Use external libsquish if found

INSTALL.md

@@ -65,6 +65,9 @@ NEW or CHANGED MINIMUM dependencies since the last major release are **bold**.
  * If you want support for HEIF/HEIC images:
  * libheif >= 1.3 (tested through 1.6; older versions may also work, we
  haven't tested)
+* If you want support for DDS files:
+ * libsquish >= 1.13
+ * But... if not found on the system, an embedded version will be used.
 
 
 Dependency control and disabling components

src/build-scripts/gh-win-installdeps.bash

@@ -43,6 +43,7 @@ vcpkg install freetype:x64-windows
 
 vcpkg install libraw:x64-windows
 vcpkg install openjpeg:x64-windows
+vcpkg install libsquish:x64-windows
 # vcpkg install ffmpeg:x64-windows # takes FOREVER!
 # vcpkg install webp:x64-windows # No such vcpkg package?a
 

src/build-scripts/install_homebrew_deps.bash

@@ -40,7 +40,8 @@ else
  brew install --display-times libtiff ilmbase openexr opencolorio
  brew install --display-times libpng giflib webp jpeg-turbo openjpeg
  brew install --display-times freetype libraw dcmtk pybind11 numpy
- brew install --display-times field3d ffmpeg libheif openvdb tbb
+ brew install --display-times field3d ffmpeg libheif libsquish
+ brew install --display-times openvdb tbb
  brew install --display-times opencv qt ptex
 fi
 

src/cmake/externalpackages.cmake

@@ -301,3 +301,13 @@ macro (find_or_download_robin_map)
  endif ()
  checked_find_package (Robinmap REQUIRED)
 endmacro()
+
+
+###########################################################################
+# libsquish
+
+option (USE_EMBEDDED_LIBSQUISH
+ "Force use of embedded Libsquish, even if external is found" OFF)
+if (NOT USE_EMBEDDED_LIBSQUISH)
+ checked_find_package (Libsquish)
+endif ()

src/cmake/modules/FindLibsquish.cmake

@@ -0,0 +1,50 @@
+# Module to find Libsquish
+#
+# This module will first look into the directories defined by the variables:
+# - Libsquish_ROOT, LIBSQUISH_INCLUDE_PATH, LIBSQUISH_LIBRARY_PATH
+#
+# This module defines the following variables:
+#
+# LIBSQUISH_FOUND True if Libsquish was found.
+# LIBSQUISH_INCLUDES Where to find Libsquish headers
+# LIBSQUISH_LIBRARIES List of libraries to link against when using Libsquish
+# LIBSQUISH_VERSION Version of Libsquish (e.g., 3.6.2)
+
+include (FindPackageHandleStandardArgs)
+
+find_path (LIBSQUISH_INCLUDE_DIR squish.h
+ HINTS
+ ${LIBSQUISH_INCLUDE_PATH}
+ ENV LIBSQUISH_INCLUDE_PATH
+ DOC "The directory where Libsquish headers reside")
+
+find_library (LIBSQUISH_LIBRARY squish
+ HINTS
+ ${LIBSQUISH_LIBRARY_PATH}
+ ENV LIBSQUISH_LIBRARY_PATH
+ DOC "The Libsquish libraries")
+
+find_package_handle_standard_args (LIBSQUISH
+ REQUIRED_VARS
+ LIBSQUISH_INCLUDE_DIR
+ LIBSQUISH_LIBRARY
+ )
+
+if (LIBSQUISH_FOUND)
+ set (LIBSQUISH_INCLUDES ${LIBSQUISH_INCLUDE_DIR})
+ set (LIBSQUISH_LIBRARIES ${LIBSQUISH_LIBRARY})
+
+ if (NOT TARGET Libsquish::Libsquish)
+ add_library(Libsquish::Libsquish UNKNOWN IMPORTED)
+ set_target_properties(Libsquish::Libsquish PROPERTIES
+ INTERFACE_INCLUDE_DIRECTORIES "${LIBSQUISH_INCLUDES}")
+
+ set_property(TARGET Libsquish::Libsquish APPEND PROPERTY
+ IMPORTED_LOCATION "${LIBSQUISH_LIBRARIES}")
+ endif ()
+endif ()
+
+mark_as_advanced (
+ LIBSQUISH_INCLUDE_DIR
+ LIBSQUISH_LIBRARY
+ )

src/dds.imageio/CMakeLists.txt

@@ -2,7 +2,16 @@
 # SPDX-License-Identifier: BSD-3-Clause
 # https://github.com/OpenImageIO/oiio/blob/master/LICENSE.md
 
-add_oiio_plugin (ddsinput.cpp squish/alpha.cpp squish/clusterfit.cpp
+if (LIBSQUISH_FOUND)
+ # External libsquish was found -- use it
+ add_oiio_plugin (ddsinput.cpp
+ LINK_LIBRARIES Libsquish::Libsquish
+ )
+else ()
+ # No external libsquish was found -- use the embedded version.
+ add_oiio_plugin (ddsinput.cpp squish/alpha.cpp squish/clusterfit.cpp
  squish/colourblock.cpp squish/colourfit.cpp squish/colourset.cpp
  squish/maths.cpp squish/rangefit.cpp squish/singlecolourfit.cpp
- squish/squish.cpp)
+ squish/squish.cpp
+ INCLUDE_DIRS "${CMAKE_CURRENT_SOURCE_DIR}/squish")
+endif ()

src/dds.imageio/ddsinput.cpp

@@ -13,7 +13,7 @@
 #include <OpenImageIO/imageio.h>
 #include <OpenImageIO/typedesc.h>
 
-#include "squish/squish.h"
+#include "squish.h"
 
 OIIO_PLUGIN_NAMESPACE_BEGIN