ppapi/examples/video_decode/video_decode.cc

   1 // Copyright (c) 2014 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 <stdio.h>
   6 #include <string.h>
   7
   8 #include <iostream>
   9 #include <queue>
  10 #include <sstream>
  11
  12 #include "ppapi/c/pp_errors.h"
  13 #include "ppapi/c/ppb_console.h"
  14 #include "ppapi/c/ppb_opengles2.h"
  15 #include "ppapi/cpp/graphics_3d.h"
  16 #include "ppapi/cpp/graphics_3d_client.h"
  17 #include "ppapi/cpp/input_event.h"
  18 #include "ppapi/cpp/instance.h"
  19 #include "ppapi/cpp/module.h"
  20 #include "ppapi/cpp/rect.h"
  21 #include "ppapi/cpp/var.h"
  22 #include "ppapi/cpp/video_decoder.h"
  23
  24 // VP8 is more likely to work on different versions of Chrome. Undefine this
  25 // to decode H264.
  26 #define USE_VP8_TESTDATA_INSTEAD_OF_H264
  27 #include "ppapi/examples/video_decode/testdata.h"
  28
  29 #include "ppapi/lib/gl/include/GLES2/gl2.h"
  30 #include "ppapi/lib/gl/include/GLES2/gl2ext.h"
  31 #include "ppapi/utility/completion_callback_factory.h"
  32
  33 // Use assert as a poor-man's CHECK, even in non-debug mode.
  34 // Since <assert.h> redefines assert on every inclusion (it doesn't use
  35 // include-guards), make sure this is the last file #include'd in this file.
  36 #undef NDEBUG
  37 #include <assert.h>
  38
  39 // Assert |context_| isn't holding any GL Errors.  Done as a macro instead of a
  40 // function to preserve line number information in the failure message.
  41 #define assertNoGLError() assert(!gles2_if_->GetError(context_->pp_resource()));
  42
  43 namespace {
  44
  45 struct Shader {
  46   Shader() : program(0), texcoord_scale_location(0) {}
  47   ~Shader() {}
  48
  49   GLuint program;
  50   GLint texcoord_scale_location;
  51 };
  52
  53 class Decoder;
  54 class MyInstance;
  55
  56 struct PendingPicture {
  57   PendingPicture(Decoder* decoder, const PP_VideoPicture& picture)
  58       : decoder(decoder), picture(picture) {}
  59   ~PendingPicture() {}
  60
  61   Decoder* decoder;
  62   PP_VideoPicture picture;
  63 };
  64
  65 class MyInstance : public pp::Instance, public pp::Graphics3DClient {
  66  public:
  67   MyInstance(PP_Instance instance, pp::Module* module);
  68   virtual ~MyInstance();
  69
  70   // pp::Instance implementation.
  71   virtual void DidChangeView(const pp::Rect& position,
  72                              const pp::Rect& clip_ignored);
  73   virtual bool HandleInputEvent(const pp::InputEvent& event);
  74
  75   // pp::Graphics3DClient implementation.
  76   virtual void Graphics3DContextLost() {
  77     // TODO(vrk/fischman): Properly reset after a lost graphics context.  In
  78     // particular need to delete context_ and re-create textures.
  79     // Probably have to recreate the decoder from scratch, because old textures
  80     // can still be outstanding in the decoder!
  81     assert(false && "Unexpectedly lost graphics context");
  82   }
  83
  84   void PaintPicture(Decoder* decoder, const PP_VideoPicture& picture);
  85
  86  private:
  87   // Log an error to the developer console and stderr by creating a temporary
  88   // object of this type and streaming to it.  Example usage:
  89   // LogError(this).s() << "Hello world: " << 42;
  90   class LogError {
  91    public:
  92     LogError(MyInstance* instance) : instance_(instance) {}
  93     ~LogError() {
  94       const std::string& msg = stream_.str();
  95       instance_->console_if_->Log(
  96           instance_->pp_instance(), PP_LOGLEVEL_ERROR, pp::Var(msg).pp_var());
  97       std::cerr << msg << std::endl;
  98     }
  99     // Impl note: it would have been nicer to have LogError derive from
 100     // std::ostringstream so that it can be streamed to directly, but lookup
 101     // rules turn streamed string literals to hex pointers on output.
 102     std::ostringstream& s() { return stream_; }
 103
 104    private:
 105     MyInstance* instance_;
 106     std::ostringstream stream_;
 107   };
 108
 109   void InitializeDecoders();
 110
 111   // GL-related functions.
 112   void InitGL();
 113   void CreateGLObjects();
 114   void Create2DProgramOnce();
 115   void CreateRectangleARBProgramOnce();
 116   void CreateExternalOESProgramOnce();
 117   Shader CreateProgram(const char* vertex_shader, const char* fragment_shader);
 118   void CreateShader(GLuint program, GLenum type, const char* source, int size);
 119   void PaintNextPicture();
 120   void PaintFinished(int32_t result);
 121
 122   pp::Size plugin_size_;
 123   bool is_painting_;
 124   // When decode outpaces render, we queue up decoded pictures for later
 125   // painting.
 126   typedef std::queue<PendingPicture> PendingPictureQueue;
 127   PendingPictureQueue pending_pictures_;
 128
 129   int num_frames_rendered_;
 130   PP_TimeTicks first_frame_delivered_ticks_;
 131   PP_TimeTicks last_swap_request_ticks_;
 132   PP_TimeTicks swap_ticks_;
 133   pp::CompletionCallbackFactory<MyInstance> callback_factory_;
 134
 135   // Unowned pointers.
 136   const PPB_Console* console_if_;
 137   const PPB_Core* core_if_;
 138   const PPB_OpenGLES2* gles2_if_;
 139
 140   // Owned data.
 141   pp::Graphics3D* context_;
 142   typedef std::vector<Decoder*> DecoderList;
 143   DecoderList video_decoders_;
 144
 145   // Shader program to draw GL_TEXTURE_2D target.
 146   Shader shader_2d_;
 147   // Shader program to draw GL_TEXTURE_RECTANGLE_ARB target.
 148   Shader shader_rectangle_arb_;
 149   // Shader program to draw GL_TEXTURE_EXTERNAL_OES target.
 150   Shader shader_external_oes_;
 151 };
 152
 153 class Decoder {
 154  public:
 155   Decoder(MyInstance* instance, int id, const pp::Graphics3D& graphics_3d);
 156   ~Decoder();
 157
 158   int id() const { return id_; }
 159   bool flushing() const { return flushing_; }
 160   bool resetting() const { return resetting_; }
 161
 162   void Reset();
 163   void RecyclePicture(const PP_VideoPicture& picture);
 164
 165   PP_TimeTicks GetAverageLatency() {
 166     return num_pictures_ ? total_latency_ / num_pictures_ : 0;
 167   }
 168
 169  private:
 170   void InitializeDone(int32_t result);
 171   void Start();
 172   void DecodeNextFrame();
 173   void DecodeDone(int32_t result);
 174   void PictureReady(int32_t result, PP_VideoPicture picture);
 175   void FlushDone(int32_t result);
 176   void ResetDone(int32_t result);
 177
 178   MyInstance* instance_;
 179   int id_;
 180
 181   pp::VideoDecoder* decoder_;
 182   pp::CompletionCallbackFactory<Decoder> callback_factory_;
 183
 184   size_t encoded_data_next_pos_to_decode_;
 185   int next_picture_id_;
 186   bool flushing_;
 187   bool resetting_;
 188
 189   const PPB_Core* core_if_;
 190   static const int kMaxDecodeDelay = 128;
 191   PP_TimeTicks decode_time_[kMaxDecodeDelay];
 192   PP_TimeTicks total_latency_;
 193   int num_pictures_;
 194 };
 195
 196 #if defined USE_VP8_TESTDATA_INSTEAD_OF_H264
 197
 198 // VP8 is stored in an IVF container.
 199 // Helpful description: http://wiki.multimedia.cx/index.php?title=IVF
 200
 201 static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
 202   size_t current_pos = *start_pos;
 203   if (current_pos == 0)
 204     current_pos = 32;  // Skip stream header.
 205   uint32_t frame_size = kData[current_pos] + (kData[current_pos + 1] << 8) +
 206                         (kData[current_pos + 2] << 16) +
 207                         (kData[current_pos + 3] << 24);
 208   current_pos += 12;  // Skip frame header.
 209   *start_pos = current_pos;
 210   *end_pos = current_pos + frame_size;
 211 }
 212
 213 #else  // !USE_VP8_TESTDATA_INSTEAD_OF_H264
 214
 215 // Returns true if the current position is at the start of a NAL unit.
 216 static bool LookingAtNAL(const unsigned char* encoded, size_t pos) {
 217   // H264 frames start with 0, 0, 0, 1 in our test data.
 218   return pos + 3 < kDataLen && encoded[pos] == 0 && encoded[pos + 1] == 0 &&
 219          encoded[pos + 2] == 0 && encoded[pos + 3] == 1;
 220 }
 221
 222 static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
 223   assert(LookingAtNAL(kData, *start_pos));
 224   *end_pos = *start_pos;
 225   *end_pos += 4;
 226   while (*end_pos < kDataLen && !LookingAtNAL(kData, *end_pos)) {
 227     ++*end_pos;
 228   }
 229 }
 230
 231 #endif  // USE_VP8_TESTDATA_INSTEAD_OF_H264
 232
 233 Decoder::Decoder(MyInstance* instance,
 234                  int id,
 235                  const pp::Graphics3D& graphics_3d)
 236     : instance_(instance),
 237       id_(id),
 238       decoder_(new pp::VideoDecoder(instance)),
 239       callback_factory_(this),
 240       encoded_data_next_pos_to_decode_(0),
 241       next_picture_id_(0),
 242       flushing_(false),
 243       resetting_(false),
 244       total_latency_(0.0),
 245       num_pictures_(0) {
 246   core_if_ = static_cast<const PPB_Core*>(
 247       pp::Module::Get()->GetBrowserInterface(PPB_CORE_INTERFACE));
 248
 249 #if defined USE_VP8_TESTDATA_INSTEAD_OF_H264
 250   const PP_VideoProfile kBitstreamProfile = PP_VIDEOPROFILE_VP8_ANY;
 251 #else
 252   const PP_VideoProfile kBitstreamProfile = PP_VIDEOPROFILE_H264MAIN;
 253 #endif
 254
 255   assert(!decoder_->is_null());
 256   decoder_->Initialize(graphics_3d,
 257                        kBitstreamProfile,
 258                        PP_HARDWAREACCELERATION_WITHFALLBACK,
 259                        callback_factory_.NewCallback(&Decoder::InitializeDone));
 260 }
 261
 262 Decoder::~Decoder() {
 263   delete decoder_;
 264 }
 265
 266 void Decoder::InitializeDone(int32_t result) {
 267   assert(decoder_);
 268   assert(result == PP_OK);
 269   Start();
 270 }
 271
 272 void Decoder::Start() {
 273   assert(decoder_);
 274
 275   encoded_data_next_pos_to_decode_ = 0;
 276
 277   // Register callback to get the first picture. We call GetPicture again in
 278   // PictureReady to continuously receive pictures as they're decoded.
 279   decoder_->GetPicture(
 280       callback_factory_.NewCallbackWithOutput(&Decoder::PictureReady));
 281
 282   // Start the decode loop.
 283   DecodeNextFrame();
 284 }
 285
 286 void Decoder::Reset() {
 287   assert(decoder_);
 288   assert(!resetting_);
 289   resetting_ = true;
 290   decoder_->Reset(callback_factory_.NewCallback(&Decoder::ResetDone));
 291 }
 292
 293 void Decoder::RecyclePicture(const PP_VideoPicture& picture) {
 294   assert(decoder_);
 295   decoder_->RecyclePicture(picture);
 296 }
 297
 298 void Decoder::DecodeNextFrame() {
 299   assert(decoder_);
 300   if (encoded_data_next_pos_to_decode_ <= kDataLen) {
 301     // If we've just reached the end of the bitstream, flush and wait.
 302     if (!flushing_ && encoded_data_next_pos_to_decode_ == kDataLen) {
 303       flushing_ = true;
 304       decoder_->Flush(callback_factory_.NewCallback(&Decoder::FlushDone));
 305       return;
 306     }
 307
 308     // Find the start of the next frame.
 309     size_t start_pos = encoded_data_next_pos_to_decode_;
 310     size_t end_pos;
 311     GetNextFrame(&start_pos, &end_pos);
 312     encoded_data_next_pos_to_decode_ = end_pos;
 313     // Decode the frame. On completion, DecodeDone will call DecodeNextFrame
 314     // to implement a decode loop.
 315     uint32_t size = static_cast<uint32_t>(end_pos - start_pos);
 316     decode_time_[next_picture_id_ % kMaxDecodeDelay] = core_if_->GetTimeTicks();
 317     decoder_->Decode(next_picture_id_++,
 318                      size,
 319                      kData + start_pos,
 320                      callback_factory_.NewCallback(&Decoder::DecodeDone));
 321   }
 322 }
 323
 324 void Decoder::DecodeDone(int32_t result) {
 325   assert(decoder_);
 326   // Break out of the decode loop on abort.
 327   if (result == PP_ERROR_ABORTED)
 328     return;
 329   assert(result == PP_OK);
 330   if (!flushing_ && !resetting_)
 331     DecodeNextFrame();
 332 }
 333
 334 void Decoder::PictureReady(int32_t result, PP_VideoPicture picture) {
 335   assert(decoder_);
 336   // Break out of the get picture loop on abort.
 337   if (result == PP_ERROR_ABORTED)
 338     return;
 339   assert(result == PP_OK);
 340
 341   num_pictures_++;
 342   PP_TimeTicks latency = core_if_->GetTimeTicks() -
 343                          decode_time_[picture.decode_id % kMaxDecodeDelay];
 344   total_latency_ += latency;
 345
 346   decoder_->GetPicture(
 347       callback_factory_.NewCallbackWithOutput(&Decoder::PictureReady));
 348   instance_->PaintPicture(this, picture);
 349 }
 350
 351 void Decoder::FlushDone(int32_t result) {
 352   assert(decoder_);
 353   assert(result == PP_OK || result == PP_ERROR_ABORTED);
 354   assert(flushing_);
 355   flushing_ = false;
 356 }
 357
 358 void Decoder::ResetDone(int32_t result) {
 359   assert(decoder_);
 360   assert(result == PP_OK);
 361   assert(resetting_);
 362   resetting_ = false;
 363
 364   Start();
 365 }
 366
 367 MyInstance::MyInstance(PP_Instance instance, pp::Module* module)
 368     : pp::Instance(instance),
 369       pp::Graphics3DClient(this),
 370       is_painting_(false),
 371       num_frames_rendered_(0),
 372       first_frame_delivered_ticks_(-1),
 373       last_swap_request_ticks_(-1),
 374       swap_ticks_(0),
 375       callback_factory_(this),
 376       context_(NULL) {
 377   console_if_ = static_cast<const PPB_Console*>(
 378       pp::Module::Get()->GetBrowserInterface(PPB_CONSOLE_INTERFACE));
 379   core_if_ = static_cast<const PPB_Core*>(
 380       pp::Module::Get()->GetBrowserInterface(PPB_CORE_INTERFACE));
 381   gles2_if_ = static_cast<const PPB_OpenGLES2*>(
 382       pp::Module::Get()->GetBrowserInterface(PPB_OPENGLES2_INTERFACE));
 383
 384   RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE);
 385 }
 386
 387 MyInstance::~MyInstance() {
 388   if (!context_)
 389     return;
 390
 391   PP_Resource graphics_3d = context_->pp_resource();
 392   if (shader_2d_.program)
 393     gles2_if_->DeleteProgram(graphics_3d, shader_2d_.program);
 394   if (shader_rectangle_arb_.program)
 395     gles2_if_->DeleteProgram(graphics_3d, shader_rectangle_arb_.program);
 396   if (shader_external_oes_.program)
 397     gles2_if_->DeleteProgram(graphics_3d, shader_external_oes_.program);
 398
 399   for (DecoderList::iterator it = video_decoders_.begin();
 400        it != video_decoders_.end();
 401        ++it)
 402     delete *it;
 403
 404   delete context_;
 405 }
 406
 407 void MyInstance::DidChangeView(const pp::Rect& position,
 408                                const pp::Rect& clip_ignored) {
 409   if (position.width() == 0 || position.height() == 0)
 410     return;
 411   if (plugin_size_.width()) {
 412     assert(position.size() == plugin_size_);
 413     return;
 414   }
 415   plugin_size_ = position.size();
 416
 417   // Initialize graphics.
 418   InitGL();
 419   InitializeDecoders();
 420 }
 421
 422 bool MyInstance::HandleInputEvent(const pp::InputEvent& event) {
 423   switch (event.GetType()) {
 424     case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
 425       pp::MouseInputEvent mouse_event(event);
 426       // Reset all decoders on mouse down.
 427       if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
 428         // Reset decoders.
 429         for (size_t i = 0; i < video_decoders_.size(); i++) {
 430           if (!video_decoders_[i]->resetting())
 431             video_decoders_[i]->Reset();
 432         }
 433       }
 434       return true;
 435     }
 436
 437     default:
 438       return false;
 439   }
 440 }
 441
 442 void MyInstance::InitializeDecoders() {
 443   assert(video_decoders_.empty());
 444   // Create two decoders with ids 0 and 1.
 445   video_decoders_.push_back(new Decoder(this, 0, *context_));
 446   video_decoders_.push_back(new Decoder(this, 1, *context_));
 447 }
 448
 449 void MyInstance::PaintPicture(Decoder* decoder,
 450                               const PP_VideoPicture& picture) {
 451   if (first_frame_delivered_ticks_ == -1)
 452     assert((first_frame_delivered_ticks_ = core_if_->GetTimeTicks()) != -1);
 453
 454   pending_pictures_.push(PendingPicture(decoder, picture));
 455   if (!is_painting_)
 456     PaintNextPicture();
 457 }
 458
 459 void MyInstance::PaintNextPicture() {
 460   assert(!is_painting_);
 461   is_painting_ = true;
 462
 463   const PendingPicture& next = pending_pictures_.front();
 464   Decoder* decoder = next.decoder;
 465   const PP_VideoPicture& picture = next.picture;
 466
 467   int x = 0;
 468   int y = 0;
 469   int half_width = plugin_size_.width() / 2;
 470   int half_height = plugin_size_.height() / 2;
 471   if (decoder->id() != 0) {
 472     x = half_width;
 473     y = half_height;
 474   }
 475
 476   PP_Resource graphics_3d = context_->pp_resource();
 477   if (picture.texture_target == GL_TEXTURE_2D) {
 478     Create2DProgramOnce();
 479     gles2_if_->UseProgram(graphics_3d, shader_2d_.program);
 480     gles2_if_->Uniform2f(
 481         graphics_3d, shader_2d_.texcoord_scale_location, 1.0, 1.0);
 482   } else if (picture.texture_target == GL_TEXTURE_RECTANGLE_ARB) {
 483     CreateRectangleARBProgramOnce();
 484     gles2_if_->UseProgram(graphics_3d, shader_rectangle_arb_.program);
 485     gles2_if_->Uniform2f(graphics_3d,
 486                          shader_rectangle_arb_.texcoord_scale_location,
 487                          static_cast<GLfloat>(picture.texture_size.width),
 488                          static_cast<GLfloat>(picture.texture_size.height));
 489   } else {
 490     assert(picture.texture_target == GL_TEXTURE_EXTERNAL_OES);
 491     CreateExternalOESProgramOnce();
 492     gles2_if_->UseProgram(graphics_3d, shader_external_oes_.program);
 493     gles2_if_->Uniform2f(
 494         graphics_3d, shader_external_oes_.texcoord_scale_location, 1.0, 1.0);
 495   }
 496
 497   gles2_if_->Viewport(graphics_3d, x, y, half_width, half_height);
 498   gles2_if_->ActiveTexture(graphics_3d, GL_TEXTURE0);
 499   gles2_if_->BindTexture(
 500       graphics_3d, picture.texture_target, picture.texture_id);
 501   gles2_if_->DrawArrays(graphics_3d, GL_TRIANGLE_STRIP, 0, 4);
 502
 503   gles2_if_->UseProgram(graphics_3d, 0);
 504
 505   last_swap_request_ticks_ = core_if_->GetTimeTicks();
 506   context_->SwapBuffers(
 507       callback_factory_.NewCallback(&MyInstance::PaintFinished));
 508 }
 509
 510 void MyInstance::PaintFinished(int32_t result) {
 511   assert(result == PP_OK);
 512   swap_ticks_ += core_if_->GetTimeTicks() - last_swap_request_ticks_;
 513   is_painting_ = false;
 514   ++num_frames_rendered_;
 515   if (num_frames_rendered_ % 50 == 0) {
 516     double elapsed = core_if_->GetTimeTicks() - first_frame_delivered_ticks_;
 517     double fps = (elapsed > 0) ? num_frames_rendered_ / elapsed : 1000;
 518     double ms_per_swap = (swap_ticks_ * 1e3) / num_frames_rendered_;
 519     double secs_average_latency = 0;
 520     for (DecoderList::iterator it = video_decoders_.begin();
 521          it != video_decoders_.end();
 522          ++it)
 523       secs_average_latency += (*it)->GetAverageLatency();
 524     secs_average_latency /= video_decoders_.size();
 525     double ms_average_latency = 1000 * secs_average_latency;
 526     LogError(this).s() << "Rendered frames: " << num_frames_rendered_
 527                        << ", fps: " << fps
 528                        << ", with average ms/swap of: " << ms_per_swap
 529                        << ", with average latency (ms) of: "
 530                        << ms_average_latency;
 531   }
 532
 533   // If the decoders were reset, this will be empty.
 534   if (pending_pictures_.empty())
 535     return;
 536
 537   const PendingPicture& next = pending_pictures_.front();
 538   Decoder* decoder = next.decoder;
 539   const PP_VideoPicture& picture = next.picture;
 540   decoder->RecyclePicture(picture);
 541   pending_pictures_.pop();
 542
 543   // Keep painting as long as we have pictures.
 544   if (!pending_pictures_.empty())
 545     PaintNextPicture();
 546 }
 547
 548 void MyInstance::InitGL() {
 549   assert(plugin_size_.width() && plugin_size_.height());
 550   is_painting_ = false;
 551
 552   assert(!context_);
 553   int32_t context_attributes[] = {
 554       PP_GRAPHICS3DATTRIB_ALPHA_SIZE,     8,
 555       PP_GRAPHICS3DATTRIB_BLUE_SIZE,      8,
 556       PP_GRAPHICS3DATTRIB_GREEN_SIZE,     8,
 557       PP_GRAPHICS3DATTRIB_RED_SIZE,       8,
 558       PP_GRAPHICS3DATTRIB_DEPTH_SIZE,     0,
 559       PP_GRAPHICS3DATTRIB_STENCIL_SIZE,   0,
 560       PP_GRAPHICS3DATTRIB_SAMPLES,        0,
 561       PP_GRAPHICS3DATTRIB_SAMPLE_BUFFERS, 0,
 562       PP_GRAPHICS3DATTRIB_WIDTH,          plugin_size_.width(),
 563       PP_GRAPHICS3DATTRIB_HEIGHT,         plugin_size_.height(),
 564       PP_GRAPHICS3DATTRIB_NONE,
 565   };
 566   context_ = new pp::Graphics3D(this, context_attributes);
 567   assert(!context_->is_null());
 568   assert(BindGraphics(*context_));
 569
 570   // Clear color bit.
 571   gles2_if_->ClearColor(context_->pp_resource(), 1, 0, 0, 1);
 572   gles2_if_->Clear(context_->pp_resource(), GL_COLOR_BUFFER_BIT);
 573
 574   assertNoGLError();
 575
 576   CreateGLObjects();
 577 }
 578
 579 void MyInstance::CreateGLObjects() {
 580   // Assign vertex positions and texture coordinates to buffers for use in
 581   // shader program.
 582   static const float kVertices[] = {
 583       -1, -1, -1, 1, 1, -1, 1, 1,  // Position coordinates.
 584       0,  1,  0,  0, 1, 1,  1, 0,  // Texture coordinates.
 585   };
 586
 587   GLuint buffer;
 588   gles2_if_->GenBuffers(context_->pp_resource(), 1, &buffer);
 589   gles2_if_->BindBuffer(context_->pp_resource(), GL_ARRAY_BUFFER, buffer);
 590
 591   gles2_if_->BufferData(context_->pp_resource(),
 592                         GL_ARRAY_BUFFER,
 593                         sizeof(kVertices),
 594                         kVertices,
 595                         GL_STATIC_DRAW);
 596   assertNoGLError();
 597 }
 598
 599 static const char kVertexShader[] =
 600     "varying vec2 v_texCoord;            \n"
 601     "attribute vec4 a_position;          \n"
 602     "attribute vec2 a_texCoord;          \n"
 603     "uniform vec2 v_scale;               \n"
 604     "void main()                         \n"
 605     "{                                   \n"
 606     "    v_texCoord = v_scale * a_texCoord; \n"
 607     "    gl_Position = a_position;       \n"
 608     "}";
 609
 610 void MyInstance::Create2DProgramOnce() {
 611   if (shader_2d_.program)
 612     return;
 613   static const char kFragmentShader2D[] =
 614       "precision mediump float;            \n"
 615       "varying vec2 v_texCoord;            \n"
 616       "uniform sampler2D s_texture;        \n"
 617       "void main()                         \n"
 618       "{"
 619       "    gl_FragColor = texture2D(s_texture, v_texCoord); \n"
 620       "}";
 621   shader_2d_ = CreateProgram(kVertexShader, kFragmentShader2D);
 622   assertNoGLError();
 623 }
 624
 625 void MyInstance::CreateRectangleARBProgramOnce() {
 626   if (shader_rectangle_arb_.program)
 627     return;
 628   static const char kFragmentShaderRectangle[] =
 629       "#extension GL_ARB_texture_rectangle : require\n"
 630       "precision mediump float;            \n"
 631       "varying vec2 v_texCoord;            \n"
 632       "uniform sampler2DRect s_texture;    \n"
 633       "void main()                         \n"
 634       "{"
 635       "    gl_FragColor = texture2DRect(s_texture, v_texCoord).rgba; \n"
 636       "}";
 637   shader_rectangle_arb_ =
 638       CreateProgram(kVertexShader, kFragmentShaderRectangle);
 639   assertNoGLError();
 640 }
 641
 642 void MyInstance::CreateExternalOESProgramOnce() {
 643   if (shader_external_oes_.program)
 644     return;
 645   static const char kFragmentShaderExternal[] =
 646       "#extension GL_OES_EGL_image_external : require\n"
 647       "precision mediump float;            \n"
 648       "varying vec2 v_texCoord;            \n"
 649       "uniform samplerExternalOES s_texture; \n"
 650       "void main()                         \n"
 651       "{"
 652       "    gl_FragColor = texture2D(s_texture, v_texCoord); \n"
 653       "}";
 654   shader_external_oes_ = CreateProgram(kVertexShader, kFragmentShaderExternal);
 655   assertNoGLError();
 656 }
 657
 658 Shader MyInstance::CreateProgram(const char* vertex_shader,
 659                                  const char* fragment_shader) {
 660   Shader shader;
 661
 662   // Create shader program.
 663   shader.program = gles2_if_->CreateProgram(context_->pp_resource());
 664   CreateShader(
 665       shader.program, GL_VERTEX_SHADER, vertex_shader,
 666       static_cast<uint32_t>(strlen(vertex_shader)));
 667   CreateShader(shader.program,
 668                GL_FRAGMENT_SHADER,
 669                fragment_shader,
 670                static_cast<int>(strlen(fragment_shader)));
 671   gles2_if_->LinkProgram(context_->pp_resource(), shader.program);
 672   gles2_if_->UseProgram(context_->pp_resource(), shader.program);
 673   gles2_if_->Uniform1i(
 674       context_->pp_resource(),
 675       gles2_if_->GetUniformLocation(
 676           context_->pp_resource(), shader.program, "s_texture"),
 677       0);
 678   assertNoGLError();
 679
 680   shader.texcoord_scale_location = gles2_if_->GetUniformLocation(
 681       context_->pp_resource(), shader.program, "v_scale");
 682
 683   GLint pos_location = gles2_if_->GetAttribLocation(
 684       context_->pp_resource(), shader.program, "a_position");
 685   GLint tc_location = gles2_if_->GetAttribLocation(
 686       context_->pp_resource(), shader.program, "a_texCoord");
 687   assertNoGLError();
 688
 689   gles2_if_->EnableVertexAttribArray(context_->pp_resource(), pos_location);
 690   gles2_if_->VertexAttribPointer(
 691       context_->pp_resource(), pos_location, 2, GL_FLOAT, GL_FALSE, 0, 0);
 692   gles2_if_->EnableVertexAttribArray(context_->pp_resource(), tc_location);
 693   gles2_if_->VertexAttribPointer(
 694       context_->pp_resource(),
 695       tc_location,
 696       2,
 697       GL_FLOAT,
 698       GL_FALSE,
 699       0,
 700       static_cast<float*>(0) + 8);  // Skip position coordinates.
 701
 702   gles2_if_->UseProgram(context_->pp_resource(), 0);
 703   assertNoGLError();
 704   return shader;
 705 }
 706
 707 void MyInstance::CreateShader(GLuint program,
 708                               GLenum type,
 709                               const char* source,
 710                               int size) {
 711   GLuint shader = gles2_if_->CreateShader(context_->pp_resource(), type);
 712   gles2_if_->ShaderSource(context_->pp_resource(), shader, 1, &source, &size);
 713   gles2_if_->CompileShader(context_->pp_resource(), shader);
 714   gles2_if_->AttachShader(context_->pp_resource(), program, shader);
 715   gles2_if_->DeleteShader(context_->pp_resource(), shader);
 716 }
 717
 718 // This object is the global object representing this plugin library as long
 719 // as it is loaded.
 720 class MyModule : public pp::Module {
 721  public:
 722   MyModule() : pp::Module() {}
 723   virtual ~MyModule() {}
 724
 725   virtual pp::Instance* CreateInstance(PP_Instance instance) {
 726     return new MyInstance(instance, this);
 727   }
 728 };
 729
 730 }  // anonymous namespace
 731
 732 namespace pp {
 733 // Factory function for your specialization of the Module object.
 734 Module* CreateModule() {
 735   return new MyModule();
 736 }
 737 }  // namespace pp