[cc] Add nearest neighbor filtering for TextureLayer.

cc/resources/resource_provider.cc

 // Copyright 2012 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 "cc/resources/resource_provider.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/containers/hash_tables.h"
@@ skipping 578 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   // Just store the information. Mailbox will be consumed in LockForRead().
   ResourceId id = next_id_++;
   DCHECK(mailbox.IsValid());
   Resource& resource = resources_[id];
   if (mailbox.IsTexture()) {
     resource = Resource(0,
                         gfx::Size(),
                         Resource::External,
                         mailbox.target(),
-                        GL_LINEAR,
+                        mailbox.nearest_neighbor() ? GL_NEAREST : GL_LINEAR,

[danakj, 2014/11/04 21:30:23]

can you add a test to resource_provider_unittest.cc for this change to show it's
working?

[jackhou1, 2014/11/12 03:35:17]

I added a bit to ResourceProviderTest.TextureMailbox_GLTexture2D.

I realised it's possible for someone creating the mailbox to pass in a texture
with GL_LINEAR filters, but TextureMailbox::nearest_neighbor set to true. Would
it be better to set the filters on the texture here based on
TextureMailbox::nearest_neighbor, or set Resource::filter by checking what's set
on the texture?

[piman, 2014/11/12 04:43:26]

That's a user error then.
No, that would be redundant changes.
No, reading what's on the texture would involve a round-trip (slow).

                         0,
                         GL_CLAMP_TO_EDGE,
                         TextureHintImmutable,
                         RGBA_8888);
   } else {
     DCHECK(mailbox.IsSharedMemory());
     base::SharedMemory* shared_memory = mailbox.shared_memory();
     DCHECK(shared_memory->memory());
     uint8_t* pixels = reinterpret_cast<uint8_t*>(shared_memory->memory());
     DCHECK(pixels);
     scoped_ptr<SharedBitmap> shared_bitmap;
     if (shared_bitmap_manager_) {
       shared_bitmap =
           shared_bitmap_manager_->GetBitmapForSharedMemory(shared_memory);
     }
     resource = Resource(pixels,
                         shared_bitmap.release(),
                         mailbox.shared_memory_size(),
                         Resource::External,
-                        GL_LINEAR,
+                        mailbox.nearest_neighbor() ? GL_NEAREST : GL_LINEAR,
                         GL_CLAMP_TO_EDGE);
   }
   resource.allocated = true;
   resource.mailbox = mailbox;
   resource.release_callback_impl =
       base::Bind(&SingleReleaseCallbackImpl::Run,
                  base::Owned(release_callback_impl.release()));
   resource.allow_overlay = mailbox.allow_overlay();
   return id;
 }
@@ skipping 698 matching lines @@
                                      blocking_main_thread_task_runner_);
       continue;
     }
 
     ResourceId local_id = next_id_++;
     Resource& resource = resources_[local_id];
     if (it->is_software) {
       resource = Resource(it->mailbox_holder.mailbox,
                           it->size,
                           Resource::Delegated,
-                          GL_LINEAR,
+                          it->filter,

[danakj, 2014/11/04 21:30:23]

can you add a test to resource_provider_unittest.cc for this change to show it's
working?

[jackhou1, 2014/11/12 03:35:17]

Huh, looks like Resource::filter is never read for anything if it's a software
resource. I guess the software renderer always assumes linear filtering? Is
there a way to force software rendering so I can fiddle with it?

[piman, 2014/11/12 04:43:26]

--disable-gpu

[jackhou1, 2014/11/12 05:05:53]

Looks like Patch Set 9 works fine with --disable-gpu. I guess blink is choosing
an already implemented code path.

                           it->is_repeated ? GL_REPEAT : GL_CLAMP_TO_EDGE);
     } else {
       resource = Resource(0,
                           it->size,
                           Resource::Delegated,
                           it->mailbox_holder.texture_target,
                           it->filter,
                           0,
                           it->is_repeated ? GL_REPEAT : GL_CLAMP_TO_EDGE,
                           TextureHintImmutable,
@@ skipping 715 matching lines @@
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->ContextGL() : NULL;
 }
 
 class GrContext* ResourceProvider::GrContext() const {
   ContextProvider* context_provider = output_surface_->context_provider();
   return context_provider ? context_provider->GrContext() : NULL;
 }
 
 }  // namespace cc