Merge pull request #758 from CesiumGS/fix-mipmap-textures

Fix loading KTX2 textures with mipmaps

Author: lilleyse

.github/workflows/main.yml

@@ -138,7 +138,9 @@ jobs:
         if: ${{ runner.os == 'Linux' && matrix.config.name != 'AlmaLinux 8 - GCC' }}
         run: |
           sudo apt update
-          sudo apt install -y doxygen clang-tidy-15 gcovr
+          sudo apt install -y doxygen clang-tidy-15 clang-format-15 gcovr
+          sudo update-alternatives --install /usr/bin/clang-format clang-format /usr/bin/clang-format-15 100
+          sudo update-alternatives --set clang-format /usr/bin/clang-format-15
           sudo pip3 install conan==1.63.0 black==23.1.0 flake8==7.1.1 --ignore-installed
 
       # Could not figure out how to add Chocolatey libraries to the PATH automatically with refreshenv, so
@@ -151,6 +153,7 @@ jobs:
         run: |
           choco install -y conan --version 1.63.0
           choco install -y llvm --version=15.0.7 --allow-downgrade
+          echo "C:/Program Files/LLVM/bin" >> $env:GITHUB_PATH
           pip3 install black==23.1.0 flake8==7.1.1 requests
           echo "C:/Program Files/conan/conan" >> $env:GITHUB_PATH
 

CHANGES.md

@@ -1,5 +1,9 @@
 # Change Log
 
+### v0.25.0 - 2025-12-19
+
+* Fixed loading KTX2 textures with mipmaps.
+
 ### v0.25.0 - 2025-04-01
 
 * **Breaking change:** Cesium for Omniverse now requires Kit 106.5 or above (Isaac Sim 4.5.0 or above).

src/core/src/FabricTexture.cpp

@@ -119,9 +119,15 @@ void FabricTexture::setImage(const CesiumGltf::ImageCesium& image, TransferFunct
     } else {
         // As of Kit 105.1, omni::ui::kAutoCalculateStride doesn't work for compressed textures. This value somehow works.
         const auto stride = isCompressed ? 4ULL * static_cast<uint64_t>(image.width) : omni::ui::kAutoCalculateStride;
-        const auto data = reinterpret_cast<const uint8_t*>(image.pixelData.data());
+        auto data = reinterpret_cast<const uint8_t*>(image.pixelData.data());
         const auto dimensions = carb::Uint2{static_cast<uint32_t>(image.width), static_cast<uint32_t>(image.height)};
 
+        if (!image.mipPositions.empty()) {
+            // Just set the first mip level for now
+            // Later, investigate using setMipMappedBytesData
+            data = data + image.mipPositions[0].byteOffset;
+        }
+
         _pTexture->setBytesData(data, dimensions, stride, imageFormat);
     }
 }

vcpkg/ports/ktx/portfile.cmake

@@ -1,7 +1,7 @@
 vcpkg_from_github(
     OUT_SOURCE_PATH SOURCE_PATH
     REPO KhronosGroup/KTX-Software
-    REF "v${VERSION}"
+    REF "refs/tags/v${VERSION}"
     SHA512 5a89f8986464705ec36ac1becaddd0ff335e4c3c235468aaef0e963fcfeda4c0d669a086b91e61c16a3ae9e1fa5bf456dccf12cc65720e1a22e7cc0f30552541
     HEAD_REF master
     PATCHES