From a2ad1c96066e8d9e21a42f6a56ae1517a788b51c Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Fri, 20 Oct 2017 11:37:41 +0100
Subject: [PATCH] Added built-in support for lighting.vert

---
 src/osgTerrain/GeometryPool.cpp          |  5 ++++-
 src/osgTerrain/shaders/lighting_vert.cpp | 25 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 src/osgTerrain/shaders/lighting_vert.cpp

diff --git a/src/osgTerrain/GeometryPool.cpp b/src/osgTerrain/GeometryPool.cpp
index c7fb3c5f8..e028aa99d 100644
--- a/src/osgTerrain/GeometryPool.cpp
+++ b/src/osgTerrain/GeometryPool.cpp
@@ -554,7 +554,10 @@ osg::ref_ptr<osg::Program> GeometryPool::getOrCreateProgram(LayerTypes& layerTyp
     _programMap[layerTypes] = program;
 
     // add shader that provides the lighting functions
-    program->addShader(osgDB::readRefShaderFile("shaders/lighting.vert"));
+    {
+        #include "shaders/lighting_vert.cpp"
+        program->addShader(osgDB::readRefShaderFileWithFallback(osg::Shader::VERTEX, "shaders/lighting.vert", lighting_vert));
+    }
 
     // OSG_NOTICE<<") creating new Program "<<program.get()<<std::endl;
     {
diff --git a/src/osgTerrain/shaders/lighting_vert.cpp b/src/osgTerrain/shaders/lighting_vert.cpp
new file mode 100644
index 000000000..a0ac0f8ac
--- /dev/null
+++ b/src/osgTerrain/shaders/lighting_vert.cpp
@@ -0,0 +1,25 @@
+char lighting_vert[] = "#pragma requires(LIGHTING)\n"
+                       "\n"
+                       "void directionalLight( int lightNum, vec3 normal, inout vec4 color )\n"
+                       "{\n"
+                       "    vec3 n = normalize(gl_NormalMatrix * normal);\n"
+                       "\n"
+                       "    float NdotL = dot( n, normalize(gl_LightSource[lightNum].position.xyz) );\n"
+                       "    NdotL = max( 0.0, NdotL );\n"
+                       "\n"
+                       "    float NdotHV = dot( n, gl_LightSource[lightNum].halfVector.xyz );\n"
+                       "    NdotHV = max( 0.0, NdotHV );\n"
+                       "#if 1\n"
+                       "    color *= gl_LightSource[lightNum].ambient +\n"
+                       "             gl_LightSource[lightNum].diffuse * NdotL;\n"
+                       "#else\n"
+                       "    color *= gl_FrontLightModelProduct.sceneColor +\n"
+                       "             gl_FrontLightProduct[lightNum].ambient +\n"
+                       "             gl_FrontLightProduct[lightNum].diffuse * NdotL;\n"
+                       "#endif\n"
+                       "#if 0\n"
+                       "    if ( NdotL * NdotHV > 0.0 )\n"
+                       "        color += gl_FrontLightProduct[lightNum].specular * pow( NdotHV, gl_FrontMaterial.shininess );\n"
+                       "#endif\n"
+                       "}\n"
+                       "\n";