Added test setting 'ShyotlUseLegacyTextureBatching' to disable new texture indexing. The new indexing method requires heavy branching in shaders, which some hardware may not perfom well with.

indra/llrender/llglslshader.cpp

@@ -37,6 +37,7 @@
 #include "llshadermgr.h"
 #include "llfile.h"
 #include "llrender.h"
+#include "llcontrol.h"
 
 #if LL_DARWIN
 #include "OpenGL/OpenGL.h"
@@ -131,7 +132,8 @@ BOOL LLGLSLShader::createShader(vector<string> * attributes,
 	// Create program
 	mProgramObject = glCreateProgramObjectARB();
 
-	if (gGLManager.mGLVersion < 3.1f)
+	static const LLCachedControl<bool> no_texture_indexing("ShyotlUseLegacyTextureBatching",false);
+	if (gGLManager.mGLVersion < 3.1f || no_texture_indexing)
 	{ //force indexed texture channels to 1 if GL version is old (performance improvement for drivers with poor branching shader model support)
 		mFeatures.mIndexedTextureChannels = llmin(mFeatures.mIndexedTextureChannels, 1);
 	}
@@ -161,7 +163,7 @@ BOOL LLGLSLShader::createShader(vector<string> * attributes,
 		return FALSE;
 	}
 
-	if (gGLManager.mGLVersion < 3.1f)
+	if (gGLManager.mGLVersion < 3.1f || no_texture_indexing)
 	{ //attachShaderFeatures may have set the number of indexed texture channels, so set to 1 again
 		mFeatures.mIndexedTextureChannels = llmin(mFeatures.mIndexedTextureChannels, 1);
 	}

indra/newview/app_settings/settings.xml

@@ -488,7 +488,28 @@
       <key>Value</key>
       <integer>0</integer>
     </map>
-
+    <key>ShyotlUseLegacyRenderPath</key>
+    <map>
+      <key>Comment</key>
+      <string>Use deprecated pre-3.x OpenGL api calls.</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>0</integer>
+    </map>
+    <key>ShyotlUseLegacyTextureBatching</key>
+    <map>
+      <key>Comment</key>
+      <string>Disable usage of extra samplers in shaders. Decreases batch sizes, however also reduces branching in shaders drastcially.</string>
+      <key>Persist</key>
+      <integer>1</integer>
+      <key>Type</key>
+      <string>Boolean</string>
+      <key>Value</key>
+      <integer>0</integer>
+    </map>  
     <key>ResetFocusOnSelfClick</key>
 		<map>
 		<key>Comment</key>
@@ -500,7 +521,6 @@
 		<key>Value</key>
 		<integer>1</integer>
 		</map>
-
     <key>MoyFastMiniMap</key>
     <map>
       <key>Comment</key>

indra/newview/llviewercontrol.cpp

@@ -648,6 +648,8 @@ void settings_setup_listeners()
 	//See LL jira VWR-3258 comment section. Implemented by LL in 2.1 -Shyotl
 	gSavedSettings.getControl("ShyotlRenderUseStreamVBO")->getSignal()->connect(boost::bind(&handleResetVertexBuffersChanged, _2));
 	gSavedSettings.getControl("ShyotlRenderVBOStrideMode")->getSignal()->connect(boost::bind(&handleResetVertexBuffersChanged, _2));
+	gSavedSettings.getControl("ShyotlUseLegacyRenderPath")->getSignal()->connect(boost::bind(&handleSetShaderChanged, _2));
+	gSavedSettings.getControl("ShyotlUseLegacyTextureBatching")->getSignal()->connect(boost::bind(&handleSetShaderChanged, _2));
 	gSavedSettings.getControl("SianaRenderOmitBlankVBO")->getSignal()->connect(boost::bind(&handleResetVertexBuffersChanged, _2));
 	gSavedSettings.getControl("RenderUseFBO")->getSignal()->connect(boost::bind(&handleRenderUseFBOChanged, _2));
 	gSavedSettings.getControl("RenderDeferredNoise")->getSignal()->connect(boost::bind(&handleReleaseGLBufferChanged, _2));

indra/newview/llviewershadermgr.cpp

@@ -654,7 +654,8 @@ BOOL LLViewerShaderMgr::loadBasicShaders()
 	shaders.reserve(13);
 	S32 ch = gGLManager.mNumTextureImageUnits-1;
 
-	if (gGLManager.mGLVersion < 3.1f)
+	static const LLCachedControl<bool> no_texture_indexing("ShyotlUseLegacyTextureBatching",false);
+	if (gGLManager.mGLVersion < 3.1f || no_texture_indexing)
 	{ //force to 1 texture index channel for old drivers
 		ch = 1;
 	}

indra/newview/llvovolume.cpp

@@ -3657,7 +3657,8 @@ void LLVolumeGeometryManager::genDrawInfo(LLSpatialGroup* group, U32 mask, std::
 
 	S32 texture_index_channels = gGLManager.mNumTextureImageUnits-1; //always reserve one for shiny for now just for simplicity
 	
-	if (gGLManager.mGLVersion < 3.1f)
+	static const LLCachedControl<bool> no_texture_indexing("ShyotlUseLegacyTextureBatching",false);
+	if (gGLManager.mGLVersion < 3.1f || no_texture_indexing)
 	{
 		texture_index_channels = 1;
 	}