Add a very simple example pepper plugin that uses a 3d context

ppapi/examples/gles2/gles2.cc

Index: ppapi/examples/gles2/gles2.cc
diff --git a/ppapi/examples/gles2/gles2.cc b/ppapi/examples/gles2/gles2.cc
new file mode 100644
index 0000000000000000000000000000000000000000..38542112cea9d422606288086e622134f53b9c56
--- /dev/null
+++ b/ppapi/examples/gles2/gles2.cc
@@ -0,0 +1,163 @@
+// Copyright (c) 2012 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.
+
+#include <string.h>
+
+#include <iostream>
+#include <sstream>
+
+#include "ppapi/c/dev/ppb_console_dev.h"
+#include "ppapi/c/pp_errors.h"
+#include "ppapi/c/ppb_opengles2.h"
+#include "ppapi/cpp/graphics_3d.h"
+#include "ppapi/cpp/graphics_3d_client.h"
+#include "ppapi/cpp/instance.h"
+#include "ppapi/cpp/module.h"
+#include "ppapi/cpp/rect.h"
+#include "ppapi/cpp/var.h"
+#include "ppapi/lib/gl/include/GLES2/gl2.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>
+
+// 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() \
+  assert(!gles2_if_->GetError(context_->pp_resource()));
+
+namespace {
+
+class GLES2DemoInstance : public pp::Instance,
+                          public pp::Graphics3DClient {
+ public:
+  GLES2DemoInstance(PP_Instance instance, pp::Module* module);
+  virtual ~GLES2DemoInstance();
+
+  // pp::Instance implementation (see PPP_Instance).
+  virtual void DidChangeView(const pp::Rect& position,
+                             const pp::Rect& clip_ignored);
+
+  // pp::Graphics3DClient implementation.
+  virtual void Graphics3DContextLost() {
+    // TODO(jamesr): What's the state of context_? Should we delete the old one
+    // or try to revive it somehow?

[piman, 2012/03/08 00:03:44]

The context is dead, indeed you need to destroy it and recreate it.

Note, I don't think recreating the context directly from the
Graphics3DContextLost callback is tested or even works in all cases. I know
Flash will do so on the next draw, which will go back to the main loop first
(having posted a task).

+    // For now, just delete it and construct+bind a new context.
+    delete context_;
+    context_ = NULL;
+    InitGL();
+  }
+
+ private:
+
+  // GL-related functions.
+  void InitGL();
+  void FlickerAndPaint(int32_t result, bool paint_blue);
+
+  pp::Size plugin_size_;
+  pp::CompletionCallbackFactory<GLES2DemoInstance> callback_factory_;
+
+  // Unowned pointers.
+  const PPB_OpenGLES2* gles2_if_;
+
+  // Owned data.
+  pp::Graphics3D* context_;
+};
+
+GLES2DemoInstance::GLES2DemoInstance(PP_Instance instance, pp::Module* module)
+    : pp::Instance(instance), pp::Graphics3DClient(this),
+      callback_factory_(this),
+      context_(NULL) {
+  assert((gles2_if_ = static_cast<const PPB_OpenGLES2*>(
+      module->GetBrowserInterface(PPB_OPENGLES2_INTERFACE))));
+}
+
+GLES2DemoInstance::~GLES2DemoInstance() {
+  delete context_;
+}
+
+void GLES2DemoInstance::DidChangeView(
+    const pp::Rect& position, const pp::Rect& clip_ignored) {
+  if (position.width() == 0 || position.height() == 0)
+    return;
+  if (plugin_size_.width()) {
+    assert(position.size() == plugin_size_);
+    return;
+  }
+  plugin_size_ = position.size();
+
+  // Initialize graphics.
+  InitGL();
+}
+
+// This object is the global object representing this plugin library as long
+// as it is loaded.
+class GLES2DemoModule : public pp::Module {
+ public:
+  GLES2DemoModule() : pp::Module() {}
+  virtual ~GLES2DemoModule() {}
+
+  virtual pp::Instance* CreateInstance(PP_Instance instance) {
+    return new GLES2DemoInstance(instance, this);
+  }
+};
+
+void GLES2DemoInstance::InitGL() {
+  assert(plugin_size_.width() && plugin_size_.height());
+
+  assert(!context_);
+  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, plugin_size_.width(),
+    PP_GRAPHICS3DATTRIB_HEIGHT, plugin_size_.height(),
+    PP_GRAPHICS3DATTRIB_NONE,
+  };
+  context_ = new pp::Graphics3D(this, context_attributes);
+  assert(!context_->is_null());
+  assert(BindGraphics(*context_));
+
+  // Clear color bit.
+  gles2_if_->ClearColor(context_->pp_resource(), 0, 1, 0, 1);
+  gles2_if_->Clear(context_->pp_resource(), GL_COLOR_BUFFER_BIT);
+
+  assertNoGLError();
+
+  FlickerAndPaint(0, true);
+}
+
+void GLES2DemoInstance::FlickerAndPaint(int32_t result, bool paint_blue) {
+  if (result != 0)
+    return;
+  float r = paint_blue ? 0 : 1;
+  float g = 0;
+  float b = paint_blue ? 1 : 0;
+  float a = 0.75;
+  gles2_if_->ClearColor(context_->pp_resource(), r, g, b, a);
+  gles2_if_->Clear(context_->pp_resource(), GL_COLOR_BUFFER_BIT);
+  assertNoGLError();
+
+  pp::CompletionCallback cb = callback_factory_.NewCallback(
+      &GLES2DemoInstance::FlickerAndPaint, !paint_blue);
+  context_->SwapBuffers(cb);
+  assertNoGLError();
+}
+
+}  // anonymous namespace
+
+namespace pp {
+// Factory function for your specialization of the Module object.
+Module* CreateModule() {
+  return new GLES2DemoModule();
+}
+}  // namespace pp