Improve FXAA quality and performance when GL version is greater then 4

Adds gather4 support under GLSL 4.0+

Author: Rye Cogtail

indra/llrender/llshadermgr.cpp

@@ -595,8 +595,6 @@ GLuint LLShaderMgr::loadShaderFile(const std::string& filename, S32 & shader_lev
                 extra_code_text[extra_code_count++] = strdup("precision highp float;\n");
             }
         }
-
-        extra_code_text[extra_code_count++] = strdup("#define FXAA_GLSL_130 1\n");
     }
 
     // Use alpha float to store bit flags

indra/newview/app_settings/shaders/class1/deferred/fxaaF.glsl

@@ -256,6 +256,10 @@ A. Or use FXAA_GREEN_AS_LUMA.
     #define FXAA_GLSL_130 0
 #endif
 /*--------------------------------------------------------------------------*/
+#ifndef FXAA_GLSL_400
+    #define FXAA_GLSL_400 0
+#endif
+/*--------------------------------------------------------------------------*/
 #ifndef FXAA_HLSL_3
     #define FXAA_HLSL_3 0
 #endif
@@ -342,8 +346,8 @@ A. Or use FXAA_GREEN_AS_LUMA.
     // 1 = API supports gather4 on alpha channel.
     // 0 = API does not support gather4 on alpha channel.
     //
-    #if (FXAA_GLSL_130 == 0)
-        #define FXAA_GATHER4_ALPHA 0
+    #if (FXAA_GLSL_400 == 1)
+        #define FXAA_GATHER4_ALPHA 1
     #endif
     #if (FXAA_HLSL_5 == 1)
         #define FXAA_GATHER4_ALPHA 1
@@ -652,7 +656,7 @@ NOTE the other tuning knobs are now in the shader function inputs!
                                 API PORTING
 
 ============================================================================*/
-#if (FXAA_GLSL_120 == 1) || (FXAA_GLSL_130 == 1)
+#if (FXAA_GLSL_120 == 1) || (FXAA_GLSL_130 == 1) || (FXAA_GLSL_400 == 1)
     #define FxaaBool bool
     #define FxaaDiscard discard
     #define FxaaFloat float
@@ -714,6 +718,16 @@ NOTE the other tuning knobs are now in the shader function inputs!
     #endif
 #endif
 /*--------------------------------------------------------------------------*/
+#if (FXAA_GLSL_400 == 1)
+    // Requires "#version 400" or better
+    #define FxaaTexTop(t, p) textureLod(t, p, 0.0)
+    #define FxaaTexOff(t, p, o, r) textureLodOffset(t, p, 0.0, o)
+    #define FxaaTexAlpha4(t, p) textureGather(t, p, 3)
+    #define FxaaTexOffAlpha4(t, p, o) textureGatherOffset(t, p, o, 3)
+    #define FxaaTexGreen4(t, p) textureGather(t, p, 1)
+    #define FxaaTexOffGreen4(t, p, o) textureGatherOffset(t, p, o, 1)
+#endif
+/*--------------------------------------------------------------------------*/
 #if (FXAA_HLSL_3 == 1) || (FXAA_360 == 1) || (FXAA_PS3 == 1)
     #define FxaaInt2 float2
     #define FxaaTex sampler2D

indra/newview/llviewershadermgr.cpp

@@ -2345,6 +2345,16 @@ bool LLViewerShaderMgr::loadShadersDeferred()
         gFXAAProgram.mShaderFiles.clear();
         gFXAAProgram.mShaderFiles.push_back(make_pair("deferred/postDeferredV.glsl", GL_VERTEX_SHADER));
         gFXAAProgram.mShaderFiles.push_back(make_pair("deferred/fxaaF.glsl", GL_FRAGMENT_SHADER));
+
+        if (gGLManager.mGLVersion > 3.9)
+        {
+            gFXAAProgram.addPermutation("FXAA_GLSL_400", "1");
+        }
+        else
+        {
+            gFXAAProgram.addPermutation("FXAA_GLSL_130", "1");
+        }
+
         gFXAAProgram.mShaderLevel = mShaderLevel[SHADER_DEFERRED];
         success = gFXAAProgram.createShader();
         llassert(success);