From fa58d0164463dbec8a4fe69fbaf2c0d95b56a747 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 25 Oct 2017 16:29:25 +0100
Subject: [PATCH] Added optimization for text where the colour alpha value is
 0.0, returning early to aovid any GL calls.

---
 src/osgText/Text.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/osgText/Text.cpp b/src/osgText/Text.cpp
index cfc7cf969..94ac0e923 100644
--- a/src/osgText/Text.cpp
+++ b/src/osgText/Text.cpp
@@ -1115,6 +1115,8 @@ void Text::drawImplementation(osg::RenderInfo& renderInfo) const
 
 void Text::drawImplementationSinglePass(osg::State& state, const osg::Vec4& colorMultiplier) const
 {
+    if (colorMultiplier.a()==0.0f || _color.a()==0.0f) return;
+
     osg::VertexArrayState* vas = state.getCurrentVertexArrayState();
     bool usingVertexBufferObjects = state.useVertexBufferObject(_supportsVertexBufferObjects && _useVertexBufferObjects);
     bool usingVertexArrayObjects = usingVertexBufferObjects && state.useVertexArrayObject(_useVertexArrayObject);