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