AnyImageImporter: detect KTX2

src/MagnumPlugins/AnyImageImporter/AnyImageImporter.cpp

@@ -84,6 +84,8 @@ void AnyImageImporter::doOpenFile(const std::string& filename) {
         plugin = "JpegImporter";
     else if(Utility::String::endsWith(normalized, ".jp2"))
         plugin = "Jpeg2000Importer";
+    else if(Utility::String::endsWith(normalized, ".ktx2"))
+        plugin = "KtxImporter";
     else if(Utility::String::endsWith(normalized, ".mng"))
         plugin = "MngImporter";
     else if(Utility::String::endsWith(normalized, ".pbm"))
@@ -177,6 +179,9 @@ void AnyImageImporter::doOpenData(Containers::ArrayView<const char> data) {
     /* https://en.wikipedia.org/wiki/JPEG#Syntax_and_structure */
     else if(dataString.hasPrefix("\xff\xd8\xff"_s))
         plugin = "JpegImporter";
+    /* https://github.khronos.org/KTX-Specification/#_identifier */
+    else if(dataString.hasPrefix("\xabKTX 20\xbb\r\n\x1a\n"_s))
+        plugin = "KtxImporter";
     /* https://en.wikipedia.org/wiki/Portable_Network_Graphics#File_header */
     else if(dataString.hasPrefix("\x89PNG\x0d\x0a\x1a\x0a"_s))
         plugin = "PngImporter";

src/MagnumPlugins/AnyImageImporter/Test/AnyImageImporterTest.cpp

@@ -91,6 +91,7 @@ constexpr struct {
     {"JPEG data", "gray.jpg", fileCallback, "JpegImporter"},
     {"JPEG uppercase", "uppercase.JPG", nullptr, "JpegImporter"},
     {"JPEG2000", "image.jp2", nullptr, "Jpeg2000Importer"},
+    {"KTX", "image.ktx2", nullptr, "KtxImporter"},
     {"EXR", "image.exr", nullptr, "OpenExrImporter"},
     {"EXR data", "image.exr", fileCallback, "OpenExrImporter"},
     {"HDR", "rgb.hdr", nullptr, "HdrImporter"},
@@ -123,7 +124,8 @@ const struct {
     {"just one zero byte", "\x00"_s, "00"},
     {"DDS, but no space", "DDS!"_s, "44445321"},
     {"TIFF, but too short", "II\x2a"_s, "49492a"},
-    {"TIFF, but no zero byte", "MM\xff\x2a"_s, "4d4dff2a"}
+    {"TIFF, but no zero byte", "MM\xff\x2a"_s, "4d4dff2a"},
+    {"KTX, but wrong version", "\xabKTX 30\xbb\r\n\x1a\n"_s, "ab4b5458"}
 };
 
 constexpr struct {