qt5base-lts/tests/manual/rhi/shared/dds_bc1.h
Laszlo Agocs 53599592e0 Introduce the Qt graphics abstraction as private QtGui helpers
Comes with backends for Vulkan, Metal, Direct3D 11.1, and OpenGL (ES).

All APIs are private for now.

Shader conditioning (i.e. generating a QRhiShader in memory or on disk
from some shader source code) is done via the tools and APIs provided
by qt-labs/qtshadertools.

The OpenGL support follows the cross-platform tradition of requiring
ES 2.0 only, while optionally using some (ES) 3.x features. It can
operate in core profile contexts as well.

Task-number: QTBUG-70287
Change-Id: I246f2e36d562e404012c05db2aa72487108aa7cc
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
2019-06-13 10:13:45 +02:00

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4.8 KiB
C

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static const quint32 DDS_MAGIC = 0x20534444; // 'DDS '
static const quint32 DDS_FOURCC = 4;
#define FOURCC(c0, c1, c2, c3) ((c0) | ((c1) << 8) | ((c2) << 16) | ((c3 << 24)))
struct DDS_PIXELFORMAT {
quint32 size;
quint32 flags;
quint32 fourCC;
quint32 rgbBitCount;
quint32 rBitMask;
quint32 gBitMask;
quint32 bBitMask;
quint32 aBitMask;
};
struct DDS_HEADER {
quint32 size;
quint32 flags;
quint32 height;
quint32 width;
quint32 pitch;
quint32 depth;
quint32 mipMapCount;
quint32 reserved1[11];
DDS_PIXELFORMAT pixelFormat;
quint32 caps;
quint32 caps2;
quint32 caps3;
quint32 caps4;
quint32 reserved2;
};
static quint32 bc1size(const QSize &size)
{
static const quint32 blockSize = 8; // 8 bytes for BC1
const quint32 bytesPerLine = qMax<quint32>(1, (size.width() + 3) / 4) * blockSize;
const quint32 ySize = qMax<quint32>(1, (size.height() + 3) / 4);
return bytesPerLine * ySize;
}
static QByteArrayList loadBC1(const QString &filename, QSize *size)
{
QFile f(filename);
if (!f.open(QIODevice::ReadOnly)) {
qWarning("Failed to open %s", qPrintable(filename));
return QByteArrayList();
}
quint32 magic = 0;
f.read(reinterpret_cast<char *>(&magic), sizeof(magic));
if (magic != DDS_MAGIC) {
qWarning("%s is not a DDS file", qPrintable(filename));
return QByteArrayList();
}
DDS_HEADER header;
f.read(reinterpret_cast<char *>(&header), sizeof(header));
if (header.size != sizeof(DDS_HEADER)) {
qWarning("Invalid DDS header size");
return QByteArrayList();
}
if (header.pixelFormat.size != sizeof(DDS_PIXELFORMAT)) {
qWarning("Invalid DDS pixel format size");
return QByteArrayList();
}
if (!(header.pixelFormat.flags & DDS_FOURCC)) {
qWarning("Invalid DDS pixel format");
return QByteArrayList();
}
if (header.pixelFormat.fourCC != FOURCC('D', 'X', 'T', '1')) {
qWarning("Only DXT1 (BC1) is supported");
return QByteArrayList();
}
QByteArrayList data;
QSize sz(header.width, header.height);
for (quint32 level = 0; level < header.mipMapCount; ++level) {
data.append(f.read(bc1size(sz)));
sz.setWidth(qMax(1, sz.width() / 2));
sz.setHeight(qMax(1, sz.height() / 2));
}
if (size)
*size = QSize(header.width, header.height);
return data;
}