Re-land^2 WebVR compositor bypass via BrowserMain context + mailbox

chrome/browser/android/vr_shell/mailbox_to_surface_bridge.cc

Index: chrome/browser/android/vr_shell/mailbox_to_surface_bridge.cc
diff --git a/chrome/browser/android/vr_shell/mailbox_to_surface_bridge.cc b/chrome/browser/android/vr_shell/mailbox_to_surface_bridge.cc
new file mode 100644
index 0000000000000000000000000000000000000000..0972c3e4268cf2d2f1e430568b302c477400a4f6
--- /dev/null
+++ b/chrome/browser/android/vr_shell/mailbox_to_surface_bridge.cc
@@ -0,0 +1,345 @@
+// Copyright 2017 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 "chrome/browser/android/vr_shell/mailbox_to_surface_bridge.h"
+
+#include <string>
+
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/sys_info.h"
+#include "cc/output/context_provider.h"
+#include "content/public/browser/android/compositor.h"
+#include "gpu/GLES2/gl2extchromium.h"
+#include "gpu/command_buffer/client/gles2_interface.h"
+#include "gpu/command_buffer/common/mailbox.h"
+#include "gpu/command_buffer/common/mailbox_holder.h"
+#include "gpu/command_buffer/common/sync_token.h"
+#include "gpu/ipc/client/gpu_channel_host.h"
+#include "gpu/ipc/common/gpu_surface_tracker.h"
+#include "services/ui/public/cpp/gpu/context_provider_command_buffer.h"
+#include "ui/gl/android/surface_texture.h"
+
+#include <android/native_window_jni.h>
+
+#define VOID_OFFSET(x) reinterpret_cast<void*>(x)
+#define SHADER(Src) #Src
+
+namespace {
+
+const char kQuadCopyVertex[] = SHADER(
+    /* clang-format off */
+    attribute vec4 a_Position;
+    attribute vec2 a_TexCoordinate;
+    varying vec2 v_TexCoordinate;
+    void main() {
+      v_TexCoordinate = a_TexCoordinate;
+      gl_Position = a_Position;
+    }
+); /* clang-format on */
+
+const char kQuadCopyFragment[] = SHADER(
+    /* clang-format off */
+    precision highp float;
+    uniform sampler2D u_Texture;
+    varying vec2 v_TexCoordinate;
+    void main() {
+      gl_FragColor = texture2D(u_Texture, v_TexCoordinate);
+    }
+); /* clang-format on */
+
+const float kQuadVertices[] = {
+    // clang-format off
+    // x     y    u,   v
+    -1.f,  1.f, 0.f, 1.f,
+    -1.f, -1.f, 0.f, 0.f,
+     1.f, -1.f, 1.f, 0.f,
+     1.f,  1.f, 1.f, 1.f};
+static constexpr int kQuadVerticesSize = sizeof(kQuadVertices);
+
+GLuint CompileShader(gpu::gles2::GLES2Interface* gl,
+                     GLenum shader_type,
+                     const GLchar* shader_source) {
+  GLuint shader_handle = gl->CreateShader(shader_type);
+  if (shader_handle != 0) {
+    // Pass in the shader source.
+    GLint len = strlen(shader_source);
+    gl->ShaderSource(shader_handle, 1, &shader_source, &len);
+    // Compile the shader.
+    gl->CompileShader(shader_handle);
+    // Get the compilation status.
+    GLint status = 0;
+    gl->GetShaderiv(shader_handle, GL_COMPILE_STATUS, &status);
+    if (status == GL_FALSE) {
+      GLint info_log_length = 0;
+      gl->GetShaderiv(shader_handle, GL_INFO_LOG_LENGTH, &info_log_length);
+      auto str_info_log = base::MakeUnique<GLchar[]>(info_log_length + 1);
+      gl->GetShaderInfoLog(shader_handle, info_log_length, nullptr,
+                           str_info_log.get());
+      DLOG(ERROR) << "Error compiling shader: " << str_info_log.get();
+      gl->DeleteShader(shader_handle);
+      shader_handle = 0;
+    }
+  }
+
+  return shader_handle;
+}
+
+GLuint CreateAndLinkProgram(gpu::gles2::GLES2Interface* gl,
+                            GLuint vertex_shader_handle,
+                            GLuint fragment_shader_handle) {
+  GLuint program_handle = gl->CreateProgram();
+
+  if (program_handle != 0) {
+    // Bind the vertex shader to the program.
+    gl->AttachShader(program_handle, vertex_shader_handle);
+
+    // Bind the fragment shader to the program.
+    gl->AttachShader(program_handle, fragment_shader_handle);
+
+    // Link the two shaders together into a program.
+    gl->LinkProgram(program_handle);
+
+    // Get the link status.
+    GLint link_status = 0;
+    gl->GetProgramiv(program_handle, GL_LINK_STATUS, &link_status);
+
+    // If the link failed, delete the program.
+    if (link_status == GL_FALSE) {
+      GLint info_log_length;
+      gl->GetProgramiv(program_handle, GL_INFO_LOG_LENGTH, &info_log_length);
+
+      auto str_info_log = base::MakeUnique<GLchar[]>(info_log_length + 1);
+      gl->GetProgramInfoLog(program_handle, info_log_length, nullptr,
+                            str_info_log.get());
+      DLOG(ERROR) << "Error compiling program: " << str_info_log.get();
+      gl->DeleteProgram(program_handle);
+      program_handle = 0;
+    }
+  }
+
+  return program_handle;
+}
+
+GLuint ConsumeTexture(gpu::gles2::GLES2Interface* gl,
+                      const gpu::MailboxHolder& mailbox) {
+  TRACE_EVENT0("gpu", "MailboxToSurfaceBridge::ConsumeTexture");
+  gl->WaitSyncTokenCHROMIUM(mailbox.sync_token.GetConstData());
+
+  return gl->CreateAndConsumeTextureCHROMIUM(GL_TEXTURE_2D,
+                                             mailbox.mailbox.name);
+}
+
+}  // namespace
+
+namespace vr_shell {
+
+MailboxToSurfaceBridge::MailboxToSurfaceBridge() : weak_ptr_factory_(this) {}
+
+MailboxToSurfaceBridge::~MailboxToSurfaceBridge() {
+  if (surface_handle_) {
+    // Unregister from the surface tracker to avoid a resource leak.
+    gpu::GpuSurfaceTracker* tracker = gpu::GpuSurfaceTracker::Get();
+    tracker->UnregisterViewSurface(surface_handle_);
+  }
+  DestroyContext();
+}
+
+void MailboxToSurfaceBridge::OnContextAvailable(
+    scoped_refptr<cc::ContextProvider> provider) {
+  // Must save a reference to the ContextProvider to keep it alive,
+  // otherwise the GL context created from it becomes invalid.
+  context_provider_ = std::move(provider);
+
+  if (!context_provider_->BindToCurrentThread()) {
+    DLOG(ERROR) << "Failed to init ContextProvider";
+    return;
+  }
+
+  gl_ = context_provider_->ContextGL();
+
+  if (!gl_) {
+    DLOG(ERROR) << "Did not get a GL context";
+    return;
+  }
+  InitializeRenderer();
+}
+
+void MailboxToSurfaceBridge::CreateSurface(
+    gl::SurfaceTexture* surface_texture) {
+  ANativeWindow* window = surface_texture->CreateSurface();
+  gpu::GpuSurfaceTracker* tracker = gpu::GpuSurfaceTracker::Get();
+  ANativeWindow_acquire(window);
+  // Skip ANativeWindow_setBuffersGeometry, the default size appears to work.
+  surface_handle_ = tracker->AddSurfaceForNativeWidget(window);
+
+  auto surface = base::MakeUnique<gl::ScopedJavaSurface>(surface_texture);
+  tracker->RegisterViewSurface(surface_handle_, surface->j_surface().obj());
+  // Unregistering happens in the destructor.
+  ANativeWindow_release(window);
+
+  // Our attributes must be compatible with the shared offscreen
+  // surface used by virtualized contexts, otherwise mailbox
+  // synchronization doesn't work properly - it assumes a shared
+  // underlying GL context. See GetCompositorContextAttributes
+  // in content/browser/renderer_host/compositor_impl_android.cc
+  // and crbug.com/699330.
+
+  gpu::gles2::ContextCreationAttribHelper attributes;
+  attributes.alpha_size = -1;
+  attributes.red_size = 8;
+  attributes.green_size = 8;
+  attributes.blue_size = 8;
+  attributes.stencil_size = 0;
+  attributes.depth_size = 0;
+  attributes.samples = 0;
+  attributes.sample_buffers = 0;
+  attributes.bind_generates_resource = false;
+  if (base::SysInfo::IsLowEndDevice()) {
+    attributes.alpha_size = 0;
+    attributes.red_size = 5;
+    attributes.green_size = 6;
+    attributes.blue_size = 5;
+  }
+
+  content::Compositor::CreateContextProvider(
+      surface_handle_, attributes, gpu::SharedMemoryLimits::ForMailboxContext(),
+      base::Bind(&MailboxToSurfaceBridge::OnContextAvailable,
+                 weak_ptr_factory_.GetWeakPtr()));
+}
+
+void MailboxToSurfaceBridge::ResizeSurface(int width, int height) {
+  if (!gl_) {
+    // We're not initialized yet, save the requested size for later.
+    needs_resize_ = true;
+    resize_width_ = width;
+    resize_height_ = height;
+    return;
+  }
+  DVLOG(1) << __FUNCTION__ << ": resize Surface to " <<
+      width << "x" << height;
+  gl_->ResizeCHROMIUM(width, height, 1.f, false);
+  gl_->Viewport(0, 0, width, height);
+}
+
+bool MailboxToSurfaceBridge::CopyMailboxToSurfaceAndSwap(
+    const gpu::MailboxHolder& mailbox) {
+  if (!gl_) {
+    // We may not have a context yet, i.e. due to surface initialization
+    // being incomplete. This is not an error, but we obviously can't draw
+    // yet.
+    return false;
+  }
+
+  if (needs_resize_) {
+    ResizeSurface(resize_width_, resize_height_);
+    needs_resize_ = false;
+  }
+
+  GLuint sourceTexture = ConsumeTexture(gl_, mailbox);
+  DrawQuad(sourceTexture);
+  gl_->SwapBuffers();
+  return true;
+}
+
+void MailboxToSurfaceBridge::DestroyContext() {
+  gl_ = nullptr;
+  context_provider_ = nullptr;
+}
+
+void MailboxToSurfaceBridge::InitializeRenderer() {
+  GLuint vertex_shader_handle =
+      CompileShader(gl_, GL_VERTEX_SHADER, kQuadCopyVertex);
+  if (!vertex_shader_handle) {
+    DestroyContext();
+    return;
+  }
+
+  GLuint fragment_shader_handle =
+      CompileShader(gl_, GL_FRAGMENT_SHADER, kQuadCopyFragment);
+  if (!fragment_shader_handle) {
+    DestroyContext();
+    return;
+  }
+
+  GLuint program_handle =
+      CreateAndLinkProgram(gl_, vertex_shader_handle, fragment_shader_handle);
+  if (!program_handle) {
+    DestroyContext();
+    return;
+  }
+
+  // Once the program is linked the shader objects are no longer needed
+  gl_->DeleteShader(vertex_shader_handle);
+  gl_->DeleteShader(fragment_shader_handle);
+
+  GLuint position_handle = gl_->GetAttribLocation(program_handle, "a_Position");
+  GLuint texCoord_handle =
+      gl_->GetAttribLocation(program_handle, "a_TexCoordinate");
+  GLuint texUniform_handle =
+      gl_->GetUniformLocation(program_handle, "u_Texture");
+
+  GLuint vertexBuffer = 0;
+  gl_->GenBuffers(1, &vertexBuffer);
+  gl_->BindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
+  gl_->BufferData(GL_ARRAY_BUFFER, kQuadVerticesSize, kQuadVertices,
+                  GL_STATIC_DRAW);
+
+  // Set state once only, we assume that nobody else modifies GL state in a way
+  // that would interfere with our operations.
+  gl_->Disable(GL_CULL_FACE);
+  gl_->DepthMask(GL_FALSE);
+  gl_->Disable(GL_DEPTH_TEST);
+  gl_->Disable(GL_SCISSOR_TEST);
+  gl_->Disable(GL_BLEND);
+  gl_->Disable(GL_POLYGON_OFFSET_FILL);
+
+  // Not using gl_->Viewport, we assume that it defaults to the whole
+  // surface and gets updated by ResizeSurface externally as
+  // appropriate.
+
+  gl_->UseProgram(program_handle);
+
+  // Bind vertex attributes
+  gl_->BindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
+
+  gl_->EnableVertexAttribArray(position_handle);
+  gl_->EnableVertexAttribArray(texCoord_handle);
+
+  static constexpr size_t VERTEX_STRIDE = sizeof(float) * 4;
+  static constexpr size_t POSITION_ELEMENTS = 2;
+  static constexpr size_t TEXCOORD_ELEMENTS = 2;
+  static constexpr size_t POSITION_OFFSET = 0;
+  static constexpr size_t TEXCOORD_OFFSET = sizeof(float) * 2;
+
+  gl_->VertexAttribPointer(position_handle, POSITION_ELEMENTS, GL_FLOAT, false,
+                           VERTEX_STRIDE, VOID_OFFSET(POSITION_OFFSET));
+  gl_->VertexAttribPointer(texCoord_handle, TEXCOORD_ELEMENTS, GL_FLOAT, false,
+                           VERTEX_STRIDE, VOID_OFFSET(TEXCOORD_OFFSET));
+
+  gl_->ActiveTexture(GL_TEXTURE0);
+  gl_->Uniform1i(texUniform_handle, 0);
+}
+
+void MailboxToSurfaceBridge::DrawQuad(unsigned int texture_handle) {
+  // We're redrawing over the entire viewport, but it's generally more
+  // efficient on mobile tiling GPUs to clear anyway as a hint that
+  // we're done with the old content. TODO(klausw,crbug.com/700389):
+  // investigate using gl_->DiscardFramebufferEXT here since that's more
+  // efficient on desktop, but it would need a capability check since
+  // it's not supported on older devices such as Nexus 5X.
+  gl_->Clear(GL_COLOR_BUFFER_BIT);
+
+  // Configure texture. This is a 1:1 pixel copy since the surface
+  // size is resized to match the source canvas, so we can use
+  // GL_NEAREST.
+  gl_->BindTexture(GL_TEXTURE_2D, texture_handle);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+  gl_->TexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+  gl_->DrawArrays(GL_TRIANGLE_FAN, 0, 4);
+}
+
+}  // namespace vr_shell