WebVR: match GVR renderbuffer resolution to canvas resolution

chrome/browser/android/vr_shell/vr_shell_gl.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/android/vr_shell/vr_shell_gl.h"
 
 #include <limits>
 #include <utility>
 
 #include "base/android/jni_android.h"
@@ skipping 341 matching lines @@
 
   gvr_api_->InitializeGl();
   webvr_head_pose_.assign(kPoseRingBufferSize,
                           gvr_api_->GetHeadSpaceFromStartSpaceRotation(
                               gvr::GvrApi::GetTimePointNow()));
 
   std::vector<gvr::BufferSpec> specs;
   // For kFramePrimaryBuffer (primary VrShell and WebVR content)
   specs.push_back(gvr_api_->CreateBufferSpec());
   render_size_primary_ = specs[kFramePrimaryBuffer].GetSize();
+  render_size_primary_vrshell_ = render_size_primary_;
 
   // For kFrameHeadlockedBuffer (for WebVR insecure content warning).
   // Set this up at fixed resolution, the (smaller) FOV gets set below.
   specs.push_back(gvr_api_->CreateBufferSpec());
   specs.back().SetSize(kHeadlockedBufferDimensions);
   render_size_headlocked_ = specs[kFrameHeadlockedBuffer].GetSize();
 
   swap_chain_.reset(new gvr::SwapChain(gvr_api_->CreateSwapChain(specs)));
 
   vr_shell_renderer_.reset(new VrShellRenderer());
@@ skipping 259 matching lines @@
 }
 
 void VrShellGl::DrawFrame() {
   TRACE_EVENT0("gpu", "VrShellGl::DrawFrame");
 
   // Reset the viewport list to just the pair of viewports for the
   // primary buffer each frame. Head-locked viewports get added by
   // DrawVrShell if needed.
   buffer_viewport_list_->SetToRecommendedBufferViewports();
 
+  // Resize render buffers to match desired resolution when switching
+  // modes between WebVR and VrShell mode.
+  if (web_vr_mode_) {
+    // If needed, resize the primary buffer for use with WebVR so that
+    // it matches the canvas size used for WebGL rendering.
+    if (render_size_primary_ != render_size_primary_webvr_) {
+      if (!render_size_primary_webvr_.width) {
+        DVLOG(2) << "WebVR rendering size not known yet, dropping frame";
+        return;
+      }
+      render_size_primary_ = render_size_primary_webvr_;
+      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
+    }
+  } else {
+    // Restore high resolution for VrShell mode.
+    if (render_size_primary_ != render_size_primary_vrshell_) {
+      render_size_primary_ = render_size_primary_vrshell_;
+      swap_chain_->ResizeBuffer(kFramePrimaryBuffer, render_size_primary_);
+    }
+  }
+
   gvr::Frame frame = swap_chain_->AcquireFrame();
   if (!frame.is_valid()) {
     return;
   }
   frame.BindBuffer(kFramePrimaryBuffer);
   if (web_vr_mode_) {
     DrawWebVr();
   }
 
   uint16_t frame_index;
@@ skipping 391 matching lines @@
   TRACE_EVENT0("gpu", "VrShellGl::ContentBoundsChanged");
   content_tex_css_width_ = width;
   content_tex_css_height_ = height;
 }
 
 void VrShellGl::ContentPhysicalBoundsChanged(int width, int height) {
   if (content_surface_texture_.get())
     content_surface_texture_->SetDefaultBufferSize(width, height);
   content_tex_physical_size_.width = width;
   content_tex_physical_size_.height = height;
+  render_size_primary_webvr_.width = width;
+  render_size_primary_webvr_.height = height;
 }
 
 void VrShellGl::UIBoundsChanged(int width, int height) {
   ui_tex_css_width_ = width;
   ui_tex_css_height_ = height;
 }
 
 void VrShellGl::UIPhysicalBoundsChanged(int width, int height) {
   if (ui_surface_texture_.get())
     ui_surface_texture_->SetDefaultBufferSize(width, height);
@@ skipping 96 matching lines @@
     const base::Callback<void(device::mojom::VRDisplayInfoPtr)>& callback,
     uint32_t device_id) {
   device::mojom::VRDisplayInfoPtr info = VrShell::CreateVRDisplayInfo(
       gvr_api_.get(), content_tex_physical_size_, device_id);
   main_thread_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&RunVRDisplayInfoCallback, callback, base::Passed(&info)));
 }
 
 }  // namespace vr_shell