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39
40#include "qastchandler_p.h"
41#include "qtexturefiledata_p.h"
42
43#include <private/qnumeric_p.h>
44
45#include <QFile>
46#include <QDebug>
47#include <QSize>
48
49QT_BEGIN_NAMESPACE
50
51struct AstcHeader
52{
53 quint8 magic[4];
54 quint8 blockDimX;
55 quint8 blockDimY;
56 quint8 blockDimZ;
57 quint8 xSize[3];
58 quint8 ySize[3];
59 quint8 zSize[3];
60};
61
62bool QAstcHandler::canRead(const QByteArray &suffix, const QByteArray &block)
63{
64 Q_UNUSED(suffix);
65
66 return block.startsWith("\x13\xAB\xA1\x5C");
67}
68
69quint32 QAstcHandler::astcGLFormat(quint8 xBlockDim, quint8 yBlockDim) const
70{
71 static const quint32 glFormatRGBABase = 0x93B0; // GL_COMPRESSED_RGBA_ASTC_4x4_KHR
72 static const quint32 glFormatSRGBBase = 0x93D0; // GL_COMPRESSED_SRGB8_ALPHA8_ASTC_4x4_KHR
73
74 static QSize dims[14] = {
75 { 4, 4 }, // GL_COMPRESSED_xxx_ASTC_4x4_KHR
76 { 5, 4 }, // GL_COMPRESSED_xxx_ASTC_5x4_KHR
77 { 5, 5 }, // GL_COMPRESSED_xxx_ASTC_5x5_KHR
78 { 6, 5 }, // GL_COMPRESSED_xxx_ASTC_6x5_KHR
79 { 6, 6 }, // GL_COMPRESSED_xxx_ASTC_6x6_KHR
80 { 8, 5 }, // GL_COMPRESSED_xxx_ASTC_8x5_KHR
81 { 8, 6 }, // GL_COMPRESSED_xxx_ASTC_8x6_KHR
82 { 8, 8 }, // GL_COMPRESSED_xxx_ASTC_8x8_KHR
83 { 10, 5 }, // GL_COMPRESSED_xxx_ASTC_10x5_KHR
84 { 10, 6 }, // GL_COMPRESSED_xxx_ASTC_10x6_KHR
85 { 10, 8 }, // GL_COMPRESSED_xxx_ASTC_10x8_KHR
86 { 10, 10 }, // GL_COMPRESSED_xxx_ASTC_10x10_KHR
87 { 12, 10 }, // GL_COMPRESSED_xxx_ASTC_12x10_KHR
88 { 12, 12 } // GL_COMPRESSED_xxx_ASTC_12x12_KHR
89 };
90
91 const QSize dim(xBlockDim, yBlockDim);
92 int index = -1;
93 for (int i = 0; i < 14; i++) {
94 if (dim == dims[i]) {
95 index = i;
96 break;
97 }
98 }
99 if (index < 0)
100 return 0;
101
102 bool useSrgb = qEnvironmentVariableIsSet("QT_ASTCHANDLER_USE_SRGB")
103 || logName().toLower().contains("srgb");
104
105 return useSrgb ? (glFormatSRGBBase + index) : (glFormatRGBABase + index);
106}
107
108QTextureFileData QAstcHandler::read()
109{
110 QTextureFileData nullData;
111 QTextureFileData res;
112
113 if (!device())
114 return nullData;
115
116 QByteArray fileData = device()->readAll();
117 if (fileData.size() < int(sizeof(AstcHeader)) || !canRead(QByteArray(), fileData)) {
118 qCDebug(lcQtGuiTextureIO, "Not an ASTC file: %s", logName().constData());
119 return nullData;
120 }
121 res.setData(fileData);
122
123 const AstcHeader *header = reinterpret_cast<const AstcHeader *>(fileData.constData());
124
125 int xSz = int(header->xSize[0]) | int(header->xSize[1]) << 8 | int(header->xSize[2]) << 16;
126 int ySz = int(header->ySize[0]) | int(header->ySize[1]) << 8 | int(header->ySize[2]) << 16;
127 int zSz = int(header->zSize[0]) | int(header->zSize[1]) << 8 | int(header->zSize[2]) << 16;
128
129 quint32 glFmt = astcGLFormat(header->blockDimX, header->blockDimY);
130
131 if (!xSz || !ySz || !zSz || !glFmt || header->blockDimZ != 1) {
132 qCDebug(lcQtGuiTextureIO, "Invalid ASTC header data in file %s", logName().constData());
133 return nullData;
134 }
135
136 res.setSize(QSize(xSz, ySz));
137 res.setGLFormat(0); // 0 for compressed textures
138 res.setGLInternalFormat(glFmt);
139 //? BaseInternalFormat
140
141 int xBlocks = (xSz + header->blockDimX - 1) / header->blockDimX;
142 int yBlocks = (ySz + header->blockDimY - 1) / header->blockDimY;
143 int zBlocks = (zSz + header->blockDimZ - 1) / header->blockDimZ;
144
145 int byteCount = 0;
146 bool oob = mul_overflow(xBlocks, yBlocks, &byteCount)
147 || mul_overflow(byteCount, zBlocks, &byteCount)
148 || mul_overflow(byteCount, 16, &byteCount);
149
150
151 res.setDataOffset(sizeof(AstcHeader));
152 res.setNumLevels(1);
153 res.setDataLength(byteCount);
154
155 if (oob || !res.isValid()) {
156 qCDebug(lcQtGuiTextureIO, "Invalid ASTC file %s", logName().constData());
157 return nullData;
158 }
159
160 res.setLogName(logName());
161
162#if 0
163 qDebug() << "ASTC file handler read" << res << res.dataOffset() << res.dataLength();
164#endif
165 return res;
166}
167
168QT_END_NAMESPACE
169