Fixed the osg::Light so that it requires the user to explicitly define which

OpenGL light is being operated on, and also now relies upong the standard
osg::State handling of OpenGL modes to switch on the appropriate lights.

The previous static counter mechansim for the light number was causing a
redundent light to be created when the osg plugin created the first osg::Light
to use a prototype for other osg::Light's to be cloned from in the
.osg plugin execution.

The static count mechanism also prevent the lights modes being controlled
independantly from the setting of the light paramters themselves.  This
meant that a light once created was global, and couldn't be turned off
locally via the OSG's support for OpenGL mode enabling/disabling.  This
has been overcome with the new implementation, the user has complete
flexiblity of when and where to use the different lights at their
disposal.

src/osgPlugins/dw/ReaderWriterDW.cpp

@@ -44,6 +44,7 @@ public:
         opacity=1; specular=0; specexp=0; fname="";TextureWidth=1; TextureHeight=1;
         ctx=NULL; tx=NULL; id=0; dstate=NULL;colour[0]=colour[1]=colour[2]=colour[3]=1;
         bright=halfIn=halfOut=falloff=0;atyp=NONE;
+        _lightnum=0;
     }
     ~dwmaterial() { }
     void settexture() {
@@ -135,14 +136,15 @@ public:
         fname= (buff+13);
         fname+= ".tga";
     }
-    LightSource *makeLight(const Vec4 pos) {
+    LightSource *makeLight(const Vec4 pos)
+    {
         Light *lt= new Light;
         Vec4 cdef;
         cdef[0]=cdef[1]=cdef[2]=0.0f; cdef[3]=0.0f;
+        lt->setLightNum(_lightnum++);
         lt->setSpecular(colour*bright/2.0f);
         lt->setDiffuse(colour*bright/4.0f);
         lt->setAmbient(cdef);
-        lt->on();
         if (atyp==NONE) ;
         else if (atyp==INVERSE_DIST) {
             lt->setLinearAttenuation(1.0f);
@@ -174,6 +176,7 @@ private:
     float bright,halfIn,halfOut,falloff; // light brightness
     Image *ctx;
     Texture *tx;
+    int _lightnum;
     StateSet *dstate; // used to represent the dw material in OSG
 };
 // structure to use as data for tesselation

src/osgPlugins/osg/Light.cpp

@@ -32,6 +32,16 @@ bool Light_readLocalData(Object& obj, Input& fr)
 
     Light& light = static_cast<Light&>(obj);
 
+    if (fr[0].matchWord("light_num"))
+    {
+        int lightnum=0;
+        if (fr[1].getInt(lightnum))
+        {
+            light.setLightNum(lightnum);
+            fr += 2;
+            iteratorAdvanced = true;
+        }
+    }
 
 #define ReadVec4(A,B) {  \
     if (fr[0].matchWord(B) && \
@@ -96,6 +106,8 @@ bool Light_writeLocalData(const Object& obj,Output& fw)
 {
     const Light& light = static_cast<const Light&>(obj);
 
+    fw.indent() << "light_num " << light.getLightNum() << std::endl;
+
     // Vec4's
     fw.indent() << "ambient " << light.getAmbient() << std::endl;
     fw.indent() << "diffuse " << light.getDiffuse() << std::endl;