gpu: use the RenderContext class in a few friendly places.

src/scene.cpp

@@ -191,15 +191,17 @@ Array<Light *> const &Scene::GetLights() const
 
 void Scene::Render() // XXX: rename to Blit()
 {
+    RenderContext rc;
+    rc.SetDepthTest(true);
+    rc.SetAlphaBlend(true);
+
 #if defined USE_D3D9 || defined _XBOX
 #else
-    glEnable(GL_DEPTH_TEST);
     glDepthFunc(GL_LEQUAL);
 #if defined HAVE_GL_2X && !defined __APPLE__
     glEnable(GL_ALPHA_TEST);
     glAlphaFunc(GL_GEQUAL, 0.01f);
 #endif
-    glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 #endif
 
@@ -347,11 +349,9 @@ void Scene::Render() // XXX: rename to Blit()
 #if defined USE_D3D9 || defined _XBOX
     /* TODO */
 #else
-    glDisable(GL_DEPTH_TEST);
 #   if defined HAVE_GL_2X && !defined __APPLE__
     glDisable(GL_ALPHA_TEST);
 #   endif
-    glDisable(GL_BLEND);
 #endif
 }
 

tutorial/08_fbo.cpp

@@ -83,9 +83,11 @@ public:
             /* FIXME: this object never cleans up */
         }
 
-        m_fbo->Bind();
         /* FIXME: we should just disable depth test in the shader */
-        Video::Clear(ClearMask::Depth);
+        RenderContext rc;
+        rc.SetDepthTest(false);
+
+        m_fbo->Bind();
         m_shader->Bind();
 
 #if _XBOX