Debug|Oculus Rift: Trying to figure out LibOVR rendering

At least the blue frame background is showing, so LibOVR succeeds in
drawing to the window. But why is the frame drawn by Doomsday full of
black/missing?

doomsday/libappfw/src/basewindow.cpp

@@ -22,6 +22,8 @@
 #include "de/BaseGuiApp"
 #include "de/VRConfig"
 
+#include <de/GLState>
+
 namespace de {
 
 DENG2_PIMPL(BaseWindow)
@@ -169,6 +171,18 @@ void BaseWindow::postDraw()
     if(vr.mode() == VRConfig::OculusRift)
     {
         vr.oculusRift().endFrame();
+
+        /*
+        GLTarget defaultTarget;
+        GLState::push()
+                .setTarget(defaultTarget)
+                .setViewport(Rectangleui::fromSize(defaultTarget.size()))
+                .apply();
+        glClearColor(1, 0, 1, 1);
+        glClear(GL_COLOR_BUFFER_BIT);
+        canvas().QGLWidget::swapBuffers();
+        GLState::pop().apply();
+        */
     }
 
     // The timer loop was paused when the frame was requested to be drawn.

doomsday/libappfw/src/vr/oculusrift.cpp

@@ -53,9 +53,9 @@ DENG2_PIMPL(OculusRift)
     ovrHmd hmd;
     ovrEyeType currentEye;
     ovrPosef headPose[2];
-    bool needPose[2] { true, true };
+    //bool needPose[2] { true, true };
     ovrEyeRenderDesc render[2];
-    ovrGLTexture textures[2];
+    ovrTexture textures[2];
     ovrFovPort fov[2];
     float fovXDegrees;
     ovrFrameTiming timing;
@@ -140,8 +140,7 @@ DENG2_PIMPL(OculusRift)
             // Use the default FOV.
             fov[eye] = hmd->DefaultEyeFov[eye];
 
-            size[eye] = ovrHmd_GetFovTextureSize(hmd, ovrEyeType(eye),
-                                                 hmd->DefaultEyeFov[eye],
+            size[eye] = ovrHmd_GetFovTextureSize(hmd, ovrEyeType(eye), fov[eye],
                                                  1.0f /*density*/);
         }
 
@@ -176,12 +175,14 @@ DENG2_PIMPL(OculusRift)
 
         for(int eye = 0; eye < 2; ++eye)
         {
-            ovrGLTexture &tex = textures[eye];
+            ovrGLTexture tex;
 
             tex.OGL.Header.API            = ovrRenderAPI_OpenGL;
             tex.OGL.Header.TextureSize    = Sizei(w, h);
-            tex.OGL.Header.RenderViewport = Recti(eye == 0? 0 : w/2, 0, w/2, h);
+            tex.OGL.Header.RenderViewport = Recti(eye == 0? 0 : ((w + 1) / 2), 0, w/2, h);
             tex.OGL.TexId                 = framebuffer().colorTexture().glName();
+
+            textures[eye] = tex.Texture;
         }
     }
 #endif
@@ -208,6 +209,8 @@ DENG2_PIMPL(OculusRift)
         window = &CanvasWindow::main().as<BaseWindow>();
         DENG2_ASSERT(window->isVisible());
 
+        DENG2_ASSERT(QGLContext::currentContext() != 0);
+
         // Observe key events for dismissing the Health and Safety warning.
         window->canvas().audienceForKeyEvent() += this;
 
@@ -254,6 +257,9 @@ DENG2_PIMPL(OculusRift)
         }
 
         ovrHmd_AttachToWindow(hmd, window->nativeHandle(), NULL, NULL);
+
+        float clearColor[4] = { 0.0f, 0.5f, 1.0f, 0.0f };
+        ovrHmd_SetFloatArray(hmd, "DistortionClearColor", clearColor, 4);
 #endif
     }
 
@@ -337,10 +343,16 @@ DENG2_PIMPL(OculusRift)
 
     void updateEyePose()
     {
-        DENG2_ASSERT(frameOngoing);
+        if(!frameOngoing)
+        {
+            //qDebug() << "Tried to updateEyePose without frame ongoing";
+            //DENG2_PRINT_BACKTRACE();
+            return;
+        }
+        //DENG2_ASSERT(frameOngoing);
 
-        if(!needPose[currentEye]) return;
-        needPose[currentEye] = false;
+        //if(!needPose[currentEye]) return;
+        //needPose[currentEye] = false;
 
         ovrPosef &pose = headPose[currentEye];
 
@@ -369,25 +381,30 @@ DENG2_PIMPL(OculusRift)
     void beginFrame()
     {
         DENG2_ASSERT(isReady());
+        DENG2_ASSERT(!frameOngoing);
 
+        frameOngoing = true;
         timing = ovrHmd_BeginFrame(hmd, 0);
     }
 
     void endFrame()
     {
-        /*
-        GLTarget defaultTarget;
+        DENG2_ASSERT(frameOngoing);
+
+        /*GLTarget defaultTarget;
         GLState::push()
                 .setTarget(defaultTarget)
                 .setViewport(Rectangleui::fromSize(defaultTarget.size()))
                 .apply();*/
 
-        ovrHmd_EndFrame(hmd, headPose, &textures[0].Texture);
+        ovrHmd_EndFrame(hmd, headPose, textures);
 
         dismissHealthAndSafetyWarningOnTap();
 
-        GLState::considerNativeStateUndefined();
+        //GLState::considerNativeStateUndefined();
         //GLState::pop().apply();
+
+        frameOngoing = false;
     }
 #endif
 };
@@ -411,7 +428,6 @@ void OculusRift::beginFrame()
 {
 #ifdef DENG_HAVE_OCULUS_API    
     if(!isReady() || !d->inited || d->frameOngoing) return;
-    d->frameOngoing = true;
 
     // Begin the frame and acquire timing information.
     d->beginFrame();
@@ -422,7 +438,6 @@ void OculusRift::endFrame()
 {
 #ifdef DENG_HAVE_OCULUS_API
     if(!isReady() || !d->frameOngoing) return;
-    d->frameOngoing = false;
 
     // End the frame and let the Oculus SDK handle displaying it with the
     // appropriate transformation.
@@ -436,7 +451,8 @@ void OculusRift::setCurrentEye(int index)
     if(d->hmd)
     {
         d->currentEye = d->hmd->EyeRenderOrder[index];
-        d->needPose[d->currentEye] = true;
+        //d->needPose[d->currentEye] = true;
+        d->updateEyePose();
     }
 #else
     DENG2_UNUSED(index);