Don't re-read the same glsl files over and over again

(cherry picked from commit 048076b8e32a8d348e4b1b4dc72fef860f4498bd)

Change-Id: I10b4badaba01630e1a054b3d4d9cc4720822511a
Reviewed-on: https://gerrit.libreoffice.org/19246
Reviewed-by: Miklos Vajna <vmiklos@collabora.co.uk>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

1 files changed, 17 insertions, 4 deletions

diff --git a/vcl/source/opengl/OpenGLHelper.cxx b/vcl/source/opengl/OpenGLHelper.cxx
index 538e4670180f..43317d506fc6 100644
--- a/vcl/source/opengl/OpenGLHelper.cxx
+++ b/vcl/source/opengl/OpenGLHelper.cxx
@@ -66,6 +66,7 @@ OString loadShader(const OUString& rFilename)
 {
     OUString aFileURL = getShaderFolder() + rFilename +".glsl";
     osl::File aFile(aFileURL);
+    SAL_INFO("vcl.opengl", "Reading " << aFileURL);
     if(aFile.open(osl_File_OpenFlag_Read) == osl::FileBase::E_None)
     {
         sal_uInt64 nSize = 0;
@@ -85,6 +86,18 @@ OString loadShader(const OUString& rFilename)
     return OString();
 }
 
+OString& getShaderSource(const OUString& rFilename)
+{
+    static std::unordered_map<OUString, OString, OUStringHash> aMap;
+
+    if (aMap.find(rFilename) == aMap.end())
+    {
+        aMap[rFilename] = loadShader(rFilename);
+    }
+
+    return aMap[rFilename];
+}
+
 }
 
 namespace {
@@ -189,8 +202,8 @@ namespace
                              const OString& rPreamble )
     {
         // read shaders source
-        OString aVertexShaderSource = loadShader( rVertexShaderName );
-        OString aFragmentShaderSource = loadShader( rFragmentShaderName );
+        OString aVertexShaderSource = getShaderSource( rVertexShaderName );
+        OString aFragmentShaderSource = getShaderSource( rFragmentShaderName );
 
         // get info about the graphic device
 #if defined( SAL_UNX ) && !defined( MACOSX ) && !defined( IOS )&& !defined( ANDROID )
@@ -374,8 +387,8 @@ GLint OpenGLHelper::LoadShaders(const OUString& rVertexShaderName,
     GLint ProgramID = glCreateProgram();
 
     // read shaders from file
-    OString aVertexShaderSource = loadShader(rVertexShaderName);
-    OString aFragmentShaderSource = loadShader(rFragmentShaderName);
+    OString aVertexShaderSource = getShaderSource(rVertexShaderName);
+    OString aFragmentShaderSource = getShaderSource(rFragmentShaderName);
 
 
     GLint bBinaryResult = GL_FALSE;