From afc7c2b449b686a81e5e4277a77dc24e51d098c0 Mon Sep 17 00:00:00 2001
From: Shyotl <Shyotl@gmail.com>
Date: Wed, 12 Sep 2012 02:13:36 -0500
Subject: [PATCH] Better robustness when loading shaders. Redundant shaders
 (eg: "deferred/shadowF.glsl") will only need to be compiled once, and
 LLShaderMgr::mShaderObjects won't have previous entries mistakenly
 overwritten as a result.

---
 indra/llrender/llshadermgr.cpp      | 10 +++++++++-
 indra/llrender/llshadermgr.h        | 10 +++++++++-
 indra/newview/llviewershadermgr.cpp |  6 +++---
 3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/indra/llrender/llshadermgr.cpp b/indra/llrender/llshadermgr.cpp
index 2531df4b6..234d2e141 100644
--- a/indra/llrender/llshadermgr.cpp
+++ b/indra/llrender/llshadermgr.cpp
@@ -525,6 +525,14 @@ void LLShaderMgr::dumpObjectLog(GLhandleARB ret, BOOL warns)
 
 GLhandleARB LLShaderMgr::loadShaderFile(const std::string& filename, S32 & shader_level, GLenum type, S32 texture_index_channels)
 {
+	std::pair<std::multimap<std::string, CachedObjectInfo >::iterator, std::multimap<std::string, CachedObjectInfo>::iterator> range;
+	range = mShaderObjects.equal_range(filename);
+	for (std::multimap<std::string, CachedObjectInfo>::iterator it = range.first; it != range.second;++it)
+	{
+		if((*it).second.mLevel == shader_level && (*it).second.mType == type)
+			return (*it).second.mHandle;
+	}
+
 	GLenum error = GL_NO_ERROR;
 	if (gDebugGL)
 	{
@@ -888,7 +896,7 @@ GLhandleARB LLShaderMgr::loadShaderFile(const std::string& filename, S32 & shade
 	if (ret)
 	{
 		// Add shader file to map
-		mShaderObjects[filename] = ret;
+		mShaderObjects.insert(make_pair(filename,CachedObjectInfo(ret,try_gpu_class,type)));
 		shader_level = try_gpu_class;
 	}
 	else
diff --git a/indra/llrender/llshadermgr.h b/indra/llrender/llshadermgr.h
index b06d61b3e..fc9242f7c 100644
--- a/indra/llrender/llshadermgr.h
+++ b/indra/llrender/llshadermgr.h
@@ -185,8 +185,16 @@ public:
 	virtual void updateShaderUniforms(LLGLSLShader * shader) = 0; // Pure Virtual
 
 public:
+	struct CachedObjectInfo
+	{
+		CachedObjectInfo(GLhandleARB handle, U32 level, GLenum type) : 
+			mHandle(handle), mLevel(level), mType(type) {}
+		GLhandleARB mHandle;	//Actual handle of the opengl shader object.
+		U32 mLevel;				//Level /might/ not be needed, but it's stored to ensure there's no change in behavior.
+		GLenum mType;			//GL_VERTEX_SHADER_ARB or GL_FRAGMENT_SHADER_ARB. Tracked because some utility shaders can be loaded as both types (carefully).
+	};
 	// Map of shader names to compiled
-	std::map<std::string, GLhandleARB> mShaderObjects;
+	std::multimap<std::string, CachedObjectInfo > mShaderObjects;	//Singu Note: Packing more info here. Doing such provides capability to skip unneeded duplicate loading..
 
 	//global (reserved slot) shader parameters
 	std::vector<std::string> mReservedAttribs;
diff --git a/indra/newview/llviewershadermgr.cpp b/indra/newview/llviewershadermgr.cpp
index 75b2170fb..356cc6cac 100644
--- a/indra/newview/llviewershadermgr.cpp
+++ b/indra/newview/llviewershadermgr.cpp
@@ -576,10 +576,10 @@ void LLViewerShaderMgr::setShaders()
 
 		//Flag base shader objects for deletion
 		//Don't worry-- they won't be deleted until no programs refrence them.
-		std::map<std::string, GLhandleARB>::iterator it = mShaderObjects.begin();
+		std::multimap<std::string, LLShaderMgr::CachedObjectInfo >::iterator it = mShaderObjects.begin();
 		for(; it!=mShaderObjects.end();++it)
-			if(it->second)
-				glDeleteObjectARB(it->second);
+			if(it->second.mHandle)
+				glDeleteObjectARB(it->second.mHandle);
 		mShaderObjects.clear(); 
 	}
 	else