src/content/common/gpu/client/gl_helper.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/common/gpu/client/gl_helper.h"
   6
   7 #include <queue>
   8 #include <string>
   9
  10 #include "base/bind.h"
  11 #include "base/debug/trace_event.h"
  12 #include "base/lazy_instance.h"
  13 #include "base/logging.h"
  14 #include "base/memory/ref_counted.h"
  15 #include "base/message_loop/message_loop.h"
  16 #include "base/strings/string_util.h"
  17 #include "base/time/time.h"
  18 #include "content/common/gpu/client/gl_helper_readback_support.h"
  19 #include "content/common/gpu/client/gl_helper_scaling.h"
  20 #include "gpu/GLES2/gl2extchromium.h"
  21 #include "gpu/command_buffer/client/context_support.h"
  22 #include "gpu/command_buffer/common/mailbox.h"
  23 #include "gpu/command_buffer/common/mailbox_holder.h"
  24 #include "media/base/video_frame.h"
  25 #include "media/base/video_util.h"
  26 #include "third_party/skia/include/core/SkRegion.h"
  27 #include "ui/gfx/rect.h"
  28 #include "ui/gfx/size.h"
  29
  30 using gpu::gles2::GLES2Interface;
  31
  32 namespace {
  33
  34 class ScopedFlush {
  35  public:
  36   explicit ScopedFlush(gpu::gles2::GLES2Interface* gl) : gl_(gl) {}
  37
  38   ~ScopedFlush() { gl_->Flush(); }
  39
  40  private:
  41   gpu::gles2::GLES2Interface* gl_;
  42
  43   DISALLOW_COPY_AND_ASSIGN(ScopedFlush);
  44 };
  45
  46 // Helper class for allocating and holding an RGBA texture of a given
  47 // size and an associated framebuffer.
  48 class TextureFrameBufferPair {
  49  public:
  50   TextureFrameBufferPair(GLES2Interface* gl, gfx::Size size)
  51       : texture_(gl), framebuffer_(gl), size_(size) {
  52     content::ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl, texture_);
  53     gl->TexImage2D(GL_TEXTURE_2D,
  54                    0,
  55                    GL_RGBA,
  56                    size.width(),
  57                    size.height(),
  58                    0,
  59                    GL_RGBA,
  60                    GL_UNSIGNED_BYTE,
  61                    NULL);
  62     content::ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(
  63         gl, framebuffer_);
  64     gl->FramebufferTexture2D(
  65         GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture_, 0);
  66   }
  67
  68   GLuint texture() const { return texture_.id(); }
  69   GLuint framebuffer() const { return framebuffer_.id(); }
  70   gfx::Size size() const { return size_; }
  71
  72  private:
  73   content::ScopedTexture texture_;
  74   content::ScopedFramebuffer framebuffer_;
  75   gfx::Size size_;
  76
  77   DISALLOW_COPY_AND_ASSIGN(TextureFrameBufferPair);
  78 };
  79
  80 // Helper class for holding a scaler, a texture for the output of that
  81 // scaler and an associated frame buffer. This is inteded to be used
  82 // when the output of a scaler is to be sent to a readback.
  83 class ScalerHolder {
  84  public:
  85   ScalerHolder(GLES2Interface* gl, content::GLHelper::ScalerInterface* scaler)
  86       : texture_and_framebuffer_(gl, scaler->DstSize()), scaler_(scaler) {}
  87
  88   void Scale(GLuint src_texture) {
  89     scaler_->Scale(src_texture, texture_and_framebuffer_.texture());
  90   }
  91
  92   content::GLHelper::ScalerInterface* scaler() const { return scaler_.get(); }
  93   TextureFrameBufferPair* texture_and_framebuffer() {
  94     return &texture_and_framebuffer_;
  95   }
  96   GLuint texture() const { return texture_and_framebuffer_.texture(); }
  97
  98  private:
  99   TextureFrameBufferPair texture_and_framebuffer_;
 100   scoped_ptr<content::GLHelper::ScalerInterface> scaler_;
 101
 102   DISALLOW_COPY_AND_ASSIGN(ScalerHolder);
 103 };
 104
 105 }  // namespace
 106
 107 namespace content {
 108 typedef GLHelperReadbackSupport::FormatSupport FormatSupport;
 109
 110 // Implements GLHelper::CropScaleReadbackAndCleanTexture and encapsulates
 111 // the data needed for it.
 112 class GLHelper::CopyTextureToImpl
 113     : public base::SupportsWeakPtr<GLHelper::CopyTextureToImpl> {
 114  public:
 115   CopyTextureToImpl(GLES2Interface* gl,
 116                     gpu::ContextSupport* context_support,
 117                     GLHelper* helper)
 118       : gl_(gl),
 119         context_support_(context_support),
 120         helper_(helper),
 121         flush_(gl),
 122         max_draw_buffers_(0) {
 123     const GLubyte* extensions = gl_->GetString(GL_EXTENSIONS);
 124     if (!extensions)
 125       return;
 126     std::string extensions_string =
 127         " " + std::string(reinterpret_cast<const char*>(extensions)) + " ";
 128     if (extensions_string.find(" GL_EXT_draw_buffers ") != std::string::npos) {
 129       gl_->GetIntegerv(GL_MAX_DRAW_BUFFERS_EXT, &max_draw_buffers_);
 130     }
 131   }
 132   ~CopyTextureToImpl() { CancelRequests(); }
 133
 134   GLuint ConsumeMailboxToTexture(const gpu::Mailbox& mailbox,
 135                                  uint32 sync_point) {
 136     return helper_->ConsumeMailboxToTexture(mailbox, sync_point);
 137   }
 138
 139   void CropScaleReadbackAndCleanTexture(
 140       GLuint src_texture,
 141       const gfx::Size& src_size,
 142       const gfx::Rect& src_subrect,
 143       const gfx::Size& dst_size,
 144       unsigned char* out,
 145       const SkColorType out_color_type,
 146       const base::Callback<void(bool)>& callback,
 147       GLHelper::ScalerQuality quality);
 148
 149   void ReadbackTextureSync(GLuint texture,
 150                            const gfx::Rect& src_rect,
 151                            unsigned char* out,
 152                            SkColorType format);
 153
 154   void ReadbackTextureAsync(GLuint texture,
 155                             const gfx::Size& dst_size,
 156                             unsigned char* out,
 157                             SkColorType color_type,
 158                             const base::Callback<void(bool)>& callback);
 159
 160   // Reads back bytes from the currently bound frame buffer.
 161   // Note that dst_size is specified in bytes, not pixels.
 162   void ReadbackAsync(const gfx::Size& dst_size,
 163                      int32 bytes_per_row,     // generally dst_size.width() * 4
 164                      int32 row_stride_bytes,  // generally dst_size.width() * 4
 165                      unsigned char* out,
 166                      GLenum format,
 167                      GLenum type,
 168                      size_t bytes_per_pixel,
 169                      const base::Callback<void(bool)>& callback);
 170
 171   void ReadbackPlane(TextureFrameBufferPair* source,
 172                      const scoped_refptr<media::VideoFrame>& target,
 173                      int plane,
 174                      int size_shift,
 175                      const gfx::Rect& dst_subrect,
 176                      ReadbackSwizzle swizzle,
 177                      const base::Callback<void(bool)>& callback);
 178
 179   GLuint CopyAndScaleTexture(GLuint texture,
 180                              const gfx::Size& src_size,
 181                              const gfx::Size& dst_size,
 182                              bool vertically_flip_texture,
 183                              GLHelper::ScalerQuality quality);
 184
 185   ReadbackYUVInterface* CreateReadbackPipelineYUV(
 186       GLHelper::ScalerQuality quality,
 187       const gfx::Size& src_size,
 188       const gfx::Rect& src_subrect,
 189       const gfx::Size& dst_size,
 190       const gfx::Rect& dst_subrect,
 191       bool flip_vertically,
 192       bool use_mrt);
 193
 194   // Returns the maximum number of draw buffers available,
 195   // 0 if GL_EXT_draw_buffers is not available.
 196   GLint MaxDrawBuffers() const { return max_draw_buffers_; }
 197
 198   FormatSupport GetReadbackConfig(SkColorType color_type,
 199                                   bool can_swizzle,
 200                                   GLenum* format,
 201                                   GLenum* type,
 202                                   size_t* bytes_per_pixel);
 203
 204  private:
 205   // A single request to CropScaleReadbackAndCleanTexture.
 206   // The main thread can cancel the request, before it's handled by the helper
 207   // thread, by resetting the texture and pixels fields. Alternatively, the
 208   // thread marks that it handles the request by resetting the pixels field
 209   // (meaning it guarantees that the callback with be called).
 210   // In either case, the callback must be called exactly once, and the texture
 211   // must be deleted by the main thread gl.
 212   struct Request {
 213     Request(const gfx::Size& size_,
 214             int32 bytes_per_row_,
 215             int32 row_stride_bytes_,
 216             unsigned char* pixels_,
 217             const base::Callback<void(bool)>& callback_)
 218         : done(false),
 219           size(size_),
 220           bytes_per_row(bytes_per_row_),
 221           row_stride_bytes(row_stride_bytes_),
 222           pixels(pixels_),
 223           callback(callback_),
 224           buffer(0),
 225           query(0) {}
 226
 227     bool done;
 228     gfx::Size size;
 229     int bytes_per_row;
 230     int row_stride_bytes;
 231     unsigned char* pixels;
 232     base::Callback<void(bool)> callback;
 233     GLuint buffer;
 234     GLuint query;
 235   };
 236
 237   // A readback pipeline that also converts the data to YUV before
 238   // reading it back.
 239   class ReadbackYUVImpl : public ReadbackYUVInterface {
 240    public:
 241     ReadbackYUVImpl(GLES2Interface* gl,
 242                     CopyTextureToImpl* copy_impl,
 243                     GLHelperScaling* scaler_impl,
 244                     GLHelper::ScalerQuality quality,
 245                     const gfx::Size& src_size,
 246                     const gfx::Rect& src_subrect,
 247                     const gfx::Size& dst_size,
 248                     const gfx::Rect& dst_subrect,
 249                     bool flip_vertically,
 250                     ReadbackSwizzle swizzle);
 251
 252     void ReadbackYUV(const gpu::Mailbox& mailbox,
 253                      uint32 sync_point,
 254                      const scoped_refptr<media::VideoFrame>& target,
 255                      const base::Callback<void(bool)>& callback) override;
 256
 257     ScalerInterface* scaler() override { return scaler_.scaler(); }
 258
 259    private:
 260     GLES2Interface* gl_;
 261     CopyTextureToImpl* copy_impl_;
 262     gfx::Size dst_size_;
 263     gfx::Rect dst_subrect_;
 264     ReadbackSwizzle swizzle_;
 265     ScalerHolder scaler_;
 266     ScalerHolder y_;
 267     ScalerHolder u_;
 268     ScalerHolder v_;
 269
 270     DISALLOW_COPY_AND_ASSIGN(ReadbackYUVImpl);
 271   };
 272
 273   // A readback pipeline that also converts the data to YUV before
 274   // reading it back. This one uses Multiple Render Targets, which
 275   // may not be supported on all platforms.
 276   class ReadbackYUV_MRT : public ReadbackYUVInterface {
 277    public:
 278     ReadbackYUV_MRT(GLES2Interface* gl,
 279                     CopyTextureToImpl* copy_impl,
 280                     GLHelperScaling* scaler_impl,
 281                     GLHelper::ScalerQuality quality,
 282                     const gfx::Size& src_size,
 283                     const gfx::Rect& src_subrect,
 284                     const gfx::Size& dst_size,
 285                     const gfx::Rect& dst_subrect,
 286                     bool flip_vertically,
 287                     ReadbackSwizzle swizzle);
 288
 289     void ReadbackYUV(const gpu::Mailbox& mailbox,
 290                      uint32 sync_point,
 291                      const scoped_refptr<media::VideoFrame>& target,
 292                      const base::Callback<void(bool)>& callback) override;
 293
 294     ScalerInterface* scaler() override { return scaler_.scaler(); }
 295
 296    private:
 297     GLES2Interface* gl_;
 298     CopyTextureToImpl* copy_impl_;
 299     gfx::Size dst_size_;
 300     gfx::Rect dst_subrect_;
 301     GLHelper::ScalerQuality quality_;
 302     ReadbackSwizzle swizzle_;
 303     ScalerHolder scaler_;
 304     scoped_ptr<content::GLHelperScaling::ShaderInterface> pass1_shader_;
 305     scoped_ptr<content::GLHelperScaling::ShaderInterface> pass2_shader_;
 306     TextureFrameBufferPair y_;
 307     ScopedTexture uv_;
 308     TextureFrameBufferPair u_;
 309     TextureFrameBufferPair v_;
 310
 311     DISALLOW_COPY_AND_ASSIGN(ReadbackYUV_MRT);
 312   };
 313
 314   // Copies the block of pixels specified with |src_subrect| from |src_texture|,
 315   // scales it to |dst_size|, writes it into a texture, and returns its ID.
 316   // |src_size| is the size of |src_texture|.
 317   GLuint ScaleTexture(GLuint src_texture,
 318                       const gfx::Size& src_size,
 319                       const gfx::Rect& src_subrect,
 320                       const gfx::Size& dst_size,
 321                       bool vertically_flip_texture,
 322                       bool swizzle,
 323                       SkColorType color_type,
 324                       GLHelper::ScalerQuality quality);
 325
 326   // Converts each four consecutive pixels of the source texture into one pixel
 327   // in the result texture with each pixel channel representing the grayscale
 328   // color of one of the four original pixels:
 329   // R1G1B1A1 R2G2B2A2 R3G3B3A3 R4G4B4A4 -> X1X2X3X4
 330   // The resulting texture is still an RGBA texture (which is ~4 times narrower
 331   // than the original). If rendered directly, it wouldn't show anything useful,
 332   // but the data in it can be used to construct a grayscale image.
 333   // |encoded_texture_size| is the exact size of the resulting RGBA texture. It
 334   // is equal to src_size.width()/4 rounded upwards. Some channels in the last
 335   // pixel ((-src_size.width()) % 4) to be exact) are padding and don't contain
 336   // useful data.
 337   // If swizzle is set to true, the transformed pixels are reordered:
 338   // R1G1B1A1 R2G2B2A2 R3G3B3A3 R4G4B4A4 -> X3X2X1X4.
 339   GLuint EncodeTextureAsGrayscale(GLuint src_texture,
 340                                   const gfx::Size& src_size,
 341                                   gfx::Size* const encoded_texture_size,
 342                                   bool vertically_flip_texture,
 343                                   bool swizzle);
 344
 345   static void nullcallback(bool success) {}
 346   void ReadbackDone(Request *request, int bytes_per_pixel);
 347   void FinishRequest(Request* request, bool result);
 348   void CancelRequests();
 349
 350   static const float kRGBtoYColorWeights[];
 351   static const float kRGBtoUColorWeights[];
 352   static const float kRGBtoVColorWeights[];
 353   static const float kRGBtoGrayscaleColorWeights[];
 354
 355   GLES2Interface* gl_;
 356   gpu::ContextSupport* context_support_;
 357   GLHelper* helper_;
 358
 359   // A scoped flush that will ensure all resource deletions are flushed when
 360   // this object is destroyed. Must be declared before other Scoped* fields.
 361   ScopedFlush flush_;
 362
 363   std::queue<Request*> request_queue_;
 364   GLint max_draw_buffers_;
 365 };
 366
 367 GLHelper::ScalerInterface* GLHelper::CreateScaler(ScalerQuality quality,
 368                                                   const gfx::Size& src_size,
 369                                                   const gfx::Rect& src_subrect,
 370                                                   const gfx::Size& dst_size,
 371                                                   bool vertically_flip_texture,
 372                                                   bool swizzle) {
 373   InitScalerImpl();
 374   return scaler_impl_->CreateScaler(quality,
 375                                     src_size,
 376                                     src_subrect,
 377                                     dst_size,
 378                                     vertically_flip_texture,
 379                                     swizzle);
 380 }
 381
 382 GLuint GLHelper::CopyTextureToImpl::ScaleTexture(
 383     GLuint src_texture,
 384     const gfx::Size& src_size,
 385     const gfx::Rect& src_subrect,
 386     const gfx::Size& dst_size,
 387     bool vertically_flip_texture,
 388     bool swizzle,
 389     SkColorType color_type,
 390     GLHelper::ScalerQuality quality) {
 391   GLuint dst_texture = 0u;
 392   gl_->GenTextures(1, &dst_texture);
 393   {
 394     GLenum format = GL_RGBA, type = GL_UNSIGNED_BYTE;
 395     ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, dst_texture);
 396
 397     // Use GL_RGBA for destination/temporary texture unless we're working with
 398     // 16-bit data
 399     if (color_type == kRGB_565_SkColorType) {
 400       format = GL_RGB;
 401       type = GL_UNSIGNED_SHORT_5_6_5;
 402     }
 403
 404     gl_->TexImage2D(GL_TEXTURE_2D,
 405                     0,
 406                     format,
 407                     dst_size.width(),
 408                     dst_size.height(),
 409                     0,
 410                     format,
 411                     type,
 412                     NULL);
 413   }
 414   scoped_ptr<ScalerInterface> scaler(
 415       helper_->CreateScaler(quality,
 416                             src_size,
 417                             src_subrect,
 418                             dst_size,
 419                             vertically_flip_texture,
 420                             swizzle));
 421   scaler->Scale(src_texture, dst_texture);
 422   return dst_texture;
 423 }
 424
 425 GLuint GLHelper::CopyTextureToImpl::EncodeTextureAsGrayscale(
 426     GLuint src_texture,
 427     const gfx::Size& src_size,
 428     gfx::Size* const encoded_texture_size,
 429     bool vertically_flip_texture,
 430     bool swizzle) {
 431   GLuint dst_texture = 0u;
 432   gl_->GenTextures(1, &dst_texture);
 433   // The size of the encoded texture.
 434   *encoded_texture_size =
 435       gfx::Size((src_size.width() + 3) / 4, src_size.height());
 436   {
 437     ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, dst_texture);
 438     gl_->TexImage2D(GL_TEXTURE_2D,
 439                     0,
 440                     GL_RGBA,
 441                     encoded_texture_size->width(),
 442                     encoded_texture_size->height(),
 443                     0,
 444                     GL_RGBA,
 445                     GL_UNSIGNED_BYTE,
 446                     NULL);
 447   }
 448
 449   helper_->InitScalerImpl();
 450   scoped_ptr<ScalerInterface> grayscale_scaler(
 451       helper_->scaler_impl_.get()->CreatePlanarScaler(
 452           src_size,
 453           gfx::Rect(0, 0, (src_size.width() + 3) & ~3, src_size.height()),
 454           *encoded_texture_size,
 455           vertically_flip_texture,
 456           swizzle,
 457           kRGBtoGrayscaleColorWeights));
 458   grayscale_scaler->Scale(src_texture, dst_texture);
 459   return dst_texture;
 460 }
 461
 462 void GLHelper::CopyTextureToImpl::ReadbackAsync(
 463     const gfx::Size& dst_size,
 464     int32 bytes_per_row,
 465     int32 row_stride_bytes,
 466     unsigned char* out,
 467     GLenum format,
 468     GLenum type,
 469     size_t bytes_per_pixel,
 470     const base::Callback<void(bool)>& callback) {
 471   TRACE_EVENT0("mirror", "GLHelper::CopyTextureToImpl::ReadbackAsync");
 472   Request* request =
 473       new Request(dst_size, bytes_per_row, row_stride_bytes, out, callback);
 474   request_queue_.push(request);
 475   request->buffer = 0u;
 476
 477   gl_->GenBuffers(1, &request->buffer);
 478   gl_->BindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, request->buffer);
 479   gl_->BufferData(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM,
 480                   bytes_per_pixel * dst_size.GetArea(),
 481                   NULL,
 482                   GL_STREAM_READ);
 483
 484   request->query = 0u;
 485   gl_->GenQueriesEXT(1, &request->query);
 486   gl_->BeginQueryEXT(GL_ASYNC_PIXEL_PACK_COMPLETED_CHROMIUM, request->query);
 487   gl_->ReadPixels(0,
 488                   0,
 489                   dst_size.width(),
 490                   dst_size.height(),
 491                   format,
 492                   type,
 493                   NULL);
 494   gl_->EndQueryEXT(GL_ASYNC_PIXEL_PACK_COMPLETED_CHROMIUM);
 495   gl_->BindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, 0);
 496   context_support_->SignalQuery(
 497       request->query,
 498       base::Bind(&CopyTextureToImpl::ReadbackDone, AsWeakPtr(),
 499                  request, bytes_per_pixel));
 500 }
 501
 502 void GLHelper::CopyTextureToImpl::CropScaleReadbackAndCleanTexture(
 503     GLuint src_texture,
 504     const gfx::Size& src_size,
 505     const gfx::Rect& src_subrect,
 506     const gfx::Size& dst_size,
 507     unsigned char* out,
 508     const SkColorType out_color_type,
 509     const base::Callback<void(bool)>& callback,
 510     GLHelper::ScalerQuality quality) {
 511   GLenum format, type;
 512   size_t bytes_per_pixel;
 513   SkColorType readback_color_type = out_color_type;
 514   // Single-component textures are not supported by all GPUs, so  we implement
 515   // kAlpha_8_SkColorType support here via a special encoding (see below) using
 516   // a 32-bit texture to represent an 8-bit image.
 517   // Thus we use generic 32-bit readback in this case.
 518   if (out_color_type == kAlpha_8_SkColorType) {
 519     readback_color_type = kRGBA_8888_SkColorType;
 520   }
 521
 522   FormatSupport supported = GetReadbackConfig(
 523       readback_color_type, true, &format, &type, &bytes_per_pixel);
 524
 525   if (supported == GLHelperReadbackSupport::NOT_SUPPORTED) {
 526     callback.Run(false);
 527     return;
 528   }
 529
 530   GLuint texture = src_texture;
 531
 532   // Scale texture if needed
 533   // Optimization: SCALER_QUALITY_FAST is just a single bilinear pass, which we
 534   // can do just as well in EncodeTextureAsGrayscale, which we will do if
 535   // out_color_type is kAlpha_8_SkColorType, so let's skip the scaling step
 536   // in that case.
 537   bool scale_texture = out_color_type != kAlpha_8_SkColorType ||
 538                        quality != GLHelper::SCALER_QUALITY_FAST;
 539   if (scale_texture) {
 540     // Don't swizzle during the scale step for kAlpha_8_SkColorType.
 541     // We will swizzle in the encode step below if needed.
 542     bool scale_swizzle = out_color_type == kAlpha_8_SkColorType
 543                              ? false
 544                              : supported == GLHelperReadbackSupport::SWIZZLE;
 545     texture =
 546         ScaleTexture(src_texture,
 547                      src_size,
 548                      src_subrect,
 549                      dst_size,
 550                      true,
 551                      scale_swizzle,
 552                      out_color_type == kAlpha_8_SkColorType ? kN32_SkColorType
 553                                                             : out_color_type,
 554                      quality);
 555     DCHECK(texture);
 556   }
 557
 558   gfx::Size readback_texture_size = dst_size;
 559   // Encode texture to grayscale if needed.
 560   if (out_color_type == kAlpha_8_SkColorType) {
 561     // Do the vertical flip here if we haven't already done it when we scaled
 562     // the texture.
 563     bool encode_as_grayscale_vertical_flip = !scale_texture;
 564     // EncodeTextureAsGrayscale by default creates a texture which should be
 565     // read back as RGBA, so need to swizzle if the readback format is BGRA.
 566     bool encode_as_grayscale_swizzle = format == GL_BGRA_EXT;
 567     GLuint tmp_texture =
 568         EncodeTextureAsGrayscale(texture,
 569                                  dst_size,
 570                                  &readback_texture_size,
 571                                  encode_as_grayscale_vertical_flip,
 572                                  encode_as_grayscale_swizzle);
 573     // If the scaled texture was created - delete it
 574     if (scale_texture)
 575       gl_->DeleteTextures(1, &texture);
 576     texture = tmp_texture;
 577     DCHECK(texture);
 578   }
 579
 580   // Readback the pixels of the resulting texture
 581   ScopedFramebuffer dst_framebuffer(gl_);
 582   ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(gl_,
 583                                                              dst_framebuffer);
 584   ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 585   gl_->FramebufferTexture2D(GL_FRAMEBUFFER,
 586                             GL_COLOR_ATTACHMENT0,
 587                             GL_TEXTURE_2D,
 588                             texture,
 589                             0);
 590
 591   int32 bytes_per_row = out_color_type == kAlpha_8_SkColorType
 592                             ? dst_size.width()
 593                             : dst_size.width() * bytes_per_pixel;
 594
 595   ReadbackAsync(readback_texture_size,
 596                 bytes_per_row,
 597                 bytes_per_row,
 598                 out,
 599                 format,
 600                 type,
 601                 bytes_per_pixel,
 602                 callback);
 603   gl_->DeleteTextures(1, &texture);
 604 }
 605
 606 void GLHelper::CopyTextureToImpl::ReadbackTextureSync(
 607     GLuint texture,
 608     const gfx::Rect& src_rect,
 609     unsigned char* out,
 610     SkColorType color_type) {
 611   GLenum format, type;
 612   size_t bytes_per_pixel;
 613   FormatSupport supported =
 614       GetReadbackConfig(color_type, false, &format, &type, &bytes_per_pixel);
 615   if (supported == GLHelperReadbackSupport::NOT_SUPPORTED) {
 616     return;
 617   }
 618
 619   ScopedFramebuffer dst_framebuffer(gl_);
 620   ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(gl_,
 621                                                              dst_framebuffer);
 622   ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 623   gl_->FramebufferTexture2D(
 624       GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
 625   gl_->ReadPixels(src_rect.x(),
 626                   src_rect.y(),
 627                   src_rect.width(),
 628                   src_rect.height(),
 629                   format,
 630                   type,
 631                   out);
 632 }
 633
 634 void GLHelper::CopyTextureToImpl::ReadbackTextureAsync(
 635     GLuint texture,
 636     const gfx::Size& dst_size,
 637     unsigned char* out,
 638     SkColorType color_type,
 639     const base::Callback<void(bool)>& callback) {
 640   GLenum format, type;
 641   size_t bytes_per_pixel;
 642   FormatSupport supported =
 643       GetReadbackConfig(color_type, false, &format, &type, &bytes_per_pixel);
 644   if (supported == GLHelperReadbackSupport::NOT_SUPPORTED) {
 645     callback.Run(false);
 646     return;
 647   }
 648
 649   ScopedFramebuffer dst_framebuffer(gl_);
 650   ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(gl_,
 651                                                              dst_framebuffer);
 652   ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 653   gl_->FramebufferTexture2D(GL_FRAMEBUFFER,
 654                             GL_COLOR_ATTACHMENT0,
 655                             GL_TEXTURE_2D,
 656                             texture,
 657                             0);
 658   ReadbackAsync(dst_size,
 659                 dst_size.width() * bytes_per_pixel,
 660                 dst_size.width() * bytes_per_pixel,
 661                 out,
 662                 format,
 663                 type,
 664                 bytes_per_pixel,
 665                 callback);
 666 }
 667
 668 GLuint GLHelper::CopyTextureToImpl::CopyAndScaleTexture(
 669     GLuint src_texture,
 670     const gfx::Size& src_size,
 671     const gfx::Size& dst_size,
 672     bool vertically_flip_texture,
 673     GLHelper::ScalerQuality quality) {
 674   return ScaleTexture(src_texture,
 675                       src_size,
 676                       gfx::Rect(src_size),
 677                       dst_size,
 678                       vertically_flip_texture,
 679                       false,
 680                       kRGBA_8888_SkColorType,  // GL_RGBA
 681                       quality);
 682 }
 683
 684 void GLHelper::CopyTextureToImpl::ReadbackDone(Request* finished_request,
 685                                                int bytes_per_pixel) {
 686   TRACE_EVENT0("mirror",
 687                "GLHelper::CopyTextureToImpl::CheckReadbackFramebufferComplete");
 688   finished_request->done = true;
 689
 690   // We process transfer requests in the order they were received, regardless
 691   // of the order we get the callbacks in.
 692   while (!request_queue_.empty()) {
 693     Request* request = request_queue_.front();
 694     if (!request->done) {
 695       break;
 696     }
 697
 698     bool result = false;
 699     if (request->buffer != 0) {
 700       gl_->BindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, request->buffer);
 701       unsigned char* data = static_cast<unsigned char*>(gl_->MapBufferCHROMIUM(
 702           GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, GL_READ_ONLY));
 703       if (data) {
 704         result = true;
 705         if (request->bytes_per_row == request->size.width() * bytes_per_pixel &&
 706             request->bytes_per_row == request->row_stride_bytes) {
 707           memcpy(request->pixels, data,
 708                  request->size.GetArea() * bytes_per_pixel);
 709         } else {
 710           unsigned char* out = request->pixels;
 711           for (int y = 0; y < request->size.height(); y++) {
 712             memcpy(out, data, request->bytes_per_row);
 713             out += request->row_stride_bytes;
 714             data += request->size.width() * bytes_per_pixel;
 715           }
 716         }
 717         gl_->UnmapBufferCHROMIUM(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM);
 718       }
 719       gl_->BindBuffer(GL_PIXEL_PACK_TRANSFER_BUFFER_CHROMIUM, 0);
 720     }
 721     FinishRequest(request, result);
 722   }
 723 }
 724
 725 void GLHelper::CopyTextureToImpl::FinishRequest(Request* request, bool result) {
 726   TRACE_EVENT0("mirror", "GLHelper::CopyTextureToImpl::FinishRequest");
 727   DCHECK(request_queue_.front() == request);
 728   request_queue_.pop();
 729   request->callback.Run(result);
 730   ScopedFlush flush(gl_);
 731   if (request->query != 0) {
 732     gl_->DeleteQueriesEXT(1, &request->query);
 733     request->query = 0;
 734   }
 735   if (request->buffer != 0) {
 736     gl_->DeleteBuffers(1, &request->buffer);
 737     request->buffer = 0;
 738   }
 739   delete request;
 740 }
 741
 742 void GLHelper::CopyTextureToImpl::CancelRequests() {
 743   while (!request_queue_.empty()) {
 744     Request* request = request_queue_.front();
 745     FinishRequest(request, false);
 746   }
 747 }
 748
 749 FormatSupport GLHelper::CopyTextureToImpl::GetReadbackConfig(
 750     SkColorType color_type,
 751     bool can_swizzle,
 752     GLenum* format,
 753     GLenum* type,
 754     size_t* bytes_per_pixel) {
 755   return helper_->readback_support_->GetReadbackConfig(
 756       color_type, can_swizzle, format, type, bytes_per_pixel);
 757 }
 758
 759 GLHelper::GLHelper(GLES2Interface* gl, gpu::ContextSupport* context_support)
 760     : gl_(gl),
 761       context_support_(context_support),
 762       readback_support_(new GLHelperReadbackSupport(gl)) {}
 763
 764 GLHelper::~GLHelper() {}
 765
 766 void GLHelper::CropScaleReadbackAndCleanTexture(
 767     GLuint src_texture,
 768     const gfx::Size& src_size,
 769     const gfx::Rect& src_subrect,
 770     const gfx::Size& dst_size,
 771     unsigned char* out,
 772     const SkColorType out_color_type,
 773     const base::Callback<void(bool)>& callback,
 774     GLHelper::ScalerQuality quality) {
 775   InitCopyTextToImpl();
 776   copy_texture_to_impl_->CropScaleReadbackAndCleanTexture(src_texture,
 777                                                           src_size,
 778                                                           src_subrect,
 779                                                           dst_size,
 780                                                           out,
 781                                                           out_color_type,
 782                                                           callback,
 783                                                           quality);
 784 }
 785
 786 void GLHelper::CropScaleReadbackAndCleanMailbox(
 787     const gpu::Mailbox& src_mailbox,
 788     uint32 sync_point,
 789     const gfx::Size& src_size,
 790     const gfx::Rect& src_subrect,
 791     const gfx::Size& dst_size,
 792     unsigned char* out,
 793     const SkColorType out_color_type,
 794     const base::Callback<void(bool)>& callback,
 795     GLHelper::ScalerQuality quality) {
 796   GLuint mailbox_texture = ConsumeMailboxToTexture(src_mailbox, sync_point);
 797   CropScaleReadbackAndCleanTexture(mailbox_texture,
 798                                    src_size,
 799                                    src_subrect,
 800                                    dst_size,
 801                                    out,
 802                                    out_color_type,
 803                                    callback,
 804                                    quality);
 805   gl_->DeleteTextures(1, &mailbox_texture);
 806 }
 807
 808 void GLHelper::ReadbackTextureSync(GLuint texture,
 809                                    const gfx::Rect& src_rect,
 810                                    unsigned char* out,
 811                                    SkColorType format) {
 812   InitCopyTextToImpl();
 813   copy_texture_to_impl_->ReadbackTextureSync(texture, src_rect, out, format);
 814 }
 815
 816 void GLHelper::ReadbackTextureAsync(
 817     GLuint texture,
 818     const gfx::Size& dst_size,
 819     unsigned char* out,
 820     SkColorType color_type,
 821     const base::Callback<void(bool)>& callback) {
 822   InitCopyTextToImpl();
 823   copy_texture_to_impl_->ReadbackTextureAsync(texture,
 824                                               dst_size,
 825                                               out,
 826                                               color_type,
 827                                               callback);
 828 }
 829
 830 GLuint GLHelper::CopyTexture(GLuint texture, const gfx::Size& size) {
 831   InitCopyTextToImpl();
 832   return copy_texture_to_impl_->CopyAndScaleTexture(
 833       texture, size, size, false, GLHelper::SCALER_QUALITY_FAST);
 834 }
 835
 836 GLuint GLHelper::CopyAndScaleTexture(GLuint texture,
 837                                      const gfx::Size& src_size,
 838                                      const gfx::Size& dst_size,
 839                                      bool vertically_flip_texture,
 840                                      ScalerQuality quality) {
 841   InitCopyTextToImpl();
 842   return copy_texture_to_impl_->CopyAndScaleTexture(
 843       texture, src_size, dst_size, vertically_flip_texture, quality);
 844 }
 845
 846 GLuint GLHelper::CompileShaderFromSource(const GLchar* source, GLenum type) {
 847   GLuint shader = gl_->CreateShader(type);
 848   GLint length = strlen(source);
 849   gl_->ShaderSource(shader, 1, &source, &length);
 850   gl_->CompileShader(shader);
 851   GLint compile_status = 0;
 852   gl_->GetShaderiv(shader, GL_COMPILE_STATUS, &compile_status);
 853   if (!compile_status) {
 854     GLint log_length = 0;
 855     gl_->GetShaderiv(shader, GL_INFO_LOG_LENGTH, &log_length);
 856     if (log_length) {
 857       scoped_ptr<GLchar[]> log(new GLchar[log_length]);
 858       GLsizei returned_log_length = 0;
 859       gl_->GetShaderInfoLog(
 860           shader, log_length, &returned_log_length, log.get());
 861       LOG(ERROR) << std::string(log.get(), returned_log_length);
 862     }
 863     gl_->DeleteShader(shader);
 864     return 0;
 865   }
 866   return shader;
 867 }
 868
 869 void GLHelper::InitCopyTextToImpl() {
 870   // Lazily initialize |copy_texture_to_impl_|
 871   if (!copy_texture_to_impl_)
 872     copy_texture_to_impl_.reset(
 873         new CopyTextureToImpl(gl_, context_support_, this));
 874 }
 875
 876 void GLHelper::InitScalerImpl() {
 877   // Lazily initialize |scaler_impl_|
 878   if (!scaler_impl_)
 879     scaler_impl_.reset(new GLHelperScaling(gl_, this));
 880 }
 881
 882 GLint GLHelper::MaxDrawBuffers() {
 883   InitCopyTextToImpl();
 884   return copy_texture_to_impl_->MaxDrawBuffers();
 885 }
 886
 887 void GLHelper::CopySubBufferDamage(GLuint texture,
 888                                    GLuint previous_texture,
 889                                    const SkRegion& new_damage,
 890                                    const SkRegion& old_damage) {
 891   SkRegion region(old_damage);
 892   if (region.op(new_damage, SkRegion::kDifference_Op)) {
 893     ScopedFramebuffer dst_framebuffer(gl_);
 894     ScopedFramebufferBinder<GL_FRAMEBUFFER> framebuffer_binder(gl_,
 895                                                                dst_framebuffer);
 896     ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 897     gl_->FramebufferTexture2D(GL_FRAMEBUFFER,
 898                               GL_COLOR_ATTACHMENT0,
 899                               GL_TEXTURE_2D,
 900                               previous_texture,
 901                               0);
 902     for (SkRegion::Iterator it(region); !it.done(); it.next()) {
 903       const SkIRect& rect = it.rect();
 904       gl_->CopyTexSubImage2D(GL_TEXTURE_2D,
 905                              0,
 906                              rect.x(),
 907                              rect.y(),
 908                              rect.x(),
 909                              rect.y(),
 910                              rect.width(),
 911                              rect.height());
 912     }
 913     gl_->Flush();
 914   }
 915 }
 916
 917 GLuint GLHelper::CreateTexture() {
 918   GLuint texture = 0u;
 919   gl_->GenTextures(1, &texture);
 920   content::ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 921   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 922   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 923   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 924   gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 925   return texture;
 926 }
 927
 928 void GLHelper::DeleteTexture(GLuint texture_id) {
 929   gl_->DeleteTextures(1, &texture_id);
 930 }
 931
 932 uint32 GLHelper::InsertSyncPoint() { return gl_->InsertSyncPointCHROMIUM(); }
 933
 934 void GLHelper::WaitSyncPoint(uint32 sync_point) {
 935   gl_->WaitSyncPointCHROMIUM(sync_point);
 936 }
 937
 938 gpu::MailboxHolder GLHelper::ProduceMailboxHolderFromTexture(
 939     GLuint texture_id) {
 940   gpu::Mailbox mailbox;
 941   gl_->GenMailboxCHROMIUM(mailbox.name);
 942   gl_->ProduceTextureDirectCHROMIUM(texture_id, GL_TEXTURE_2D, mailbox.name);
 943   return gpu::MailboxHolder(mailbox, GL_TEXTURE_2D, InsertSyncPoint());
 944 }
 945
 946 GLuint GLHelper::ConsumeMailboxToTexture(const gpu::Mailbox& mailbox,
 947                                          uint32 sync_point) {
 948   if (mailbox.IsZero())
 949     return 0;
 950   if (sync_point)
 951     WaitSyncPoint(sync_point);
 952   GLuint texture =
 953       gl_->CreateAndConsumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox.name);
 954   return texture;
 955 }
 956
 957 void GLHelper::ResizeTexture(GLuint texture, const gfx::Size& size) {
 958   content::ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 959   gl_->TexImage2D(GL_TEXTURE_2D,
 960                   0,
 961                   GL_RGB,
 962                   size.width(),
 963                   size.height(),
 964                   0,
 965                   GL_RGB,
 966                   GL_UNSIGNED_BYTE,
 967                   NULL);
 968 }
 969
 970 void GLHelper::CopyTextureSubImage(GLuint texture, const gfx::Rect& rect) {
 971   content::ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 972   gl_->CopyTexSubImage2D(GL_TEXTURE_2D,
 973                          0,
 974                          rect.x(),
 975                          rect.y(),
 976                          rect.x(),
 977                          rect.y(),
 978                          rect.width(),
 979                          rect.height());
 980 }
 981
 982 void GLHelper::CopyTextureFullImage(GLuint texture, const gfx::Size& size) {
 983   content::ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl_, texture);
 984   gl_->CopyTexImage2D(
 985       GL_TEXTURE_2D, 0, GL_RGB, 0, 0, size.width(), size.height(), 0);
 986 }
 987
 988 void GLHelper::Flush() {
 989   gl_->Flush();
 990 }
 991
 992 void GLHelper::CopyTextureToImpl::ReadbackPlane(
 993     TextureFrameBufferPair* source,
 994     const scoped_refptr<media::VideoFrame>& target,
 995     int plane,
 996     int size_shift,
 997     const gfx::Rect& dst_subrect,
 998     ReadbackSwizzle swizzle,
 999     const base::Callback<void(bool)>& callback) {
1000   gl_->BindFramebuffer(GL_FRAMEBUFFER, source->framebuffer());
1001   size_t offset = target->stride(plane) * (dst_subrect.y() >> size_shift) +
1002       (dst_subrect.x() >> size_shift);
1003   ReadbackAsync(source->size(),
1004                 dst_subrect.width() >> size_shift,
1005                 target->stride(plane),
1006                 target->data(plane) + offset,
1007                 (swizzle == kSwizzleBGRA) ? GL_BGRA_EXT : GL_RGBA,
1008                 GL_UNSIGNED_BYTE,
1009                 4,
1010                 callback);
1011 }
1012
1013 const float GLHelper::CopyTextureToImpl::kRGBtoYColorWeights[] = {
1014     0.257f, 0.504f, 0.098f, 0.0625f};
1015 const float GLHelper::CopyTextureToImpl::kRGBtoUColorWeights[] = {
1016     -0.148f, -0.291f, 0.439f, 0.5f};
1017 const float GLHelper::CopyTextureToImpl::kRGBtoVColorWeights[] = {
1018     0.439f, -0.368f, -0.071f, 0.5f};
1019 const float GLHelper::CopyTextureToImpl::kRGBtoGrayscaleColorWeights[] = {
1020     0.213f, 0.715f, 0.072f, 0.0f};
1021
1022 // YUV readback constructors. Initiates the main scaler pipeline and
1023 // one planar scaler for each of the Y, U and V planes.
1024 GLHelper::CopyTextureToImpl::ReadbackYUVImpl::ReadbackYUVImpl(
1025     GLES2Interface* gl,
1026     CopyTextureToImpl* copy_impl,
1027     GLHelperScaling* scaler_impl,
1028     GLHelper::ScalerQuality quality,
1029     const gfx::Size& src_size,
1030     const gfx::Rect& src_subrect,
1031     const gfx::Size& dst_size,
1032     const gfx::Rect& dst_subrect,
1033     bool flip_vertically,
1034     ReadbackSwizzle swizzle)
1035     : gl_(gl),
1036       copy_impl_(copy_impl),
1037       dst_size_(dst_size),
1038       dst_subrect_(dst_subrect),
1039       swizzle_(swizzle),
1040       scaler_(gl,
1041               scaler_impl->CreateScaler(quality,
1042                                         src_size,
1043                                         src_subrect,
1044                                         dst_subrect.size(),
1045                                         flip_vertically,
1046                                         false)),
1047       y_(gl,
1048          scaler_impl->CreatePlanarScaler(
1049              dst_subrect.size(),
1050              gfx::Rect(0,
1051                        0,
1052                        (dst_subrect.width() + 3) & ~3,
1053                        dst_subrect.height()),
1054              gfx::Size((dst_subrect.width() + 3) / 4, dst_subrect.height()),
1055              false,
1056              (swizzle == kSwizzleBGRA),
1057              kRGBtoYColorWeights)),
1058       u_(gl,
1059          scaler_impl->CreatePlanarScaler(
1060              dst_subrect.size(),
1061              gfx::Rect(0,
1062                        0,
1063                        (dst_subrect.width() + 7) & ~7,
1064                        (dst_subrect.height() + 1) & ~1),
1065              gfx::Size((dst_subrect.width() + 7) / 8,
1066                        (dst_subrect.height() + 1) / 2),
1067              false,
1068              (swizzle == kSwizzleBGRA),
1069              kRGBtoUColorWeights)),
1070       v_(gl,
1071          scaler_impl->CreatePlanarScaler(
1072              dst_subrect.size(),
1073              gfx::Rect(0,
1074                        0,
1075                        (dst_subrect.width() + 7) & ~7,
1076                        (dst_subrect.height() + 1) & ~1),
1077              gfx::Size((dst_subrect.width() + 7) / 8,
1078                        (dst_subrect.height() + 1) / 2),
1079              false,
1080              (swizzle == kSwizzleBGRA),
1081              kRGBtoVColorWeights)) {
1082   DCHECK(!(dst_size.width() & 1));
1083   DCHECK(!(dst_size.height() & 1));
1084   DCHECK(!(dst_subrect.width() & 1));
1085   DCHECK(!(dst_subrect.height() & 1));
1086   DCHECK(!(dst_subrect.x() & 1));
1087   DCHECK(!(dst_subrect.y() & 1));
1088 }
1089
1090 static void CallbackKeepingVideoFrameAlive(
1091     scoped_refptr<media::VideoFrame> video_frame,
1092     const base::Callback<void(bool)>& callback,
1093     bool success) {
1094   callback.Run(success);
1095 }
1096
1097 void GLHelper::CopyTextureToImpl::ReadbackYUVImpl::ReadbackYUV(
1098     const gpu::Mailbox& mailbox,
1099     uint32 sync_point,
1100     const scoped_refptr<media::VideoFrame>& target,
1101     const base::Callback<void(bool)>& callback) {
1102   GLuint mailbox_texture =
1103       copy_impl_->ConsumeMailboxToTexture(mailbox, sync_point);
1104
1105   // Scale texture to right size.
1106   scaler_.Scale(mailbox_texture);
1107   gl_->DeleteTextures(1, &mailbox_texture);
1108
1109   // Convert the scaled texture in to Y, U and V planes.
1110   y_.Scale(scaler_.texture());
1111   u_.Scale(scaler_.texture());
1112   v_.Scale(scaler_.texture());
1113
1114   if (target->coded_size() != dst_size_) {
1115     DCHECK(target->coded_size() == dst_size_);
1116     LOG(ERROR) << "ReadbackYUV size error!";
1117     callback.Run(false);
1118     return;
1119   }
1120
1121   // Read back planes, one at a time. Keep the video frame alive while doing the
1122   // readback.
1123   copy_impl_->ReadbackPlane(y_.texture_and_framebuffer(),
1124                             target,
1125                             media::VideoFrame::kYPlane,
1126                             0,
1127                             dst_subrect_,
1128                             swizzle_,
1129                             base::Bind(&nullcallback));
1130   copy_impl_->ReadbackPlane(u_.texture_and_framebuffer(),
1131                             target,
1132                             media::VideoFrame::kUPlane,
1133                             1,
1134                             dst_subrect_,
1135                             swizzle_,
1136                             base::Bind(&nullcallback));
1137   copy_impl_->ReadbackPlane(
1138       v_.texture_and_framebuffer(),
1139       target,
1140       media::VideoFrame::kVPlane,
1141       1,
1142       dst_subrect_,
1143       swizzle_,
1144       base::Bind(&CallbackKeepingVideoFrameAlive, target, callback));
1145   gl_->BindFramebuffer(GL_FRAMEBUFFER, 0);
1146   media::LetterboxYUV(target.get(), dst_subrect_);
1147 }
1148
1149 // YUV readback constructors. Initiates the main scaler pipeline and
1150 // one planar scaler for each of the Y, U and V planes.
1151 GLHelper::CopyTextureToImpl::ReadbackYUV_MRT::ReadbackYUV_MRT(
1152     GLES2Interface* gl,
1153     CopyTextureToImpl* copy_impl,
1154     GLHelperScaling* scaler_impl,
1155     GLHelper::ScalerQuality quality,
1156     const gfx::Size& src_size,
1157     const gfx::Rect& src_subrect,
1158     const gfx::Size& dst_size,
1159     const gfx::Rect& dst_subrect,
1160     bool flip_vertically,
1161     ReadbackSwizzle swizzle)
1162     : gl_(gl),
1163       copy_impl_(copy_impl),
1164       dst_size_(dst_size),
1165       dst_subrect_(dst_subrect),
1166       quality_(quality),
1167       swizzle_(swizzle),
1168       scaler_(gl,
1169               scaler_impl->CreateScaler(quality,
1170                                         src_size,
1171                                         src_subrect,
1172                                         dst_subrect.size(),
1173                                         false,
1174                                         false)),
1175       pass1_shader_(scaler_impl->CreateYuvMrtShader(
1176           dst_subrect.size(),
1177           gfx::Rect(0, 0, (dst_subrect.width() + 3) & ~3, dst_subrect.height()),
1178           gfx::Size((dst_subrect.width() + 3) / 4, dst_subrect.height()),
1179           flip_vertically,
1180           (swizzle == kSwizzleBGRA),
1181           GLHelperScaling::SHADER_YUV_MRT_PASS1)),
1182       pass2_shader_(scaler_impl->CreateYuvMrtShader(
1183           gfx::Size((dst_subrect.width() + 3) / 4, dst_subrect.height()),
1184           gfx::Rect(0,
1185                     0,
1186                     (dst_subrect.width() + 7) / 8 * 2,
1187                     dst_subrect.height()),
1188           gfx::Size((dst_subrect.width() + 7) / 8,
1189                     (dst_subrect.height() + 1) / 2),
1190           false,
1191           (swizzle == kSwizzleBGRA),
1192           GLHelperScaling::SHADER_YUV_MRT_PASS2)),
1193       y_(gl, gfx::Size((dst_subrect.width() + 3) / 4, dst_subrect.height())),
1194       uv_(gl),
1195       u_(gl,
1196          gfx::Size((dst_subrect.width() + 7) / 8,
1197                    (dst_subrect.height() + 1) / 2)),
1198       v_(gl,
1199          gfx::Size((dst_subrect.width() + 7) / 8,
1200                    (dst_subrect.height() + 1) / 2)) {
1201
1202   content::ScopedTextureBinder<GL_TEXTURE_2D> texture_binder(gl, uv_);
1203   gl->TexImage2D(GL_TEXTURE_2D,
1204                  0,
1205                  GL_RGBA,
1206                  (dst_subrect.width() + 3) / 4,
1207                  dst_subrect.height(),
1208                  0,
1209                  GL_RGBA,
1210                  GL_UNSIGNED_BYTE,
1211                  NULL);
1212
1213   DCHECK(!(dst_size.width() & 1));
1214   DCHECK(!(dst_size.height() & 1));
1215   DCHECK(!(dst_subrect.width() & 1));
1216   DCHECK(!(dst_subrect.height() & 1));
1217   DCHECK(!(dst_subrect.x() & 1));
1218   DCHECK(!(dst_subrect.y() & 1));
1219 }
1220
1221 void GLHelper::CopyTextureToImpl::ReadbackYUV_MRT::ReadbackYUV(
1222     const gpu::Mailbox& mailbox,
1223     uint32 sync_point,
1224     const scoped_refptr<media::VideoFrame>& target,
1225     const base::Callback<void(bool)>& callback) {
1226   GLuint mailbox_texture =
1227       copy_impl_->ConsumeMailboxToTexture(mailbox, sync_point);
1228
1229   GLuint texture;
1230   if (quality_ == GLHelper::SCALER_QUALITY_FAST) {
1231     // Optimization: SCALER_QUALITY_FAST is just a single bilinear
1232     // pass, which pass1_shader_ can do just as well, so let's skip
1233     // the actual scaling in that case.
1234     texture = mailbox_texture;
1235   } else {
1236     // Scale texture to right size.
1237     scaler_.Scale(mailbox_texture);
1238     texture = scaler_.texture();
1239   }
1240
1241   std::vector<GLuint> outputs(2);
1242   // Convert the scaled texture in to Y, U and V planes.
1243   outputs[0] = y_.texture();
1244   outputs[1] = uv_;
1245   pass1_shader_->Execute(texture, outputs);
1246
1247   gl_->DeleteTextures(1, &mailbox_texture);
1248
1249   outputs[0] = u_.texture();
1250   outputs[1] = v_.texture();
1251   pass2_shader_->Execute(uv_, outputs);
1252
1253   if (target->coded_size() != dst_size_) {
1254     DCHECK(target->coded_size() == dst_size_);
1255     LOG(ERROR) << "ReadbackYUV size error!";
1256     callback.Run(false);
1257     return;
1258   }
1259
1260   // Read back planes, one at a time.
1261   copy_impl_->ReadbackPlane(&y_,
1262                             target,
1263                             media::VideoFrame::kYPlane,
1264                             0,
1265                             dst_subrect_,
1266                             swizzle_,
1267                             base::Bind(&nullcallback));
1268   copy_impl_->ReadbackPlane(&u_,
1269                             target,
1270                             media::VideoFrame::kUPlane,
1271                             1,
1272                             dst_subrect_,
1273                             swizzle_,
1274                             base::Bind(&nullcallback));
1275   copy_impl_->ReadbackPlane(
1276       &v_,
1277       target,
1278       media::VideoFrame::kVPlane,
1279       1,
1280       dst_subrect_,
1281       swizzle_,
1282       base::Bind(&CallbackKeepingVideoFrameAlive, target, callback));
1283   gl_->BindFramebuffer(GL_FRAMEBUFFER, 0);
1284   media::LetterboxYUV(target.get(), dst_subrect_);
1285 }
1286
1287 bool GLHelper::IsReadbackConfigSupported(SkColorType color_type) {
1288   DCHECK(readback_support_.get());
1289   GLenum format, type;
1290   size_t bytes_per_pixel;
1291   FormatSupport support = readback_support_->GetReadbackConfig(
1292       color_type, false, &format, &type, &bytes_per_pixel);
1293
1294   return (support == GLHelperReadbackSupport::SUPPORTED);
1295 }
1296
1297 ReadbackYUVInterface* GLHelper::CopyTextureToImpl::CreateReadbackPipelineYUV(
1298     GLHelper::ScalerQuality quality,
1299     const gfx::Size& src_size,
1300     const gfx::Rect& src_subrect,
1301     const gfx::Size& dst_size,
1302     const gfx::Rect& dst_subrect,
1303     bool flip_vertically,
1304     bool use_mrt) {
1305   helper_->InitScalerImpl();
1306   // Just query if the best readback configuration needs a swizzle In
1307   // ReadbackPlane() we will choose GL_RGBA/GL_BGRA_EXT based on swizzle
1308   GLenum format, type;
1309   size_t bytes_per_pixel;
1310   FormatSupport supported = GetReadbackConfig(
1311       kRGBA_8888_SkColorType, true, &format, &type, &bytes_per_pixel);
1312   DCHECK((format == GL_RGBA || format == GL_BGRA_EXT) &&
1313          type == GL_UNSIGNED_BYTE);
1314
1315   ReadbackSwizzle swizzle = kSwizzleNone;
1316   if (supported == GLHelperReadbackSupport::SWIZZLE)
1317     swizzle = kSwizzleBGRA;
1318
1319   if (max_draw_buffers_ >= 2 && use_mrt) {
1320     return new ReadbackYUV_MRT(gl_,
1321                                this,
1322                                helper_->scaler_impl_.get(),
1323                                quality,
1324                                src_size,
1325                                src_subrect,
1326                                dst_size,
1327                                dst_subrect,
1328                                flip_vertically,
1329                                swizzle);
1330   }
1331   return new ReadbackYUVImpl(gl_,
1332                              this,
1333                              helper_->scaler_impl_.get(),
1334                              quality,
1335                              src_size,
1336                              src_subrect,
1337                              dst_size,
1338                              dst_subrect,
1339                              flip_vertically,
1340                              swizzle);
1341 }
1342
1343 ReadbackYUVInterface* GLHelper::CreateReadbackPipelineYUV(
1344     ScalerQuality quality,
1345     const gfx::Size& src_size,
1346     const gfx::Rect& src_subrect,
1347     const gfx::Size& dst_size,
1348     const gfx::Rect& dst_subrect,
1349     bool flip_vertically,
1350     bool use_mrt) {
1351   InitCopyTextToImpl();
1352   return copy_texture_to_impl_->CreateReadbackPipelineYUV(quality,
1353                                                           src_size,
1354                                                           src_subrect,
1355                                                           dst_size,
1356                                                           dst_subrect,
1357                                                           flip_vertically,
1358                                                           use_mrt);
1359 }
1360
1361 }  // namespace content