vk: Fix mipmap generation for npot textures

src/rhi/qrhi.cpp

@@ -4088,7 +4088,7 @@ int QRhi::ubufAligned(int v) const
  */
 int QRhi::mipLevelsForSize(const QSize &size) const
 {
-    return qCeil(std::log2(qMax(size.width(), size.height()))) + 1;
+    return qFloor(std::log2(qMax(size.width(), size.height()))) + 1;
 }
 
 /*!
@@ -4097,8 +4097,8 @@ int QRhi::mipLevelsForSize(const QSize &size) const
  */
 QSize QRhi::sizeForMipLevel(int mipLevel, const QSize &baseLevelSize) const
 {
-    const int w = qFloor(float(qMax(1, baseLevelSize.width() >> mipLevel)));
-    const int h = qFloor(float(qMax(1, baseLevelSize.height() >> mipLevel)));
+    const int w = qMax(1, baseLevelSize.width() >> mipLevel);
+    const int h = qMax(1, baseLevelSize.height() >> mipLevel);
     return QSize(w, h);
 }
 

src/rhi/qrhivulkan.cpp

@@ -2636,8 +2636,8 @@ void QRhiVulkan::enqueueResourceUpdates(QRhiCommandBuffer *cb, QRhiResourceUpdat
                 region.srcSubresource.baseArrayLayer = 0;
                 region.srcSubresource.layerCount = layerCount;
 
-                region.srcOffsets[1].x = w;
-                region.srcOffsets[1].y = h;
+                region.srcOffsets[1].x = qMax(1, w);
+                region.srcOffsets[1].y = qMax(1, h);
                 region.srcOffsets[1].z = 1;
 
                 region.dstSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
@@ -2645,8 +2645,8 @@ void QRhiVulkan::enqueueResourceUpdates(QRhiCommandBuffer *cb, QRhiResourceUpdat
                 region.dstSubresource.baseArrayLayer = 0;
                 region.dstSubresource.layerCount = layerCount;
 
-                region.dstOffsets[1].x = w >> 1;
-                region.dstOffsets[1].y = h >> 1;
+                region.dstOffsets[1].x = qMax(1, w >> 1);
+                region.dstOffsets[1].y = qMax(1, h >> 1);
                 region.dstOffsets[1].z = 1;
 
                 df->vkCmdBlitImage(cbD->cb,