SConstruct : Fix linking with OpenEXR 3

Author: johnhaddon

SConstruct

@@ -1299,7 +1299,7 @@ if doConfigure :
 	# library names	if necessary
 	boostVersion = None
 	boostVersionHeader = env.FindFile( "boost/version.hpp", dependencyIncludes )
-	if (boostVersionHeader ==None):
+	if boostVersionHeader is None :
 		sys.stderr.write( "ERROR : unable to find the boost headers, check BOOST_INCLUDE_PATH.\n" )
 		Exit( 1 )
 
@@ -1319,6 +1319,23 @@ if doConfigure :
 		sys.stderr.write( "ERROR : unable to determine boost version from \"%s\".\n" % boostVersionHeader )
 		Exit( 1 )
 
+	# Figure out the OpenEXR version
+
+	exrVersionHeader = env.FindFile( "OpenEXR/OpenEXRConfig.h", dependencyIncludes )
+	if exrVersionHeader is None :
+		sys.stderr.write( "ERROR : unable to find `OpenEXR/OpenEXRConfig.h`, check OPENEXR_INCLUDE_PATH.\n" )
+		Exit( 1 )
+
+	exrMajorVersion = None
+	for line in open( str( exrVersionHeader ) ) :
+		m = re.match( r'^#define OPENEXR_VERSION_STRING "(\d)\.(\d)\.(\d)"$', line )
+		if m :
+			exrMajorVersion = int( m.group( 1 ) )
+
+	if exrMajorVersion is None :
+		sys.stderr.write( "ERROR : unable to determine OpenEXR version from \"{}\".\n".format( exrVersionHeader ) )
+		Exit( 1 )
+
 	env.Append( LIBS = [
 			"boost_filesystem" + env["BOOST_LIB_SUFFIX"],
 			"boost_regex" + env["BOOST_LIB_SUFFIX"],
@@ -1358,34 +1375,29 @@ if doConfigure :
 
 	c.Finish()
 
+if exrMajorVersion >= 3 :
+	env.Append( LIBS = [ "OpenEXR" + env["OPENEXR_LIB_SUFFIX"] ] )
+else :
+	env.Append(
+		LIBS = [
+			"IlmImf" + env["OPENEXR_LIB_SUFFIX"],
+			# Windows OpenEXR adds version numbers to all libraries except Half.
+			"Half" + ( env["OPENEXR_LIB_SUFFIX"] if env["PLATFORM"] != "win32" else "" )
+		]
+	)
+
 env.Append( LIBS = [
 		"tbb" + env["TBB_LIB_SUFFIX"],
 		"blosc" + env["BLOSC_LIB_SUFFIX"],
 		"Iex" + env["OPENEXR_LIB_SUFFIX"],
 		"Imath" + env["OPENEXR_LIB_SUFFIX"],
-		"IlmImf" + env["OPENEXR_LIB_SUFFIX"],
 		"IlmThread" + env["OPENEXR_LIB_SUFFIX"],
+		# Link Windows zlib against static library to avoid potential conflicts
+		# with system provided version.
+		"z" if env["PLATFORM"] != "win32" else "zlibstatic"
 	]
 )
 
-# Windows OpenEXR adds version numbers to libraries except Half
-# Link Windows zlib against static library to avoid potential conflicts
-# with system provided version
-if env["PLATFORM"] != "win32" :
-	env.Append( LIBS = [
-			"Half" + env["OPENEXR_LIB_SUFFIX"],
-			"z",
-		]
-	)
-
-else :
-	env.Append( LIBS= [
-			"Half",
-			"zlibstatic",
-		]
-	)
-
-
 Help( o.GenerateHelpText( env ) )
 
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