Ticket #434: water.434.patch

source/renderer/Renderer.cpp

@@ -1274 +1274 @@
     RenderModels();
     ogl_WarnIfError();
 
-    // render transparent stuff, so it can overlap models/terrain
-    MICROLOG(L"render transparent");
-    RenderTransparentModels();
-    ogl_WarnIfError();
-
     // render water
     if (m_WaterManager->m_RenderWater && g_Game)
     {
+        // We no longer render transparent objects twice, once before water
+        // and once after water (ticket 434); except that when fancy water is disabled
+        // we have to draw the underwater portion of transparent objects twice.
+        if (!m_WaterManager->WillRenderFancyWater())
+        {
+            // render underwater transparent stuff before plain water;
+            // use a clipping plane so that we only draw things below the water plane
+            MICROLOG(L"render underwater transparent");
+            double eqn[] = { 0.0, -1.0, 0.0, m_WaterManager->m_WaterHeight };
+            glClipPlane(GL_CLIP_PLANE0, eqn);
+            glEnable(GL_CLIP_PLANE0);
+            RenderTransparentModels();
+            ogl_WarnIfError();
+            glDisable(GL_CLIP_PLANE0);
+        }
+        
         MICROLOG(L"render water");
         m->terrainRenderer->RenderWater();
         ogl_WarnIfError();
-        
-        // render transparent stuff again, so it can overlap the water
-        MICROLOG(L"render transparent 2");
-        RenderTransparentModels();
-        ogl_WarnIfError();
-        
-        // TODO: Maybe think of a better way to deal with transparent objects;
-        // they can appear both under and above water (seaweed vs. trees), but doing
-        // 2 renders causes (a) inefficiency and (b) darker over-water objects (e.g.
-        // trees) than usual because the transparent bits get overwritten twice.
-        // This doesn't look particularly bad, but it is noticeable if you try
-        // turning the water off. On the other hand every user will have water
-        // on all the time, so it might not be worth worrying about.
     }
+    
+    // render transparent stuff, so it can overlap models/terrain
+    MICROLOG(L"render transparent");
+    RenderTransparentModels();
+    ogl_WarnIfError();
 
     // Clean up texture blend mode so particles and other things render OK 
     // (really this should be cleaned up by whoever set it)