Fixed|Renderer: Z-buffering of sky models

3D models won't look right without Z buffering, however they must not interfere with world geometry. This commit enables Z buffering for sky models and clears the depth buffer afterwards. Excessive clears of the depth buffer could be avoided by using a separate depth buffer for the sky, however the sky stencil should be drawn there as well. This could be a topic for a future refactoring. IssueID #1922
skyjake · Dec 20, 2014 · f25548d · f25548d
1 parent 0322974
commit f25548d
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Showing 3 changed files with 15 additions and 17 deletions.
diff --git a/doomsday/client/src/render/r_main.cpp b/doomsday/client/src/render/r_main.cpp
@@ -296,7 +296,8 @@ void Rend_Draw3DPlayerSprites()
     Rend_ModelViewMatrix(false /* don't apply view angle rotation */);
 
     static GLTexture localDepth; // note: static!
-    GLTarget::AlternativeBuffer altDepth(GLState::current().target(), localDepth, GLTarget::DepthStencil);
+    GLTarget::AlternativeBuffer altDepth(GLState::current().target(), localDepth,
+                                         GLTarget::DepthStencil);
 
     for(int i = 0; i < DDMAXPSPRITES; ++i)
     {

diff --git a/doomsday/client/src/render/rend_main.cpp b/doomsday/client/src/render/rend_main.cpp
@@ -3504,8 +3504,11 @@ static void drawSky()
     }
 
     // We do not want to update color and/or depth.
-    glDisable(GL_DEPTH_TEST);
-    GLState::push().setColorMask(gl::WriteNone).apply();
+    GLState::push()
+            .setDepthTest(false)
+            .setDepthWrite(false)
+            .setColorMask(gl::WriteNone)
+            .apply();
 
     // Mask out stencil buffer, setting the drawn areas to 1.
     glEnable(GL_STENCIL_TEST);
@@ -3524,7 +3527,6 @@ static void drawSky()
 
     // Restore previous GL state.
     GLState::pop().apply();
-    glEnable(GL_DEPTH_TEST);
     glDisable(GL_STENCIL_TEST);
 
     // Now, only render where the stencil is set to 1.
@@ -3541,7 +3543,6 @@ static void drawSky()
 
     // Return GL state to normal.
     glDisable(GL_STENCIL_TEST);
-    glEnable(GL_DEPTH_TEST);
 }
 
 static bool generateHaloForVisSprite(vissprite_t const *spr, bool primary = false)

diff --git a/doomsday/client/src/render/skydrawable.cpp b/doomsday/client/src/render/skydrawable.cpp
@@ -452,9 +452,10 @@ DENG2_PIMPL(SkyDrawable)
     {
         if(!haveModels) return;
 
-        // We don't want anything written in the depth buffer.
-        glDisable(GL_DEPTH_TEST);
-        glDepthMask(GL_FALSE);
+        // Sky models use depth testing, but they won't interfere with world geometry.
+        glEnable(GL_DEPTH_TEST);
+        glDepthMask(GL_TRUE);
+        glClear(GL_DEPTH_BUFFER_BIT);
 
         glMatrixMode(GL_MODELVIEW);
         glPushMatrix();
@@ -505,15 +506,12 @@ DENG2_PIMPL(SkyDrawable)
             Rend_DrawModel(vis);
         }
 
-        // We don't want that anything interferes with what was drawn.
-        //glClear(GL_DEPTH_BUFFER_BIT);
-
         glMatrixMode(GL_MODELVIEW);
         glPopMatrix();
 
-        // Restore assumed default GL state.
-        glDepthMask(GL_TRUE);
-        glEnable(GL_DEPTH_TEST);
+        // We don't want that anything in the world geometry interferes with what was
+        // drawn in the sky.
+        glClear(GL_DEPTH_BUFFER_BIT);
     }
 
     void setupModels(Record const *def)
@@ -694,13 +692,11 @@ MaterialVariantSpec const &SkyDrawable::layerMaterialSpec(bool masked) // static
                                  0, -1, -1, false, true, false, false);
 }
 
-namespace {
-void markSphereForRebuild()
+static void markSphereForRebuild()
 {
     // Defer this task until draw time, when we can be sure we are in the correct thread.
     hemisphere.needRebuild = true;
 }
-}
 
 void SkyDrawable::consoleRegister() // static
 {