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Unified Diff: cc/resources/texture_compressor_etc1.cc

Issue 1535833002: Delete CC. (Closed) Base URL: git@github.com:domokit/mojo.git@moz-5
Patch Set: rebase Created 4 years, 11 months ago
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Index: cc/resources/texture_compressor_etc1.cc
diff --git a/cc/resources/texture_compressor_etc1.cc b/cc/resources/texture_compressor_etc1.cc
deleted file mode 100644
index 61c4438c21862342f8cf0ca10b19a375364a581c..0000000000000000000000000000000000000000
--- a/cc/resources/texture_compressor_etc1.cc
+++ /dev/null
@@ -1,503 +0,0 @@
-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// See the following specification for details on the ETC1 format:
-// https://www.khronos.org/registry/gles/extensions/OES/OES_compressed_ETC1_RGB8_texture.txt
-
-#include "cc/resources/texture_compressor_etc1.h"
-
-#include <string.h>
-#include <limits>
-
-#include "base/logging.h"
-
-// Defining the following macro will cause the error metric function to weigh
-// each color channel differently depending on how the human eye can perceive
-// them. This can give a slight improvement in image quality at the cost of a
-// performance hit.
-// #define USE_PERCEIVED_ERROR_METRIC
-
-namespace {
-
-template <typename T>
-inline T clamp(T val, T min, T max) {
- return val < min ? min : (val > max ? max : val);
-}
-
-inline uint8_t round_to_5_bits(float val) {
- return clamp<uint8_t>(val * 31.0f / 255.0f + 0.5f, 0, 31);
-}
-
-inline uint8_t round_to_4_bits(float val) {
- return clamp<uint8_t>(val * 15.0f / 255.0f + 0.5f, 0, 15);
-}
-
-union Color {
- struct BgraColorType {
- uint8_t b;
- uint8_t g;
- uint8_t r;
- uint8_t a;
- } channels;
- uint8_t components[4];
- uint32_t bits;
-};
-
-/*
- * Codeword tables.
- * See: Table 3.17.2
- */
-static const int16_t g_codeword_tables[8][4] = {{-8, -2, 2, 8},
- {-17, -5, 5, 17},
- {-29, -9, 9, 29},
- {-42, -13, 13, 42},
- {-60, -18, 18, 60},
- {-80, -24, 24, 80},
- {-106, -33, 33, 106},
- {-183, -47, 47, 183}};
-
-/*
- * Maps modifier indices to pixel index values.
- * See: Table 3.17.3
- */
-static const uint8_t g_mod_to_pix[4] = {3, 2, 0, 1};
-
-/*
- * The ETC1 specification index texels as follows:
- *
- * [a][e][i][m] [ 0][ 4][ 8][12]
- * [b][f][j][n] <-> [ 1][ 5][ 9][13]
- * [c][g][k][o] [ 2][ 6][10][14]
- * [d][h][l][p] [ 3][ 7][11][15]
- *
- * However, when extracting sub blocks from BGRA data the natural array
- * indexing order ends up different:
- *
- * vertical0: [a][e][b][f] horizontal0: [a][e][i][m]
- * [c][g][d][h] [b][f][j][n]
- * vertical1: [i][m][j][n] horizontal1: [c][g][k][o]
- * [k][o][l][p] [d][h][l][p]
- *
- * In order to translate from the natural array indices in a sub block to the
- * indices (number) used by specification and hardware we use this table.
- */
-static const uint8_t g_idx_to_num[4][8] = {
- {0, 4, 1, 5, 2, 6, 3, 7}, // Vertical block 0.
- {8, 12, 9, 13, 10, 14, 11, 15}, // Vertical block 1.
- {0, 4, 8, 12, 1, 5, 9, 13}, // Horizontal block 0.
- {2, 6, 10, 14, 3, 7, 11, 15} // Horizontal block 1.
-};
-
-inline void WriteColors444(uint8_t* block,
- const Color& color0,
- const Color& color1) {
- block[0] = (color0.channels.r & 0xf0) | (color1.channels.r >> 4);
- block[1] = (color0.channels.g & 0xf0) | (color1.channels.g >> 4);
- block[2] = (color0.channels.b & 0xf0) | (color1.channels.b >> 4);
-}
-
-inline void WriteColors555(uint8_t* block,
- const Color& color0,
- const Color& color1) {
- // Table for conversion to 3-bit two complement format.
- static const uint8_t two_compl_trans_table[8] = {
- 4, // -4 (100b)
- 5, // -3 (101b)
- 6, // -2 (110b)
- 7, // -1 (111b)
- 0, // 0 (000b)
- 1, // 1 (001b)
- 2, // 2 (010b)
- 3, // 3 (011b)
- };
-
- int16_t delta_r =
- static_cast<int16_t>(color1.channels.r >> 3) - (color0.channels.r >> 3);
- int16_t delta_g =
- static_cast<int16_t>(color1.channels.g >> 3) - (color0.channels.g >> 3);
- int16_t delta_b =
- static_cast<int16_t>(color1.channels.b >> 3) - (color0.channels.b >> 3);
- DCHECK(delta_r >= -4 && delta_r <= 3);
- DCHECK(delta_g >= -4 && delta_g <= 3);
- DCHECK(delta_b >= -4 && delta_b <= 3);
-
- block[0] = (color0.channels.r & 0xf8) | two_compl_trans_table[delta_r + 4];
- block[1] = (color0.channels.g & 0xf8) | two_compl_trans_table[delta_g + 4];
- block[2] = (color0.channels.b & 0xf8) | two_compl_trans_table[delta_b + 4];
-}
-
-inline void WriteCodewordTable(uint8_t* block,
- uint8_t sub_block_id,
- uint8_t table) {
- DCHECK_LT(sub_block_id, 2);
- DCHECK_LT(table, 8);
-
- uint8_t shift = (2 + (3 - sub_block_id * 3));
- block[3] &= ~(0x07 << shift);
- block[3] |= table << shift;
-}
-
-inline void WritePixelData(uint8_t* block, uint32_t pixel_data) {
- block[4] |= pixel_data >> 24;
- block[5] |= (pixel_data >> 16) & 0xff;
- block[6] |= (pixel_data >> 8) & 0xff;
- block[7] |= pixel_data & 0xff;
-}
-
-inline void WriteFlip(uint8_t* block, bool flip) {
- block[3] &= ~0x01;
- block[3] |= static_cast<uint8_t>(flip);
-}
-
-inline void WriteDiff(uint8_t* block, bool diff) {
- block[3] &= ~0x02;
- block[3] |= static_cast<uint8_t>(diff) << 1;
-}
-
-/**
- * Compress and rounds BGR888 into BGR444. The resulting BGR444 color is
- * expanded to BGR888 as it would be in hardware after decompression. The
- * actual 444-bit data is available in the four most significant bits of each
- * channel.
- */
-inline Color MakeColor444(const float* bgr) {
- uint8_t b4 = round_to_4_bits(bgr[0]);
- uint8_t g4 = round_to_4_bits(bgr[1]);
- uint8_t r4 = round_to_4_bits(bgr[2]);
- Color bgr444;
- bgr444.channels.b = (b4 << 4) | b4;
- bgr444.channels.g = (g4 << 4) | g4;
- bgr444.channels.r = (r4 << 4) | r4;
- return bgr444;
-}
-
-/**
- * Compress and rounds BGR888 into BGR555. The resulting BGR555 color is
- * expanded to BGR888 as it would be in hardware after decompression. The
- * actual 555-bit data is available in the five most significant bits of each
- * channel.
- */
-inline Color MakeColor555(const float* bgr) {
- uint8_t b5 = round_to_5_bits(bgr[0]);
- uint8_t g5 = round_to_5_bits(bgr[1]);
- uint8_t r5 = round_to_5_bits(bgr[2]);
- Color bgr555;
- bgr555.channels.b = (b5 << 3) | (b5 >> 2);
- bgr555.channels.g = (g5 << 3) | (g5 >> 2);
- bgr555.channels.r = (r5 << 3) | (r5 >> 2);
- return bgr555;
-}
-
-/**
- * Constructs a color from a given base color and luminance value.
- */
-inline Color MakeColor(const Color& base, int16_t lum) {
- int b = static_cast<int>(base.channels.b) + lum;
- int g = static_cast<int>(base.channels.g) + lum;
- int r = static_cast<int>(base.channels.r) + lum;
- Color color;
- color.channels.b = static_cast<uint8_t>(clamp(b, 0, 255));
- color.channels.g = static_cast<uint8_t>(clamp(g, 0, 255));
- color.channels.r = static_cast<uint8_t>(clamp(r, 0, 255));
- return color;
-}
-
-/**
- * Calculates the error metric for two colors. A small error signals that the
- * colors are similar to each other, a large error the signals the opposite.
- */
-inline uint32_t GetColorError(const Color& u, const Color& v) {
-#ifdef USE_PERCEIVED_ERROR_METRIC
- float delta_b = static_cast<float>(u.channels.b) - v.channels.b;
- float delta_g = static_cast<float>(u.channels.g) - v.channels.g;
- float delta_r = static_cast<float>(u.channels.r) - v.channels.r;
- return static_cast<uint32_t>(0.299f * delta_b * delta_b +
- 0.587f * delta_g * delta_g +
- 0.114f * delta_r * delta_r);
-#else
- int delta_b = static_cast<int>(u.channels.b) - v.channels.b;
- int delta_g = static_cast<int>(u.channels.g) - v.channels.g;
- int delta_r = static_cast<int>(u.channels.r) - v.channels.r;
- return delta_b * delta_b + delta_g * delta_g + delta_r * delta_r;
-#endif
-}
-
-void GetAverageColor(const Color* src, float* avg_color) {
- uint32_t sum_b = 0, sum_g = 0, sum_r = 0;
-
- for (unsigned int i = 0; i < 8; ++i) {
- sum_b += src[i].channels.b;
- sum_g += src[i].channels.g;
- sum_r += src[i].channels.r;
- }
-
- const float kInv8 = 1.0f / 8.0f;
- avg_color[0] = static_cast<float>(sum_b) * kInv8;
- avg_color[1] = static_cast<float>(sum_g) * kInv8;
- avg_color[2] = static_cast<float>(sum_r) * kInv8;
-}
-
-void ComputeLuminance(uint8_t* block,
- const Color* src,
- const Color& base,
- int sub_block_id,
- const uint8_t* idx_to_num_tab) {
- uint32_t best_tbl_err = std::numeric_limits<uint32_t>::max();
- uint8_t best_tbl_idx = 0;
- uint8_t best_mod_idx[8][8]; // [table][texel]
-
- // Try all codeword tables to find the one giving the best results for this
- // block.
- for (unsigned int tbl_idx = 0; tbl_idx < 8; ++tbl_idx) {
- // Pre-compute all the candidate colors; combinations of the base color and
- // all available luminance values.
- Color candidate_color[4]; // [modifier]
- for (unsigned int mod_idx = 0; mod_idx < 4; ++mod_idx) {
- int16_t lum = g_codeword_tables[tbl_idx][mod_idx];
- candidate_color[mod_idx] = MakeColor(base, lum);
- }
-
- uint32_t tbl_err = 0;
-
- for (unsigned int i = 0; i < 8; ++i) {
- // Try all modifiers in the current table to find which one gives the
- // smallest error.
- uint32_t best_mod_err = std::numeric_limits<uint32_t>::max();
- for (unsigned int mod_idx = 0; mod_idx < 4; ++mod_idx) {
- const Color& color = candidate_color[mod_idx];
-
- uint32_t mod_err = GetColorError(src[i], color);
- if (mod_err < best_mod_err) {
- best_mod_idx[tbl_idx][i] = mod_idx;
- best_mod_err = mod_err;
-
- if (mod_err == 0)
- break; // We cannot do any better than this.
- }
- }
-
- tbl_err += best_mod_err;
- if (tbl_err > best_tbl_err)
- break; // We're already doing worse than the best table so skip.
- }
-
- if (tbl_err < best_tbl_err) {
- best_tbl_err = tbl_err;
- best_tbl_idx = tbl_idx;
-
- if (tbl_err == 0)
- break; // We cannot do any better than this.
- }
- }
-
- WriteCodewordTable(block, sub_block_id, best_tbl_idx);
-
- uint32_t pix_data = 0;
-
- for (unsigned int i = 0; i < 8; ++i) {
- uint8_t mod_idx = best_mod_idx[best_tbl_idx][i];
- uint8_t pix_idx = g_mod_to_pix[mod_idx];
-
- uint32_t lsb = pix_idx & 0x1;
- uint32_t msb = pix_idx >> 1;
-
- // Obtain the texel number as specified in the standard.
- int texel_num = idx_to_num_tab[i];
- pix_data |= msb << (texel_num + 16);
- pix_data |= lsb << (texel_num);
- }
-
- WritePixelData(block, pix_data);
-}
-
-/**
- * Tries to compress the block under the assumption that it's a single color
- * block. If it's not the function will bail out without writing anything to
- * the destination buffer.
- */
-bool TryCompressSolidBlock(uint8_t* dst, const Color* src) {
- for (unsigned int i = 1; i < 16; ++i) {
- if (src[i].bits != src[0].bits)
- return false;
- }
-
- // Clear destination buffer so that we can "or" in the results.
- memset(dst, 0, 8);
-
- float src_color_float[3] = {static_cast<float>(src->channels.b),
- static_cast<float>(src->channels.g),
- static_cast<float>(src->channels.r)};
- Color base = MakeColor555(src_color_float);
-
- WriteDiff(dst, true);
- WriteFlip(dst, false);
- WriteColors555(dst, base, base);
-
- uint8_t best_tbl_idx = 0;
- uint8_t best_mod_idx = 0;
- uint32_t best_mod_err = std::numeric_limits<uint32_t>::max();
-
- // Try all codeword tables to find the one giving the best results for this
- // block.
- for (unsigned int tbl_idx = 0; tbl_idx < 8; ++tbl_idx) {
- // Try all modifiers in the current table to find which one gives the
- // smallest error.
- for (unsigned int mod_idx = 0; mod_idx < 4; ++mod_idx) {
- int16_t lum = g_codeword_tables[tbl_idx][mod_idx];
- const Color& color = MakeColor(base, lum);
-
- uint32_t mod_err = GetColorError(*src, color);
- if (mod_err < best_mod_err) {
- best_tbl_idx = tbl_idx;
- best_mod_idx = mod_idx;
- best_mod_err = mod_err;
-
- if (mod_err == 0)
- break; // We cannot do any better than this.
- }
- }
-
- if (best_mod_err == 0)
- break;
- }
-
- WriteCodewordTable(dst, 0, best_tbl_idx);
- WriteCodewordTable(dst, 1, best_tbl_idx);
-
- uint8_t pix_idx = g_mod_to_pix[best_mod_idx];
- uint32_t lsb = pix_idx & 0x1;
- uint32_t msb = pix_idx >> 1;
-
- uint32_t pix_data = 0;
- for (unsigned int i = 0; i < 2; ++i) {
- for (unsigned int j = 0; j < 8; ++j) {
- // Obtain the texel number as specified in the standard.
- int texel_num = g_idx_to_num[i][j];
- pix_data |= msb << (texel_num + 16);
- pix_data |= lsb << (texel_num);
- }
- }
-
- WritePixelData(dst, pix_data);
- return true;
-}
-
-void CompressBlock(uint8_t* dst, const Color* ver_src, const Color* hor_src) {
- if (TryCompressSolidBlock(dst, ver_src))
- return;
-
- const Color* sub_block_src[4] = {ver_src, ver_src + 8, hor_src, hor_src + 8};
-
- Color sub_block_avg[4];
- bool use_differential[2] = {true, true};
-
- // Compute the average color for each sub block and determine if differential
- // coding can be used.
- for (unsigned int i = 0, j = 1; i < 4; i += 2, j += 2) {
- float avg_color_0[3];
- GetAverageColor(sub_block_src[i], avg_color_0);
- Color avg_color_555_0 = MakeColor555(avg_color_0);
-
- float avg_color_1[3];
- GetAverageColor(sub_block_src[j], avg_color_1);
- Color avg_color_555_1 = MakeColor555(avg_color_1);
-
- for (unsigned int light_idx = 0; light_idx < 3; ++light_idx) {
- int u = avg_color_555_0.components[light_idx] >> 3;
- int v = avg_color_555_1.components[light_idx] >> 3;
-
- int component_diff = v - u;
- if (component_diff < -4 || component_diff > 3) {
- use_differential[i / 2] = false;
- sub_block_avg[i] = MakeColor444(avg_color_0);
- sub_block_avg[j] = MakeColor444(avg_color_1);
- } else {
- sub_block_avg[i] = avg_color_555_0;
- sub_block_avg[j] = avg_color_555_1;
- }
- }
- }
-
- // Compute the error of each sub block before adjusting for luminance. These
- // error values are later used for determining if we should flip the sub
- // block or not.
- uint32_t sub_block_err[4] = {0};
- for (unsigned int i = 0; i < 4; ++i) {
- for (unsigned int j = 0; j < 8; ++j) {
- sub_block_err[i] += GetColorError(sub_block_avg[i], sub_block_src[i][j]);
- }
- }
-
- bool flip =
- sub_block_err[2] + sub_block_err[3] < sub_block_err[0] + sub_block_err[1];
-
- // Clear destination buffer so that we can "or" in the results.
- memset(dst, 0, 8);
-
- WriteDiff(dst, use_differential[!!flip]);
- WriteFlip(dst, flip);
-
- uint8_t sub_block_off_0 = flip ? 2 : 0;
- uint8_t sub_block_off_1 = sub_block_off_0 + 1;
-
- if (use_differential[!!flip]) {
- WriteColors555(dst, sub_block_avg[sub_block_off_0],
- sub_block_avg[sub_block_off_1]);
- } else {
- WriteColors444(dst, sub_block_avg[sub_block_off_0],
- sub_block_avg[sub_block_off_1]);
- }
-
- // Compute luminance for the first sub block.
- ComputeLuminance(dst, sub_block_src[sub_block_off_0],
- sub_block_avg[sub_block_off_0], 0,
- g_idx_to_num[sub_block_off_0]);
- // Compute luminance for the second sub block.
- ComputeLuminance(dst, sub_block_src[sub_block_off_1],
- sub_block_avg[sub_block_off_1], 1,
- g_idx_to_num[sub_block_off_1]);
-}
-
-} // namespace
-
-namespace cc {
-
-void TextureCompressorETC1::Compress(const uint8_t* src,
- uint8_t* dst,
- int width,
- int height,
- Quality quality) {
- DCHECK(width >= 4 && (width & 3) == 0);
- DCHECK(height >= 4 && (height & 3) == 0);
-
- Color ver_blocks[16];
- Color hor_blocks[16];
-
- for (int y = 0; y < height; y += 4, src += width * 4 * 4) {
- for (int x = 0; x < width; x += 4, dst += 8) {
- const Color* row0 = reinterpret_cast<const Color*>(src + x * 4);
- const Color* row1 = row0 + width;
- const Color* row2 = row1 + width;
- const Color* row3 = row2 + width;
-
- memcpy(ver_blocks, row0, 8);
- memcpy(ver_blocks + 2, row1, 8);
- memcpy(ver_blocks + 4, row2, 8);
- memcpy(ver_blocks + 6, row3, 8);
- memcpy(ver_blocks + 8, row0 + 2, 8);
- memcpy(ver_blocks + 10, row1 + 2, 8);
- memcpy(ver_blocks + 12, row2 + 2, 8);
- memcpy(ver_blocks + 14, row3 + 2, 8);
-
- memcpy(hor_blocks, row0, 16);
- memcpy(hor_blocks + 4, row1, 16);
- memcpy(hor_blocks + 8, row2, 16);
- memcpy(hor_blocks + 12, row3, 16);
-
- CompressBlock(dst, ver_blocks, hor_blocks);
- }
- }
-}
-
-} // namespace cc
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