[PPAPI] Compositor API implementation.

Implement the compositor API which allows a plugin to combine different sources of visual data efficiently, such as PPB_ImageData and OpengGL texture.

API Proposal http://goo.gl/V7xcu3

BUG=374383

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=277208

Review URL: https://codereview.chromium.org/298023004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@277422 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 968 insertions, 0 deletions

diff --git a/ppapi/examples/compositor/compositor.cc b/ppapi/examples/compositor/compositor.cc
new file mode 100644
index 0000000..d437bc84
--- /dev/null
+++ b/ppapi/examples/compositor/compositor.cc
@@ -0,0 +1,439 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Needed on Windows to get |M_PI| from math.h.
+#ifdef _WIN32
+#define _USE_MATH_DEFINES
+#endif
+
+#include <math.h>
+
+#include <vector>
+
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/pp_input_event.h"
+#include "ppapi/cpp/compositor.h"
+#include "ppapi/cpp/compositor_layer.h"
+#include "ppapi/cpp/graphics_3d.h"
+#include "ppapi/cpp/graphics_3d_client.h"
+#include "ppapi/cpp/image_data.h"
+#include "ppapi/cpp/input_event.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/rect.h"
+#include "ppapi/cpp/var_dictionary.h"
+#include "ppapi/examples/compositor/spinning_cube.h"
+#include "ppapi/lib/gl/gles2/gl2ext_ppapi.h"
+#include "ppapi/lib/gl/include/GLES2/gl2.h"
+#include "ppapi/lib/gl/include/GLES2/gl2ext.h"
+#include "ppapi/utility/completion_callback_factory.h"
+
+// Use assert as a poor-man's CHECK, even in non-debug mode.
+// Since <assert.h> redefines assert on every inclusion (it doesn't use
+// include-guards), make sure this is the last file #include'd in this file.
+#undef NDEBUG
+#include <assert.h>
+
+// When compiling natively on Windows, PostMessage can be #define-d to
+// something else.
+#ifdef PostMessage
+#undef PostMessage
+#endif
+
+// Assert |context_| isn't holding any GL Errors.  Done as a macro instead of a
+// function to preserve line number information in the failure message.
+#define AssertNoGLError() \
+  PP_DCHECK(!glGetError());
+
+namespace {
+
+const int32_t kTextureWidth = 800;
+const int32_t kTextureHeight = 800;
+const int32_t kImageWidth = 256;
+const int32_t kImageHeight = 256;
+
+class DemoInstance : public pp::Instance, public pp::Graphics3DClient {
+ public:
+  DemoInstance(PP_Instance instance);
+  virtual ~DemoInstance();
+
+  // pp::Instance implementation (see PPP_Instance).
+  virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]);
+  virtual void DidChangeView(const pp::Rect& position,
+                             const pp::Rect& clip);
+  virtual bool HandleInputEvent(const pp::InputEvent& event);
+
+  // pp::Graphics3DClient implementation.
+  virtual void Graphics3DContextLost();
+
+ private:
+  // GL-related functions.
+  void InitGL(int32_t result);
+  GLuint PrepareFramebuffer();
+  pp::ImageData PrepareImage();
+  void Paint(int32_t result, int32_t frame);
+  void OnTextureReleased(int32_t result, GLuint texture);
+  void OnImageReleased(int32_t result, const pp::ImageData& image);
+
+  pp::CompletionCallbackFactory<DemoInstance> callback_factory_;
+
+  // Owned data.
+  pp::Graphics3D* context_;
+
+  GLuint fbo_;
+  GLuint rbo_;
+
+  std::vector<GLuint> textures_;
+  std::vector<pp::ImageData> images_;
+
+  pp::Compositor compositor_;
+  pp::CompositorLayer color_layer_;
+  pp::CompositorLayer stable_texture_layer_;
+  pp::CompositorLayer texture_layer_;
+  pp::CompositorLayer image_layer_;
+
+  bool rebuild_layers_;
+  int32_t total_resource_;
+
+  SpinningCube* cube_;
+};
+
+DemoInstance::DemoInstance(PP_Instance instance)
+    : pp::Instance(instance),
+      pp::Graphics3DClient(this),
+      callback_factory_(this),
+      context_(NULL),
+      fbo_(0),
+      rbo_(0),
+      compositor_(this),
+      rebuild_layers_(false),
+      total_resource_(0),
+      cube_(new SpinningCube()) {
+  RequestInputEvents(PP_INPUTEVENT_CLASS_MOUSE);
+}
+
+DemoInstance::~DemoInstance() {
+  delete cube_;
+  assert(glTerminatePPAPI());
+  delete context_;
+}
+
+bool DemoInstance::Init(uint32_t /*argc*/,
+                        const char* /*argn*/[],
+                        const char* /*argv*/[]) {
+  return !!glInitializePPAPI(pp::Module::Get()->get_browser_interface());
+}
+
+void DemoInstance::DidChangeView(
+    const pp::Rect& position, const pp::Rect& /*clip*/) {
+  if (position.width() == 0 || position.height() == 0)
+    return;
+  // Initialize graphics.
+  InitGL(0);
+}
+
+bool DemoInstance::HandleInputEvent(const pp::InputEvent& event) {
+  switch (event.GetType()) {
+    case PP_INPUTEVENT_TYPE_MOUSEDOWN:
+      rebuild_layers_ = true;
+      return true;
+    default:
+      break;
+  }
+  return false;
+}
+
+void DemoInstance::Graphics3DContextLost() {
+  fbo_ = 0;
+  rbo_ = 0;
+  compositor_.ResetLayers();
+  color_layer_ = pp::CompositorLayer();
+  stable_texture_layer_ = pp::CompositorLayer();
+  texture_layer_ = pp::CompositorLayer();
+  image_layer_ = pp::CompositorLayer();
+  total_resource_ -= static_cast<int32_t>(textures_.size());
+  textures_.clear();
+  delete context_;
+  context_ = NULL;
+  cube_->OnGLContextLost();
+  pp::CompletionCallback cb = callback_factory_.NewCallback(
+      &DemoInstance::InitGL);
+  pp::Module::Get()->core()->CallOnMainThread(0, cb, 0);
+}
+
+void DemoInstance::InitGL(int32_t /*result*/) {
+  if (context_)
+    return;
+  int32_t context_attributes[] = {
+    PP_GRAPHICS3DATTRIB_ALPHA_SIZE, 8,
+    PP_GRAPHICS3DATTRIB_BLUE_SIZE, 8,
+    PP_GRAPHICS3DATTRIB_GREEN_SIZE, 8,
+    PP_GRAPHICS3DATTRIB_RED_SIZE, 8,
+    PP_GRAPHICS3DATTRIB_DEPTH_SIZE, 0,
+    PP_GRAPHICS3DATTRIB_STENCIL_SIZE, 0,
+    PP_GRAPHICS3DATTRIB_SAMPLES, 0,
+    PP_GRAPHICS3DATTRIB_SAMPLE_BUFFERS, 0,
+    PP_GRAPHICS3DATTRIB_WIDTH, 32,
+    PP_GRAPHICS3DATTRIB_HEIGHT, 32,
+    PP_GRAPHICS3DATTRIB_NONE,
+  };
+  context_ = new pp::Graphics3D(this, context_attributes);
+  assert(!context_->is_null());
+  assert(BindGraphics(compositor_));
+
+  glSetCurrentContextPPAPI(context_->pp_resource());
+
+  cube_->Init(kTextureWidth, kTextureHeight);
+
+  Paint(PP_OK, 0);
+}
+
+GLuint DemoInstance::PrepareFramebuffer() {
+  GLuint texture = 0;
+  if (textures_.empty()) {
+    total_resource_++;
+    // Create a texture object
+    glGenTextures(1, &texture);
+    glBindTexture(GL_TEXTURE_2D, texture);
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kTextureWidth, kTextureHeight, 0,
+                 GL_RGBA, GL_UNSIGNED_BYTE, NULL);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+    glBindTexture(GL_TEXTURE_2D, 0);
+  } else {
+    texture = textures_.back();
+    textures_.pop_back();
+  }
+
+  if (!rbo_) {
+    // create a renderbuffer object to store depth info
+    glGenRenderbuffers(1, &rbo_);
+    glBindRenderbuffer(GL_RENDERBUFFER, rbo_);
+    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT16,
+        kTextureWidth, kTextureHeight);
+    glBindRenderbuffer(GL_RENDERBUFFER, 0);
+  }
+
+  if (!fbo_) {
+    // create a framebuffer object
+    glGenFramebuffers(1, &fbo_);
+  }
+
+  glBindFramebuffer(GL_FRAMEBUFFER, fbo_);
+
+  // attach the texture to FBO color attachment point
+  glFramebufferTexture2D(GL_FRAMEBUFFER,
+                         GL_COLOR_ATTACHMENT0,
+                         GL_TEXTURE_2D,
+                         texture,
+                         0);
+
+  // attach the renderbuffer to depth attachment point
+  glFramebufferRenderbuffer(GL_FRAMEBUFFER,
+                            GL_DEPTH_ATTACHMENT,
+                            GL_RENDERBUFFER,
+                            rbo_);
+
+  // check FBO status
+  GLenum status = glCheckFramebufferStatus(GL_FRAMEBUFFER);
+  assert(status == GL_FRAMEBUFFER_COMPLETE);
+
+  AssertNoGLError();
+  return texture;
+}
+
+pp::ImageData DemoInstance::PrepareImage() {
+  if (images_.empty()) {
+    total_resource_++;
+    return pp::ImageData(this,
+                         PP_IMAGEDATAFORMAT_RGBA_PREMUL,
+                         pp::Size(kImageWidth, kImageHeight),
+                         false);
+  }
+  pp::ImageData image = images_.back();
+  images_.pop_back();
+  return image;
+}
+
+void DemoInstance::Paint(int32_t result, int32_t frame) {
+  assert(result == PP_OK);
+
+  if (result != PP_OK || !context_)
+    return;
+
+  int32_t rv;
+
+  if (rebuild_layers_) {
+    compositor_.ResetLayers();
+    color_layer_ = pp::CompositorLayer();
+    stable_texture_layer_ = pp::CompositorLayer();
+    texture_layer_ = pp::CompositorLayer();
+    image_layer_ = pp::CompositorLayer();
+    frame = 0;
+    rebuild_layers_ = false;
+  }
+
+  float factor_sin = sin(M_PI / 180 * frame);
+  float factor_cos = cos(M_PI / 180 * frame);
+  {
+    // Set the background color layer.
+    if (color_layer_.is_null()) {
+      color_layer_ = compositor_.AddLayer();
+      assert(!color_layer_.is_null());
+      static const float transform[16] = {
+        1.0f, 0.0f, 0.0f, 0.0f,
+        0.0f, 1.0f, 0.0f, 0.0f,
+        0.0f, 0.0f, 1.0f, 0.0f,
+        0.0f, 0.0f, 0.0f, 1.0f,
+      };
+      rv = color_layer_.SetTransform(transform);
+      assert(rv == PP_OK);
+    }
+    rv = color_layer_.SetColor(fabs(factor_sin),
+                               fabs(factor_cos),
+                               fabs(factor_sin * factor_cos),
+                               1.0f,
+                               pp::Size(800, 600));
+    assert(rv == PP_OK);
+  }
+
+  {
+    // Set the image layer
+    if (image_layer_.is_null()) {
+      image_layer_ = compositor_.AddLayer();
+      assert(!image_layer_.is_null());
+    }
+    float x = frame % 800;
+    float y = 200 - 200 * factor_sin;
+    const float transform[16] = {
+      fabs(factor_sin) + 0.2f, 0.0f, 0.0f, 0.0f,
+      0.0f, fabs(factor_sin) + 0.2f, 0.0f, 0.0f,
+      0.0f, 0.0f, 1.0f, 0.0f,
+         x,    y, 0.0f, 1.0f,
+    };
+    rv = image_layer_.SetTransform(transform);
+    assert(rv == PP_OK);
+
+    pp::ImageData image = PrepareImage();
+    uint8_t *p = static_cast<uint8_t*>(image.data());
+    for (int x = 0; x < kImageWidth; ++x) {
+      for (int y = 0; y < kImageHeight; ++y) {
+        *(p++) = frame;
+        *(p++) = frame * x;
+        *(p++) = frame * y;
+        *(p++) = 255;
+      }
+    }
+    rv = image_layer_.SetImage(image, pp::Size(kImageWidth, kImageHeight),
+        callback_factory_.NewCallback(&DemoInstance::OnImageReleased, image));
+    assert(rv == PP_OK_COMPLETIONPENDING);
+  }
+
+  {
+    // Set the stable texture layer
+    if (stable_texture_layer_.is_null()) {
+      stable_texture_layer_ = compositor_.AddLayer();
+      assert(!stable_texture_layer_.is_null());
+      GLuint texture = PrepareFramebuffer();
+      cube_->UpdateForTimeDelta(0.02f);
+      cube_->Draw();
+      rv = stable_texture_layer_.SetTexture(
+          *context_,
+          texture, pp::Size(600, 600),
+          callback_factory_.NewCallback(&DemoInstance::OnTextureReleased,
+                                        texture));
+      assert(rv == PP_OK_COMPLETIONPENDING);
+      rv = stable_texture_layer_.SetPremultipliedAlpha(PP_FALSE);
+      assert(rv == PP_OK);
+    }
+
+    int32_t delta = 200 * fabsf(factor_sin);
+    if (delta != 0) {
+      int32_t x_y = 25 + delta;
+      int32_t w_h =  650 - delta - delta;
+      rv = stable_texture_layer_.SetClipRect(pp::Rect(x_y, x_y, w_h, w_h));
+    } else {
+      rv = stable_texture_layer_.SetClipRect(pp::Rect());
+    }
+    assert(rv == PP_OK);
+
+    const float transform[16] = {
+      factor_cos, -factor_sin, 0.0f, 0.0f,
+      factor_sin, factor_cos, 0.0f, 0.0f,
+      0.0f, 0.0f, 1.0f, 0.0f,
+      50.0f, 50.0f, 0.0f, 1.0f,
+    };
+    rv = stable_texture_layer_.SetTransform(transform);
+    assert(rv == PP_OK);
+  }
+
+  {
+    // Set the dynamic texture layer.
+    if (texture_layer_.is_null()) {
+      texture_layer_ = compositor_.AddLayer();
+      assert(!texture_layer_.is_null());
+      static const float transform[16] = {
+        1.0f, 0.0f, 0.0f, 0.0f,
+        0.0f, 1.0f, 0.0f, 0.0f,
+        0.0f, 0.0f, 1.0f, 0.0f,
+        200.0f, 0.0f, 0.0f, 1.0f,
+      };
+      rv = texture_layer_.SetTransform(transform);
+      assert(rv == PP_OK);
+     }
+
+    GLuint texture = PrepareFramebuffer();
+    cube_->UpdateForTimeDelta(0.02f);
+    cube_->Draw();
+    rv = texture_layer_.SetTexture(*context_, texture, pp::Size(400, 400),
+        callback_factory_.NewCallback(&DemoInstance::OnTextureReleased,
+                                      texture));
+    assert(rv == PP_OK_COMPLETIONPENDING);
+    rv = texture_layer_.SetPremultipliedAlpha(PP_FALSE);
+    assert(rv == PP_OK);
+  }
+
+  rv = compositor_.CommitLayers(
+      callback_factory_.NewCallback(&DemoInstance::Paint, ++frame));
+  assert(rv == PP_OK_COMPLETIONPENDING);
+
+  pp::VarDictionary dict;
+  dict.Set(pp::Var("total_resource"), pp::Var(total_resource_));
+  dict.Set(pp::Var("free_resource"),
+      pp::Var((int32_t)(textures_.size() + images_.size())));
+  PostMessage(dict);
+}
+
+void DemoInstance::OnTextureReleased(int32_t result, GLuint texture) {
+  if (result == PP_OK)
+    textures_.push_back(texture);
+}
+
+void DemoInstance::OnImageReleased(int32_t result, const pp::ImageData& image) {
+  if (result == PP_OK)
+    images_.push_back(image);
+}
+
+// This object is the global object representing this plugin library as long
+// as it is loaded.
+class DemoModule : public pp::Module {
+ public:
+  DemoModule() : Module() {}
+  virtual ~DemoModule() {}
+
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new DemoInstance(instance);
+  }
+};
+
+}  // anonymous namespace
+
+namespace pp {
+// Factory function for your specialization of the Module object.
+Module* CreateModule() {
+  return new DemoModule();
+}
+}  // namespace pp
diff --git a/ppapi/examples/compositor/compositor.html b/ppapi/examples/compositor/compositor.html
new file mode 100644
index 0000000..a0dcfbe
--- /dev/null
+++ b/ppapi/examples/compositor/compositor.html
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html>
+  <!--
+  Copyright 2014 The Chromium Authors. All rights reserved.
+  Use of this source code is governed by a BSD-style license that can be
+  found in the LICENSE file.
+  -->
+<head>
+  <title>GLES2 Spinning Cube Example</title>
+</head>
+
+<body>
+
+<embed id="plugin" type="application/x-ppapi-example-compositor"
+  width="800" height="600"/> <br/>
+  Total resource: <input id="total" > <br/>
+  Free resource: <input id="free" > <br/>
+<script type="text/javascript">
+  var plugin = document.getElementById('plugin');
+  var total = document.getElementById('total');
+  var free = document.getElementById('free');
+  plugin.addEventListener('message', function(message) {
+    total.value = message.data.total_resource;
+    free.value = message.data.free_resource;
+  }, false);
+</script>
+</body>
+</html>
diff --git a/ppapi/examples/compositor/spinning_cube.cc b/ppapi/examples/compositor/spinning_cube.cc
new file mode 100644
index 0000000..2e76699
--- /dev/null
+++ b/ppapi/examples/compositor/spinning_cube.cc
@@ -0,0 +1,459 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This example program is based on Simple_VertexShader.c from:
+
+//
+// Book:      OpenGL(R) ES 2.0 Programming Guide
+// Authors:   Aaftab Munshi, Dan Ginsburg, Dave Shreiner
+// ISBN-10:   0321502795
+// ISBN-13:   9780321502797
+// Publisher: Addison-Wesley Professional
+// URLs:      http://safari.informit.com/9780321563835
+//            http://www.opengles-book.com
+//
+
+#include "ppapi/examples/compositor/spinning_cube.h"
+
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <algorithm>
+
+#include "ppapi/lib/gl/include/GLES2/gl2.h"
+
+namespace {
+
+const float kPi = 3.14159265359f;
+
+int GenerateCube(GLuint *vbo_vertices,
+                 GLuint *vbo_indices) {
+  const int num_indices = 36;
+
+  const GLfloat cube_vertices[] = {
+    -0.5f, -0.5f, -0.5f,
+     0.5f, -0.5f, -0.5f,
+     0.5f, -0.5f,  0.5f,
+    -0.5f, -0.5f,  0.5f,
+    -0.5f,  0.5f, -0.5f,
+     0.5f,  0.5f, -0.5f,
+     0.5f,  0.5f,  0.5f,
+    -0.5f,  0.5f,  0.5f,
+  };
+
+  const GLushort cube_indices[] = {
+    0, 2, 1,
+    0, 3, 2,
+    4, 5, 6,
+    4, 6, 7,
+    3, 6, 2,
+    3, 7, 6,
+    0, 1, 5,
+    0, 5, 4,
+    0, 7, 3,
+    0, 4, 7,
+    1, 2, 6,
+    1, 6, 5,
+  };
+
+  if (vbo_vertices) {
+    glGenBuffers(1, vbo_vertices);
+    glBindBuffer(GL_ARRAY_BUFFER, *vbo_vertices);
+    glBufferData(GL_ARRAY_BUFFER,
+                 sizeof(cube_vertices),
+                 cube_vertices,
+                 GL_STATIC_DRAW);
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+  }
+
+  if (vbo_indices) {
+    glGenBuffers(1, vbo_indices);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, *vbo_indices);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER,
+                 sizeof(cube_indices),
+                 cube_indices,
+                 GL_STATIC_DRAW);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
+  }
+
+  return num_indices;
+}
+
+GLuint LoadShader(GLenum type,
+                  const char* shader_source) {
+  GLuint shader = glCreateShader(type);
+  glShaderSource(shader, 1, &shader_source, NULL);
+  glCompileShader(shader);
+
+  GLint compiled = 0;
+  glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+
+  if (!compiled) {
+    glDeleteShader(shader);
+    return 0;
+  }
+
+  return shader;
+}
+
+GLuint LoadProgram(const char* vertext_shader_source,
+                   const char* fragment_shader_source) {
+  GLuint vertex_shader = LoadShader(GL_VERTEX_SHADER,
+                                    vertext_shader_source);
+  if (!vertex_shader)
+    return 0;
+
+  GLuint fragment_shader = LoadShader(GL_FRAGMENT_SHADER,
+                                      fragment_shader_source);
+  if (!fragment_shader) {
+    glDeleteShader(vertex_shader);
+    return 0;
+  }
+
+  GLuint program_object = glCreateProgram();
+  glAttachShader(program_object, vertex_shader);
+  glAttachShader(program_object, fragment_shader);
+
+  glLinkProgram(program_object);
+
+  glDeleteShader(vertex_shader);
+  glDeleteShader(fragment_shader);
+
+  GLint linked = 0;
+  glGetProgramiv(program_object, GL_LINK_STATUS, &linked);
+
+  if (!linked) {
+    glDeleteProgram(program_object);
+    return 0;
+  }
+
+  return program_object;
+}
+
+class ESMatrix {
+ public:
+  GLfloat m[4][4];
+
+  ESMatrix() {
+    LoadZero();
+  }
+
+  void LoadZero() {
+    memset(this, 0x0, sizeof(ESMatrix));
+  }
+
+  void LoadIdentity() {
+    LoadZero();
+    m[0][0] = 1.0f;
+    m[1][1] = 1.0f;
+    m[2][2] = 1.0f;
+    m[3][3] = 1.0f;
+  }
+
+  void Multiply(ESMatrix* a, ESMatrix* b) {
+    ESMatrix result;
+    for (int i = 0; i < 4; ++i) {
+      result.m[i][0] = (a->m[i][0] * b->m[0][0]) +
+                       (a->m[i][1] * b->m[1][0]) +
+                       (a->m[i][2] * b->m[2][0]) +
+                       (a->m[i][3] * b->m[3][0]);
+
+      result.m[i][1] = (a->m[i][0] * b->m[0][1]) +
+                       (a->m[i][1] * b->m[1][1]) +
+                       (a->m[i][2] * b->m[2][1]) +
+                       (a->m[i][3] * b->m[3][1]);
+
+      result.m[i][2] = (a->m[i][0] * b->m[0][2]) +
+                       (a->m[i][1] * b->m[1][2]) +
+                       (a->m[i][2] * b->m[2][2]) +
+                       (a->m[i][3] * b->m[3][2]);
+
+      result.m[i][3] = (a->m[i][0] * b->m[0][3]) +
+                       (a->m[i][1] * b->m[1][3]) +
+                       (a->m[i][2] * b->m[2][3]) +
+                       (a->m[i][3] * b->m[3][3]);
+    }
+    *this = result;
+  }
+
+  void Frustum(float left,
+               float right,
+               float bottom,
+               float top,
+               float near_z,
+               float far_z) {
+    float delta_x = right - left;
+    float delta_y = top - bottom;
+    float delta_z = far_z - near_z;
+
+    if ((near_z <= 0.0f) ||
+        (far_z <= 0.0f) ||
+        (delta_z <= 0.0f) ||
+        (delta_y <= 0.0f) ||
+        (delta_y <= 0.0f))
+      return;
+
+    ESMatrix frust;
+    frust.m[0][0] = 2.0f * near_z / delta_x;
+    frust.m[0][1] = frust.m[0][2] = frust.m[0][3] = 0.0f;
+
+    frust.m[1][1] = 2.0f * near_z / delta_y;
+    frust.m[1][0] = frust.m[1][2] = frust.m[1][3] = 0.0f;
+
+    frust.m[2][0] = (right + left) / delta_x;
+    frust.m[2][1] = (top + bottom) / delta_y;
+    frust.m[2][2] = -(near_z + far_z) / delta_z;
+    frust.m[2][3] = -1.0f;
+
+    frust.m[3][2] = -2.0f * near_z * far_z / delta_z;
+    frust.m[3][0] = frust.m[3][1] = frust.m[3][3] = 0.0f;
+
+    Multiply(&frust, this);
+  }
+
+  void Perspective(float fov_y, float aspect, float near_z, float far_z) {
+    GLfloat frustum_h = tanf(fov_y / 360.0f * kPi) * near_z;
+    GLfloat frustum_w = frustum_h * aspect;
+    Frustum(-frustum_w, frustum_w, -frustum_h, frustum_h, near_z, far_z);
+  }
+
+  void Translate(GLfloat tx, GLfloat ty, GLfloat tz) {
+    m[3][0] += m[0][0] * tx + m[1][0] * ty + m[2][0] * tz;
+    m[3][1] += m[0][1] * tx + m[1][1] * ty + m[2][1] * tz;
+    m[3][2] += m[0][2] * tx + m[1][2] * ty + m[2][2] * tz;
+    m[3][3] += m[0][3] * tx + m[1][3] * ty + m[2][3] * tz;
+  }
+
+  void Rotate(GLfloat angle, GLfloat x, GLfloat y, GLfloat z) {
+    GLfloat mag = sqrtf(x * x + y * y + z * z);
+
+    GLfloat sin_angle = sinf(angle * kPi / 180.0f);
+    GLfloat cos_angle = cosf(angle * kPi / 180.0f);
+    if (mag > 0.0f) {
+      GLfloat xx, yy, zz, xy, yz, zx, xs, ys, zs;
+      GLfloat one_minus_cos;
+      ESMatrix rotation;
+
+      x /= mag;
+      y /= mag;
+      z /= mag;
+
+      xx = x * x;
+      yy = y * y;
+      zz = z * z;
+      xy = x * y;
+      yz = y * z;
+      zx = z * x;
+      xs = x * sin_angle;
+      ys = y * sin_angle;
+      zs = z * sin_angle;
+      one_minus_cos = 1.0f - cos_angle;
+
+      rotation.m[0][0] = (one_minus_cos * xx) + cos_angle;
+      rotation.m[0][1] = (one_minus_cos * xy) - zs;
+      rotation.m[0][2] = (one_minus_cos * zx) + ys;
+      rotation.m[0][3] = 0.0F;
+
+      rotation.m[1][0] = (one_minus_cos * xy) + zs;
+      rotation.m[1][1] = (one_minus_cos * yy) + cos_angle;
+      rotation.m[1][2] = (one_minus_cos * yz) - xs;
+      rotation.m[1][3] = 0.0F;
+
+      rotation.m[2][0] = (one_minus_cos * zx) - ys;
+      rotation.m[2][1] = (one_minus_cos * yz) + xs;
+      rotation.m[2][2] = (one_minus_cos * zz) + cos_angle;
+      rotation.m[2][3] = 0.0F;
+
+      rotation.m[3][0] = 0.0F;
+      rotation.m[3][1] = 0.0F;
+      rotation.m[3][2] = 0.0F;
+      rotation.m[3][3] = 1.0F;
+
+      Multiply(&rotation, this);
+    }
+  }
+};
+
+float RotationForTimeDelta(float delta_time) {
+  return delta_time * 40.0f;
+}
+
+float RotationForDragDistance(float drag_distance) {
+  return drag_distance / 5; // Arbitrary damping.
+}
+
+}  // namespace
+
+class SpinningCube::GLState {
+ public:
+  GLState();
+
+  void OnGLContextLost();
+
+  GLfloat angle_;  // Survives losing the GL context.
+
+  GLuint program_object_;
+  GLint position_location_;
+  GLint mvp_location_;
+  GLuint vbo_vertices_;
+  GLuint vbo_indices_;
+  int num_indices_;
+  ESMatrix mvp_matrix_;
+};
+
+SpinningCube::GLState::GLState()
+    : angle_(0) {
+  OnGLContextLost();
+}
+
+void SpinningCube::GLState::OnGLContextLost() {
+  program_object_ = 0;
+  position_location_ = 0;
+  mvp_location_ = 0;
+  vbo_vertices_ = 0;
+  vbo_indices_ = 0;
+  num_indices_ = 0;
+}
+
+SpinningCube::SpinningCube()
+    : initialized_(false),
+      width_(0),
+      height_(0),
+      state_(new GLState()),
+      fling_multiplier_(1.0f),
+      direction_(1) {
+  state_->angle_ = 45.0f;
+}
+
+SpinningCube::~SpinningCube() {
+  if (!initialized_)
+    return;
+  if (state_->vbo_vertices_)
+    glDeleteBuffers(1, &state_->vbo_vertices_);
+  if (state_->vbo_indices_)
+    glDeleteBuffers(1, &state_->vbo_indices_);
+  if (state_->program_object_)
+    glDeleteProgram(state_->program_object_);
+
+  delete state_;
+}
+
+void SpinningCube::Init(uint32_t width, uint32_t height) {
+  width_ = width;
+  height_ = height;
+
+  if (!initialized_) {
+    initialized_ = true;
+    const char vertext_shader_source[] =
+        "uniform mat4 u_mvpMatrix;                   \n"
+        "attribute vec4 a_position;                  \n"
+        "varying vec4 v_color;                       \n"
+        "void main()                                 \n"
+        "{                                           \n"
+        "   gl_Position = u_mvpMatrix * a_position;  \n"
+        "   v_color = vec4(a_position.x + 0.5,       \n"
+        "                  a_position.y + 0.5,       \n"
+        "                  a_position.z + 0.5,       \n"
+        "                  0.8);                     \n"
+        "}                                           \n";
+
+    const char fragment_shader_source[] =
+        "precision mediump float;                    \n"
+        "varying vec4 v_color;                       \n"
+        "void main()                                 \n"
+        "{                                           \n"
+        "  gl_FragColor = v_color;                   \n"
+        "}                                           \n";
+
+    state_->program_object_ = LoadProgram(
+        vertext_shader_source, fragment_shader_source);
+    state_->position_location_ = glGetAttribLocation(
+        state_->program_object_, "a_position");
+    state_->mvp_location_ = glGetUniformLocation(
+        state_->program_object_, "u_mvpMatrix");
+    state_->num_indices_ = GenerateCube(&state_->vbo_vertices_,
+                                        &state_->vbo_indices_);
+
+    glClearColor(0.0f, 0.0f, 0.0f, 0.2f);
+  }
+}
+
+void SpinningCube::OnGLContextLost() {
+  // TODO(yzshen): Is it correct that in this case we don't need to do cleanup
+  // for program and buffers?
+  initialized_ = false;
+  height_ = 0;
+  width_ = 0;
+  state_->OnGLContextLost();
+}
+
+void SpinningCube::SetFlingMultiplier(float drag_distance,
+                                      float drag_time) {
+  fling_multiplier_ = RotationForDragDistance(drag_distance) /
+      RotationForTimeDelta(drag_time);
+
+}
+
+void SpinningCube::UpdateForTimeDelta(float delta_time) {
+  state_->angle_ += RotationForTimeDelta(delta_time) * fling_multiplier_;
+  if (state_->angle_ >= 360.0f)
+    state_->angle_ -= 360.0f;
+
+  // Arbitrary 50-step linear reduction in spin speed.
+  if (fling_multiplier_ > 1.0f) {
+    fling_multiplier_ =
+        std::max(1.0f, fling_multiplier_ - (fling_multiplier_ - 1.0f) / 50);
+  }
+
+  Update();
+}
+
+void SpinningCube::UpdateForDragDistance(float distance) {
+  state_->angle_ += RotationForDragDistance(distance);
+  if (state_->angle_ >= 360.0f )
+    state_->angle_ -= 360.0f;
+
+  Update();
+}
+
+void SpinningCube::Draw() {
+  glViewport(0, 0, width_, height_);
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+  glEnable(GL_DEPTH_TEST);
+  glUseProgram(state_->program_object_);
+
+  glBindBuffer(GL_ARRAY_BUFFER, state_->vbo_vertices_);
+  glVertexAttribPointer(state_->position_location_,
+                        3,
+                        GL_FLOAT,
+                        GL_FALSE, 3 * sizeof(GLfloat),
+                        0);
+  glEnableVertexAttribArray(state_->position_location_);
+
+  glUniformMatrix4fv(state_->mvp_location_,
+                     1,
+                     GL_FALSE,
+                     (GLfloat*) &state_->mvp_matrix_.m[0][0]);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, state_->vbo_indices_);
+  glDrawElements(GL_TRIANGLES,
+                 state_->num_indices_,
+                 GL_UNSIGNED_SHORT,
+                 0);
+}
+
+void SpinningCube::Update() {
+  float aspect = static_cast<GLfloat>(width_) / static_cast<GLfloat>(height_);
+
+  ESMatrix perspective;
+  perspective.LoadIdentity();
+  perspective.Perspective(60.0f, aspect, 1.0f, 20.0f );
+
+  ESMatrix modelview;
+  modelview.LoadIdentity();
+  modelview.Translate(0.0, 0.0, -2.0);
+  modelview.Rotate(state_->angle_ * direction_, 1.0, 0.0, 1.0);
+
+  state_->mvp_matrix_.Multiply(&modelview, &perspective);
+}
diff --git a/ppapi/examples/compositor/spinning_cube.h b/ppapi/examples/compositor/spinning_cube.h
new file mode 100644
index 0000000..84a302c2
--- /dev/null
+++ b/ppapi/examples/compositor/spinning_cube.h
@@ -0,0 +1,42 @@
+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef PPAPI_EXAMPLES_GLES2_SPINNING_CUBE_SPINNING_CUBE_H_
+#define PPAPI_EXAMPLES_GLES2_SPINNING_CUBE_SPINNING_CUBE_H_
+
+#include "ppapi/c/pp_stdint.h"
+
+class SpinningCube {
+ public:
+  SpinningCube();
+  ~SpinningCube();
+
+  void Init(uint32_t width, uint32_t height);
+  void set_direction(int direction) { direction_ = direction; }
+  void SetFlingMultiplier(float drag_distance, float drag_time);
+  void UpdateForTimeDelta(float delta_time);
+  void UpdateForDragDistance(float distance);
+  void Draw();
+
+  void OnGLContextLost();
+
+ private:
+  class GLState;
+
+  // Disallow copy and assign.
+  SpinningCube(const SpinningCube& other);
+  SpinningCube& operator=(const SpinningCube& other);
+
+  void Update();
+
+  bool initialized_;
+  uint32_t width_;
+  uint32_t height_;
+  // Owned ptr.
+  GLState* state_;
+  float fling_multiplier_;
+  int direction_;
+};
+
+#endif  // PPAPI_EXAMPLES_GLES2_SPINNING_CUBE_SPINNING_CUBE_H_