KTX2 / KTX support

.gitmodules

@@ -134,4 +134,15 @@
 	path = dependencies/DirectX-Headers
 	url = https://github.com/Tom94/DirectX-Headers
 	shallow = true
-
+[submodule "dependencies/KTX-Software"]
+	path = dependencies/KTX-Software
+	url = https://github.com/Tom94/KTX-Software
+	shallow = true
+[submodule "dependencies/bcdec"]
+	path = dependencies/bcdec
+	url = https://github.com/Tom94/bcdec
+	shallow = true
+[submodule "dependencies/etcdec"]
+	path = dependencies/etcdec
+	url = https://github.com/Tom94/etcdec
+	shallow = true

CMakeLists.txt

@@ -158,6 +158,7 @@ set(TEV_SOURCES
     include/tev/imageio/JpegTurboImageLoader.h src/imageio/JpegTurboImageLoader.cpp
     include/tev/imageio/JpegTurboImageSaver.h src/imageio/JpegTurboImageSaver.cpp
     include/tev/imageio/JxrImageLoader.h src/imageio/JxrImageLoader.cpp
+    include/tev/imageio/KtxImageLoader.h src/imageio/KtxImageLoader.cpp
     include/tev/imageio/PfmImageLoader.h src/imageio/PfmImageLoader.cpp
     include/tev/imageio/PngImageLoader.h src/imageio/PngImageLoader.cpp
     include/tev/imageio/PngImageSaver.h src/imageio/PngImageSaver.cpp
@@ -276,7 +277,7 @@ endif()
 
 target_compile_definitions(tev PRIVATE ${TEV_DEFINITIONS})
 
-set(TEV_LIBS cfitsio clip exif_static gdcm-tev JPEG::JPEG jxrglue libraw::libraw_r nanogui OpenEXR::OpenEXR openjpeg-tev png_static tiff webpdemux XMPCore xsimd)
+set(TEV_LIBS cfitsio clip exif_static gdcm-tev JPEG::JPEG jxrglue ktx_read libraw::libraw_r nanogui OpenEXR::OpenEXR openjpeg-tev png_static tiff webpdemux XMPCore xsimd)
 if (MSVC)
     list(APPEND TEV_LIBS wsock32 ws2_32)
 endif()

README.md

@@ -142,6 +142,7 @@ $ cpack --config build/CPackConfig.cmake
 - __PFM__, PAM, PNM, PBM, PGM, PPM (generally: see [NetPBM](https://netpbm.sourceforge.net/) and [PFM](https://www.pauldebevec.com/Research/HDR/PFM/))
 - __QOI__ (via [qoi](https://github.com/phoboslab/qoi))
 - __DDS__ (via [DirectXTex](https://github.com/microsoft/DirectXTex))
+- __KTX2__, __KTX__ (via [KTX-Software](https://github.com/KhronosGroup/KTX-Software), [bcdec](https://github.com/iOrange/bcdec), and [encdec](https://github.com/iOrange/etcdec))
 - __WEBP__ (via [libwebp](https://chromium.googlesource.com/webm/libwebp))
 - __TIFF__, __DNG__ (via [libtiff](https://gitlab.com/libtiff/libtiff))
 - __AVIF__ (including gain maps, e.g. HDR pictures from Android; via [dav1d](https://github.com/videolan/dav1d)+[libheif](https://github.com/strukturag/libheif))

dependencies/CMakeLists.txt

@@ -383,6 +383,31 @@ target_include_directories(gdcm-tev INTERFACE ${GDCM_INCLUDE_PATH})
 # Compile jxrlib for JPEG XR support
 add_subdirectory(jxrlib EXCLUDE_FROM_ALL)
 
+# Compile KTX-Software for KTX2 support
+set(BUILD_SHARED_LIBS OFF CACHE BOOL " " FORCE)
+set(KTX_FEATURE_JS OFF CACHE BOOL " " FORCE)
+set(KTX_FEATURE_TESTS OFF CACHE BOOL " " FORCE)
+set(KTX_FEATURE_TOOLS OFF CACHE BOOL " " FORCE)
+set(LIBKTX_VERSION_READ_ONLY ON CACHE BOOL " " FORCE)
+set(LIBKTX_VERSION_FULL OFF CACHE BOOL " " FORCE)
+set(LIBKTX_FEATURE_KTX1 ON CACHE BOOL " " FORCE)
+set(LIBKTX_FEATURE_KTX2 ON CACHE BOOL " " FORCE)
+set(LIBKTX_FEATURE_VK_UPLOAD OFF CACHE BOOL " " FORCE)
+set(LIBKTX_FEATURE_GL_UPLOAD OFF CACHE BOOL " " FORCE)
+set(LIBKTX_FEATURE_ETC_UNPACK ON CACHE BOOL " " FORCE)
+
+if (HAS_SSE2)
+    if (APPLE)
+        # Since we're targeting macOS 10.15 and later, Intel macOS always has SSE4.1
+        set(ASTCENC_ISA_SSE41 ON)
+    else()
+        # Otherwise, assume only SSE2, *not* ASTENC's default of AVX2 on Intel platforms
+        set(ASTCENC_ISA_SSE2 ON)
+    endif()
+endif()
+
+add_subdirectory(KTX-Software EXCLUDE_FROM_ALL)
+
 # Cross-platform SIMD
 set(XSIMD_SKIP_INSTALL ON CACHE BOOL " " FORCE)
 add_subdirectory(xsimd EXCLUDE_FROM_ALL)

include/tev/imageio/KtxImageLoader.h

@@ -0,0 +1,35 @@
+/*
+ * tev -- the EDR viewer
+ *
+ * Copyright (C) 2026 Thomas Müller <[email protected]>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <tev/Image.h>
+#include <tev/imageio/ImageLoader.h>
+
+namespace tev {
+
+class KtxImageLoader final : public ImageLoader {
+public:
+    Task<std::vector<ImageData>> load(
+        std::istringstream& iStream, const fs::path& path, std::string_view channelSelector, const ImageLoaderSettings& settings, int priority
+    ) const override;
+
+    std::string name() const override { return "KTX"; }
+};
+
+} // namespace tev

src/HelpWindow.cpp

@@ -231,6 +231,7 @@ HelpWindow::HelpWindow(Widget* parent, weak_ptr<Ipc> weakIpc, function<void()> c
     addSpacer(about, 20);
 
     addLibrary(about, "args", "Single-header argument parsing library");
+    addLibrary(about, "bcdec", "Single-header BC1-BC7 decoder library");
     addLibrary(about, "cfitsio", "FITS data file library");
     addLibrary(about, "clip", "Cross-platform clipboard library");
     addLibrary(about, "concurrentqueue", "Cross-platform lightweight semaphore");
@@ -242,10 +243,12 @@ HelpWindow::HelpWindow(Widget* parent, weak_ptr<Ipc> weakIpc, function<void()> c
     addLibrary(about, "DirectXMath", "DirectX math library");
     addLibrary(about, "DirectX-Headers", "DirectX headers");
 #endif
+    addLibrary(about, "etcdec", "Single-header ETC/EAC decoder library");
     addLibrary(about, "GDCM", "Grassroots library for DICOM medical files");
     addLibrary(about, "Glad", "Multi-language GL loader-generator");
     addLibrary(about, "GLFW", "OpenGL desktop development library");
     addLibrary(about, "jxrlib", "JPEG XR image format library");
+    addLibrary(about, "KTX-Software", "KTX (Khronos texture) library");
 #ifdef TEV_SUPPORT_HEIC
     addLibrary(about, "libde265", "Open h.265 video codec library");
 #endif

src/ImageViewer.cpp

@@ -2437,6 +2437,7 @@ void ImageViewer::openImageDialog() {
                 {"jpeg,jpg",                "JPEG image"                       },
                 {"jxl",                     "JPEG XL image"                    },
                 {"jxr,hdp,wdp",             "JPEG XR image"                    },
+                {"ktx,ktx2",                "Khronos texture"                  },
                 {"pam,pbm,pfm,pgm,pnm,ppm", "Portable *Map image"              },
                 {"pic",                     "PIC image"                        },
                 {"png",                     "Portable Network Graphics image"  },

src/imageio/ImageLoader.cpp

@@ -27,6 +27,7 @@
 #include <tev/imageio/Jpeg2000ImageLoader.h>
 #include <tev/imageio/JpegTurboImageLoader.h>
 #include <tev/imageio/JxrImageLoader.h>
+#include <tev/imageio/KtxImageLoader.h>
 #include <tev/imageio/PfmImageLoader.h>
 #include <tev/imageio/PngImageLoader.h>
 #include <tev/imageio/QoiImageLoader.h>
@@ -68,6 +69,7 @@ const vector<unique_ptr<ImageLoader>>& ImageLoader::getLoaders() {
 #ifdef TEV_SUPPORT_JXL
         imageLoaders.emplace_back(new JxlImageLoader());
 #endif
+        imageLoaders.emplace_back(new KtxImageLoader());
         imageLoaders.emplace_back(new FitsImageLoader());
         imageLoaders.emplace_back(new QoiImageLoader());
         imageLoaders.emplace_back(new WebpImageLoader());
@@ -108,6 +110,8 @@ const vector<string_view>& ImageLoader::supportedMimeTypes() {
         "image/jpeg",
         "image/jxl",
         "image/jxr",
+        "image/ktx",
+        "image/ktx2",
         "image/png",
         "image/qoi",
         "image/tga",