content/common/gpu/media/rendering_helper.cc

   1 // Copyright 2013 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/media/rendering_helper.h"
   6
   7 #include <algorithm>
   8 #include <numeric>
   9 #include <vector>
  10
  11 #include "base/bind.h"
  12 #include "base/callback_helpers.h"
  13 #include "base/command_line.h"
  14 #include "base/mac/scoped_nsautorelease_pool.h"
  15 #include "base/message_loop/message_loop.h"
  16 #include "base/run_loop.h"
  17 #include "base/strings/stringize_macros.h"
  18 #include "base/synchronization/waitable_event.h"
  19 #include "base/time/time.h"
  20 #include "ui/gl/gl_context.h"
  21 #include "ui/gl/gl_implementation.h"
  22 #include "ui/gl/gl_surface.h"
  23
  24 #if defined(OS_WIN)
  25 #include <windows.h>
  26 #endif
  27
  28 #if defined(USE_X11)
  29 #include "ui/gfx/x/x11_types.h"
  30 #endif
  31
  32 #if defined(ARCH_CPU_X86_FAMILY) && defined(USE_X11)
  33 #include "ui/gl/gl_surface_glx.h"
  34 #define GL_VARIANT_GLX 1
  35 #else
  36 #include "ui/gl/gl_surface_egl.h"
  37 #define GL_VARIANT_EGL 1
  38 #endif
  39
  40 #if defined(USE_OZONE)
  41 #if defined(OS_CHROMEOS)
  42 #include "ui/display/chromeos/display_configurator.h"
  43 #include "ui/display/types/native_display_delegate.h"
  44 #endif  // defined(OS_CHROMEOS)
  45 #include "ui/ozone/public/ozone_platform.h"
  46 #include "ui/platform_window/platform_window.h"
  47 #include "ui/platform_window/platform_window_delegate.h"
  48 #endif  // defined(USE_OZONE)
  49
  50 // Helper for Shader creation.
  51 static void CreateShader(GLuint program,
  52                          GLenum type,
  53                          const char* source,
  54                          int size) {
  55   GLuint shader = glCreateShader(type);
  56   glShaderSource(shader, 1, &source, &size);
  57   glCompileShader(shader);
  58   int result = GL_FALSE;
  59   glGetShaderiv(shader, GL_COMPILE_STATUS, &result);
  60   if (!result) {
  61     char log[4096];
  62     glGetShaderInfoLog(shader, arraysize(log), NULL, log);
  63     LOG(FATAL) << log;
  64   }
  65   glAttachShader(program, shader);
  66   glDeleteShader(shader);
  67   CHECK_EQ(static_cast<int>(glGetError()), GL_NO_ERROR);
  68 }
  69
  70 namespace content {
  71 namespace {
  72
  73 void WaitForSwapAck(const base::Closure& callback, gfx::SwapResult result) {
  74   callback.Run();
  75 }
  76
  77 }  // namespace
  78
  79 #if defined(USE_OZONE)
  80
  81 class DisplayConfiguratorObserver : public ui::DisplayConfigurator::Observer {
  82  public:
  83   DisplayConfiguratorObserver(base::RunLoop* loop) : loop_(loop) {}
  84   ~DisplayConfiguratorObserver() override {}
  85
  86  private:
  87   // ui::DisplayConfigurator::Observer overrides:
  88   void OnDisplayModeChanged(
  89       const ui::DisplayConfigurator::DisplayStateList& outputs) override {
  90     if (!loop_)
  91       return;
  92     loop_->Quit();
  93     loop_ = nullptr;
  94   }
  95   void OnDisplayModeChangeFailed(
  96       const ui::DisplayConfigurator::DisplayStateList& outputs,
  97       ui::MultipleDisplayState failed_new_state) override {
  98     LOG(FATAL) << "Could not configure display";
  99   }
 100
 101   base::RunLoop* loop_;
 102
 103   DISALLOW_COPY_AND_ASSIGN(DisplayConfiguratorObserver);
 104 };
 105
 106 class RenderingHelper::StubOzoneDelegate : public ui::PlatformWindowDelegate {
 107  public:
 108   StubOzoneDelegate() : accelerated_widget_(gfx::kNullAcceleratedWidget) {
 109     platform_window_ = ui::OzonePlatform::GetInstance()->CreatePlatformWindow(
 110         this, gfx::Rect());
 111   }
 112   ~StubOzoneDelegate() override {}
 113
 114   void OnBoundsChanged(const gfx::Rect& new_bounds) override {}
 115
 116   void OnDamageRect(const gfx::Rect& damaged_region) override {}
 117
 118   void DispatchEvent(ui::Event* event) override {}
 119
 120   void OnCloseRequest() override {}
 121   void OnClosed() override {}
 122
 123   void OnWindowStateChanged(ui::PlatformWindowState new_state) override {}
 124
 125   void OnLostCapture() override {};
 126
 127   void OnAcceleratedWidgetAvailable(gfx::AcceleratedWidget widget,
 128                                     float device_pixel_ratio) override {
 129     accelerated_widget_ = widget;
 130   }
 131
 132   void OnActivationChanged(bool active) override {};
 133
 134   gfx::AcceleratedWidget accelerated_widget() const {
 135     return accelerated_widget_;
 136   }
 137
 138   gfx::Size GetSize() { return platform_window_->GetBounds().size(); }
 139
 140   ui::PlatformWindow* platform_window() const { return platform_window_.get(); }
 141
 142  private:
 143   scoped_ptr<ui::PlatformWindow> platform_window_;
 144   gfx::AcceleratedWidget accelerated_widget_;
 145
 146   DISALLOW_COPY_AND_ASSIGN(StubOzoneDelegate);
 147 };
 148
 149 #endif  // defined(USE_OZONE)
 150
 151 RenderingHelperParams::RenderingHelperParams()
 152     : rendering_fps(0), warm_up_iterations(0), render_as_thumbnails(false) {
 153 }
 154
 155 RenderingHelperParams::~RenderingHelperParams() {}
 156
 157 VideoFrameTexture::VideoFrameTexture(uint32 texture_target,
 158                                      uint32 texture_id,
 159                                      const base::Closure& no_longer_needed_cb)
 160     : texture_target_(texture_target),
 161       texture_id_(texture_id),
 162       no_longer_needed_cb_(no_longer_needed_cb) {
 163   DCHECK(!no_longer_needed_cb_.is_null());
 164 }
 165
 166 VideoFrameTexture::~VideoFrameTexture() {
 167   base::ResetAndReturn(&no_longer_needed_cb_).Run();
 168 }
 169
 170 RenderingHelper::RenderedVideo::RenderedVideo()
 171     : is_flushing(false), frames_to_drop(0) {
 172 }
 173
 174 RenderingHelper::RenderedVideo::~RenderedVideo() {
 175 }
 176
 177 // static
 178 void RenderingHelper::InitializeOneOff(base::WaitableEvent* done) {
 179   base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
 180 #if GL_VARIANT_GLX
 181   cmd_line->AppendSwitchASCII(switches::kUseGL,
 182                               gfx::kGLImplementationDesktopName);
 183 #else
 184   cmd_line->AppendSwitchASCII(switches::kUseGL, gfx::kGLImplementationEGLName);
 185 #endif
 186
 187   if (!gfx::GLSurface::InitializeOneOff())
 188     LOG(FATAL) << "Could not initialize GL";
 189   done->Signal();
 190 }
 191
 192 RenderingHelper::RenderingHelper() : ignore_vsync_(false) {
 193   window_ = gfx::kNullAcceleratedWidget;
 194   Clear();
 195 }
 196
 197 RenderingHelper::~RenderingHelper() {
 198   CHECK_EQ(videos_.size(), 0U) << "Must call UnInitialize before dtor.";
 199   Clear();
 200 }
 201
 202 void RenderingHelper::Setup() {
 203 #if defined(OS_WIN)
 204   window_ = CreateWindowEx(0,
 205                            L"Static",
 206                            L"VideoDecodeAcceleratorTest",
 207                            WS_OVERLAPPEDWINDOW | WS_VISIBLE,
 208                            0,
 209                            0,
 210                            GetSystemMetrics(SM_CXSCREEN),
 211                            GetSystemMetrics(SM_CYSCREEN),
 212                            NULL,
 213                            NULL,
 214                            NULL,
 215                            NULL);
 216 #elif defined(USE_X11)
 217   Display* display = gfx::GetXDisplay();
 218   Screen* screen = DefaultScreenOfDisplay(display);
 219
 220   CHECK(display);
 221
 222   XSetWindowAttributes window_attributes;
 223   memset(&window_attributes, 0, sizeof(window_attributes));
 224   window_attributes.background_pixel =
 225       BlackPixel(display, DefaultScreen(display));
 226   window_attributes.override_redirect = true;
 227   int depth = DefaultDepth(display, DefaultScreen(display));
 228
 229   window_ = XCreateWindow(display,
 230                           DefaultRootWindow(display),
 231                           0,
 232                           0,
 233                           XWidthOfScreen(screen),
 234                           XHeightOfScreen(screen),
 235                           0 /* border width */,
 236                           depth,
 237                           CopyFromParent /* class */,
 238                           CopyFromParent /* visual */,
 239                           (CWBackPixel | CWOverrideRedirect),
 240                           &window_attributes);
 241   XStoreName(display, window_, "VideoDecodeAcceleratorTest");
 242   XSelectInput(display, window_, ExposureMask);
 243   XMapWindow(display, window_);
 244 #elif defined(USE_OZONE)
 245   base::MessageLoop::ScopedNestableTaskAllower nest_loop(
 246       base::MessageLoop::current());
 247   base::RunLoop wait_window_resize;
 248
 249   platform_window_delegate_.reset(new RenderingHelper::StubOzoneDelegate());
 250   window_ = platform_window_delegate_->accelerated_widget();
 251   gfx::Size window_size(800, 600);
 252   // Ignore the vsync provider by default. On ChromeOS this will be set
 253   // accordingly based on the display configuration.
 254   ignore_vsync_ = true;
 255 #if defined(OS_CHROMEOS)
 256   // We hold onto the main loop here to wait for the DisplayController
 257   // to give us the size of the display so we can create a window of
 258   // the same size.
 259   base::RunLoop wait_display_setup;
 260   DisplayConfiguratorObserver display_setup_observer(&wait_display_setup);
 261   display_configurator_.reset(new ui::DisplayConfigurator());
 262   display_configurator_->SetDelegateForTesting(0);
 263   display_configurator_->AddObserver(&display_setup_observer);
 264   display_configurator_->Init(true);
 265   display_configurator_->ForceInitialConfigure(0);
 266   // Make sure all the display configuration is applied.
 267   wait_display_setup.Run();
 268   display_configurator_->RemoveObserver(&display_setup_observer);
 269
 270   gfx::Size framebuffer_size = display_configurator_->framebuffer_size();
 271   if (!framebuffer_size.IsEmpty()) {
 272     window_size = framebuffer_size;
 273     ignore_vsync_ = false;
 274   }
 275 #endif
 276   if (ignore_vsync_)
 277     DVLOG(1) << "Ignoring vsync provider";
 278
 279   platform_window_delegate_->platform_window()->SetBounds(
 280       gfx::Rect(window_size));
 281
 282   // On Ozone/DRI, platform windows are associated with the physical
 283   // outputs. Association is achieved by matching the bounds of the
 284   // window with the origin & modeset of the display output. Until a
 285   // window is associated with a display output, we cannot get vsync
 286   // events, because there is no hardware to get events from. Here we
 287   // wait for the window to resized and therefore associated with
 288   // display output to be sure that we will get such events.
 289   wait_window_resize.RunUntilIdle();
 290 #else
 291 #error unknown platform
 292 #endif
 293   CHECK(window_ != gfx::kNullAcceleratedWidget);
 294 }
 295
 296 void RenderingHelper::TearDown() {
 297 #if defined(OS_WIN)
 298   if (window_)
 299     DestroyWindow(window_);
 300 #elif defined(USE_X11)
 301   // Destroy resources acquired in Initialize, in reverse-acquisition order.
 302   if (window_) {
 303     CHECK(XUnmapWindow(gfx::GetXDisplay(), window_));
 304     CHECK(XDestroyWindow(gfx::GetXDisplay(), window_));
 305   }
 306 #elif defined(USE_OZONE)
 307   platform_window_delegate_.reset();
 308 #if defined(OS_CHROMEOS)
 309   display_configurator_->PrepareForExit();
 310   display_configurator_.reset();
 311 #endif
 312 #endif
 313   window_ = gfx::kNullAcceleratedWidget;
 314 }
 315
 316 void RenderingHelper::Initialize(const RenderingHelperParams& params,
 317                                  base::WaitableEvent* done) {
 318   // Use videos_.size() != 0 as a proxy for the class having already been
 319   // Initialize()'d, and UnInitialize() before continuing.
 320   if (videos_.size()) {
 321     base::WaitableEvent done(false, false);
 322     UnInitialize(&done);
 323     done.Wait();
 324   }
 325
 326   render_task_.Reset(
 327       base::Bind(&RenderingHelper::RenderContent, base::Unretained(this)));
 328
 329   frame_duration_ = params.rendering_fps > 0
 330                         ? base::TimeDelta::FromSeconds(1) / params.rendering_fps
 331                         : base::TimeDelta();
 332
 333   render_as_thumbnails_ = params.render_as_thumbnails;
 334   message_loop_ = base::MessageLoop::current();
 335
 336   gl_surface_ = gfx::GLSurface::CreateViewGLSurface(window_);
 337 #if defined(USE_OZONE)
 338   gl_surface_->Resize(platform_window_delegate_->GetSize());
 339 #endif  // defined(USE_OZONE)
 340   screen_size_ = gl_surface_->GetSize();
 341
 342   gl_context_ = gfx::GLContext::CreateGLContext(
 343       NULL, gl_surface_.get(), gfx::PreferIntegratedGpu);
 344   CHECK(gl_context_->MakeCurrent(gl_surface_.get()));
 345
 346   CHECK_GT(params.window_sizes.size(), 0U);
 347   videos_.resize(params.window_sizes.size());
 348   LayoutRenderingAreas(params.window_sizes);
 349
 350   if (render_as_thumbnails_) {
 351     CHECK_EQ(videos_.size(), 1U);
 352
 353     GLint max_texture_size;
 354     glGetIntegerv(GL_MAX_TEXTURE_SIZE, &max_texture_size);
 355     CHECK_GE(max_texture_size, params.thumbnails_page_size.width());
 356     CHECK_GE(max_texture_size, params.thumbnails_page_size.height());
 357
 358     thumbnails_fbo_size_ = params.thumbnails_page_size;
 359     thumbnail_size_ = params.thumbnail_size;
 360
 361     glGenFramebuffersEXT(1, &thumbnails_fbo_id_);
 362     glGenTextures(1, &thumbnails_texture_id_);
 363     glBindTexture(GL_TEXTURE_2D, thumbnails_texture_id_);
 364     glTexImage2D(GL_TEXTURE_2D,
 365                  0,
 366                  GL_RGB,
 367                  thumbnails_fbo_size_.width(),
 368                  thumbnails_fbo_size_.height(),
 369                  0,
 370                  GL_RGB,
 371                  GL_UNSIGNED_SHORT_5_6_5,
 372                  NULL);
 373     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 374     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 375     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 376     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 377     glBindTexture(GL_TEXTURE_2D, 0);
 378
 379     glBindFramebufferEXT(GL_FRAMEBUFFER, thumbnails_fbo_id_);
 380     glFramebufferTexture2DEXT(GL_FRAMEBUFFER,
 381                               GL_COLOR_ATTACHMENT0,
 382                               GL_TEXTURE_2D,
 383                               thumbnails_texture_id_,
 384                               0);
 385
 386     GLenum fb_status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER);
 387     CHECK(fb_status == GL_FRAMEBUFFER_COMPLETE) << fb_status;
 388     glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 389     glClear(GL_COLOR_BUFFER_BIT);
 390     glBindFramebufferEXT(GL_FRAMEBUFFER,
 391                          gl_surface_->GetBackingFrameBufferObject());
 392   }
 393
 394   // These vertices and texture coords. map (0,0) in the texture to the
 395   // bottom left of the viewport.  Since we get the video frames with the
 396   // the top left at (0,0) we need to flip the texture y coordinate
 397   // in the vertex shader for this to be rendered the right way up.
 398   // In the case of thumbnail rendering we use the same vertex shader
 399   // to render the FBO the screen, where we do not want this flipping.
 400   static const float kVertices[] =
 401       { -1.f, 1.f, -1.f, -1.f, 1.f, 1.f, 1.f, -1.f, };
 402   static const float kTextureCoords[] = { 0, 1, 0, 0, 1, 1, 1, 0, };
 403   static const char kVertexShader[] = STRINGIZE(
 404       varying vec2 interp_tc;
 405       attribute vec4 in_pos;
 406       attribute vec2 in_tc;
 407       uniform bool tex_flip;
 408       void main() {
 409         if (tex_flip)
 410           interp_tc = vec2(in_tc.x, 1.0 - in_tc.y);
 411         else
 412           interp_tc = in_tc;
 413         gl_Position = in_pos;
 414       });
 415
 416 #if GL_VARIANT_EGL
 417   static const char kFragmentShader[] =
 418       "#extension GL_OES_EGL_image_external : enable\n"
 419       "precision mediump float;\n"
 420       "varying vec2 interp_tc;\n"
 421       "uniform sampler2D tex;\n"
 422       "#ifdef GL_OES_EGL_image_external\n"
 423       "uniform samplerExternalOES tex_external;\n"
 424       "#endif\n"
 425       "void main() {\n"
 426       "  vec4 color = texture2D(tex, interp_tc);\n"
 427       "#ifdef GL_OES_EGL_image_external\n"
 428       "  color += texture2D(tex_external, interp_tc);\n"
 429       "#endif\n"
 430       "  gl_FragColor = color;\n"
 431       "}\n";
 432 #else
 433   static const char kFragmentShader[] = STRINGIZE(
 434       varying vec2 interp_tc;
 435       uniform sampler2D tex;
 436       void main() {
 437         gl_FragColor = texture2D(tex, interp_tc);
 438       });
 439 #endif
 440   program_ = glCreateProgram();
 441   CreateShader(
 442       program_, GL_VERTEX_SHADER, kVertexShader, arraysize(kVertexShader));
 443   CreateShader(program_,
 444                GL_FRAGMENT_SHADER,
 445                kFragmentShader,
 446                arraysize(kFragmentShader));
 447   glLinkProgram(program_);
 448   int result = GL_FALSE;
 449   glGetProgramiv(program_, GL_LINK_STATUS, &result);
 450   if (!result) {
 451     char log[4096];
 452     glGetShaderInfoLog(program_, arraysize(log), NULL, log);
 453     LOG(FATAL) << log;
 454   }
 455   glUseProgram(program_);
 456   glDeleteProgram(program_);
 457
 458   glUniform1i(glGetUniformLocation(program_, "tex_flip"), 0);
 459   glUniform1i(glGetUniformLocation(program_, "tex"), 0);
 460   GLint tex_external = glGetUniformLocation(program_, "tex_external");
 461   if (tex_external != -1) {
 462     glUniform1i(tex_external, 1);
 463   }
 464   int pos_location = glGetAttribLocation(program_, "in_pos");
 465   glEnableVertexAttribArray(pos_location);
 466   glVertexAttribPointer(pos_location, 2, GL_FLOAT, GL_FALSE, 0, kVertices);
 467   int tc_location = glGetAttribLocation(program_, "in_tc");
 468   glEnableVertexAttribArray(tc_location);
 469   glVertexAttribPointer(tc_location, 2, GL_FLOAT, GL_FALSE, 0, kTextureCoords);
 470
 471   if (frame_duration_ != base::TimeDelta()) {
 472     int warm_up_iterations = params.warm_up_iterations;
 473 #if defined(USE_OZONE)
 474     // On Ozone the VSyncProvider can't provide a vsync interval until
 475     // we render at least a frame, so we warm up with at least one
 476     // frame.
 477     // On top of this, we want to make sure all the buffers backing
 478     // the GL surface are cleared, otherwise we can see the previous
 479     // test's last frames, so we set warm up iterations to 2, to clear
 480     // the front and back buffers.
 481     warm_up_iterations = std::max(2, warm_up_iterations);
 482 #endif
 483     WarmUpRendering(warm_up_iterations);
 484   }
 485
 486   // It's safe to use Unretained here since |rendering_thread_| will be stopped
 487   // in VideoDecodeAcceleratorTest.TearDown(), while the |rendering_helper_| is
 488   // a member of that class. (See video_decode_accelerator_unittest.cc.)
 489   gfx::VSyncProvider* vsync_provider = gl_surface_->GetVSyncProvider();
 490
 491   // VSync providers rely on the underlying CRTC to get the timing. In headless
 492   // mode the surface isn't associated with a CRTC so the vsync provider can not
 493   // get the timing, meaning it will not call UpdateVsyncParameters() ever.
 494   if (!ignore_vsync_ && vsync_provider && frame_duration_ != base::TimeDelta())
 495     vsync_provider->GetVSyncParameters(base::Bind(
 496         &RenderingHelper::UpdateVSyncParameters, base::Unretained(this), done));
 497   else
 498     done->Signal();
 499 }
 500
 501 // The rendering for the first few frames is slow (e.g., 100ms on Peach Pit).
 502 // This affects the numbers measured in the performance test. We try to render
 503 // several frames here to warm up the rendering.
 504 void RenderingHelper::WarmUpRendering(int warm_up_iterations) {
 505   unsigned int texture_id;
 506   scoped_ptr<GLubyte[]> emptyData(new GLubyte[screen_size_.GetArea() * 2]());
 507   glGenTextures(1, &texture_id);
 508   glBindTexture(GL_TEXTURE_2D, texture_id);
 509   glTexImage2D(GL_TEXTURE_2D,
 510                0,
 511                GL_RGB,
 512                screen_size_.width(),
 513                screen_size_.height(),
 514                0,
 515                GL_RGB,
 516                GL_UNSIGNED_SHORT_5_6_5,
 517                emptyData.get());
 518   for (int i = 0; i < warm_up_iterations; ++i) {
 519     RenderTexture(GL_TEXTURE_2D, texture_id);
 520
 521     // Need to allow nestable tasks since WarmUpRendering() is called from
 522     // within another task on the renderer thread.
 523     base::MessageLoop::ScopedNestableTaskAllower allow(
 524         base::MessageLoop::current());
 525     base::RunLoop wait_for_swap_ack;
 526     gl_surface_->SwapBuffersAsync(
 527         base::Bind(&WaitForSwapAck, wait_for_swap_ack.QuitClosure()));
 528     wait_for_swap_ack.Run();
 529   }
 530   glDeleteTextures(1, &texture_id);
 531 }
 532
 533 void RenderingHelper::UnInitialize(base::WaitableEvent* done) {
 534   CHECK_EQ(base::MessageLoop::current(), message_loop_);
 535
 536   render_task_.Cancel();
 537
 538   if (render_as_thumbnails_) {
 539     glDeleteTextures(1, &thumbnails_texture_id_);
 540     glDeleteFramebuffersEXT(1, &thumbnails_fbo_id_);
 541   }
 542
 543   gl_surface_->Destroy();
 544   gl_context_->ReleaseCurrent(gl_surface_.get());
 545   gl_context_ = NULL;
 546   gl_surface_ = NULL;
 547
 548   Clear();
 549   done->Signal();
 550 }
 551
 552 void RenderingHelper::CreateTexture(uint32 texture_target,
 553                                     uint32* texture_id,
 554                                     const gfx::Size& size,
 555                                     base::WaitableEvent* done) {
 556   if (base::MessageLoop::current() != message_loop_) {
 557     message_loop_->PostTask(FROM_HERE,
 558                             base::Bind(&RenderingHelper::CreateTexture,
 559                                        base::Unretained(this),
 560                                        texture_target,
 561                                        texture_id,
 562                                        size,
 563                                        done));
 564     return;
 565   }
 566   glGenTextures(1, texture_id);
 567   glBindTexture(texture_target, *texture_id);
 568   if (texture_target == GL_TEXTURE_2D) {
 569     glTexImage2D(GL_TEXTURE_2D,
 570                  0,
 571                  GL_RGBA,
 572                  size.width(),
 573                  size.height(),
 574                  0,
 575                  GL_RGBA,
 576                  GL_UNSIGNED_BYTE,
 577                  NULL);
 578   }
 579   glTexParameteri(texture_target, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 580   glTexParameteri(texture_target, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 581   // OpenGLES2.0.25 section 3.8.2 requires CLAMP_TO_EDGE for NPOT textures.
 582   glTexParameteri(texture_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 583   glTexParameteri(texture_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 584   CHECK_EQ(static_cast<int>(glGetError()), GL_NO_ERROR);
 585   done->Signal();
 586 }
 587
 588 // Helper function to set GL viewport.
 589 static inline void GLSetViewPort(const gfx::Rect& area) {
 590   glViewport(area.x(), area.y(), area.width(), area.height());
 591   glScissor(area.x(), area.y(), area.width(), area.height());
 592 }
 593
 594 void RenderingHelper::RenderThumbnail(uint32 texture_target,
 595                                       uint32 texture_id) {
 596   CHECK_EQ(base::MessageLoop::current(), message_loop_);
 597   const int width = thumbnail_size_.width();
 598   const int height = thumbnail_size_.height();
 599   const int thumbnails_in_row = thumbnails_fbo_size_.width() / width;
 600   const int thumbnails_in_column = thumbnails_fbo_size_.height() / height;
 601   const int row = (frame_count_ / thumbnails_in_row) % thumbnails_in_column;
 602   const int col = frame_count_ % thumbnails_in_row;
 603
 604   gfx::Rect area(col * width, row * height, width, height);
 605
 606   glUniform1i(glGetUniformLocation(program_, "tex_flip"), 0);
 607   glBindFramebufferEXT(GL_FRAMEBUFFER, thumbnails_fbo_id_);
 608   GLSetViewPort(area);
 609   RenderTexture(texture_target, texture_id);
 610   glBindFramebufferEXT(GL_FRAMEBUFFER,
 611                        gl_surface_->GetBackingFrameBufferObject());
 612
 613   // Need to flush the GL commands before we return the tnumbnail texture to
 614   // the decoder.
 615   glFlush();
 616   ++frame_count_;
 617 }
 618
 619 void RenderingHelper::QueueVideoFrame(
 620     size_t window_id,
 621     scoped_refptr<VideoFrameTexture> video_frame) {
 622   CHECK_EQ(base::MessageLoop::current(), message_loop_);
 623   RenderedVideo* video = &videos_[window_id];
 624   DCHECK(!video->is_flushing);
 625
 626   video->pending_frames.push(video_frame);
 627
 628   if (video->frames_to_drop > 0 && video->pending_frames.size() > 1) {
 629     --video->frames_to_drop;
 630     video->pending_frames.pop();
 631   }
 632
 633   // Schedules the first RenderContent() if need.
 634   if (scheduled_render_time_.is_null()) {
 635     scheduled_render_time_ = base::TimeTicks::Now();
 636     message_loop_->PostTask(FROM_HERE, render_task_.callback());
 637   }
 638 }
 639
 640 void RenderingHelper::RenderTexture(uint32 texture_target, uint32 texture_id) {
 641   // The ExternalOES sampler is bound to GL_TEXTURE1 and the Texture2D sampler
 642   // is bound to GL_TEXTURE0.
 643   if (texture_target == GL_TEXTURE_2D) {
 644     glActiveTexture(GL_TEXTURE0 + 0);
 645   } else if (texture_target == GL_TEXTURE_EXTERNAL_OES) {
 646     glActiveTexture(GL_TEXTURE0 + 1);
 647   }
 648   glBindTexture(texture_target, texture_id);
 649   glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 650   glBindTexture(texture_target, 0);
 651   CHECK_EQ(static_cast<int>(glGetError()), GL_NO_ERROR);
 652 }
 653
 654 void RenderingHelper::DeleteTexture(uint32 texture_id) {
 655   CHECK_EQ(base::MessageLoop::current(), message_loop_);
 656   glDeleteTextures(1, &texture_id);
 657   CHECK_EQ(static_cast<int>(glGetError()), GL_NO_ERROR);
 658 }
 659
 660 scoped_refptr<gfx::GLContext> RenderingHelper::GetGLContext() {
 661   return gl_context_;
 662 }
 663
 664 void* RenderingHelper::GetGLContextHandle() {
 665   return gl_context_->GetHandle();
 666 }
 667
 668 void* RenderingHelper::GetGLDisplay() {
 669   return gl_surface_->GetDisplay();
 670 }
 671
 672 void RenderingHelper::Clear() {
 673   videos_.clear();
 674   message_loop_ = NULL;
 675   gl_context_ = NULL;
 676   gl_surface_ = NULL;
 677
 678   render_as_thumbnails_ = false;
 679   frame_count_ = 0;
 680   thumbnails_fbo_id_ = 0;
 681   thumbnails_texture_id_ = 0;
 682 }
 683
 684 void RenderingHelper::GetThumbnailsAsRGB(std::vector<unsigned char>* rgb,
 685                                          bool* alpha_solid,
 686                                          base::WaitableEvent* done) {
 687   CHECK(render_as_thumbnails_);
 688
 689   const size_t num_pixels = thumbnails_fbo_size_.GetArea();
 690   std::vector<unsigned char> rgba;
 691   rgba.resize(num_pixels * 4);
 692   glBindFramebufferEXT(GL_FRAMEBUFFER, thumbnails_fbo_id_);
 693   glPixelStorei(GL_PACK_ALIGNMENT, 1);
 694   // We can only count on GL_RGBA/GL_UNSIGNED_BYTE support.
 695   glReadPixels(0,
 696                0,
 697                thumbnails_fbo_size_.width(),
 698                thumbnails_fbo_size_.height(),
 699                GL_RGBA,
 700                GL_UNSIGNED_BYTE,
 701                &rgba[0]);
 702   glBindFramebufferEXT(GL_FRAMEBUFFER,
 703                        gl_surface_->GetBackingFrameBufferObject());
 704   rgb->resize(num_pixels * 3);
 705   // Drop the alpha channel, but check as we go that it is all 0xff.
 706   bool solid = true;
 707   unsigned char* rgb_ptr = &((*rgb)[0]);
 708   unsigned char* rgba_ptr = &rgba[0];
 709   for (size_t i = 0; i < num_pixels; ++i) {
 710     *rgb_ptr++ = *rgba_ptr++;
 711     *rgb_ptr++ = *rgba_ptr++;
 712     *rgb_ptr++ = *rgba_ptr++;
 713     solid = solid && (*rgba_ptr == 0xff);
 714     rgba_ptr++;
 715   }
 716   *alpha_solid = solid;
 717
 718   done->Signal();
 719 }
 720
 721 void RenderingHelper::Flush(size_t window_id) {
 722   videos_[window_id].is_flushing = true;
 723 }
 724
 725 void RenderingHelper::RenderContent() {
 726   CHECK_EQ(base::MessageLoop::current(), message_loop_);
 727
 728   // Update the VSync params.
 729   //
 730   // It's safe to use Unretained here since |rendering_thread_| will be stopped
 731   // in VideoDecodeAcceleratorTest.TearDown(), while the |rendering_helper_| is
 732   // a member of that class. (See video_decode_accelerator_unittest.cc.)
 733   gfx::VSyncProvider* vsync_provider = gl_surface_->GetVSyncProvider();
 734   if (vsync_provider && !ignore_vsync_) {
 735     vsync_provider->GetVSyncParameters(base::Bind(
 736         &RenderingHelper::UpdateVSyncParameters, base::Unretained(this),
 737         static_cast<base::WaitableEvent*>(NULL)));
 738   }
 739
 740   int tex_flip = 1;
 741 #if defined(USE_OZONE)
 742   // Ozone surfaceless renders flipped from normal GL, so there's no need to
 743   // do an extra flip.
 744   tex_flip = 0;
 745 #endif  // defined(USE_OZONE)
 746   glUniform1i(glGetUniformLocation(program_, "tex_flip"), tex_flip);
 747
 748   // Frames that will be returned to the client (via the no_longer_needed_cb)
 749   // after this vector falls out of scope at the end of this method. We need
 750   // to keep references to them until after SwapBuffers() call below.
 751   std::vector<scoped_refptr<VideoFrameTexture> > frames_to_be_returned;
 752   bool need_swap_buffer = false;
 753   if (render_as_thumbnails_) {
 754     // In render_as_thumbnails_ mode, we render the FBO content on the
 755     // screen instead of the decoded textures.
 756     GLSetViewPort(videos_[0].render_area);
 757     RenderTexture(GL_TEXTURE_2D, thumbnails_texture_id_);
 758     need_swap_buffer = true;
 759   } else {
 760     for (RenderedVideo& video : videos_) {
 761       if (video.pending_frames.empty())
 762         continue;
 763       need_swap_buffer = true;
 764       scoped_refptr<VideoFrameTexture> frame = video.pending_frames.front();
 765       GLSetViewPort(video.render_area);
 766       RenderTexture(frame->texture_target(), frame->texture_id());
 767
 768       if (video.pending_frames.size() > 1 || video.is_flushing) {
 769         frames_to_be_returned.push_back(video.pending_frames.front());
 770         video.pending_frames.pop();
 771       } else {
 772         ++video.frames_to_drop;
 773       }
 774     }
 775   }
 776
 777   base::Closure schedule_frame = base::Bind(
 778       &RenderingHelper::ScheduleNextRenderContent, base::Unretained(this));
 779   if (!need_swap_buffer ||
 780       !gl_surface_->SwapBuffersAsync(
 781           base::Bind(&WaitForSwapAck, schedule_frame)))
 782     schedule_frame.Run();
 783 }
 784
 785 // Helper function for the LayoutRenderingAreas(). The |lengths| are the
 786 // heights(widths) of the rows(columns). It scales the elements in
 787 // |lengths| proportionally so that the sum of them equal to |total_length|.
 788 // It also outputs the coordinates of the rows(columns) to |offsets|.
 789 static void ScaleAndCalculateOffsets(std::vector<int>* lengths,
 790                                      std::vector<int>* offsets,
 791                                      int total_length) {
 792   int sum = std::accumulate(lengths->begin(), lengths->end(), 0);
 793   for (size_t i = 0; i < lengths->size(); ++i) {
 794     lengths->at(i) = lengths->at(i) * total_length / sum;
 795     offsets->at(i) = (i == 0) ? 0 : offsets->at(i - 1) + lengths->at(i - 1);
 796   }
 797 }
 798
 799 void RenderingHelper::LayoutRenderingAreas(
 800     const std::vector<gfx::Size>& window_sizes) {
 801   // Find the number of colums and rows.
 802   // The smallest n * n or n * (n + 1) > number of windows.
 803   size_t cols = sqrt(videos_.size() - 1) + 1;
 804   size_t rows = (videos_.size() + cols - 1) / cols;
 805
 806   // Find the widths and heights of the grid.
 807   std::vector<int> widths(cols);
 808   std::vector<int> heights(rows);
 809   std::vector<int> offset_x(cols);
 810   std::vector<int> offset_y(rows);
 811
 812   for (size_t i = 0; i < window_sizes.size(); ++i) {
 813     const gfx::Size& size = window_sizes[i];
 814     widths[i % cols] = std::max(widths[i % cols], size.width());
 815     heights[i / cols] = std::max(heights[i / cols], size.height());
 816   }
 817
 818   ScaleAndCalculateOffsets(&widths, &offset_x, screen_size_.width());
 819   ScaleAndCalculateOffsets(&heights, &offset_y, screen_size_.height());
 820
 821   // Put each render_area_ in the center of each cell.
 822   for (size_t i = 0; i < window_sizes.size(); ++i) {
 823     const gfx::Size& size = window_sizes[i];
 824     float scale =
 825         std::min(static_cast<float>(widths[i % cols]) / size.width(),
 826                  static_cast<float>(heights[i / cols]) / size.height());
 827
 828     // Don't scale up the texture.
 829     scale = std::min(1.0f, scale);
 830
 831     size_t w = scale * size.width();
 832     size_t h = scale * size.height();
 833     size_t x = offset_x[i % cols] + (widths[i % cols] - w) / 2;
 834     size_t y = offset_y[i / cols] + (heights[i / cols] - h) / 2;
 835     videos_[i].render_area = gfx::Rect(x, y, w, h);
 836   }
 837 }
 838
 839 void RenderingHelper::UpdateVSyncParameters(base::WaitableEvent* done,
 840                                             const base::TimeTicks timebase,
 841                                             const base::TimeDelta interval) {
 842   vsync_timebase_ = timebase;
 843   vsync_interval_ = interval;
 844
 845   if (done)
 846     done->Signal();
 847 }
 848
 849 void RenderingHelper::DropOneFrameForAllVideos() {
 850   for (RenderedVideo& video : videos_) {
 851     if (video.pending_frames.empty())
 852       continue;
 853
 854     if (video.pending_frames.size() > 1 || video.is_flushing) {
 855       video.pending_frames.pop();
 856     } else {
 857       ++video.frames_to_drop;
 858     }
 859   }
 860 }
 861
 862 void RenderingHelper::ScheduleNextRenderContent() {
 863   scheduled_render_time_ += frame_duration_;
 864   base::TimeTicks now = base::TimeTicks::Now();
 865   base::TimeTicks target;
 866
 867   if (vsync_interval_ != base::TimeDelta()) {
 868     // Schedules the next RenderContent() at latest VSYNC before the
 869     // |scheduled_render_time_|.
 870     target = std::max(now + vsync_interval_, scheduled_render_time_);
 871
 872     int64 intervals = (target - vsync_timebase_) / vsync_interval_;
 873     target = vsync_timebase_ + intervals * vsync_interval_;
 874   } else {
 875     target = std::max(now, scheduled_render_time_);
 876   }
 877
 878   // When the rendering falls behind, drops frames.
 879   while (scheduled_render_time_ < target) {
 880     scheduled_render_time_ += frame_duration_;
 881     DropOneFrameForAllVideos();
 882   }
 883
 884   message_loop_->PostDelayedTask(
 885       FROM_HERE, render_task_.callback(), target - now);
 886 }
 887 }  // namespace content