Linear filter for texture object in 2d context

third_party/WebKit/Source/platform/graphics/OffscreenCanvasFrameDispatcherImpl.cpp

 // 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 "platform/graphics/OffscreenCanvasFrameDispatcherImpl.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/quads/texture_draw_quad.h"
 #include "gpu/command_buffer/client/gles2_interface.h"
 #include "platform/CrossThreadFunctional.h"
@@ skipping 96 matching lines @@
   image->imageForCurrentFrame(ColorBehavior::transformToGlobalTarget())
       ->readPixels(info, dstPixels->data(), info.minRowBytes(), 0, 0);
 
   GLuint textureId = 0u;
   gl->GenTextures(1, &textureId);
   gl->BindTexture(GL_TEXTURE_2D, textureId);
   GLenum format =
       (kN32_SkColorType == kRGBA_8888_SkColorType) ? GL_RGBA : GL_BGRA_EXT;
   gl->TexImage2D(GL_TEXTURE_2D, 0, format, m_width, m_height, 0, format,
                  GL_UNSIGNED_BYTE, 0);
-  gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
   gl->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
   gl->TexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, m_width, m_height, format,
                     GL_UNSIGNED_BYTE, dstPixels->data());
 
   gpu::Mailbox mailbox;
   gl->GenMailboxCHROMIUM(mailbox.name);
   gl->ProduceTextureCHROMIUM(GL_TEXTURE_2D, mailbox.name);
 
   const GLuint64 fenceSync = gl->InsertFenceSyncCHROMIUM();
@@ skipping 66 matching lines @@
 
   cc::SharedQuadState* sqs = pass->CreateAndAppendSharedQuadState();
   sqs->SetAll(gfx::Transform(), bounds.size(), bounds, bounds, false, 1.f,
               SkBlendMode::kSrcOver, 0);
 
   cc::TransferableResource resource;
   resource.id = m_nextResourceId;
   resource.format = cc::ResourceFormat::RGBA_8888;
   // TODO(crbug.com/645590): filter should respect the image-rendering CSS
   // property of associated canvas element.
-  resource.filter = GL_LINEAR;
+  resource.filter = GL_NEAREST;

[Justin Novosad, 2017/01/04 20:38:01]

I don't understand how this fixes the problem.  What we want is LINEAR
filtering, not NEAREST.  The problem was that the request for GL_LINEAR was
being ignored for some reason.

   resource.size = gfx::Size(m_width, m_height);
   // TODO(crbug.com/646022): making this overlay-able.
   resource.is_overlay_candidate = false;
 
   bool yflipped = false;
   OffscreenCanvasCommitType commitType;
   DEFINE_THREAD_SAFE_STATIC_LOCAL(
       EnumerationHistogram, commitTypeHistogram,
       new EnumerationHistogram("OffscreenCanvas.CommitType",
                                OffscreenCanvasCommitTypeCount));
@@ skipping 197 matching lines @@
 
 void OffscreenCanvasFrameDispatcherImpl::reshape(int width, int height) {
   if (m_width != width || m_height != height) {
     m_width = width;
     m_height = height;
     m_changeSizeForNextCommit = true;
   }
 }
 
 }  // namespace blink