Pulled SSAO out into its own shader to support running at a lower-than-native framebuffer resolution (defaults at half-resolution [SHRenderSSAOResolutionScale=.5] ). This doesn't improve the slow ssao/shadow softening, however, as that bit remains unchanged.

indra/llrender/llshadermgr.cpp

@@ -1177,6 +1177,7 @@ void LLShaderMgr::initAttribsAndUniforms()
 	mReservedUniforms.push_back("depth_cutoff");
 	mReservedUniforms.push_back("norm_cutoff");
 	mReservedUniforms.push_back("shadow_target_width");
+	mReservedUniforms.push_back("downsampled_depth_scale");
 	
 	llassert(mReservedUniforms.size() == LLShaderMgr::DEFERRED_SHADOW_TARGET_WIDTH+1);
 
@@ -1195,6 +1196,7 @@ void LLShaderMgr::initAttribsAndUniforms()
 	mReservedUniforms.push_back("dof_height");
 
 	mReservedUniforms.push_back("depthMap");
+	mReservedUniforms.push_back("depthMapDownsampled");
 	mReservedUniforms.push_back("shadowMap0");
 	mReservedUniforms.push_back("shadowMap1");
 	mReservedUniforms.push_back("shadowMap2");

indra/llrender/llshadermgr.h

@@ -136,6 +136,7 @@ public:
 		DEFERRED_DEPTH_CUTOFF,
 		DEFERRED_NORM_CUTOFF,
 		DEFERRED_SHADOW_TARGET_WIDTH,
+		DEFERRED_DOWNSAMPLED_DEPTH_SCALE,
 
 		FXAA_TC_SCALE,
 		FXAA_RCP_SCREEN_RES,
@@ -152,6 +153,7 @@ public:
 		DOF_HEIGHT,
 
 		DEFERRED_DEPTH,
+		DEFERRED_DOWNSAMPLED_DEPTH,
 		DEFERRED_SHADOW0,
 		DEFERRED_SHADOW1,
 		DEFERRED_SHADOW2,