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Unified Diff: src/utils/SkTextureCompressor_ASTC.cpp

Issue 444103002: Revert of Initial ASTC decoder -- currently only supports 2D LDR decomrpession modes. (Closed) Base URL: https://skia.googlesource.com/skia.git@master
Patch Set: Created 6 years, 4 months ago
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Index: src/utils/SkTextureCompressor_ASTC.cpp
diff --git a/src/utils/SkTextureCompressor_ASTC.cpp b/src/utils/SkTextureCompressor_ASTC.cpp
index dbb90f122bc0a00c4169d4e1e826e88286b49b42..8efffdfc9e8f04e035009bfc17a207ab8297758c 100644
--- a/src/utils/SkTextureCompressor_ASTC.cpp
+++ b/src/utils/SkTextureCompressor_ASTC.cpp
@@ -10,7 +10,6 @@
#include "SkBlitter.h"
#include "SkEndian.h"
-#include "SkMath.h"
// This table contains the weight values for each texel. This is used in determining
// how to convert a 12x12 grid of alpha values into a 6x5 grid of index values. Since
@@ -262,1741 +261,10 @@
}
////////////////////////////////////////////////////////////////////////////////
-//
-// ASTC Decoder
-//
-// Full details available in the spec:
-// http://www.khronos.org/registry/gles/extensions/OES/OES_texture_compression_astc.txt
-//
-////////////////////////////////////////////////////////////////////////////////
-
-// Enable this to assert whenever a decoded block has invalid ASTC values. Otherwise,
-// each invalid block will result in a disgusting magenta color.
-#define ASSERT_ASTC_DECODE_ERROR 0
-
-// Reverse 64-bit integer taken from TAOCP 4a, although it's better
-// documented at this site:
-// http://matthewarcus.wordpress.com/2012/11/18/reversing-a-64-bit-word/
-
-template <typename T, T m, int k>
-static inline T swap_bits(T p) {
- T q = ((p>>k)^p) & m;
- return p^q^(q<<k);
-}
-
-static inline uint64_t reverse64(uint64_t n) {
- static const uint64_t m0 = 0x5555555555555555LLU;
- static const uint64_t m1 = 0x0300c0303030c303LLU;
- static const uint64_t m2 = 0x00c0300c03f0003fLLU;
- static const uint64_t m3 = 0x00000ffc00003fffLLU;
- n = ((n>>1)&m0) | (n&m0)<<1;
- n = swap_bits<uint64_t, m1, 4>(n);
- n = swap_bits<uint64_t, m2, 8>(n);
- n = swap_bits<uint64_t, m3, 20>(n);
- n = (n >> 34) | (n << 30);
- return n;
-}
-
-// An ASTC block is 128 bits. We represent it as two 64-bit integers in order
-// to efficiently operate on the block using bitwise operations.
-struct ASTCBlock {
- uint64_t fLow;
- uint64_t fHigh;
-
- // Reverses the bits of an ASTC block, making the LSB of the
- // 128 bit block the MSB.
- inline void reverse() {
- const uint64_t newLow = reverse64(this->fHigh);
- this->fHigh = reverse64(this->fLow);
- this->fLow = newLow;
- }
-};
-
-// Writes the given color to every pixel in the block. This is used by void-extent
-// blocks (a special constant-color encoding of a block) and by the error function.
-static inline void write_constant_color(uint8_t* dst, int blockDimX, int blockDimY,
- int dstRowBytes, SkColor color) {
- for (int y = 0; y < blockDimY; ++y) {
- SkColor *dstColors = reinterpret_cast<SkColor*>(dst);
- for (int x = 0; x < blockDimX; ++x) {
- dstColors[x] = color;
- }
- dst += dstRowBytes;
- }
-}
-
-// Sets the entire block to the ASTC "error" color, a disgusting magenta
-// that's not supposed to appear in natural images.
-static inline void write_error_color(uint8_t* dst, int blockDimX, int blockDimY,
- int dstRowBytes) {
- static const SkColor kASTCErrorColor = SkColorSetRGB(0xFF, 0, 0xFF);
-
-#if ASSERT_ASTC_DECODE_ERROR
- SkDEBUGFAIL("ASTC decoding error!\n");
-#endif
-
- write_constant_color(dst, blockDimX, blockDimY, dstRowBytes, kASTCErrorColor);
-}
-
-// Reads up to 64 bits of the ASTC block starting from bit
-// 'from' and going up to but not including bit 'to'. 'from' starts
-// counting from the LSB, counting up to the MSB. Returns -1 on
-// error.
-static uint64_t read_astc_bits(const ASTCBlock &block, int from, int to) {
- SkASSERT(0 <= from && from <= 128);
- SkASSERT(0 <= to && to <= 128);
-
- const int nBits = to - from;
- if (0 == nBits) {
- return 0;
- }
-
- if (nBits < 0 || 64 <= nBits) {
- SkDEBUGFAIL("ASTC -- shouldn't read more than 64 bits");
- return -1;
- }
-
- // Remember, the 'to' bit isn't read.
- uint64_t result = 0;
- if (to <= 64) {
- // All desired bits are in the low 64-bits.
- result = (block.fLow >> from) & ((1ULL << nBits) - 1);
- } else if (from >= 64) {
- // All desired bits are in the high 64-bits.
- result = (block.fHigh >> (from - 64)) & ((1ULL << nBits) - 1);
- } else {
- // from < 64 && to > 64
- SkASSERT(nBits > (64 - from));
- const int nLow = 64 - from;
- const int nHigh = nBits - nLow;
- result =
- ((block.fLow >> from) & ((1ULL << nLow) - 1)) |
- ((block.fHigh & ((1ULL << nHigh) - 1)) << nLow);
- }
-
- return result;
-}
-
-// Returns the number of bits needed to represent a number
-// in the given power-of-two range (excluding the power of two itself).
-static inline int bits_for_range(int x) {
- SkASSERT(SkIsPow2(x));
- SkASSERT(0 != x);
- // Since we know it's a power of two, there should only be one bit set,
- // meaning the number of trailing zeros is 31 minus the number of leading
- // zeros.
- return 31 - SkCLZ(x);
-}
-
-// Clamps an integer to the range [0, 255]
-static inline int clamp_byte(int x) {
- return SkClampMax(x, 255);
-}
-
-// Helper function defined in the ASTC spec, section C.2.14
-// It transfers a few bits of precision from one value to another.
-static inline void bit_transfer_signed(int *a, int *b) {
- *b >>= 1;
- *b |= *a & 0x80;
- *a >>= 1;
- *a &= 0x3F;
- if ( (*a & 0x20) != 0 ) {
- *a -= 0x40;
- }
-}
-
-// Helper function defined in the ASTC spec, section C.2.14
-// It uses the value in the blue channel to tint the red and green
-static inline SkColor blue_contract(int a, int r, int g, int b) {
- return SkColorSetARGB(a, (r + b) >> 1, (g + b) >> 1, b);
-}
-
-// Helper function that decodes two colors from eight values. If isRGB is true,
-// then the pointer 'v' contains six values and the last two are considered to be
-// 0xFF. If isRGB is false, then all eight values come from the pointer 'v'. This
-// corresponds to the decode procedure for the following endpoint modes:
-// kLDR_RGB_Direct_ColorEndpointMode
-// kLDR_RGBA_Direct_ColorEndpointMode
-static inline void decode_rgba_direct(const int *v, SkColor *endpoints, bool isRGB) {
-
- int v6 = 0xFF;
- int v7 = 0xFF;
- if (!isRGB) {
- v6 = v[6];
- v7 = v[7];
- }
-
- const int s0 = v[0] + v[2] + v[4];
- const int s1 = v[1] + v[3] + v[5];
-
- if (s1 >= s0) {
- endpoints[0] = SkColorSetARGB(v6, v[0], v[2], v[4]);
- endpoints[1] = SkColorSetARGB(v7, v[1], v[3], v[5]);
- } else {
- endpoints[0] = blue_contract(v7, v[1], v[3], v[5]);
- endpoints[1] = blue_contract(v6, v[0], v[2], v[4]);
- }
-}
-
-// Helper function that decodes two colors from six values. If isRGB is true,
-// then the pointer 'v' contains four values and the last two are considered to be
-// 0xFF. If isRGB is false, then all six values come from the pointer 'v'. This
-// corresponds to the decode procedure for the following endpoint modes:
-// kLDR_RGB_BaseScale_ColorEndpointMode
-// kLDR_RGB_BaseScaleWithAlpha_ColorEndpointMode
-static inline void decode_rgba_basescale(const int *v, SkColor *endpoints, bool isRGB) {
-
- int v4 = 0xFF;
- int v5 = 0xFF;
- if (!isRGB) {
- v4 = v[4];
- v5 = v[5];
- }
-
- endpoints[0] = SkColorSetARGB(v4,
- (v[0]*v[3]) >> 8,
- (v[1]*v[3]) >> 8,
- (v[2]*v[3]) >> 8);
- endpoints[1] = SkColorSetARGB(v5, v[0], v[1], v[2]);
-}
-
-// Helper function that decodes two colors from eight values. If isRGB is true,
-// then the pointer 'v' contains six values and the last two are considered to be
-// 0xFF. If isRGB is false, then all eight values come from the pointer 'v'. This
-// corresponds to the decode procedure for the following endpoint modes:
-// kLDR_RGB_BaseOffset_ColorEndpointMode
-// kLDR_RGBA_BaseOffset_ColorEndpointMode
-//
-// If isRGB is true, then treat this as if v6 and v7 are meant to encode full alpha values.
-static inline void decode_rgba_baseoffset(const int *v, SkColor *endpoints, bool isRGB) {
- int v0 = v[0];
- int v1 = v[1];
- int v2 = v[2];
- int v3 = v[3];
- int v4 = v[4];
- int v5 = v[5];
- int v6 = isRGB ? 0xFF : v[6];
- // The 0 is here because this is an offset, not a direct value
- int v7 = isRGB ? 0 : v[7];
-
- bit_transfer_signed(&v1, &v0);
- bit_transfer_signed(&v3, &v2);
- bit_transfer_signed(&v5, &v4);
- if (!isRGB) {
- bit_transfer_signed(&v7, &v6);
- }
-
- int c[2][4];
- if ((v1 + v3 + v5) >= 0) {
- c[0][0] = v6;
- c[0][1] = v0;
- c[0][2] = v2;
- c[0][3] = v4;
-
- c[1][0] = v6 + v7;
- c[1][1] = v0 + v1;
- c[1][2] = v2 + v3;
- c[1][3] = v4 + v5;
- } else {
- c[0][0] = v6 + v7;
- c[0][1] = (v0 + v1 + v4 + v5) >> 1;
- c[0][2] = (v2 + v3 + v4 + v5) >> 1;
- c[0][3] = v4 + v5;
-
- c[1][0] = v6;
- c[1][1] = (v0 + v4) >> 1;
- c[1][2] = (v2 + v4) >> 1;
- c[1][3] = v4;
- }
-
- endpoints[0] = SkColorSetARGB(clamp_byte(c[0][0]),
- clamp_byte(c[0][1]),
- clamp_byte(c[0][2]),
- clamp_byte(c[0][3]));
-
- endpoints[1] = SkColorSetARGB(clamp_byte(c[1][0]),
- clamp_byte(c[1][1]),
- clamp_byte(c[1][2]),
- clamp_byte(c[1][3]));
-}
-
-
-// A helper class used to decode bit values from standard integer values.
-// We can't use this class with ASTCBlock because then it would need to
-// handle multi-value ranges, and it's non-trivial to lookup a range of bits
-// that splits across two different ints.
-template <typename T>
-class SkTBits {
-public:
- SkTBits(const T val) : fVal(val) { }
-
- // Returns the bit at the given position
- T operator [](const int idx) const {
- return (fVal >> idx) & 1;
- }
-
- // Returns the bits in the given range, inclusive
- T operator ()(const int end, const int start) const {
- SkASSERT(end >= start);
- return (fVal >> start) & ((1ULL << ((end - start) + 1)) - 1);
- }
-
-private:
- const T fVal;
-};
-
-// This algorithm matches the trit block decoding in the spec (Table C.2.14)
-static void decode_trit_block(int* dst, int nBits, const uint64_t &block) {
-
- SkTBits<uint64_t> blockBits(block);
-
- // According to the spec, a trit block, which contains five values,
- // has the following layout:
- //
- // 27 26 25 24 23 22 21 20 19 18 17 16
- // -----------------------------------------------
- // |T7 | m4 |T6 T5 | m3 |T4 |
- // -----------------------------------------------
- //
- // 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- // --------------------------------------------------------------
- // | m2 |T3 T2 | m1 |T1 T0 | m0 |
- // --------------------------------------------------------------
- //
- // Where the m's are variable width depending on the number of bits used
- // to encode the values (anywhere from 0 to 6). Since 3^5 = 243, the extra
- // byte labeled T (whose bits are interleaved where 0 is the LSB and 7 is
- // the MSB), contains five trit values. To decode the trit values, the spec
- // says that we need to follow the following algorithm:
- //
- // if T[4:2] = 111
- // C = { T[7:5], T[1:0] }; t4 = t3 = 2
- // else
- // C = T[4:0]
- //
- // if T[6:5] = 11
- // t4 = 2; t3 = T[7]
- // else
- // t4 = T[7]; t3 = T[6:5]
- //
- // if C[1:0] = 11
- // t2 = 2; t1 = C[4]; t0 = { C[3], C[2]&~C[3] }
- // else if C[3:2] = 11
- // t2 = 2; t1 = 2; t0 = C[1:0]
- // else
- // t2 = C[4]; t1 = C[3:2]; t0 = { C[1], C[0]&~C[1] }
- //
- // The following C++ code is meant to mirror this layout and algorithm as
- // closely as possible.
-
- int m[5];
- if (0 == nBits) {
- memset(m, 0, sizeof(m));
- } else {
- SkASSERT(nBits < 8);
- m[0] = static_cast<int>(blockBits(nBits - 1, 0));
- m[1] = static_cast<int>(blockBits(2*nBits - 1 + 2, nBits + 2));
- m[2] = static_cast<int>(blockBits(3*nBits - 1 + 4, 2*nBits + 4));
- m[3] = static_cast<int>(blockBits(4*nBits - 1 + 5, 3*nBits + 5));
- m[4] = static_cast<int>(blockBits(5*nBits - 1 + 7, 4*nBits + 7));
- }
-
- int T =
- static_cast<int>(blockBits(nBits + 1, nBits)) |
- (static_cast<int>(blockBits(2*nBits + 2 + 1, 2*nBits + 2)) << 2) |
- (static_cast<int>(blockBits[3*nBits + 4] << 4)) |
- (static_cast<int>(blockBits(4*nBits + 5 + 1, 4*nBits + 5)) << 5) |
- (static_cast<int>(blockBits[5*nBits + 7] << 7));
-
- int t[5];
-
- int C;
- SkTBits<int> Tbits(T);
- if (0x7 == Tbits(4, 2)) {
- C = (Tbits(7, 5) << 2) | Tbits(1, 0);
- t[3] = t[4] = 2;
- } else {
- C = Tbits(4, 0);
- if (Tbits(6, 5) == 0x3) {
- t[4] = 2; t[3] = Tbits[7];
- } else {
- t[4] = Tbits[7]; t[3] = Tbits(6, 5);
- }
- }
-
- SkTBits<int> Cbits(C);
- if (Cbits(1, 0) == 0x3) {
- t[2] = 2;
- t[1] = Cbits[4];
- t[0] = (Cbits[3] << 1) | (Cbits[2] & (0x1 & ~(Cbits[3])));
- } else if (Cbits(3, 2) == 0x3) {
- t[2] = 2;
- t[1] = 2;
- t[0] = Cbits(1, 0);
- } else {
- t[2] = Cbits[4];
- t[1] = Cbits(3, 2);
- t[0] = (Cbits[1] << 1) | (Cbits[0] & (0x1 & ~(Cbits[1])));
- }
-
-#if SK_DEBUG
- // Make sure all of the decoded values have a trit less than three
- // and a bit value within the range of the allocated bits.
- for (int i = 0; i < 5; ++i) {
- SkASSERT(t[i] < 3);
- SkASSERT(m[i] < (1 << nBits));
- }
-#endif
-
- for (int i = 0; i < 5; ++i) {
- *dst = (t[i] << nBits) + m[i];
- ++dst;
- }
-}
-
-// This algorithm matches the quint block decoding in the spec (Table C.2.15)
-static void decode_quint_block(int* dst, int nBits, const uint64_t &block) {
- SkTBits<uint64_t> blockBits(block);
-
- // According to the spec, a quint block, which contains three values,
- // has the following layout:
- //
- //
- // 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
- // --------------------------------------------------------------------------
- // |Q6 Q5 | m2 |Q4 Q3 | m1 |Q2 Q1 Q0 | m0 |
- // --------------------------------------------------------------------------
- //
- // Where the m's are variable width depending on the number of bits used
- // to encode the values (anywhere from 0 to 4). Since 5^3 = 125, the extra
- // 7-bit value labeled Q (whose bits are interleaved where 0 is the LSB and 6 is
- // the MSB), contains three quint values. To decode the quint values, the spec
- // says that we need to follow the following algorithm:
- //
- // if Q[2:1] = 11 and Q[6:5] = 00
- // q2 = { Q[0], Q[4]&~Q[0], Q[3]&~Q[0] }; q1 = q0 = 4
- // else
- // if Q[2:1] = 11
- // q2 = 4; C = { Q[4:3], ~Q[6:5], Q[0] }
- // else
- // q2 = T[6:5]; C = Q[4:0]
- //
- // if C[2:0] = 101
- // q1 = 4; q0 = C[4:3]
- // else
- // q1 = C[4:3]; q0 = C[2:0]
- //
- // The following C++ code is meant to mirror this layout and algorithm as
- // closely as possible.
-
- int m[3];
- if (0 == nBits) {
- memset(m, 0, sizeof(m));
- } else {
- SkASSERT(nBits < 8);
- m[0] = static_cast<int>(blockBits(nBits - 1, 0));
- m[1] = static_cast<int>(blockBits(2*nBits - 1 + 3, nBits + 3));
- m[2] = static_cast<int>(blockBits(3*nBits - 1 + 5, 2*nBits + 5));
- }
-
- int Q =
- static_cast<int>(blockBits(nBits + 2, nBits)) |
- (static_cast<int>(blockBits(2*nBits + 3 + 1, 2*nBits + 3)) << 3) |
- (static_cast<int>(blockBits(3*nBits + 5 + 1, 3*nBits + 5)) << 5);
-
- int q[3];
- SkTBits<int> Qbits(Q); // quantum?
-
- if (Qbits(2, 1) == 0x3 && Qbits(6, 5) == 0) {
- const int notBitZero = (0x1 & ~(Qbits[0]));
- q[2] = (Qbits[0] << 2) | ((Qbits[4] & notBitZero) << 1) | (Qbits[3] & notBitZero);
- q[1] = 4;
- q[0] = 4;
- } else {
- int C;
- if (Qbits(2, 1) == 0x3) {
- q[2] = 4;
- C = (Qbits(4, 3) << 3) | ((0x3 & ~(Qbits(6, 5))) << 1) | Qbits[0];
- } else {
- q[2] = Qbits(6, 5);
- C = Qbits(4, 0);
- }
-
- SkTBits<int> Cbits(C);
- if (Cbits(2, 0) == 0x5) {
- q[1] = 4;
- q[0] = Cbits(4, 3);
- } else {
- q[1] = Cbits(4, 3);
- q[0] = Cbits(2, 0);
- }
- }
-
-#if SK_DEBUG
- for (int i = 0; i < 3; ++i) {
- SkASSERT(q[i] < 5);
- SkASSERT(m[i] < (1 << nBits));
- }
-#endif
-
- for (int i = 0; i < 3; ++i) {
- *dst = (q[i] << nBits) + m[i];
- ++dst;
- }
-}
-
-// Function that decodes a sequence of integers stored as an ISE (Integer
-// Sequence Encoding) bit stream. The full details of this function are outlined
-// in section C.2.12 of the ASTC spec. A brief overview is as follows:
-//
-// - Each integer in the sequence is bounded by a specific range r.
-// - The range of each value determines the way the bit stream is interpreted,
-// - If the range is a power of two, then the sequence is a sequence of bits
-// - If the range is of the form 3*2^n, then the sequence is stored as a
-// sequence of blocks, each block contains 5 trits and 5 bit sequences, which
-// decodes into 5 values.
-// - Similarly, if the range is of the form 5*2^n, then the sequence is stored as a
-// sequence of blocks, each block contains 3 quints and 3 bit sequences, which
-// decodes into 3 values.
-static bool decode_integer_sequence(
- int* dst, // The array holding the destination bits
- int dstSize, // The maximum size of the array
- int nVals, // The number of values that we'd like to decode
- const ASTCBlock &block, // The block that we're decoding from
- int startBit, // The bit from which we're going to do the reading
- int endBit, // The bit at which we stop reading (not inclusive)
- bool bReadForward, // If true, then read LSB -> MSB, else read MSB -> LSB
- int nBits, // The number of bits representing this encoding
- int nTrits, // The number of trits representing this encoding
- int nQuints // The number of quints representing this encoding
-) {
- // If we want more values than we have, then fail.
- if (nVals > dstSize) {
- return false;
- }
-
- ASTCBlock src = block;
-
- if (!bReadForward) {
- src.reverse();
- startBit = 128 - startBit;
- endBit = 128 - endBit;
- }
-
- while (nVals > 0) {
-
- if (nTrits > 0) {
- SkASSERT(0 == nQuints);
-
- int endBlockBit = startBit + 8 + 5*nBits;
- if (endBlockBit > endBit) {
- endBlockBit = endBit;
- }
-
- decode_trit_block(dst, nBits, read_astc_bits(src, startBit, endBlockBit));
- dst += 5;
- nVals -= 5;
- startBit = endBlockBit;
-
- } else if (nQuints > 0) {
- SkASSERT(0 == nTrits);
-
- int endBlockBit = startBit + 7 + 3*nBits;
- if (endBlockBit > endBit) {
- endBlockBit = endBit;
- }
-
- decode_quint_block(dst, nBits, read_astc_bits(src, startBit, endBlockBit));
- dst += 3;
- nVals -= 3;
- startBit = endBlockBit;
-
- } else {
- // Just read the bits, but don't read more than we have...
- int endValBit = startBit + nBits;
- if (endValBit > endBit) {
- endValBit = endBit;
- }
-
- SkASSERT(endValBit - startBit < 31);
- *dst = static_cast<int>(read_astc_bits(src, startBit, endValBit));
- ++dst;
- --nVals;
- startBit = endValBit;
- }
- }
-
- return true;
-}
-
-// Helper function that unquantizes some (seemingly random) generated
-// numbers... meant to match the ASTC hardware. This function is used
-// to unquantize both colors (Table C.2.16) and weights (Table C.2.26)
-static inline int unquantize_value(unsigned mask, int A, int B, int C, int D) {
- int T = D * C + B;
- T = T ^ A;
- T = (A & mask) | (T >> 2);
- SkASSERT(T < 256);
- return T;
-}
-
-// Helper function to replicate the bits in x that represents an oldPrec
-// precision integer into a prec precision integer. For example:
-// 255 == replicate_bits(7, 3, 8);
-static inline int replicate_bits(int x, int oldPrec, int prec) {
- while (oldPrec < prec) {
- const int toShift = SkMin32(prec-oldPrec, oldPrec);
- x = (x << toShift) | (x >> (oldPrec - toShift));
- oldPrec += toShift;
- }
-
- // Make sure that no bits are set outside the desired precision.
- SkASSERT((-(1 << prec) & x) == 0);
- return x;
-}
-
-// Returns the unquantized value of a color that's represented only as
-// a set of bits.
-static inline int unquantize_bits_color(int val, int nBits) {
- return replicate_bits(val, nBits, 8);
-}
-
-// Returns the unquantized value of a color that's represented as a
-// trit followed by nBits bits. This algorithm follows the sequence
-// defined in section C.2.13 of the ASTC spec.
-static inline int unquantize_trit_color(int val, int nBits) {
- SkASSERT(nBits > 0);
- SkASSERT(nBits < 7);
-
- const int D = (val >> nBits) & 0x3;
- SkASSERT(D < 3);
-
- const int A = -(val & 0x1) & 0x1FF;
-
- static const int Cvals[6] = { 204, 93, 44, 22, 11, 5 };
- const int C = Cvals[nBits - 1];
-
- int B = 0;
- const SkTBits<int> valBits(val);
- switch (nBits) {
- case 1:
- B = 0;
- break;
-
- case 2: {
- const int b = valBits[1];
- B = (b << 1) | (b << 2) | (b << 4) | (b << 8);
- }
- break;
-
- case 3: {
- const int cb = valBits(2, 1);
- B = cb | (cb << 2) | (cb << 7);
- }
- break;
-
- case 4: {
- const int dcb = valBits(3, 1);
- B = dcb | (dcb << 6);
- }
- break;
-
- case 5: {
- const int edcb = valBits(4, 1);
- B = (edcb << 5) | (edcb >> 2);
- }
- break;
-
- case 6: {
- const int fedcb = valBits(5, 1);
- B = (fedcb << 4) | (fedcb >> 4);
- }
- break;
- }
-
- return unquantize_value(0x80, A, B, C, D);
-}
-
-// Returns the unquantized value of a color that's represented as a
-// quint followed by nBits bits. This algorithm follows the sequence
-// defined in section C.2.13 of the ASTC spec.
-static inline int unquantize_quint_color(int val, int nBits) {
- const int D = (val >> nBits) & 0x7;
- SkASSERT(D < 5);
-
- const int A = -(val & 0x1) & 0x1FF;
-
- static const int Cvals[5] = { 113, 54, 26, 13, 6 };
- SkASSERT(nBits > 0);
- SkASSERT(nBits < 6);
-
- const int C = Cvals[nBits - 1];
-
- int B = 0;
- const SkTBits<int> valBits(val);
- switch (nBits) {
- case 1:
- B = 0;
- break;
-
- case 2: {
- const int b = valBits[1];
- B = (b << 2) | (b << 3) | (b << 8);
- }
- break;
-
- case 3: {
- const int cb = valBits(2, 1);
- B = (cb >> 1) | (cb << 1) | (cb << 7);
- }
- break;
-
- case 4: {
- const int dcb = valBits(3, 1);
- B = (dcb >> 1) | (dcb << 6);
- }
- break;
-
- case 5: {
- const int edcb = valBits(4, 1);
- B = (edcb << 5) | (edcb >> 3);
- }
- break;
- }
-
- return unquantize_value(0x80, A, B, C, D);
-}
-
-// This algorithm takes a list of integers, stored in vals, and unquantizes them
-// in place. This follows the algorithm laid out in section C.2.13 of the ASTC spec.
-static void unquantize_colors(int *vals, int nVals, int nBits, int nTrits, int nQuints) {
- for (int i = 0; i < nVals; ++i) {
- if (nTrits > 0) {
- SkASSERT(nQuints == 0);
- vals[i] = unquantize_trit_color(vals[i], nBits);
- } else if (nQuints > 0) {
- SkASSERT(nTrits == 0);
- vals[i] = unquantize_quint_color(vals[i], nBits);
- } else {
- SkASSERT(nQuints == 0 && nTrits == 0);
- vals[i] = unquantize_bits_color(vals[i], nBits);
- }
- }
-}
-
-// Returns an interpolated value between c0 and c1 based on the weight. This
-// follows the algorithm laid out in section C.2.19 of the ASTC spec.
-static int interpolate_channel(int c0, int c1, int weight) {
- SkASSERT(0 <= c0 && c0 < 256);
- SkASSERT(0 <= c1 && c1 < 256);
-
- c0 = (c0 << 8) | c0;
- c1 = (c1 << 8) | c1;
-
- const int result = ((c0*(64 - weight) + c1*weight + 32) / 64) >> 8;
-
- if (result > 255) {
- return 255;
- }
-
- SkASSERT(result >= 0);
- return result;
-}
-
-// Returns an interpolated color between the two endpoints based on the weight.
-static SkColor interpolate_endpoints(const SkColor endpoints[2], int weight) {
- return SkColorSetARGB(
- interpolate_channel(SkColorGetA(endpoints[0]), SkColorGetA(endpoints[1]), weight),
- interpolate_channel(SkColorGetR(endpoints[0]), SkColorGetR(endpoints[1]), weight),
- interpolate_channel(SkColorGetG(endpoints[0]), SkColorGetG(endpoints[1]), weight),
- interpolate_channel(SkColorGetB(endpoints[0]), SkColorGetB(endpoints[1]), weight));
-}
-
-// Returns an interpolated color between the two endpoints based on the weight.
-// It uses separate weights for the channel depending on the value of the 'plane'
-// variable. By default, all channels will use weight 0, and the value of plane
-// means that weight1 will be used for:
-// 0: red
-// 1: green
-// 2: blue
-// 3: alpha
-static SkColor interpolate_dual_endpoints(
- const SkColor endpoints[2], int weight0, int weight1, int plane) {
- int a = interpolate_channel(SkColorGetA(endpoints[0]), SkColorGetA(endpoints[1]), weight0);
- int r = interpolate_channel(SkColorGetR(endpoints[0]), SkColorGetR(endpoints[1]), weight0);
- int g = interpolate_channel(SkColorGetG(endpoints[0]), SkColorGetG(endpoints[1]), weight0);
- int b = interpolate_channel(SkColorGetB(endpoints[0]), SkColorGetB(endpoints[1]), weight0);
-
- switch (plane) {
-
- case 0:
- r = interpolate_channel(
- SkColorGetR(endpoints[0]), SkColorGetR(endpoints[1]), weight1);
- break;
-
- case 1:
- g = interpolate_channel(
- SkColorGetG(endpoints[0]), SkColorGetG(endpoints[1]), weight1);
- break;
-
- case 2:
- b = interpolate_channel(
- SkColorGetB(endpoints[0]), SkColorGetB(endpoints[1]), weight1);
- break;
-
- case 3:
- a = interpolate_channel(
- SkColorGetA(endpoints[0]), SkColorGetA(endpoints[1]), weight1);
- break;
-
- default:
- SkDEBUGFAIL("Plane should be 0-3");
- break;
- }
-
- return SkColorSetARGB(a, r, g, b);
-}
-
-// A struct of decoded values that we use to carry around information
-// about the block. dimX and dimY are the dimension in texels of the block,
-// for which there is only a limited subset of valid values:
-//
-// 4x4, 5x4, 5x5, 6x5, 6x6, 8x5, 8x6, 8x8, 10x5, 10x6, 10x8, 10x10, 12x10, 12x12
-
-struct ASTCDecompressionData {
- ASTCDecompressionData(int dimX, int dimY) : fDimX(dimX), fDimY(dimY) { }
- const int fDimX; // the X dimension of the decompressed block
- const int fDimY; // the Y dimension of the decompressed block
- ASTCBlock fBlock; // the block data
- int fBlockMode; // the block header that contains the block mode.
-
- bool fDualPlaneEnabled; // is this block compressing dual weight planes?
- int fDualPlane; // the independent plane in dual plane mode.
-
- bool fVoidExtent; // is this block a single color?
- bool fError; // does this block have an error encoding?
-
- int fWeightDimX; // the x dimension of the weight grid
- int fWeightDimY; // the y dimension of the weight grid
-
- int fWeightBits; // the number of bits used for each weight value
- int fWeightTrits; // the number of trits used for each weight value
- int fWeightQuints; // the number of quints used for each weight value
-
- int fPartCount; // the number of partitions in this block
- int fPartIndex; // the partition index: only relevant if fPartCount > 0
-
- // CEM values can be anything in the range 0-15, and each corresponds to a different
- // mode that represents the color data. We only support LDR modes.
- enum ColorEndpointMode {
- kLDR_Luminance_Direct_ColorEndpointMode = 0,
- kLDR_Luminance_BaseOffset_ColorEndpointMode = 1,
- kHDR_Luminance_LargeRange_ColorEndpointMode = 2,
- kHDR_Luminance_SmallRange_ColorEndpointMode = 3,
- kLDR_LuminanceAlpha_Direct_ColorEndpointMode = 4,
- kLDR_LuminanceAlpha_BaseOffset_ColorEndpointMode = 5,
- kLDR_RGB_BaseScale_ColorEndpointMode = 6,
- kHDR_RGB_BaseScale_ColorEndpointMode = 7,
- kLDR_RGB_Direct_ColorEndpointMode = 8,
- kLDR_RGB_BaseOffset_ColorEndpointMode = 9,
- kLDR_RGB_BaseScaleWithAlpha_ColorEndpointMode = 10,
- kHDR_RGB_ColorEndpointMode = 11,
- kLDR_RGBA_Direct_ColorEndpointMode = 12,
- kLDR_RGBA_BaseOffset_ColorEndpointMode = 13,
- kHDR_RGB_LDRAlpha_ColorEndpointMode = 14,
- kHDR_RGB_HDRAlpha_ColorEndpointMode = 15
- };
- static const int kMaxColorEndpointModes = 16;
-
- // the color endpoint modes for this block.
- static const int kMaxPartitions = 4;
- ColorEndpointMode fCEM[kMaxPartitions];
-
- int fColorStartBit; // The bit position of the first bit of the color data
- int fColorEndBit; // The bit position of the last *possible* bit of the color data
-
- // Returns the number of partitions for this block.
- int numPartitions() const {
- return fPartCount;
- }
-
- // Returns the total number of weight values that are stored in this block
- int numWeights() const {
- return fWeightDimX * fWeightDimY * (fDualPlaneEnabled ? 2 : 1);
- }
-
-#ifdef SK_DEBUG
- // Returns the maximum value that any weight can take. We really only use
- // this function for debugging.
- int maxWeightValue() const {
- int maxVal = (1 << fWeightBits);
- if (fWeightTrits > 0) {
- SkASSERT(0 == fWeightQuints);
- maxVal *= 3;
- } else if (fWeightQuints > 0) {
- SkASSERT(0 == fWeightTrits);
- maxVal *= 5;
- }
- return maxVal - 1;
- }
-#endif
-
- // The number of bits needed to represent the texel weight data. This
- // comes from the 'data size determination' section of the ASTC spec (C.2.22)
- int numWeightBits() const {
- const int nWeights = this->numWeights();
- return
- ((nWeights*8*fWeightTrits + 4) / 5) +
- ((nWeights*7*fWeightQuints + 2) / 3) +
- (nWeights*fWeightBits);
- }
-
- // Returns the number of color values stored in this block. The number of
- // values stored is directly a function of the color endpoint modes.
- int numColorValues() const {
- int numValues = 0;
- for (int i = 0; i < this->numPartitions(); ++i) {
- int cemInt = static_cast<int>(fCEM[i]);
- numValues += ((cemInt >> 2) + 1) * 2;
- }
-
- return numValues;
- }
-
- // Figures out the number of bits available for color values, and fills
- // in the maximum encoding that will fit the number of color values that
- // we need. Returns false on error. (See section C.2.22 of the spec)
- bool getColorValueEncoding(int *nBits, int *nTrits, int *nQuints) const {
- if (NULL == nBits || NULL == nTrits || NULL == nQuints) {
- return false;
- }
-
- const int nColorVals = this->numColorValues();
- if (nColorVals <= 0) {
- return false;
- }
-
- const int colorBits = fColorEndBit - fColorStartBit;
- SkASSERT(colorBits > 0);
-
- // This is the minimum amount of accuracy required by the spec.
- if (colorBits < ((13 * nColorVals + 4) / 5)) {
- return false;
- }
-
- // Values can be represented as at most 8-bit values.
- // !SPEED! place this in a lookup table based on colorBits and nColorVals
- for (int i = 255; i > 0; --i) {
- int range = i + 1;
- int bits = 0, trits = 0, quints = 0;
- bool valid = false;
- if (SkIsPow2(range)) {
- bits = bits_for_range(range);
- valid = true;
- } else if ((range % 3) == 0 && SkIsPow2(range/3)) {
- trits = 1;
- bits = bits_for_range(range/3);
- valid = true;
- } else if ((range % 5) == 0 && SkIsPow2(range/5)) {
- quints = 1;
- bits = bits_for_range(range/5);
- valid = true;
- }
-
- if (valid) {
- const int actualColorBits =
- ((nColorVals*8*trits + 4) / 5) +
- ((nColorVals*7*quints + 2) / 3) +
- (nColorVals*bits);
- if (actualColorBits <= colorBits) {
- *nTrits = trits;
- *nQuints = quints;
- *nBits = bits;
- return true;
- }
- }
- }
-
- return false;
- }
-
- // Converts the sequence of color values into endpoints. The algorithm here
- // corresponds to the values determined by section C.2.14 of the ASTC spec
- void colorEndpoints(SkColor endpoints[4][2], const int* colorValues) const {
- for (int i = 0; i < this->numPartitions(); ++i) {
- switch (fCEM[i]) {
- case kLDR_Luminance_Direct_ColorEndpointMode: {
- const int* v = colorValues;
- endpoints[i][0] = SkColorSetARGB(0xFF, v[0], v[0], v[0]);
- endpoints[i][1] = SkColorSetARGB(0xFF, v[1], v[1], v[1]);
-
- colorValues += 2;
- }
- break;
-
- case kLDR_Luminance_BaseOffset_ColorEndpointMode: {
- const int* v = colorValues;
- const int L0 = (v[0] >> 2) | (v[1] & 0xC0);
- const int L1 = clamp_byte(L0 + (v[1] & 0x3F));
-
- endpoints[i][0] = SkColorSetARGB(0xFF, L0, L0, L0);
- endpoints[i][1] = SkColorSetARGB(0xFF, L1, L1, L1);
-
- colorValues += 2;
- }
- break;
-
- case kLDR_LuminanceAlpha_Direct_ColorEndpointMode: {
- const int* v = colorValues;
-
- endpoints[i][0] = SkColorSetARGB(v[2], v[0], v[0], v[0]);
- endpoints[i][1] = SkColorSetARGB(v[3], v[1], v[1], v[1]);
-
- colorValues += 4;
- }
- break;
-
- case kLDR_LuminanceAlpha_BaseOffset_ColorEndpointMode: {
- int v0 = colorValues[0];
- int v1 = colorValues[1];
- int v2 = colorValues[2];
- int v3 = colorValues[3];
-
- bit_transfer_signed(&v1, &v0);
- bit_transfer_signed(&v3, &v2);
-
- endpoints[i][0] = SkColorSetARGB(v2, v0, v0, v0);
- endpoints[i][1] = SkColorSetARGB(
- clamp_byte(v3+v2),
- clamp_byte(v1+v0),
- clamp_byte(v1+v0),
- clamp_byte(v1+v0));
-
- colorValues += 4;
- }
- break;
-
- case kLDR_RGB_BaseScale_ColorEndpointMode: {
- decode_rgba_basescale(colorValues, endpoints[i], true);
- colorValues += 4;
- }
- break;
-
- case kLDR_RGB_Direct_ColorEndpointMode: {
- decode_rgba_direct(colorValues, endpoints[i], true);
- colorValues += 6;
- }
- break;
-
- case kLDR_RGB_BaseOffset_ColorEndpointMode: {
- decode_rgba_baseoffset(colorValues, endpoints[i], true);
- colorValues += 6;
- }
- break;
-
- case kLDR_RGB_BaseScaleWithAlpha_ColorEndpointMode: {
- decode_rgba_basescale(colorValues, endpoints[i], false);
- colorValues += 6;
- }
- break;
-
- case kLDR_RGBA_Direct_ColorEndpointMode: {
- decode_rgba_direct(colorValues, endpoints[i], false);
- colorValues += 8;
- }
- break;
-
- case kLDR_RGBA_BaseOffset_ColorEndpointMode: {
- decode_rgba_baseoffset(colorValues, endpoints[i], false);
- colorValues += 8;
- }
- break;
-
- default:
- SkDEBUGFAIL("HDR mode unsupported! This should be caught sooner.");
- break;
- }
- }
- }
-
- // Follows the procedure from section C.2.17 of the ASTC specification
- int unquantizeWeight(int x) const {
- SkASSERT(x <= this->maxWeightValue());
-
- const int D = (x >> fWeightBits) & 0x7;
- const int A = -(x & 0x1) & 0x7F;
-
- SkTBits<int> xbits(x);
-
- int T = 0;
- if (fWeightTrits > 0) {
- SkASSERT(0 == fWeightQuints);
- switch (fWeightBits) {
- case 0: {
- // x is a single trit
- SkASSERT(x < 3);
-
- static const int kUnquantizationTable[3] = { 0, 32, 63 };
- T = kUnquantizationTable[x];
- }
- break;
-
- case 1: {
- const int B = 0;
- const int C = 50;
- T = unquantize_value(0x20, A, B, C, D);
- }
- break;
-
- case 2: {
- const int b = xbits[1];
- const int B = b | (b << 2) | (b << 6);
- const int C = 23;
- T = unquantize_value(0x20, A, B, C, D);
- }
- break;
-
- case 3: {
- const int cb = xbits(2, 1);
- const int B = cb | (cb << 5);
- const int C = 11;
- T = unquantize_value(0x20, A, B, C, D);
- }
- break;
-
- default:
- SkDEBUGFAIL("Too many bits for trit encoding");
- break;
- }
-
- } else if (fWeightQuints > 0) {
- SkASSERT(0 == fWeightTrits);
- switch (fWeightBits) {
- case 0: {
- // x is a single quint
- SkASSERT(x < 5);
-
- static const int kUnquantizationTable[5] = { 0, 16, 32, 47, 63 };
- T = kUnquantizationTable[x];
- }
- break;
-
- case 1: {
- const int B = 0;
- const int C = 28;
- T = unquantize_value(0x20, A, B, C, D);
- }
- break;
-
- case 2: {
- const int b = xbits[1];
- const int B = (b << 1) | (b << 6);
- const int C = 13;
- T = unquantize_value(0x20, A, B, C, D);
- }
- break;
-
- default:
- SkDEBUGFAIL("Too many bits for quint encoding");
- break;
- }
- } else {
- SkASSERT(0 == fWeightTrits);
- SkASSERT(0 == fWeightQuints);
-
- T = replicate_bits(x, fWeightBits, 6);
- }
-
- // This should bring the value within [0, 63]..
- SkASSERT(T <= 63);
-
- if (T > 32) {
- T += 1;
- }
-
- SkASSERT(T <= 64);
-
- return T;
- }
-
- // Returns the weight at the associated index. If the index is out of bounds, it
- // returns zero. It also chooses the weight appropriately based on the given dual
- // plane.
- int getWeight(const int* unquantizedWeights, int idx, bool dualPlane) const {
- const int maxIdx = (fDualPlaneEnabled ? 2 : 1) * fWeightDimX * fWeightDimY - 1;
- if (fDualPlaneEnabled) {
- const int effectiveIdx = 2*idx + (dualPlane ? 1 : 0);
- if (effectiveIdx > maxIdx) {
- return 0;
- }
- return unquantizedWeights[effectiveIdx];
- }
-
- SkASSERT(!dualPlane);
-
- if (idx > maxIdx) {
- return 0;
- } else {
- return unquantizedWeights[idx];
- }
- }
-
- // This computes the effective weight at location (s, t) of the block. This
- // weight is computed by sampling the texel weight grid (it's usually not 1-1), and
- // then applying a bilerp. The algorithm outlined here follows the algorithm
- // defined in section C.2.18 of the ASTC spec.
- int infillWeight(const int* unquantizedValues, int s, int t, bool dualPlane) const {
- const int Ds = (1024 + fDimX/2) / (fDimX - 1);
- const int Dt = (1024 + fDimY/2) / (fDimY - 1);
-
- const int cs = Ds * s;
- const int ct = Dt * t;
-
- const int gs = (cs*(fWeightDimX - 1) + 32) >> 6;
- const int gt = (ct*(fWeightDimY - 1) + 32) >> 6;
-
- const int js = gs >> 4;
- const int jt = gt >> 4;
-
- const int fs = gs & 0xF;
- const int ft = gt & 0xF;
-
- const int idx = js + jt*fWeightDimX;
- const int p00 = this->getWeight(unquantizedValues, idx, dualPlane);
- const int p01 = this->getWeight(unquantizedValues, idx + 1, dualPlane);
- const int p10 = this->getWeight(unquantizedValues, idx + fWeightDimX, dualPlane);
- const int p11 = this->getWeight(unquantizedValues, idx + fWeightDimX + 1, dualPlane);
-
- const int w11 = (fs*ft + 8) >> 4;
- const int w10 = ft - w11;
- const int w01 = fs - w11;
- const int w00 = 16 - fs - ft + w11;
-
- const int weight = (p00*w00 + p01*w01 + p10*w10 + p11*w11 + 8) >> 4;
- SkASSERT(weight <= 64);
- return weight;
- }
-
- // Unquantizes the decoded texel weights as described in section C.2.17 of
- // the ASTC specification. Additionally, it populates texelWeights with
- // the expanded weight grid, which is computed according to section C.2.18
- void texelWeights(int texelWeights[2][12][12], const int* texelValues) const {
- // Unquantized texel weights...
- int unquantizedValues[144*2]; // 12x12 blocks with dual plane decoding...
- SkASSERT(this->numWeights() <= 144*2);
-
- // Unquantize the weights and cache them
- for (int j = 0; j < this->numWeights(); ++j) {
- unquantizedValues[j] = this->unquantizeWeight(texelValues[j]);
- }
-
- // Do weight infill...
- for (int y = 0; y < fDimY; ++y) {
- for (int x = 0; x < fDimX; ++x) {
- texelWeights[0][x][y] = this->infillWeight(unquantizedValues, x, y, false);
- if (fDualPlaneEnabled) {
- texelWeights[1][x][y] = this->infillWeight(unquantizedValues, x, y, true);
- }
- }
- }
- }
-
- // Returns the partition for the texel located at position (x, y).
- // Adapted from C.2.21 of the ASTC specification
- int getPartition(int x, int y) const {
- const int partitionCount = this->numPartitions();
- int seed = fPartIndex;
- if ((fDimX * fDimY) < 31) {
- x <<= 1;
- y <<= 1;
- }
-
- seed += (partitionCount - 1) * 1024;
-
- uint32_t p = seed;
- p ^= p >> 15; p -= p << 17; p += p << 7; p += p << 4;
- p ^= p >> 5; p += p << 16; p ^= p >> 7; p ^= p >> 3;
- p ^= p << 6; p ^= p >> 17;
-
- uint32_t rnum = p;
- uint8_t seed1 = rnum & 0xF;
- uint8_t seed2 = (rnum >> 4) & 0xF;
- uint8_t seed3 = (rnum >> 8) & 0xF;
- uint8_t seed4 = (rnum >> 12) & 0xF;
- uint8_t seed5 = (rnum >> 16) & 0xF;
- uint8_t seed6 = (rnum >> 20) & 0xF;
- uint8_t seed7 = (rnum >> 24) & 0xF;
- uint8_t seed8 = (rnum >> 28) & 0xF;
- uint8_t seed9 = (rnum >> 18) & 0xF;
- uint8_t seed10 = (rnum >> 22) & 0xF;
- uint8_t seed11 = (rnum >> 26) & 0xF;
- uint8_t seed12 = ((rnum >> 30) | (rnum << 2)) & 0xF;
-
- seed1 *= seed1; seed2 *= seed2;
- seed3 *= seed3; seed4 *= seed4;
- seed5 *= seed5; seed6 *= seed6;
- seed7 *= seed7; seed8 *= seed8;
- seed9 *= seed9; seed10 *= seed10;
- seed11 *= seed11; seed12 *= seed12;
-
- int sh1, sh2, sh3;
- if (0 != (seed & 1)) {
- sh1 = (0 != (seed & 2))? 4 : 5;
- sh2 = (partitionCount == 3)? 6 : 5;
- } else {
- sh1 = (partitionCount==3)? 6 : 5;
- sh2 = (0 != (seed & 2))? 4 : 5;
- }
- sh3 = (0 != (seed & 0x10))? sh1 : sh2;
-
- seed1 >>= sh1; seed2 >>= sh2; seed3 >>= sh1; seed4 >>= sh2;
- seed5 >>= sh1; seed6 >>= sh2; seed7 >>= sh1; seed8 >>= sh2;
- seed9 >>= sh3; seed10 >>= sh3; seed11 >>= sh3; seed12 >>= sh3;
-
- const int z = 0;
- int a = seed1*x + seed2*y + seed11*z + (rnum >> 14);
- int b = seed3*x + seed4*y + seed12*z + (rnum >> 10);
- int c = seed5*x + seed6*y + seed9 *z + (rnum >> 6);
- int d = seed7*x + seed8*y + seed10*z + (rnum >> 2);
-
- a &= 0x3F;
- b &= 0x3F;
- c &= 0x3F;
- d &= 0x3F;
-
- if (partitionCount < 4) {
- d = 0;
- }
-
- if (partitionCount < 3) {
- c = 0;
- }
-
- if (a >= b && a >= c && a >= d) {
- return 0;
- } else if (b >= c && b >= d) {
- return 1;
- } else if (c >= d) {
- return 2;
- } else {
- return 3;
- }
- }
-
- // Performs the proper interpolation of the texel based on the
- // endpoints and weights.
- SkColor getTexel(const SkColor endpoints[4][2],
- const int weights[2][12][12],
- int x, int y) const {
- int part = 0;
- if (this->numPartitions() > 1) {
- part = this->getPartition(x, y);
- }
-
- SkColor result;
- if (fDualPlaneEnabled) {
- result = interpolate_dual_endpoints(
- endpoints[part], weights[0][x][y], weights[1][x][y], fDualPlane);
- } else {
- result = interpolate_endpoints(endpoints[part], weights[0][x][y]);
- }
-
-#if 1
- // !FIXME! if we're writing directly to a bitmap, then we don't need
- // to swap the red and blue channels, but since we're usually being used
- // by the SkImageDecoder_astc module, the results are expected to be in RGBA.
- result = SkColorSetARGB(
- SkColorGetA(result), SkColorGetB(result), SkColorGetG(result), SkColorGetR(result));
-#endif
-
- return result;
- }
-
- void decode() {
- // First decode the block mode.
- this->decodeBlockMode();
-
- // Now we can decode the partition information.
- fPartIndex = static_cast<int>(read_astc_bits(fBlock, 11, 23));
- fPartCount = (fPartIndex & 0x3) + 1;
- fPartIndex >>= 2;
-
- // This is illegal
- if (fDualPlaneEnabled && this->numPartitions() == 4) {
- fError = true;
- return;
- }
-
- // Based on the partition info, we can decode the color information.
- this->decodeColorData();
- }
-
- // Decodes the dual plane based on the given bit location. The final
- // location, if the dual plane is enabled, is also the end of our color data.
- // This function is only meant to be used from this->decodeColorData()
- void decodeDualPlane(int bitLoc) {
- if (fDualPlaneEnabled) {
- fDualPlane = static_cast<int>(read_astc_bits(fBlock, bitLoc - 2, bitLoc));
- fColorEndBit = bitLoc - 2;
- } else {
- fColorEndBit = bitLoc;
- }
- }
-
- // Decodes the color information based on the ASTC spec.
- void decodeColorData() {
-
- // By default, the last color bit is at the end of the texel weights
- const int lastWeight = 128 - this->numWeightBits();
-
- // If we have a dual plane then it will be at this location, too.
- int dualPlaneBitLoc = lastWeight;
-
- // If there's only one partition, then our job is (relatively) easy.
- if (this->numPartitions() == 1) {
- fCEM[0] = static_cast<ColorEndpointMode>(read_astc_bits(fBlock, 13, 17));
- fColorStartBit = 17;
-
- // Handle dual plane mode...
- this->decodeDualPlane(dualPlaneBitLoc);
-
- return;
- }
-
- // If we have more than one partition, then we need to make
- // room for the partition index.
- fColorStartBit = 29;
-
- // Read the base CEM. If it's zero, then we have no additional
- // CEM data and the endpoints for each partition share the same CEM.
- const int baseCEM = static_cast<int>(read_astc_bits(fBlock, 23, 25));
- if (0 == baseCEM) {
-
- const ColorEndpointMode sameCEM =
- static_cast<ColorEndpointMode>(read_astc_bits(fBlock, 25, 29));
-
- for (int i = 0; i < kMaxPartitions; ++i) {
- fCEM[i] = sameCEM;
- }
-
- // Handle dual plane mode...
- this->decodeDualPlane(dualPlaneBitLoc);
-
- return;
- }
-
- // Move the dual plane selector bits down based on how many
- // partitions the block contains.
- switch (this->numPartitions()) {
- case 2:
- dualPlaneBitLoc -= 2;
- break;
-
- case 3:
- dualPlaneBitLoc -= 5;
- break;
-
- case 4:
- dualPlaneBitLoc -= 8;
- break;
-
- default:
- SkDEBUGFAIL("Internal ASTC decoding error.");
- break;
- }
-
- // The rest of the CEM config will be between the dual plane bit selector
- // and the texel weight grid.
- const int lowCEM = static_cast<int>(read_astc_bits(fBlock, 23, 29));
- SkASSERT(lastWeight - dualPlaneBitLoc > 31);
- int fullCEM = static_cast<int>(read_astc_bits(fBlock, dualPlaneBitLoc, lastWeight));
-
- // Attach the config at the end of the weight grid to the CEM values
- // in the beginning of the block.
- fullCEM = (fullCEM << 6) | lowCEM;
-
- // Ignore the two least significant bits, since those are our baseCEM above.
- fullCEM = fullCEM >> 2;
-
- int C[kMaxPartitions]; // Next, decode C and M from the spec (Table C.2.12)
- for (int i = 0; i < this->numPartitions(); ++i) {
- C[i] = fullCEM & 1;
- fullCEM = fullCEM >> 1;
- }
-
- int M[kMaxPartitions];
- for (int i = 0; i < this->numPartitions(); ++i) {
- M[i] = fullCEM & 0x3;
- fullCEM = fullCEM >> 2;
- }
-
- // Construct our CEMs..
- SkASSERT(baseCEM > 0);
- for (int i = 0; i < this->numPartitions(); ++i) {
- int cem = (baseCEM - 1) * 4;
- cem += (0 == C[i])? 0 : 4;
- cem += M[i];
-
- SkASSERT(cem < 16);
- fCEM[i] = static_cast<ColorEndpointMode>(cem);
- }
-
- // Finally, if we have dual plane mode, then read the plane selector.
- this->decodeDualPlane(dualPlaneBitLoc);
- }
-
- // Decodes the block mode. This function determines whether or not we use
- // dual plane encoding, the size of the texel weight grid, and the number of
- // bits, trits and quints that are used to encode it. For more information,
- // see section C.2.10 of the ASTC spec.
- //
- // For 2D blocks, the Block Mode field is laid out as follows:
- //
- // -------------------------------------------------------------------------
- // 10 9 8 7 6 5 4 3 2 1 0 Width Height Notes
- // -------------------------------------------------------------------------
- // D H B A R0 0 0 R2 R1 B+4 A+2
- // D H B A R0 0 1 R2 R1 B+8 A+2
- // D H B A R0 1 0 R2 R1 A+2 B+8
- // D H 0 B A R0 1 1 R2 R1 A+2 B+6
- // D H 1 B A R0 1 1 R2 R1 B+2 A+2
- // D H 0 0 A R0 R2 R1 0 0 12 A+2
- // D H 0 1 A R0 R2 R1 0 0 A+2 12
- // D H 1 1 0 0 R0 R2 R1 0 0 6 10
- // D H 1 1 0 1 R0 R2 R1 0 0 10 6
- // B 1 0 A R0 R2 R1 0 0 A+6 B+6 D=0, H=0
- // x x 1 1 1 1 1 1 1 0 0 - - Void-extent
- // x x 1 1 1 x x x x 0 0 - - Reserved*
- // x x x x x x x 0 0 0 0 - - Reserved
- // -------------------------------------------------------------------------
- //
- // D - dual plane enabled
- // H, R - used to determine the number of bits/trits/quints in texel weight encoding
- // R is a three bit value whose LSB is R0 and MSB is R1
- // Width, Height - dimensions of the texel weight grid (determined by A and B)
-
- void decodeBlockMode() {
- const int blockMode = static_cast<int>(read_astc_bits(fBlock, 0, 11));
-
- // Check for special void extent encoding
- fVoidExtent = (blockMode & 0x1FF) == 0x1FC;
-
- // Check for reserved block modes
- fError = ((blockMode & 0x1C3) == 0x1C0) || ((blockMode & 0xF) == 0);
-
- // Neither reserved nor void-extent, decode as usual
- // This code corresponds to table C.2.8 of the ASTC spec
- bool highPrecision = false;
- int R = 0;
- if ((blockMode & 0x3) == 0) {
- R = ((0xC & blockMode) >> 1) | ((0x10 & blockMode) >> 4);
- const int bitsSevenAndEight = (blockMode & 0x180) >> 7;
- SkASSERT(0 <= bitsSevenAndEight && bitsSevenAndEight < 4);
-
- const int A = (blockMode >> 5) & 0x3;
- const int B = (blockMode >> 9) & 0x3;
-
- fDualPlaneEnabled = (blockMode >> 10) & 0x1;
- highPrecision = (blockMode >> 9) & 0x1;
-
- switch (bitsSevenAndEight) {
- default:
- case 0:
- fWeightDimX = 12;
- fWeightDimY = A + 2;
- break;
-
- case 1:
- fWeightDimX = A + 2;
- fWeightDimY = 12;
- break;
-
- case 2:
- fWeightDimX = A + 6;
- fWeightDimY = B + 6;
- fDualPlaneEnabled = false;
- highPrecision = false;
- break;
-
- case 3:
- if (0 == A) {
- fWeightDimX = 6;
- fWeightDimY = 10;
- } else {
- fWeightDimX = 10;
- fWeightDimY = 6;
- }
- break;
- }
- } else { // (blockMode & 0x3) != 0
- R = ((blockMode & 0x3) << 1) | ((blockMode & 0x10) >> 4);
-
- const int bitsTwoAndThree = (blockMode >> 2) & 0x3;
- SkASSERT(0 <= bitsTwoAndThree && bitsTwoAndThree < 4);
-
- const int A = (blockMode >> 5) & 0x3;
- const int B = (blockMode >> 7) & 0x3;
-
- fDualPlaneEnabled = (blockMode >> 10) & 0x1;
- highPrecision = (blockMode >> 9) & 0x1;
-
- switch (bitsTwoAndThree) {
- case 0:
- fWeightDimX = B + 4;
- fWeightDimY = A + 2;
- break;
- case 1:
- fWeightDimX = B + 8;
- fWeightDimY = A + 2;
- break;
- case 2:
- fWeightDimX = A + 2;
- fWeightDimY = B + 8;
- break;
- case 3:
- if ((B & 0x2) == 0) {
- fWeightDimX = A + 2;
- fWeightDimY = (B & 1) + 6;
- } else {
- fWeightDimX = (B & 1) + 2;
- fWeightDimY = A + 2;
- }
- break;
- }
- }
-
- // We should have set the values of R and highPrecision
- // from decoding the block mode, these are used to determine
- // the proper dimensions of our weight grid.
- if ((R & 0x6) == 0) {
- fError = true;
- } else {
- static const int kBitAllocationTable[2][6][3] = {
- {
- { 1, 0, 0 },
- { 0, 1, 0 },
- { 2, 0, 0 },
- { 0, 0, 1 },
- { 1, 1, 0 },
- { 3, 0, 0 }
- },
- {
- { 1, 0, 1 },
- { 2, 1, 0 },
- { 4, 0, 0 },
- { 2, 0, 1 },
- { 3, 1, 0 },
- { 5, 0, 0 }
- }
- };
-
- fWeightBits = kBitAllocationTable[highPrecision][R - 2][0];
- fWeightTrits = kBitAllocationTable[highPrecision][R - 2][1];
- fWeightQuints = kBitAllocationTable[highPrecision][R - 2][2];
- }
- }
-};
-
-// Reads an ASTC block from the given pointer.
-static inline void read_astc_block(ASTCDecompressionData *dst, const uint8_t* src) {
- const uint64_t* qword = reinterpret_cast<const uint64_t*>(src);
- dst->fBlock.fLow = SkEndian_SwapLE64(qword[0]);
- dst->fBlock.fHigh = SkEndian_SwapLE64(qword[1]);
- dst->decode();
-}
-
-// Take a known void-extent block, and write out the values as a constant color.
-static void decompress_void_extent(uint8_t* dst, int dstRowBytes,
- const ASTCDecompressionData &data) {
- // The top 64 bits contain 4 16-bit RGBA values.
- int a = (static_cast<int>(read_astc_bits(data.fBlock, 112, 128)) + 255) >> 8;
- int b = (static_cast<int>(read_astc_bits(data.fBlock, 96, 112)) + 255) >> 8;
- int g = (static_cast<int>(read_astc_bits(data.fBlock, 80, 96)) + 255) >> 8;
- int r = (static_cast<int>(read_astc_bits(data.fBlock, 64, 80)) + 255) >> 8;
-
- write_constant_color(dst, data.fDimX, data.fDimY, dstRowBytes, SkColorSetARGB(a, r, g, b));
-}
-
-// Decompresses a single ASTC block. It's assumed that data.fDimX and data.fDimY are
-// set and that the block has already been decoded (i.e. data.decode() has been called)
-static void decompress_astc_block(uint8_t* dst, int dstRowBytes,
- const ASTCDecompressionData &data) {
- if (data.fError) {
- write_error_color(dst, data.fDimX, data.fDimY, dstRowBytes);
- return;
- }
-
- if (data.fVoidExtent) {
- decompress_void_extent(dst, dstRowBytes, data);
- return;
- }
-
- // According to the spec, any more than 64 values is illegal. (C.2.24)
- static const int kMaxTexelValues = 64;
-
- // Decode the texel weights.
- int texelValues[kMaxTexelValues];
- bool success = decode_integer_sequence(
- texelValues, kMaxTexelValues, data.numWeights(),
- // texel data goes to the end of the 128 bit block.
- data.fBlock, 128, 128 - data.numWeightBits(), false,
- data.fWeightBits, data.fWeightTrits, data.fWeightQuints);
-
- if (!success) {
- write_error_color(dst, data.fDimX, data.fDimY, dstRowBytes);
- return;
- }
-
- // Decode the color endpoints
- int colorBits, colorTrits, colorQuints;
- if (!data.getColorValueEncoding(&colorBits, &colorTrits, &colorQuints)) {
- write_error_color(dst, data.fDimX, data.fDimY, dstRowBytes);
- return;
- }
-
- // According to the spec, any more than 18 color values is illegal. (C.2.24)
- static const int kMaxColorValues = 18;
-
- int colorValues[kMaxColorValues];
- success = decode_integer_sequence(
- colorValues, kMaxColorValues, data.numColorValues(),
- data.fBlock, data.fColorStartBit, data.fColorEndBit, true,
- colorBits, colorTrits, colorQuints);
-
- if (!success) {
- write_error_color(dst, data.fDimX, data.fDimY, dstRowBytes);
- return;
- }
-
- // Unquantize the color values after they've been decoded.
- unquantize_colors(colorValues, data.numColorValues(), colorBits, colorTrits, colorQuints);
-
- // Decode the colors into the appropriate endpoints.
- SkColor endpoints[4][2];
- data.colorEndpoints(endpoints, colorValues);
-
- // Do texel infill and decode the texel values.
- int texelWeights[2][12][12];
- data.texelWeights(texelWeights, texelValues);
-
- // Write the texels by interpolating them based on the information
- // stored in the block.
- dst += data.fDimY * dstRowBytes;
- for (int y = 0; y < data.fDimY; ++y) {
- dst -= dstRowBytes;
- SkColor* colorPtr = reinterpret_cast<SkColor*>(dst);
- for (int x = 0; x < data.fDimX; ++x) {
- colorPtr[x] = data.getTexel(endpoints, texelWeights, x, y);
- }
- }
-}
-
-////////////////////////////////////////////////////////////////////////////////
namespace SkTextureCompressor {
-bool CompressA8To12x12ASTC(uint8_t* dst, const uint8_t* src,
- int width, int height, int rowBytes) {
+bool CompressA8To12x12ASTC(uint8_t* dst, const uint8_t* src, int width, int height, int rowBytes) {
if (width < 0 || ((width % 12) != 0) || height < 0 || ((height % 12) != 0)) {
return false;
}
@@ -2017,25 +285,4 @@
(width, height, outputBuffer);
}
-void DecompressASTC(uint8_t* dst, int dstRowBytes, const uint8_t* src,
- int width, int height, int blockDimX, int blockDimY) {
- // ASTC is encoded in what they call "raster order", so that the first
- // block is the bottom-left block in the image, and the first pixel
- // is the bottom-left pixel of the image
- dst += height * dstRowBytes;
-
- ASTCDecompressionData data(blockDimX, blockDimY);
- for (int y = 0; y < height; y += blockDimY) {
- dst -= blockDimY * dstRowBytes;
- SkColor *colorPtr = reinterpret_cast<SkColor*>(dst);
- for (int x = 0; x < width; x += blockDimX) {
- read_astc_block(&data, src);
- decompress_astc_block(reinterpret_cast<uint8_t*>(colorPtr + x), dstRowBytes, data);
-
- // ASTC encoded blocks are 16 bytes (128 bits) large.
- src += 16;
- }
- }
-}
-
} // SkTextureCompressor
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