src/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   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 };
 149
 150 class Decoder {
 151  public:
 152   Decoder(MyInstance* instance, int id, const pp::Graphics3D& graphics_3d);
 153   ~Decoder();
 154
 155   int id() const { return id_; }
 156   bool flushing() const { return flushing_; }
 157   bool resetting() const { return resetting_; }
 158
 159   void Reset();
 160   void RecyclePicture(const PP_VideoPicture& picture);
 161
 162   PP_TimeTicks GetAverageLatency() {
 163     return num_pictures_ ? total_latency_ / num_pictures_ : 0;
 164   }
 165
 166  private:
 167   void InitializeDone(int32_t result);
 168   void Start();
 169   void DecodeNextFrame();
 170   void DecodeDone(int32_t result);
 171   void PictureReady(int32_t result, PP_VideoPicture picture);
 172   void FlushDone(int32_t result);
 173   void ResetDone(int32_t result);
 174
 175   MyInstance* instance_;
 176   int id_;
 177
 178   pp::VideoDecoder* decoder_;
 179   pp::CompletionCallbackFactory<Decoder> callback_factory_;
 180
 181   size_t encoded_data_next_pos_to_decode_;
 182   int next_picture_id_;
 183   bool flushing_;
 184   bool resetting_;
 185
 186   const PPB_Core* core_if_;
 187   static const int kMaxDecodeDelay = 128;
 188   PP_TimeTicks decode_time_[kMaxDecodeDelay];
 189   PP_TimeTicks total_latency_;
 190   int num_pictures_;
 191 };
 192
 193 #if defined USE_VP8_TESTDATA_INSTEAD_OF_H264
 194
 195 // VP8 is stored in an IVF container.
 196 // Helpful description: http://wiki.multimedia.cx/index.php?title=IVF
 197
 198 static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
 199   size_t current_pos = *start_pos;
 200   if (current_pos == 0)
 201     current_pos = 32;  // Skip stream header.
 202   uint32_t frame_size = kData[current_pos] + (kData[current_pos + 1] << 8) +
 203                         (kData[current_pos + 2] << 16) +
 204                         (kData[current_pos + 3] << 24);
 205   current_pos += 12;  // Skip frame header.
 206   *start_pos = current_pos;
 207   *end_pos = current_pos + frame_size;
 208 }
 209
 210 #else  // !USE_VP8_TESTDATA_INSTEAD_OF_H264
 211
 212 // Returns true if the current position is at the start of a NAL unit.
 213 static bool LookingAtNAL(const unsigned char* encoded, size_t pos) {
 214   // H264 frames start with 0, 0, 0, 1 in our test data.
 215   return pos + 3 < kDataLen && encoded[pos] == 0 && encoded[pos + 1] == 0 &&
 216          encoded[pos + 2] == 0 && encoded[pos + 3] == 1;
 217 }
 218
 219 static void GetNextFrame(size_t* start_pos, size_t* end_pos) {
 220   assert(LookingAtNAL(kData, *start_pos));
 221   *end_pos = *start_pos;
 222   *end_pos += 4;
 223   while (*end_pos < kDataLen && !LookingAtNAL(kData, *end_pos)) {
 224     ++*end_pos;
 225   }
 226 }
 227
 228 #endif  // USE_VP8_TESTDATA_INSTEAD_OF_H264
 229
 230 Decoder::Decoder(MyInstance* instance,
 231                  int id,
 232                  const pp::Graphics3D& graphics_3d)
 233     : instance_(instance),
 234       id_(id),
 235       decoder_(new pp::VideoDecoder(instance)),
 236       callback_factory_(this),
 237       encoded_data_next_pos_to_decode_(0),
 238       next_picture_id_(0),
 239       flushing_(false),
 240       resetting_(false),
 241       total_latency_(0.0),
 242       num_pictures_(0) {
 243   core_if_ = static_cast<const PPB_Core*>(
 244       pp::Module::Get()->GetBrowserInterface(PPB_CORE_INTERFACE));
 245
 246 #if defined USE_VP8_TESTDATA_INSTEAD_OF_H264
 247   const PP_VideoProfile kBitstreamProfile = PP_VIDEOPROFILE_VP8MAIN;
 248 #else
 249   const PP_VideoProfile kBitstreamProfile = PP_VIDEOPROFILE_H264MAIN;
 250 #endif
 251
 252   assert(!decoder_->is_null());
 253   decoder_->Initialize(graphics_3d,
 254                        kBitstreamProfile,
 255                        PP_TRUE /* allow_software_fallback */,
 256                        callback_factory_.NewCallback(&Decoder::InitializeDone));
 257 }
 258
 259 Decoder::~Decoder() {
 260   delete decoder_;
 261 }
 262
 263 void Decoder::InitializeDone(int32_t result) {
 264   assert(decoder_);
 265   assert(result == PP_OK);
 266   Start();
 267 }
 268
 269 void Decoder::Start() {
 270   assert(decoder_);
 271
 272   encoded_data_next_pos_to_decode_ = 0;
 273
 274   // Register callback to get the first picture. We call GetPicture again in
 275   // PictureReady to continuously receive pictures as they're decoded.
 276   decoder_->GetPicture(
 277       callback_factory_.NewCallbackWithOutput(&Decoder::PictureReady));
 278
 279   // Start the decode loop.
 280   DecodeNextFrame();
 281 }
 282
 283 void Decoder::Reset() {
 284   assert(decoder_);
 285   assert(!resetting_);
 286   resetting_ = true;
 287   decoder_->Reset(callback_factory_.NewCallback(&Decoder::ResetDone));
 288 }
 289
 290 void Decoder::RecyclePicture(const PP_VideoPicture& picture) {
 291   assert(decoder_);
 292   decoder_->RecyclePicture(picture);
 293 }
 294
 295 void Decoder::DecodeNextFrame() {
 296   assert(decoder_);
 297   if (encoded_data_next_pos_to_decode_ <= kDataLen) {
 298     // If we've just reached the end of the bitstream, flush and wait.
 299     if (!flushing_ && encoded_data_next_pos_to_decode_ == kDataLen) {
 300       flushing_ = true;
 301       decoder_->Flush(callback_factory_.NewCallback(&Decoder::FlushDone));
 302       return;
 303     }
 304
 305     // Find the start of the next frame.
 306     size_t start_pos = encoded_data_next_pos_to_decode_;
 307     size_t end_pos;
 308     GetNextFrame(&start_pos, &end_pos);
 309     encoded_data_next_pos_to_decode_ = end_pos;
 310     // Decode the frame. On completion, DecodeDone will call DecodeNextFrame
 311     // to implement a decode loop.
 312     uint32_t size = static_cast<uint32_t>(end_pos - start_pos);
 313     decode_time_[next_picture_id_ % kMaxDecodeDelay] = core_if_->GetTimeTicks();
 314     decoder_->Decode(next_picture_id_++,
 315                      size,
 316                      kData + start_pos,
 317                      callback_factory_.NewCallback(&Decoder::DecodeDone));
 318   }
 319 }
 320
 321 void Decoder::DecodeDone(int32_t result) {
 322   assert(decoder_);
 323   // Break out of the decode loop on abort.
 324   if (result == PP_ERROR_ABORTED)
 325     return;
 326   assert(result == PP_OK);
 327   if (!flushing_ && !resetting_)
 328     DecodeNextFrame();
 329 }
 330
 331 void Decoder::PictureReady(int32_t result, PP_VideoPicture picture) {
 332   assert(decoder_);
 333   // Break out of the get picture loop on abort.
 334   if (result == PP_ERROR_ABORTED)
 335     return;
 336   assert(result == PP_OK);
 337
 338   num_pictures_++;
 339   PP_TimeTicks latency = core_if_->GetTimeTicks() -
 340                          decode_time_[picture.decode_id % kMaxDecodeDelay];
 341   total_latency_ += latency;
 342
 343   decoder_->GetPicture(
 344       callback_factory_.NewCallbackWithOutput(&Decoder::PictureReady));
 345   instance_->PaintPicture(this, picture);
 346 }
 347
 348 void Decoder::FlushDone(int32_t result) {
 349   assert(decoder_);
 350   assert(result == PP_OK || result == PP_ERROR_ABORTED);
 351   assert(flushing_);
 352   flushing_ = false;
 353 }
 354
 355 void Decoder::ResetDone(int32_t result) {
 356   assert(decoder_);
 357   assert(result == PP_OK);
 358   assert(resetting_);
 359   resetting_ = false;
 360
 361   Start();
 362 }
 363
 364 MyInstance::MyInstance(PP_Instance instance, pp::Module* module)
 365     : pp::Instance(instance),
 366       pp::Graphics3DClient(this),
 367       is_painting_(false),
 368       num_frames_rendered_(0),
 369       first_frame_delivered_ticks_(-1),
 370       last_swap_request_ticks_(-1),
 371       swap_ticks_(0),
 372       callback_factory_(this),
 373       context_(NULL) {
 374   console_if_ = static_cast<const PPB_Console*>(
 375       pp::Module::Get()->GetBrowserInterface(PPB_CONSOLE_INTERFACE));
 376   core_if_ = static_cast<const PPB_Core*>(
 377       pp::Module::Get()->GetBrowserInterface(PPB_CORE_INTERFACE));
 378   gles2_if_ = static_cast<const PPB_OpenGLES2*>(
 379       pp::Module::Get()->GetBrowserInterface(PPB_OPENGLES2_INTERFACE));
 380
 381   RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE);
 382 }
 383
 384 MyInstance::~MyInstance() {
 385   if (!context_)
 386     return;
 387
 388   PP_Resource graphics_3d = context_->pp_resource();
 389   if (shader_2d_.program)
 390     gles2_if_->DeleteProgram(graphics_3d, shader_2d_.program);
 391   if (shader_rectangle_arb_.program)
 392     gles2_if_->DeleteProgram(graphics_3d, shader_rectangle_arb_.program);
 393
 394   for (DecoderList::iterator it = video_decoders_.begin();
 395        it != video_decoders_.end();
 396        ++it)
 397     delete *it;
 398
 399   delete context_;
 400 }
 401
 402 void MyInstance::DidChangeView(const pp::Rect& position,
 403                                const pp::Rect& clip_ignored) {
 404   if (position.width() == 0 || position.height() == 0)
 405     return;
 406   if (plugin_size_.width()) {
 407     assert(position.size() == plugin_size_);
 408     return;
 409   }
 410   plugin_size_ = position.size();
 411
 412   // Initialize graphics.
 413   InitGL();
 414   InitializeDecoders();
 415 }
 416
 417 bool MyInstance::HandleInputEvent(const pp::InputEvent& event) {
 418   switch (event.GetType()) {
 419     case PP_INPUTEVENT_TYPE_MOUSEDOWN: {
 420       pp::MouseInputEvent mouse_event(event);
 421       // Reset all decoders on mouse down.
 422       if (mouse_event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT) {
 423         // Reset decoders.
 424         for (size_t i = 0; i < video_decoders_.size(); i++) {
 425           if (!video_decoders_[i]->resetting())
 426             video_decoders_[i]->Reset();
 427         }
 428
 429         // Clear pending pictures.
 430         while (!pending_pictures_.empty())
 431           pending_pictures_.pop();
 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 {
 482     assert(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                          picture.texture_size.width,
 488                          picture.texture_size.height);
 489   }
 490
 491   gles2_if_->Viewport(graphics_3d, x, y, half_width, half_height);
 492   gles2_if_->ActiveTexture(graphics_3d, GL_TEXTURE0);
 493   gles2_if_->BindTexture(
 494       graphics_3d, picture.texture_target, picture.texture_id);
 495   gles2_if_->DrawArrays(graphics_3d, GL_TRIANGLE_STRIP, 0, 4);
 496
 497   gles2_if_->UseProgram(graphics_3d, 0);
 498
 499   last_swap_request_ticks_ = core_if_->GetTimeTicks();
 500   context_->SwapBuffers(
 501       callback_factory_.NewCallback(&MyInstance::PaintFinished));
 502 }
 503
 504 void MyInstance::PaintFinished(int32_t result) {
 505   assert(result == PP_OK);
 506   swap_ticks_ += core_if_->GetTimeTicks() - last_swap_request_ticks_;
 507   is_painting_ = false;
 508   ++num_frames_rendered_;
 509   if (num_frames_rendered_ % 50 == 0) {
 510     double elapsed = core_if_->GetTimeTicks() - first_frame_delivered_ticks_;
 511     double fps = (elapsed > 0) ? num_frames_rendered_ / elapsed : 1000;
 512     double ms_per_swap = (swap_ticks_ * 1e3) / num_frames_rendered_;
 513     double secs_average_latency = 0;
 514     for (DecoderList::iterator it = video_decoders_.begin();
 515          it != video_decoders_.end();
 516          ++it)
 517       secs_average_latency += (*it)->GetAverageLatency();
 518     secs_average_latency /= video_decoders_.size();
 519     double ms_average_latency = 1000 * secs_average_latency;
 520     LogError(this).s() << "Rendered frames: " << num_frames_rendered_
 521                        << ", fps: " << fps
 522                        << ", with average ms/swap of: " << ms_per_swap
 523                        << ", with average latency (ms) of: "
 524                        << ms_average_latency;
 525   }
 526
 527   // If the decoders were reset, this will be empty.
 528   if (pending_pictures_.empty())
 529     return;
 530
 531   const PendingPicture& next = pending_pictures_.front();
 532   Decoder* decoder = next.decoder;
 533   const PP_VideoPicture& picture = next.picture;
 534   decoder->RecyclePicture(picture);
 535   pending_pictures_.pop();
 536
 537   // Keep painting as long as we have pictures.
 538   if (!pending_pictures_.empty())
 539     PaintNextPicture();
 540 }
 541
 542 void MyInstance::InitGL() {
 543   assert(plugin_size_.width() && plugin_size_.height());
 544   is_painting_ = false;
 545
 546   assert(!context_);
 547   int32_t context_attributes[] = {
 548       PP_GRAPHICS3DATTRIB_ALPHA_SIZE,     8,
 549       PP_GRAPHICS3DATTRIB_BLUE_SIZE,      8,
 550       PP_GRAPHICS3DATTRIB_GREEN_SIZE,     8,
 551       PP_GRAPHICS3DATTRIB_RED_SIZE,       8,
 552       PP_GRAPHICS3DATTRIB_DEPTH_SIZE,     0,
 553       PP_GRAPHICS3DATTRIB_STENCIL_SIZE,   0,
 554       PP_GRAPHICS3DATTRIB_SAMPLES,        0,
 555       PP_GRAPHICS3DATTRIB_SAMPLE_BUFFERS, 0,
 556       PP_GRAPHICS3DATTRIB_WIDTH,          plugin_size_.width(),
 557       PP_GRAPHICS3DATTRIB_HEIGHT,         plugin_size_.height(),
 558       PP_GRAPHICS3DATTRIB_NONE,
 559   };
 560   context_ = new pp::Graphics3D(this, context_attributes);
 561   assert(!context_->is_null());
 562   assert(BindGraphics(*context_));
 563
 564   // Clear color bit.
 565   gles2_if_->ClearColor(context_->pp_resource(), 1, 0, 0, 1);
 566   gles2_if_->Clear(context_->pp_resource(), GL_COLOR_BUFFER_BIT);
 567
 568   assertNoGLError();
 569
 570   CreateGLObjects();
 571 }
 572
 573 void MyInstance::CreateGLObjects() {
 574   // Assign vertex positions and texture coordinates to buffers for use in
 575   // shader program.
 576   static const float kVertices[] = {
 577       -1, -1, -1, 1, 1, -1, 1, 1,  // Position coordinates.
 578       0,  1,  0,  0, 1, 1,  1, 0,  // Texture coordinates.
 579   };
 580
 581   GLuint buffer;
 582   gles2_if_->GenBuffers(context_->pp_resource(), 1, &buffer);
 583   gles2_if_->BindBuffer(context_->pp_resource(), GL_ARRAY_BUFFER, buffer);
 584
 585   gles2_if_->BufferData(context_->pp_resource(),
 586                         GL_ARRAY_BUFFER,
 587                         sizeof(kVertices),
 588                         kVertices,
 589                         GL_STATIC_DRAW);
 590   assertNoGLError();
 591 }
 592
 593 static const char kVertexShader[] =
 594     "varying vec2 v_texCoord;            \n"
 595     "attribute vec4 a_position;          \n"
 596     "attribute vec2 a_texCoord;          \n"
 597     "uniform vec2 v_scale;               \n"
 598     "void main()                         \n"
 599     "{                                   \n"
 600     "    v_texCoord = v_scale * a_texCoord; \n"
 601     "    gl_Position = a_position;       \n"
 602     "}";
 603
 604 void MyInstance::Create2DProgramOnce() {
 605   if (shader_2d_.program)
 606     return;
 607   static const char kFragmentShader2D[] =
 608       "precision mediump float;            \n"
 609       "varying vec2 v_texCoord;            \n"
 610       "uniform sampler2D s_texture;        \n"
 611       "void main()                         \n"
 612       "{"
 613       "    gl_FragColor = texture2D(s_texture, v_texCoord); \n"
 614       "}";
 615   shader_2d_ = CreateProgram(kVertexShader, kFragmentShader2D);
 616   assertNoGLError();
 617 }
 618
 619 void MyInstance::CreateRectangleARBProgramOnce() {
 620   if (shader_rectangle_arb_.program)
 621     return;
 622   static const char kFragmentShaderRectangle[] =
 623       "#extension GL_ARB_texture_rectangle : require\n"
 624       "precision mediump float;            \n"
 625       "varying vec2 v_texCoord;            \n"
 626       "uniform sampler2DRect s_texture;    \n"
 627       "void main()                         \n"
 628       "{"
 629       "    gl_FragColor = texture2DRect(s_texture, v_texCoord).rgba; \n"
 630       "}";
 631   shader_rectangle_arb_ =
 632       CreateProgram(kVertexShader, kFragmentShaderRectangle);
 633 }
 634
 635 Shader MyInstance::CreateProgram(const char* vertex_shader,
 636                                  const char* fragment_shader) {
 637   Shader shader;
 638
 639   // Create shader program.
 640   shader.program = gles2_if_->CreateProgram(context_->pp_resource());
 641   CreateShader(
 642       shader.program, GL_VERTEX_SHADER, vertex_shader, strlen(vertex_shader));
 643   CreateShader(shader.program,
 644                GL_FRAGMENT_SHADER,
 645                fragment_shader,
 646                strlen(fragment_shader));
 647   gles2_if_->LinkProgram(context_->pp_resource(), shader.program);
 648   gles2_if_->UseProgram(context_->pp_resource(), shader.program);
 649   gles2_if_->Uniform1i(
 650       context_->pp_resource(),
 651       gles2_if_->GetUniformLocation(
 652           context_->pp_resource(), shader.program, "s_texture"),
 653       0);
 654   assertNoGLError();
 655
 656   shader.texcoord_scale_location = gles2_if_->GetUniformLocation(
 657       context_->pp_resource(), shader.program, "v_scale");
 658
 659   GLint pos_location = gles2_if_->GetAttribLocation(
 660       context_->pp_resource(), shader.program, "a_position");
 661   GLint tc_location = gles2_if_->GetAttribLocation(
 662       context_->pp_resource(), shader.program, "a_texCoord");
 663   assertNoGLError();
 664
 665   gles2_if_->EnableVertexAttribArray(context_->pp_resource(), pos_location);
 666   gles2_if_->VertexAttribPointer(
 667       context_->pp_resource(), pos_location, 2, GL_FLOAT, GL_FALSE, 0, 0);
 668   gles2_if_->EnableVertexAttribArray(context_->pp_resource(), tc_location);
 669   gles2_if_->VertexAttribPointer(
 670       context_->pp_resource(),
 671       tc_location,
 672       2,
 673       GL_FLOAT,
 674       GL_FALSE,
 675       0,
 676       static_cast<float*>(0) + 8);  // Skip position coordinates.
 677
 678   gles2_if_->UseProgram(context_->pp_resource(), 0);
 679   assertNoGLError();
 680   return shader;
 681 }
 682
 683 void MyInstance::CreateShader(GLuint program,
 684                               GLenum type,
 685                               const char* source,
 686                               int size) {
 687   GLuint shader = gles2_if_->CreateShader(context_->pp_resource(), type);
 688   gles2_if_->ShaderSource(context_->pp_resource(), shader, 1, &source, &size);
 689   gles2_if_->CompileShader(context_->pp_resource(), shader);
 690   gles2_if_->AttachShader(context_->pp_resource(), program, shader);
 691   gles2_if_->DeleteShader(context_->pp_resource(), shader);
 692 }
 693
 694 // This object is the global object representing this plugin library as long
 695 // as it is loaded.
 696 class MyModule : public pp::Module {
 697  public:
 698   MyModule() : pp::Module() {}
 699   virtual ~MyModule() {}
 700
 701   virtual pp::Instance* CreateInstance(PP_Instance instance) {
 702     return new MyInstance(instance, this);
 703   }
 704 };
 705
 706 }  // anonymous namespace
 707
 708 namespace pp {
 709 // Factory function for your specialization of the Module object.
 710 Module* CreateModule() {
 711   return new MyModule();
 712 }
 713 }  // namespace pp