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basisu_gpu_texture.cpp
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// basisu_gpu_texture.cpp
// Copyright (C) 2019 Binomial LLC. All Rights Reserved.
//
// 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.
#include "basisu_gpu_texture.h"
#include "basisu_enc.h"
#include "basisu_pvrtc1_4.h"
#include "basisu_astc_decomp.h"
namespace basisu
{
const int8_t g_etc2_eac_tables[16][8] =
{
{ -3, -6, -9, -15, 2, 5, 8, 14 }, { -3, -7, -10, -13, 2, 6, 9, 12 }, { -2, -5, -8, -13, 1, 4, 7, 12 }, { -2, -4, -6, -13, 1, 3, 5, 12 },
{ -3, -6, -8, -12, 2, 5, 7, 11 }, { -3, -7, -9, -11, 2, 6, 8, 10 }, { -4, -7, -8, -11, 3, 6, 7, 10 }, { -3, -5, -8, -11, 2, 4, 7, 10 },
{ -2, -6, -8, -10, 1, 5, 7, 9 }, { -2, -5, -8, -10, 1, 4, 7, 9 }, { -2, -4, -8, -10, 1, 3, 7, 9 }, { -2, -5, -7, -10, 1, 4, 6, 9 },
{ -3, -4, -7, -10, 2, 3, 6, 9 }, { -1, -2, -3, -10, 0, 1, 2, 9 }, { -4, -6, -8, -9, 3, 5, 7, 8 }, { -3, -5, -7, -9, 2, 4, 6, 8 }
};
struct eac_a8_block
{
uint16_t m_base : 8;
uint16_t m_table : 4;
uint16_t m_multiplier : 4;
uint8_t m_selectors[6];
inline uint32_t get_selector(uint32_t x, uint32_t y, uint64_t selector_bits) const
{
assert((x < 4) && (y < 4));
return static_cast<uint32_t>((selector_bits >> (45 - (y + x * 4) * 3)) & 7);
}
inline uint64_t get_selector_bits() const
{
uint64_t pixels = ((uint64_t)m_selectors[0] << 40) | ((uint64_t)m_selectors[1] << 32) | ((uint64_t)m_selectors[2] << 24) | ((uint64_t)m_selectors[3] << 16) | ((uint64_t)m_selectors[4] << 8) | m_selectors[5];
return pixels;
}
};
void unpack_etc2_eac(const void *pBlock_bits, color_rgba *pPixels)
{
static_assert(sizeof(eac_a8_block) == 8, "sizeof(eac_a8_block) == 8");
const eac_a8_block *pBlock = static_cast<const eac_a8_block *>(pBlock_bits);
const int8_t *pTable = g_etc2_eac_tables[pBlock->m_table];
const uint64_t selector_bits = pBlock->get_selector_bits();
const int32_t base = pBlock->m_base;
const int32_t mul = pBlock->m_multiplier;
pPixels[0].a = clamp255(base + pTable[pBlock->get_selector(0, 0, selector_bits)] * mul);
pPixels[1].a = clamp255(base + pTable[pBlock->get_selector(1, 0, selector_bits)] * mul);
pPixels[2].a = clamp255(base + pTable[pBlock->get_selector(2, 0, selector_bits)] * mul);
pPixels[3].a = clamp255(base + pTable[pBlock->get_selector(3, 0, selector_bits)] * mul);
pPixels[4].a = clamp255(base + pTable[pBlock->get_selector(0, 1, selector_bits)] * mul);
pPixels[5].a = clamp255(base + pTable[pBlock->get_selector(1, 1, selector_bits)] * mul);
pPixels[6].a = clamp255(base + pTable[pBlock->get_selector(2, 1, selector_bits)] * mul);
pPixels[7].a = clamp255(base + pTable[pBlock->get_selector(3, 1, selector_bits)] * mul);
pPixels[8].a = clamp255(base + pTable[pBlock->get_selector(0, 2, selector_bits)] * mul);
pPixels[9].a = clamp255(base + pTable[pBlock->get_selector(1, 2, selector_bits)] * mul);
pPixels[10].a = clamp255(base + pTable[pBlock->get_selector(2, 2, selector_bits)] * mul);
pPixels[11].a = clamp255(base + pTable[pBlock->get_selector(3, 2, selector_bits)] * mul);
pPixels[12].a = clamp255(base + pTable[pBlock->get_selector(0, 3, selector_bits)] * mul);
pPixels[13].a = clamp255(base + pTable[pBlock->get_selector(1, 3, selector_bits)] * mul);
pPixels[14].a = clamp255(base + pTable[pBlock->get_selector(2, 3, selector_bits)] * mul);
pPixels[15].a = clamp255(base + pTable[pBlock->get_selector(3, 3, selector_bits)] * mul);
}
struct bc1_block
{
enum { cTotalEndpointBytes = 2, cTotalSelectorBytes = 4 };
uint8_t m_low_color[cTotalEndpointBytes];
uint8_t m_high_color[cTotalEndpointBytes];
uint8_t m_selectors[cTotalSelectorBytes];
inline uint32_t get_high_color() const { return m_high_color[0] | (m_high_color[1] << 8U); }
inline uint32_t get_low_color() const { return m_low_color[0] | (m_low_color[1] << 8U); }
static void unpack_color(uint32_t c, uint32_t &r, uint32_t &g, uint32_t &b)
{
r = (c >> 11) & 31;
g = (c >> 5) & 63;
b = c & 31;
r = (r << 3) | (r >> 2);
g = (g << 2) | (g >> 4);
b = (b << 3) | (b >> 2);
}
inline uint32_t get_selector(uint32_t x, uint32_t y) const { assert((x < 4U) && (y < 4U)); return (m_selectors[y] >> (x * 2)) & 3; }
};
// Returns true if the block uses 3 color punchthrough alpha mode.
bool unpack_bc1(const void *pBlock_bits, color_rgba *pPixels, bool set_alpha)
{
static_assert(sizeof(bc1_block) == 8, "sizeof(bc1_block) == 8");
const bc1_block *pBlock = static_cast<const bc1_block *>(pBlock_bits);
const uint32_t l = pBlock->get_low_color();
const uint32_t h = pBlock->get_high_color();
color_rgba c[4];
uint32_t r0, g0, b0, r1, g1, b1;
bc1_block::unpack_color(l, r0, g0, b0);
bc1_block::unpack_color(h, r1, g1, b1);
bool used_punchthrough = false;
if (l > h)
{
c[0].set_noclamp_rgba(r0, g0, b0, 255);
c[1].set_noclamp_rgba(r1, g1, b1, 255);
c[2].set_noclamp_rgba((r0 * 2 + r1) / 3, (g0 * 2 + g1) / 3, (b0 * 2 + b1) / 3, 255);
c[3].set_noclamp_rgba((r1 * 2 + r0) / 3, (g1 * 2 + g0) / 3, (b1 * 2 + b0) / 3, 255);
}
else
{
c[0].set_noclamp_rgba(r0, g0, b0, 255);
c[1].set_noclamp_rgba(r1, g1, b1, 255);
c[2].set_noclamp_rgba((r0 + r1) / 2, (g0 + g1) / 2, (b0 + b1) / 2, 255);
c[3].set_noclamp_rgba(0, 0, 0, 0);
used_punchthrough = true;
}
if (set_alpha)
{
for (uint32_t y = 0; y < 4; y++, pPixels += 4)
{
pPixels[0] = c[pBlock->get_selector(0, y)];
pPixels[1] = c[pBlock->get_selector(1, y)];
pPixels[2] = c[pBlock->get_selector(2, y)];
pPixels[3] = c[pBlock->get_selector(3, y)];
}
}
else
{
for (uint32_t y = 0; y < 4; y++, pPixels += 4)
{
pPixels[0].set_rgb(c[pBlock->get_selector(0, y)]);
pPixels[1].set_rgb(c[pBlock->get_selector(1, y)]);
pPixels[2].set_rgb(c[pBlock->get_selector(2, y)]);
pPixels[3].set_rgb(c[pBlock->get_selector(3, y)]);
}
}
return used_punchthrough;
}
struct bc4_block
{
enum { cBC4SelectorBits = 3, cTotalSelectorBytes = 6, cMaxSelectorValues = 8 };
uint8_t m_endpoints[2];
uint8_t m_selectors[cTotalSelectorBytes];
inline uint32_t get_low_alpha() const { return m_endpoints[0]; }
inline uint32_t get_high_alpha() const { return m_endpoints[1]; }
inline bool is_alpha6_block() const { return get_low_alpha() <= get_high_alpha(); }
inline uint64_t get_selector_bits() const
{
return ((uint64_t)((uint32_t)m_selectors[0] | ((uint32_t)m_selectors[1] << 8U) | ((uint32_t)m_selectors[2] << 16U) | ((uint32_t)m_selectors[3] << 24U))) |
(((uint64_t)m_selectors[4]) << 32U) |
(((uint64_t)m_selectors[5]) << 40U);
}
inline uint32_t get_selector(uint32_t x, uint32_t y, uint64_t selector_bits) const
{
assert((x < 4U) && (y < 4U));
return (selector_bits >> (((y * 4) + x) * cBC4SelectorBits)) & (cMaxSelectorValues - 1);
}
static inline uint32_t get_block_values6(uint8_t *pDst, uint32_t l, uint32_t h)
{
pDst[0] = static_cast<uint8_t>(l);
pDst[1] = static_cast<uint8_t>(h);
pDst[2] = static_cast<uint8_t>((l * 4 + h) / 5);
pDst[3] = static_cast<uint8_t>((l * 3 + h * 2) / 5);
pDst[4] = static_cast<uint8_t>((l * 2 + h * 3) / 5);
pDst[5] = static_cast<uint8_t>((l + h * 4) / 5);
pDst[6] = 0;
pDst[7] = 255;
return 6;
}
static inline uint32_t get_block_values8(uint8_t *pDst, uint32_t l, uint32_t h)
{
pDst[0] = static_cast<uint8_t>(l);
pDst[1] = static_cast<uint8_t>(h);
pDst[2] = static_cast<uint8_t>((l * 6 + h) / 7);
pDst[3] = static_cast<uint8_t>((l * 5 + h * 2) / 7);
pDst[4] = static_cast<uint8_t>((l * 4 + h * 3) / 7);
pDst[5] = static_cast<uint8_t>((l * 3 + h * 4) / 7);
pDst[6] = static_cast<uint8_t>((l * 2 + h * 5) / 7);
pDst[7] = static_cast<uint8_t>((l + h * 6) / 7);
return 8;
}
static inline uint32_t get_block_values(uint8_t *pDst, uint32_t l, uint32_t h)
{
if (l > h)
return get_block_values8(pDst, l, h);
else
return get_block_values6(pDst, l, h);
}
};
void unpack_bc4(const void *pBlock_bits, uint8_t *pPixels, uint32_t stride)
{
static_assert(sizeof(bc4_block) == 8, "sizeof(bc4_block) == 8");
const bc4_block *pBlock = static_cast<const bc4_block *>(pBlock_bits);
uint8_t sel_values[8];
bc4_block::get_block_values(sel_values, pBlock->get_low_alpha(), pBlock->get_high_alpha());
const uint64_t selector_bits = pBlock->get_selector_bits();
for (uint32_t y = 0; y < 4; y++, pPixels += (stride * 4U))
{
pPixels[0] = sel_values[pBlock->get_selector(0, y, selector_bits)];
pPixels[stride * 1] = sel_values[pBlock->get_selector(1, y, selector_bits)];
pPixels[stride * 2] = sel_values[pBlock->get_selector(2, y, selector_bits)];
pPixels[stride * 3] = sel_values[pBlock->get_selector(3, y, selector_bits)];
}
}
// Returns false if the block uses 3-color punchthrough alpha mode, which isn't supported on some GPU's for BC3.
bool unpack_bc3(const void *pBlock_bits, color_rgba *pPixels)
{
bool success = true;
if (unpack_bc1((const uint8_t *)pBlock_bits + sizeof(bc4_block), pPixels, true))
success = false;
unpack_bc4(pBlock_bits, &pPixels[0].a, sizeof(color_rgba));
return success;
}
// writes RG
void unpack_bc5(const void *pBlock_bits, color_rgba *pPixels)
{
unpack_bc4(pBlock_bits, &pPixels[0].r, sizeof(color_rgba));
unpack_bc4((const uint8_t *)pBlock_bits + sizeof(bc4_block), &pPixels[0].g, sizeof(color_rgba));
}
// ATC isn't officially documented, so I'm assuming these references:
// http://www.guildsoftware.com/papers/2012.Converting.DXTC.to.ATC.pdf
// https://github.com/Triang3l/S3TConv/blob/master/s3tconv_atitc.c
// The paper incorrectly says the ATC lerp factors are 1/3 and 2/3, but they are actually 3/8 and 5/8.
void unpack_atc(const void* pBlock_bits, color_rgba* pPixels)
{
const uint8_t* pBytes = static_cast<const uint8_t*>(pBlock_bits);
const uint16_t color0 = pBytes[0] | (pBytes[1] << 8U);
const uint16_t color1 = pBytes[2] | (pBytes[3] << 8U);
uint32_t sels = pBytes[4] | (pBytes[5] << 8U) | (pBytes[6] << 16U) | (pBytes[7] << 24U);
const bool mode = (color0 & 0x8000) != 0;
color_rgba c[4];
c[0].set((color0 >> 10) & 31, (color0 >> 5) & 31, color0 & 31, 255);
c[0].r = (c[0].r << 3) | (c[0].r >> 2);
c[0].g = (c[0].g << 3) | (c[0].g >> 2);
c[0].b = (c[0].b << 3) | (c[0].b >> 2);
c[3].set((color1 >> 11) & 31, (color1 >> 5) & 63, color1 & 31, 255);
c[3].r = (c[3].r << 3) | (c[3].r >> 2);
c[3].g = (c[3].g << 2) | (c[3].g >> 4);
c[3].b = (c[3].b << 3) | (c[3].b >> 2);
if (mode)
{
c[1].set(std::max(0, c[0].r - (c[3].r >> 2)), std::max(0, c[0].g - (c[3].g >> 2)), std::max(0, c[0].b - (c[3].b >> 2)), 255);
c[2] = c[0];
c[0].set(0, 0, 0, 255);
}
else
{
c[1].r = (c[0].r * 5 + c[3].r * 3) >> 3;
c[1].g = (c[0].g * 5 + c[3].g * 3) >> 3;
c[1].b = (c[0].b * 5 + c[3].b * 3) >> 3;
c[2].r = (c[0].r * 3 + c[3].r * 5) >> 3;
c[2].g = (c[0].g * 3 + c[3].g * 5) >> 3;
c[2].b = (c[0].b * 3 + c[3].b * 5) >> 3;
}
for (uint32_t i = 0; i < 16; i++)
{
const uint32_t s = sels & 3;
pPixels[i] = c[s];
sels >>= 2;
}
}
struct bc7_mode_6
{
struct
{
uint64_t m_mode : 7;
uint64_t m_r0 : 7;
uint64_t m_r1 : 7;
uint64_t m_g0 : 7;
uint64_t m_g1 : 7;
uint64_t m_b0 : 7;
uint64_t m_b1 : 7;
uint64_t m_a0 : 7;
uint64_t m_a1 : 7;
uint64_t m_p0 : 1;
} m_lo;
union
{
struct
{
uint64_t m_p1 : 1;
uint64_t m_s00 : 3;
uint64_t m_s10 : 4;
uint64_t m_s20 : 4;
uint64_t m_s30 : 4;
uint64_t m_s01 : 4;
uint64_t m_s11 : 4;
uint64_t m_s21 : 4;
uint64_t m_s31 : 4;
uint64_t m_s02 : 4;
uint64_t m_s12 : 4;
uint64_t m_s22 : 4;
uint64_t m_s32 : 4;
uint64_t m_s03 : 4;
uint64_t m_s13 : 4;
uint64_t m_s23 : 4;
uint64_t m_s33 : 4;
} m_hi;
uint64_t m_hi_bits;
};
};
static const uint32_t g_bc7_weights4[16] = { 0, 4, 9, 13, 17, 21, 26, 30, 34, 38, 43, 47, 51, 55, 60, 64 };
// The transcoder only outputs mode 6 at the moment, so this is easy.
bool unpack_bc7_mode6(const void *pBlock_bits, color_rgba *pPixels)
{
static_assert(sizeof(bc7_mode_6) == 16, "sizeof(bc7_mode_6) == 16");
const bc7_mode_6 &block = *static_cast<const bc7_mode_6 *>(pBlock_bits);
if (block.m_lo.m_mode != (1 << 6))
return false;
const uint32_t r0 = (uint32_t)((block.m_lo.m_r0 << 1) | block.m_lo.m_p0);
const uint32_t g0 = (uint32_t)((block.m_lo.m_g0 << 1) | block.m_lo.m_p0);
const uint32_t b0 = (uint32_t)((block.m_lo.m_b0 << 1) | block.m_lo.m_p0);
const uint32_t a0 = (uint32_t)((block.m_lo.m_a0 << 1) | block.m_lo.m_p0);
const uint32_t r1 = (uint32_t)((block.m_lo.m_r1 << 1) | block.m_hi.m_p1);
const uint32_t g1 = (uint32_t)((block.m_lo.m_g1 << 1) | block.m_hi.m_p1);
const uint32_t b1 = (uint32_t)((block.m_lo.m_b1 << 1) | block.m_hi.m_p1);
const uint32_t a1 = (uint32_t)((block.m_lo.m_a1 << 1) | block.m_hi.m_p1);
color_rgba vals[16];
for (uint32_t i = 0; i < 16; i++)
{
const uint32_t w = g_bc7_weights4[i];
const uint32_t iw = 64 - w;
vals[i].set_noclamp_rgba(
(r0 * iw + r1 * w + 32) >> 6,
(g0 * iw + g1 * w + 32) >> 6,
(b0 * iw + b1 * w + 32) >> 6,
(a0 * iw + a1 * w + 32) >> 6);
}
pPixels[0] = vals[block.m_hi.m_s00];
pPixels[1] = vals[block.m_hi.m_s10];
pPixels[2] = vals[block.m_hi.m_s20];
pPixels[3] = vals[block.m_hi.m_s30];
pPixels[4] = vals[block.m_hi.m_s01];
pPixels[5] = vals[block.m_hi.m_s11];
pPixels[6] = vals[block.m_hi.m_s21];
pPixels[7] = vals[block.m_hi.m_s31];
pPixels[8] = vals[block.m_hi.m_s02];
pPixels[9] = vals[block.m_hi.m_s12];
pPixels[10] = vals[block.m_hi.m_s22];
pPixels[11] = vals[block.m_hi.m_s32];
pPixels[12] = vals[block.m_hi.m_s03];
pPixels[13] = vals[block.m_hi.m_s13];
pPixels[14] = vals[block.m_hi.m_s23];
pPixels[15] = vals[block.m_hi.m_s33];
return true;
}
static inline uint32_t get_block_bits(const uint8_t* pBytes, uint32_t bit_ofs, uint32_t bits_wanted)
{
assert(bits_wanted < 32);
uint32_t v = 0;
uint32_t total_bits = 0;
while (total_bits < bits_wanted)
{
uint32_t k = pBytes[bit_ofs >> 3];
k >>= (bit_ofs & 7);
uint32_t num_bits_in_byte = 8 - (bit_ofs & 7);
v |= (k << total_bits);
total_bits += num_bits_in_byte;
bit_ofs += num_bits_in_byte;
}
return v & ((1 << bits_wanted) - 1);
}
struct bc7_mode_5
{
union
{
struct
{
uint64_t m_mode : 6;
uint64_t m_rot : 2;
uint64_t m_r0 : 7;
uint64_t m_r1 : 7;
uint64_t m_g0 : 7;
uint64_t m_g1 : 7;
uint64_t m_b0 : 7;
uint64_t m_b1 : 7;
uint64_t m_a0 : 8;
uint64_t m_a1_0 : 6;
} m_lo;
uint64_t m_lo_bits;
};
union
{
struct
{
uint64_t m_a1_1 : 2;
// bit 2
uint64_t m_c00 : 1;
uint64_t m_c10 : 2;
uint64_t m_c20 : 2;
uint64_t m_c30 : 2;
uint64_t m_c01 : 2;
uint64_t m_c11 : 2;
uint64_t m_c21 : 2;
uint64_t m_c31 : 2;
uint64_t m_c02 : 2;
uint64_t m_c12 : 2;
uint64_t m_c22 : 2;
uint64_t m_c32 : 2;
uint64_t m_c03 : 2;
uint64_t m_c13 : 2;
uint64_t m_c23 : 2;
uint64_t m_c33 : 2;
// bit 33
uint64_t m_a00 : 1;
uint64_t m_a10 : 2;
uint64_t m_a20 : 2;
uint64_t m_a30 : 2;
uint64_t m_a01 : 2;
uint64_t m_a11 : 2;
uint64_t m_a21 : 2;
uint64_t m_a31 : 2;
uint64_t m_a02 : 2;
uint64_t m_a12 : 2;
uint64_t m_a22 : 2;
uint64_t m_a32 : 2;
uint64_t m_a03 : 2;
uint64_t m_a13 : 2;
uint64_t m_a23 : 2;
uint64_t m_a33 : 2;
} m_hi;
uint64_t m_hi_bits;
};
color_rgba get_low_color() const
{
return color_rgba(cNoClamp,
(int)((m_lo.m_r0 << 1) | (m_lo.m_r0 >> 6)),
(int)((m_lo.m_g0 << 1) | (m_lo.m_g0 >> 6)),
(int)((m_lo.m_b0 << 1) | (m_lo.m_b0 >> 6)),
m_lo.m_a0);
}
color_rgba get_high_color() const
{
return color_rgba(cNoClamp,
(int)((m_lo.m_r1 << 1) | (m_lo.m_r1 >> 6)),
(int)((m_lo.m_g1 << 1) | (m_lo.m_g1 >> 6)),
(int)((m_lo.m_b1 << 1) | (m_lo.m_b1 >> 6)),
(int)m_lo.m_a1_0 | ((int)m_hi.m_a1_1 << 6));
}
void get_block_colors(color_rgba* pColors) const
{
const color_rgba low_color(get_low_color());
const color_rgba high_color(get_high_color());
for (uint32_t i = 0; i < 4; i++)
{
static const uint32_t s_bc7_weights2[4] = { 0, 21, 43, 64 };
pColors[i].set_noclamp_rgba(
(low_color.r * (64 - s_bc7_weights2[i]) + high_color.r * s_bc7_weights2[i] + 32) >> 6,
(low_color.g * (64 - s_bc7_weights2[i]) + high_color.g * s_bc7_weights2[i] + 32) >> 6,
(low_color.b * (64 - s_bc7_weights2[i]) + high_color.b * s_bc7_weights2[i] + 32) >> 6,
(low_color.a * (64 - s_bc7_weights2[i]) + high_color.a * s_bc7_weights2[i] + 32) >> 6);
}
}
uint32_t get_selector(uint32_t idx, bool alpha) const
{
const uint32_t size = (idx == 0) ? 1 : 2;
uint32_t ofs = alpha ? 97 : 66;
if (idx)
ofs += 1 + 2 * (idx - 1);
return get_block_bits(reinterpret_cast<const uint8_t*>(this), ofs, size);
}
};
bool unpack_bc7_mode5(const void* pBlock_bits, color_rgba* pPixels)
{
static_assert(sizeof(bc7_mode_5) == 16, "sizeof(bc7_mode_5) == 16");
const bc7_mode_5& block = *static_cast<const bc7_mode_5*>(pBlock_bits);
if (block.m_lo.m_mode != (1 << 5))
return false;
color_rgba block_colors[4];
block.get_block_colors(block_colors);
const uint32_t rot = block.m_lo.m_rot;
for (uint32_t i = 0; i < 16; i++)
{
const uint32_t cs = block.get_selector(i, false);
color_rgba c(block_colors[cs]);
const uint32_t as = block.get_selector(i, true);
c.a = block_colors[as].a;
if (rot > 0)
std::swap(c[3], c[rot - 1]);
pPixels[i] = c;
}
return true;
}
struct fxt1_block
{
union
{
struct
{
uint64_t m_t00 : 2;
uint64_t m_t01 : 2;
uint64_t m_t02 : 2;
uint64_t m_t03 : 2;
uint64_t m_t04 : 2;
uint64_t m_t05 : 2;
uint64_t m_t06 : 2;
uint64_t m_t07 : 2;
uint64_t m_t08 : 2;
uint64_t m_t09 : 2;
uint64_t m_t10 : 2;
uint64_t m_t11 : 2;
uint64_t m_t12 : 2;
uint64_t m_t13 : 2;
uint64_t m_t14 : 2;
uint64_t m_t15 : 2;
uint64_t m_t16 : 2;
uint64_t m_t17 : 2;
uint64_t m_t18 : 2;
uint64_t m_t19 : 2;
uint64_t m_t20 : 2;
uint64_t m_t21 : 2;
uint64_t m_t22 : 2;
uint64_t m_t23 : 2;
uint64_t m_t24 : 2;
uint64_t m_t25 : 2;
uint64_t m_t26 : 2;
uint64_t m_t27 : 2;
uint64_t m_t28 : 2;
uint64_t m_t29 : 2;
uint64_t m_t30 : 2;
uint64_t m_t31 : 2;
} m_lo;
uint64_t m_lo_bits;
uint8_t m_sels[8];
};
union
{
struct
{
#ifdef BASISU_USE_ORIGINAL_3DFX_FXT1_ENCODING
// This is the format that 3DFX's DECOMP.EXE tool expects, which I'm assuming is what the actual 3DFX hardware wanted.
// Unfortunately, color0/color1 and color2/color3 are flipped relative to the official OpenGL extension and Intel's documentation!
uint64_t m_b1 : 5;
uint64_t m_g1 : 5;
uint64_t m_r1 : 5;
uint64_t m_b0 : 5;
uint64_t m_g0 : 5;
uint64_t m_r0 : 5;
uint64_t m_b3 : 5;
uint64_t m_g3 : 5;
uint64_t m_r3 : 5;
uint64_t m_b2 : 5;
uint64_t m_g2 : 5;
uint64_t m_r2 : 5;
#else
// Intel's encoding, and the encoding in the OpenGL FXT1 spec.
uint64_t m_b0 : 5;
uint64_t m_g0 : 5;
uint64_t m_r0 : 5;
uint64_t m_b1 : 5;
uint64_t m_g1 : 5;
uint64_t m_r1 : 5;
uint64_t m_b2 : 5;
uint64_t m_g2 : 5;
uint64_t m_r2 : 5;
uint64_t m_b3 : 5;
uint64_t m_g3 : 5;
uint64_t m_r3 : 5;
#endif
uint64_t m_alpha : 1;
uint64_t m_glsb : 2;
uint64_t m_mode : 1;
} m_hi;
uint64_t m_hi_bits;
};
};
static color_rgba expand_565(const color_rgba& c)
{
return color_rgba((c.r << 3) | (c.r >> 2), (c.g << 2) | (c.g >> 4), (c.b << 3) | (c.b >> 2), 255);
}
// We only support CC_MIXED non-alpha blocks here because that's the only mode the transcoder uses at the moment.
bool unpack_fxt1(const void *p, color_rgba *pPixels)
{
const fxt1_block* pBlock = static_cast<const fxt1_block*>(p);
if (pBlock->m_hi.m_mode == 0)
return false;
if (pBlock->m_hi.m_alpha == 1)
return false;
color_rgba colors[4];
colors[0].r = pBlock->m_hi.m_r0;
colors[0].g = (uint8_t)((pBlock->m_hi.m_g0 << 1) | ((pBlock->m_lo.m_t00 >> 1) ^ (pBlock->m_hi.m_glsb & 1)));
colors[0].b = pBlock->m_hi.m_b0;
colors[0].a = 255;
colors[1].r = pBlock->m_hi.m_r1;
colors[1].g = (uint8_t)((pBlock->m_hi.m_g1 << 1) | (pBlock->m_hi.m_glsb & 1));
colors[1].b = pBlock->m_hi.m_b1;
colors[1].a = 255;
colors[2].r = pBlock->m_hi.m_r2;
colors[2].g = (uint8_t)((pBlock->m_hi.m_g2 << 1) | ((pBlock->m_lo.m_t16 >> 1) ^ (pBlock->m_hi.m_glsb >> 1)));
colors[2].b = pBlock->m_hi.m_b2;
colors[2].a = 255;
colors[3].r = pBlock->m_hi.m_r3;
colors[3].g = (uint8_t)((pBlock->m_hi.m_g3 << 1) | (pBlock->m_hi.m_glsb >> 1));
colors[3].b = pBlock->m_hi.m_b3;
colors[3].a = 255;
for (uint32_t i = 0; i < 4; i++)
colors[i] = expand_565(colors[i]);
color_rgba block0_colors[4];
block0_colors[0] = colors[0];
block0_colors[1] = color_rgba((colors[0].r * 2 + colors[1].r + 1) / 3, (colors[0].g * 2 + colors[1].g + 1) / 3, (colors[0].b * 2 + colors[1].b + 1) / 3, 255);
block0_colors[2] = color_rgba((colors[1].r * 2 + colors[0].r + 1) / 3, (colors[1].g * 2 + colors[0].g + 1) / 3, (colors[1].b * 2 + colors[0].b + 1) / 3, 255);
block0_colors[3] = colors[1];
for (uint32_t i = 0; i < 16; i++)
{
const uint32_t sel = (pBlock->m_sels[i >> 2] >> ((i & 3) * 2)) & 3;
const uint32_t x = i & 3;
const uint32_t y = i >> 2;
pPixels[x + y * 8] = block0_colors[sel];
}
color_rgba block1_colors[4];
block1_colors[0] = colors[2];
block1_colors[1] = color_rgba((colors[2].r * 2 + colors[3].r + 1) / 3, (colors[2].g * 2 + colors[3].g + 1) / 3, (colors[2].b * 2 + colors[3].b + 1) / 3, 255);
block1_colors[2] = color_rgba((colors[3].r * 2 + colors[2].r + 1) / 3, (colors[3].g * 2 + colors[2].g + 1) / 3, (colors[3].b * 2 + colors[2].b + 1) / 3, 255);
block1_colors[3] = colors[3];
for (uint32_t i = 0; i < 16; i++)
{
const uint32_t sel = (pBlock->m_sels[4 + (i >> 2)] >> ((i & 3) * 2)) & 3;
const uint32_t x = i & 3;
const uint32_t y = i >> 2;
pPixels[4 + x + y * 8] = block1_colors[sel];
}
return true;
}
struct pvrtc2_block
{
uint8_t m_modulation[4];
union
{
union
{
// Opaque mode: RGB colora=554 and colorb=555
struct
{
uint32_t m_mod_flag : 1;
uint32_t m_blue_a : 4;
uint32_t m_green_a : 5;
uint32_t m_red_a : 5;
uint32_t m_hard_flag : 1;
uint32_t m_blue_b : 5;
uint32_t m_green_b : 5;
uint32_t m_red_b : 5;
uint32_t m_opaque_flag : 1;
} m_opaque_color_data;
// Transparent mode: RGBA colora=4433 and colorb=4443
struct
{
uint32_t m_mod_flag : 1;
uint32_t m_blue_a : 3;
uint32_t m_green_a : 4;
uint32_t m_red_a : 4;
uint32_t m_alpha_a : 3;
uint32_t m_hard_flag : 1;
uint32_t m_blue_b : 4;
uint32_t m_green_b : 4;
uint32_t m_red_b : 4;
uint32_t m_alpha_b : 3;
uint32_t m_opaque_flag : 1;
} m_trans_color_data;
};
uint32_t m_color_data_bits;
};
};
static color_rgba convert_rgb_555_to_888(const color_rgba& col)
{
return color_rgba((col[0] << 3) | (col[0] >> 2), (col[1] << 3) | (col[1] >> 2), (col[2] << 3) | (col[2] >> 2), 255);
}
static color_rgba convert_rgba_5554_to_8888(const color_rgba& col)
{
return color_rgba((col[0] << 3) | (col[0] >> 2), (col[1] << 3) | (col[1] >> 2), (col[2] << 3) | (col[2] >> 2), (col[3] << 4) | col[3]);
}
// PVRTC2 is currently limited to only what our transcoder outputs (non-interpolated, hard_flag=1 modulation=0). In this mode, PVRTC2 looks much like BC1/ATC.
bool unpack_pvrtc2(const void *p, color_rgba *pPixels)
{
const pvrtc2_block* pBlock = static_cast<const pvrtc2_block*>(p);
if ((!pBlock->m_opaque_color_data.m_hard_flag) || (pBlock->m_opaque_color_data.m_mod_flag))
{
// This mode isn't supported by the transcoder, so we aren't bothering with it here.
return false;
}
color_rgba colors[4];
if (pBlock->m_opaque_color_data.m_opaque_flag)
{
// colora=554
color_rgba color_a(pBlock->m_opaque_color_data.m_red_a, pBlock->m_opaque_color_data.m_green_a, (pBlock->m_opaque_color_data.m_blue_a << 1) | (pBlock->m_opaque_color_data.m_blue_a >> 3), 255);
// colora=555
color_rgba color_b(pBlock->m_opaque_color_data.m_red_b, pBlock->m_opaque_color_data.m_green_b, pBlock->m_opaque_color_data.m_blue_b, 255);
colors[0] = convert_rgb_555_to_888(color_a);
colors[3] = convert_rgb_555_to_888(color_b);
colors[1].set((colors[0].r * 5 + colors[3].r * 3) / 8, (colors[0].g * 5 + colors[3].g * 3) / 8, (colors[0].b * 5 + colors[3].b * 3) / 8, 255);
colors[2].set((colors[0].r * 3 + colors[3].r * 5) / 8, (colors[0].g * 3 + colors[3].g * 5) / 8, (colors[0].b * 3 + colors[3].b * 5) / 8, 255);
}
else
{
// colora=4433
color_rgba color_a(
(pBlock->m_trans_color_data.m_red_a << 1) | (pBlock->m_trans_color_data.m_red_a >> 3),
(pBlock->m_trans_color_data.m_green_a << 1) | (pBlock->m_trans_color_data.m_green_a >> 3),
(pBlock->m_trans_color_data.m_blue_a << 2) | (pBlock->m_trans_color_data.m_blue_a >> 1),
pBlock->m_trans_color_data.m_alpha_a << 1);
//colorb=4443
color_rgba color_b(
(pBlock->m_trans_color_data.m_red_b << 1) | (pBlock->m_trans_color_data.m_red_b >> 3),
(pBlock->m_trans_color_data.m_green_b << 1) | (pBlock->m_trans_color_data.m_green_b >> 3),
(pBlock->m_trans_color_data.m_blue_b << 1) | (pBlock->m_trans_color_data.m_blue_b >> 3),
(pBlock->m_trans_color_data.m_alpha_b << 1) | 1);
colors[0] = convert_rgba_5554_to_8888(color_a);
colors[3] = convert_rgba_5554_to_8888(color_b);
}
colors[1].set((colors[0].r * 5 + colors[3].r * 3) / 8, (colors[0].g * 5 + colors[3].g * 3) / 8, (colors[0].b * 5 + colors[3].b * 3) / 8, (colors[0].a * 5 + colors[3].a * 3) / 8);
colors[2].set((colors[0].r * 3 + colors[3].r * 5) / 8, (colors[0].g * 3 + colors[3].g * 5) / 8, (colors[0].b * 3 + colors[3].b * 5) / 8, (colors[0].a * 3 + colors[3].a * 5) / 8);
for (uint32_t i = 0; i < 16; i++)
{
const uint32_t sel = (pBlock->m_modulation[i >> 2] >> ((i & 3) * 2)) & 3;
pPixels[i] = colors[sel];
}
return true;
}
struct etc2_eac_r11
{
uint64_t m_base : 8;
uint64_t m_table : 4;
uint64_t m_mul : 4;
uint64_t m_sels_0 : 8;
uint64_t m_sels_1 : 8;
uint64_t m_sels_2 : 8;
uint64_t m_sels_3 : 8;
uint64_t m_sels_4 : 8;
uint64_t m_sels_5 : 8;
uint64_t get_sels() const
{
return ((uint64_t)m_sels_0 << 40U) | ((uint64_t)m_sels_1 << 32U) | ((uint64_t)m_sels_2 << 24U) | ((uint64_t)m_sels_3 << 16U) | ((uint64_t)m_sels_4 << 8U) | m_sels_5;
}
void set_sels(uint64_t v)
{
m_sels_0 = (v >> 40U) & 0xFF;
m_sels_1 = (v >> 32U) & 0xFF;
m_sels_2 = (v >> 24U) & 0xFF;
m_sels_3 = (v >> 16U) & 0xFF;
m_sels_4 = (v >> 8U) & 0xFF;
m_sels_5 = v & 0xFF;
}
};
struct etc2_eac_rg11
{
etc2_eac_r11 m_c[2];
};
static void unpack_etc2_eac_r(const etc2_eac_r11* p, color_rgba* pPixels, uint32_t c)
{
const uint64_t sels = p->get_sels();
const int base = (int)p->m_base * 8 + 4;
const int mul = p->m_mul ? ((int)p->m_mul * 8) : 1;
const int table = (int)p->m_table;
for (uint32_t y = 0; y < 4; y++)
{
for (uint32_t x = 0; x < 4; x++)
{
const uint32_t shift = 45 - ((y + x * 4) * 3);
const uint32_t sel = (uint32_t)((sels >> shift) & 7);
int val = base + g_etc2_eac_tables[table][sel] * mul;
val = clamp<int>(val, 0, 2047);
// Convert to 8-bits with rounding
pPixels[x + y * 4].m_comps[c] = static_cast<uint8_t>((val * 255 + 1024) / 2047);
} // x
} // y
}
void unpack_etc2_eac_rg(const void* p, color_rgba* pPixels)
{
for (uint32_t c = 0; c < 2; c++)
{
const etc2_eac_r11* pBlock = &static_cast<const etc2_eac_rg11*>(p)->m_c[c];
unpack_etc2_eac_r(pBlock, pPixels, c);
}
}
// Unpacks to RGBA, R, RG, or A
bool unpack_block(texture_format fmt, const void* pBlock, color_rgba* pPixels)
{
switch (fmt)
{
case texture_format::cBC1:
{
unpack_bc1(pBlock, pPixels, true);
break;
}
case texture_format::cBC3:
{
return unpack_bc3(pBlock, pPixels);
}
case texture_format::cBC4:
{
// Unpack to R
unpack_bc4(pBlock, &pPixels[0].r, sizeof(color_rgba));
break;
}
case texture_format::cBC5:
{
unpack_bc5(pBlock, pPixels);
break;
}
case texture_format::cBC7:
{
// We only support modes 5 and 6.
if (!unpack_bc7_mode5(pBlock, pPixels))
{
if (!unpack_bc7_mode6(pBlock, pPixels))
return false;
}
break;
}
// Full ETC2 color blocks (planar/T/H modes) is currently unsupported in basisu, but we do support ETC2 with alpha (using ETC1 for color)
case texture_format::cETC2_RGB:
case texture_format::cETC1:
case texture_format::cETC1S:
{
return unpack_etc1(*static_cast<const etc_block*>(pBlock), pPixels);
}
case texture_format::cETC2_RGBA:
{
if (!unpack_etc1(static_cast<const etc_block*>(pBlock)[1], pPixels))
return false;
unpack_etc2_eac(pBlock, pPixels);
break;
}
case texture_format::cETC2_ALPHA:
{
// Unpack to A
unpack_etc2_eac(pBlock, pPixels);
break;
}
case texture_format::cASTC4x4:
{
const bool astc_srgb = false;