Renderer: Lumobjs and vector lights include a possible source mobj

When rendering lights, it is something useful to know which mobj
(if any) is responsible for casting the light.

Not a long-term solution, but sufficient for now.

doomsday/apps/client/include/render/lumobj.h

@@ -103,6 +103,15 @@ class Lumobj : public world::MapObject
      */
     void setSource(Source const *newSource);
 
+    /**
+     * Sets the mobj that is responsible for casting this light.
+     *
+     * @param mo  Thing.
+     */
+    void setSourceMobj(struct mobj_s const *mo);
+
+    struct mobj_s const *sourceMobj() const;
+
     /**
      * Returns the light color/intensity of the lumobj.
      *

doomsday/apps/client/include/render/vectorlightdata.h

@@ -35,6 +35,7 @@ struct VectorLightData
     de::dfloat lightSide;
     de::dfloat darkSide;     ///< Factors for world light.
     bool affectedByAmbient;
+    struct mobj_s const *sourceMobj; ///< Originating mobj, or nullptr.
 };
 
 #endif  // CLIENT_RENDER_VECTORLIGHTDATA_H

doomsday/apps/client/src/render/lumobj.cpp

@@ -42,6 +42,7 @@ dfloat Lumobj::Source::occlusion(Vector3d const & /*eye*/) const
 DENG2_PIMPL_NOREF(Lumobj)
 {
     Source const *source = nullptr;      ///< Source of the lumobj (if any, not owned).
+    mobj_t const *sourceMobj = nullptr;  ///< Mobj associated with the lumobj (if any).
     ddouble maxDistance = 0;             ///< Used when rendering to limit the number drawn lumobjs.
     Vector3f color = Vector3f(1, 1, 1);  ///< Light color/intensity.
     ddouble radius = 256;                ///< Radius in map space units.
@@ -59,6 +60,7 @@ DENG2_PIMPL_NOREF(Lumobj)
     Instance(Instance const &other)
         : de::IPrivate()
         , source     (other.source)
+        , sourceMobj (other.sourceMobj)
         , maxDistance(other.maxDistance)
         , color      (other.color)
         , radius     (other.radius)
@@ -87,6 +89,16 @@ void Lumobj::setSource(Source const *newSource)
     d->source = newSource;
 }
 
+void Lumobj::setSourceMobj(mobj_t const *mo)
+{
+    d->sourceMobj = mo;
+}
+
+mobj_t const *Lumobj::sourceMobj() const
+{
+    return d->sourceMobj;
+}
+
 Vector3f const &Lumobj::color() const
 {
     return d->color;

doomsday/apps/client/src/render/rend_main.cpp

@@ -2344,6 +2344,7 @@ static bool lightWithWorldLight(Vector3d const & /*point*/, Vector3f const &ambi
         vlight.darkSide  = .8f;
         vlight.offset    = .3f;
     }
+    vlight.sourceMobj = nullptr;
     return true;
 }
 
@@ -2370,6 +2371,7 @@ static bool lightWithLumobj(Vector3d const &point, Lumobj const &lum, VectorLigh
     vlight.lightSide         = 1;
     vlight.darkSide          = 0;
     vlight.offset            = 0;
+    vlight.sourceMobj        = lum.sourceMobj();
     return true;
 }
 
@@ -2406,6 +2408,7 @@ static bool lightWithPlaneGlow(Vector3d const &point, SectorCluster const &clust
     vlight.lightSide         = 1;
     vlight.darkSide          = 0;
     vlight.offset            = 0.3f;
+    vlight.sourceMobj        = nullptr;
     return true;
 }
 

doomsday/apps/client/src/world/p_mobj.cpp

@@ -501,6 +501,8 @@ void Mobj_GenerateLumobjs(mobj_t *mo)
     std::unique_ptr<Lumobj> lum(Rend_MakeLumobj(sprite.def()));
     if(!lum) return;
 
+    lum->setSourceMobj(mo);
+
     // A light definition may override the (auto-calculated) defaults.
     if(ded_light_t *def = lightDefByMobjState(mo->state))
     {
@@ -616,7 +618,7 @@ dfloat Mobj_ShadowStrength(mobj_t const &mob)
         ambientLightLevel = cluster.lightSourceIntensity();
     }
     Rend_ApplyLightAdaptation(ambientLightLevel);
-    
+
     // Sprites have their own shadow strength factor.
     dfloat strength = .65f;  ///< Default.
     if(!::useModels || !Mobj_ModelDef(mob))