refprec_2planes = maxprec_2planes == -1 ? 0 : 0xFFFF;
decimation_mode_count++;
}
}
}
// Ensure the end of the array contains valid data (should never get read)
for (unsigned int i = decimation_mode_count; i < WEIGHTS_MAX_DECIMATION_MODES; i++)
{
bsd.decimation_modes[i].maxprec_1plane = -1;
bsd.decimation_modes[i].maxprec_2planes = -1;
bsd.decimation_modes[i].refprec_1plane = 0;
bsd.decimation_modes[i].refprec_2planes = 0;
}
bsd.decimation_mode_count_always = 0; // Skipped for 3D modes
bsd.decimation_mode_count_selected = decimation_mode_count;
bsd.decimation_mode_count_all = decimation_mode_count;
// Construct the list of block formats referencing the decimation tables
// Clear the list to a known-bad value
for (unsigned int i = 0; i < WEIGHTS_MAX_BLOCK_MODES; i++)
{
bsd.block_mode_packed_index[i] = BLOCK_BAD_BLOCK_MODE;
}
unsigned int packed_idx = 0;
unsigned int bm_counts[2] { 0 };
// Iterate two times to build a usefully ordered list:
// - Pass 0 - keep valid single plane block modes
// - Pass 1 - keep valid dual plane block modes
for (unsigned int j = 0; j < 2; j++)
{
for (unsigned int i = 0; i < WEIGHTS_MAX_BLOCK_MODES; i++)
{
// Skip modes we've already included in a previous pass
if (bsd.block_mode_packed_index[i] != BLOCK_BAD_BLOCK_MODE)
{
continue;
}
unsigned int x_weights;
unsigned int y_weights;
unsigned int z_weights;
bool is_dual_plane;
unsigned int quant_mode;
unsigned int weight_bits;
bool valid = decode_block_mode_3d(i, x_weights, y_weights, z_weights, is_dual_plane, quant_mode, weight_bits);
// Skip invalid encodings
if (!valid || x_weights > x_texels || y_weights > y_texels || z_weights > z_texels)
{
continue;
}
// Skip encodings in the wrong iteration
if ((j == 0 && is_dual_plane) || (j == 1 && !is_dual_plane))
{
continue;
}
// Always skip encodings we can't physically encode based on bit availability
if (is_dual_plane)
{
// This is the only check we need as only support 1 partition
if ((109 - weight_bits) <= 0)
{
continue;
}
}
else
{
// This is conservative - fewer bits may be available for > 1 partition
if ((111 - weight_bits) <= 0)
{
continue;
}
}
int decimation_mode = decimation_mode_index[z_weights * 64 + y_weights * 8 + x_weights];
bsd.block_modes[packed_idx].decimation_mode = static_cast<uint8_t>(decimation_mode);
bsd.block_modes[packed_idx].quant_mode = static_cast<uint8_t>(quant_mode);
bsd.block_modes[packed_idx].weight_bits = static_cast<uint8_t>(weight_bits);
bsd.block_modes[packed_idx].is_dual_plane = static_cast<uint8_t>(is_dual_plane);
bsd.block_modes[packed_idx].mode_index = static_cast<uint16_t>(i);
bsd.block_mode_packed_index[i] = static_cast<uint16_t>(packed_idx);
bm_counts[j]++;
packed_idx++;
}
}
bsd.block_mode_count_1plane_always = 0; // Skipped for 3D modes
bsd.block_mode_count_1plane_selected = bm_counts[0];
bsd.block_mode_count_1plane_2plane_selected = bm_counts[0] + bm_counts[1];
bsd.block_mode_count_all = bm_counts[0] + bm_counts[1];
// Determine the texels to use for kmeans clustering.
assign_kmeans_texels(bsd);
delete wb;
}
/* See header for documentation. */
void init_block_size_descriptor(
unsigned int x_texels,
unsigned int y_texels,
unsigned int z_texels,
bool can_omit_modes,
unsigned int partition_count_cutoff,
float mode_cutoff,
block_size_descriptor& bsd
) {
if (z_texels > 1)
{
construct_block_size_descriptor_3d(x_texels, y_texels, z_texels, bsd);
}
else
{
construct_block_size_descriptor_2d(x_texels, y_texels, can_omit_modes, mode_cutoff, bsd);
}
init_partition_tables(bsd, can_omit_modes, partition_count_cutoff);
}