Fixed|Models|Renderer: df_brightshadow2 and transparency

With "df_brightshadow2", the alpha multiplier of the submodel needs
to be applied even though the object has another kind of transparency
(MF_SHADOW).

IssueID #1725

doomsday/client/src/render/rend_model.cpp

@@ -667,10 +667,13 @@ static void drawSubmodel(uint number, drawmodelparams_t const &parm)
         return;
 
     float alpha = parm.ambientColor[CA];
+
     // Is the submodel-defined alpha multiplier in effect?
-    if(!(parm.flags & (DDMF_BRIGHTSHADOW|DDMF_SHADOW|DDMF_ALTSHADOW)))
+    // With df_brightshadow2, the alpha multiplier will be applied anyway.
+    if(smf.testFlag(MFF_BRIGHTSHADOW2) ||
+       !(parm.flags & (DDMF_BRIGHTSHADOW|DDMF_SHADOW|DDMF_ALTSHADOW)))
     {
-        alpha *= smf.alpha * reciprocal255;
+        alpha *= smf.alpha / 255.f;
     }
 
     // Would this be visible?

doomsday/client/src/resource/resourcesystem.cpp

@@ -1629,7 +1629,7 @@ DENG2_PIMPL(ResourceSystem)
                 if(sub->frame < 0) sub->frame = 0;
                 sub->frameRange = de::max(1, subdef->frameRange); // Frame range must always be greater than zero.
 
-                sub->alpha      = byte(255 - subdef->alpha * 255);
+                sub->alpha      = byte(de::clamp(0, int(255 - subdef->alpha * 255), 255));
                 sub->blendMode  = subdef->blendMode;
 
                 // Submodel-specific flags cancel out model-scope flags!