Add 0.5f term back to contrast calculation

Engine/source/terrain/glsl/terrFeatureGLSL.cpp

@@ -1376,7 +1376,7 @@ void TerrainHeightMapBlendGLSL::processPix(Vector<ShaderComponent*>& componentLi
                detailH, blendDepth));
          }
 
-         meta->addStatement(new GenOp("      @ = max((@ * 2.0f - 1.0f) * @, 0.0f);\r\n",
+         meta->addStatement(new GenOp("      @ = max((@ * 2.0f - 1.0f) * @ + 0.5f, 0.0f);\r\n",
             detailH, detailH, blendContrast));
 
          meta->addStatement(new GenOp("   }\r\n"));

Engine/source/terrain/hlsl/terrFeatureHLSL.cpp

@@ -1456,7 +1456,7 @@ void TerrainHeightMapBlendHLSL::processPix(Vector<ShaderComponent*>& componentLi
                detailH, blendDepth));
          }
 
-         meta->addStatement(new GenOp("      @ = max((@ * 2.0f - 1.0f) * @, 0.0f);\r\n",
+         meta->addStatement(new GenOp("      @ = max((@ * 2.0f - 1.0f) * @ + 0.5f, 0.0f);\r\n",
             detailH, detailH, blendContrast));
 
          meta->addStatement(new GenOp("   }\r\n"));