d3d: add float texture upload, with example

examples/rhi/floattexture/floattexture.pro

+TEMPLATE = app
+
+QT += rhi
+
+SOURCES = \
+    floattexture.cpp
+
+RESOURCES = floattexture.qrc
+
+target.path = $$[QT_INSTALL_EXAMPLES]/rhi/floattexture
+INSTALLS += target

examples/rhi/floattexture/floattexture.qrc

+<!DOCTYPE RCC><RCC version="1.0">
+<qresource>
+  <file alias="texture.vert.qsb">../shared/texture.vert.qsb</file>
+  <file alias="texture.frag.qsb">../shared/texture.frag.qsb</file>
+  <file alias="OpenfootageNET_fieldairport-512.hdr">../shared/OpenfootageNET_fieldairport-512.hdr</file>
+</qresource>
+</RCC>

examples/rhi/rhi.pro

@@ -12,7 +12,8 @@ SUBDIRS += \
     multiwindow_threaded \
     imguidemo \
     triquadcube \
-    offscreen
+    offscreen \
+    floattexture
 
 qtConfig(vulkan) {
     SUBDIRS += \

src/rhi/qrhi.cpp

@@ -1351,8 +1351,8 @@ QRhiTextureRenderTargetDescription::QRhiTextureRenderTargetDescription(const QRh
     \note With compressed textures the first upload must always match the
     subresource size due to graphics API limitations with some backends.
 
-    sourceTopLeft() is is only supported for uncompressed textures, and
-    specifies the top-left corner of the source rectangle.
+    sourceTopLeft() is supported only for uncompressed, non-floating point
+    textures, and specifies the top-left corner of the source rectangle.
 
     \note Setting sourceSize() or sourceTopLeft() may trigger a QImage copy
     internally, depending on the format and the backend.
@@ -3093,6 +3093,11 @@ bool QRhiImplementation::isCompressedFormat(QRhiTexture::Format format) const
             || (format >= QRhiTexture::ASTC_4x4 && format <= QRhiTexture::ASTC_12x12);
 }
 
+bool QRhiImplementation::isFloatFormat(QRhiTexture::Format format) const
+{
+    return format == QRhiTexture::RGBA16F || format == QRhiTexture::RGBA32F;
+}
+
 void QRhiImplementation::compressedFormatInfo(QRhiTexture::Format format, const QSize &size,
                                               quint32 *bpl, quint32 *byteSize,
                                               QSize *blockDim) const

src/rhi/qrhi_p.h

@@ -142,6 +142,7 @@ public:
     void compressedFormatInfo(QRhiTexture::Format format, const QSize &size,
                               quint32 *bpl, quint32 *byteSize,
                               QSize *blockDim) const;
+    bool isFloatFormat(QRhiTexture::Format format) const;
     void textureFormatInfo(QRhiTexture::Format format, const QSize &size,
                            quint32 *bpl, quint32 *byteSize) const;
     quint32 approxByteSizeForTexture(QRhiTexture::Format format, const QSize &baseSize,

src/rhi/qrhid3d11.cpp

@@ -1053,6 +1053,7 @@ void QRhiD3D11::enqueueResourceUpdates(QRhiCommandBuffer *cb, QRhiResourceUpdate
                     cmd.args.updateSubRes.dst = texD->tex;
                     cmd.args.updateSubRes.dstSubRes = subres;
 
+                    bool cmdValid = true;
                     if (!mipDesc.image().isNull()) {
                         QImage img = mipDesc.image();
                         QSize size = img.size();
@@ -1096,8 +1097,26 @@ void QRhiD3D11::enqueueResourceUpdates(QRhiCommandBuffer *cb, QRhiResourceUpdate
                         cmd.args.updateSubRes.dstBox = box;
                         cmd.args.updateSubRes.src = cbD->retainData(mipDesc.data());
                         cmd.args.updateSubRes.srcRowPitch = bpl;
+                    } else if (!mipDesc.data().isEmpty() && isFloatFormat(texD->m_format)) {
+                        const QSize size = mipDesc.sourceSize().isEmpty() ? q->sizeForMipLevel(level, texD->m_pixelSize)
+                                                                          : mipDesc.sourceSize();
+                        quint32 bpl = 0;
+                        QSize blockDim;
+                        textureFormatInfo(texD->m_format, size, &bpl, nullptr);
+                        box.left = dp.x();
+                        box.top = dp.y();
+                        box.right = dp.x() + size.width();
+                        box.bottom = dp.y() + size.height();
+                        cmd.args.updateSubRes.hasDstBox = true;
+                        cmd.args.updateSubRes.dstBox = box;
+                        cmd.args.updateSubRes.src = cbD->retainData(mipDesc.data());
+                        cmd.args.updateSubRes.srcRowPitch = bpl;
+                    } else {
+                        qWarning("Invalid texture upload for %p layer=%d mip=%d", texD, layer, level);
+                        cmdValid = false;
                     }
-                    cbD->commands.append(cmd);
+                    if (cmdValid)
+                        cbD->commands.append(cmd);
                 }
             }
         } else if (u.type == QRhiResourceUpdateBatchPrivate::TextureOp::TexCopy) {