Port Moterm to Mozart.

apps/moterm/gl_helper.h

-// Copyright 2015 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 APPS_MOTERM_GL_HELPER_H_
-#define APPS_MOTERM_GL_HELPER_H_
-
-#include <GLES2/gl2.h>
-#include <MGL/mgl_types.h>
-
-#include <deque>
-#include <vector>
-
-#include "base/macros.h"
-#include "base/memory/weak_ptr.h"
-#include "mojo/public/cpp/bindings/binding.h"
-#include "mojo/services/geometry/interfaces/geometry.mojom.h"
-#include "mojo/services/gpu/interfaces/gpu.mojom.h"
-#include "mojo/services/surfaces/interfaces/surface_id.mojom.h"
-#include "mojo/services/surfaces/interfaces/surfaces.mojom.h"
-
-namespace mojo {
-class Shell;
-}
-
-// A class that helps with drawing surfaces using GL.
-class GlHelper : public mojo::ResourceReturner {
- public:
-  class Client {
-   public:
-    // Called when the surface ID changes (including the first time it becomes
-    // available).
-    virtual void OnSurfaceIdChanged(mojo::SurfaceIdPtr surface_id) = 0;
-
-    // Called when the GL context is lost.
-    virtual void OnContextLost() = 0;
-
-    // Called when the frame with ID |frame_id| (from |EndFrame()|) is drawn for
-    // the first time. Use this to rate-limit draws.
-    virtual void OnFrameDisplayed(uint32_t frame_id) = 0;
-  };
-
-  // Both |client| and |shell| must outlive us. |texture_format| is the texture
-  // format to use, e.g., |GL_RGBA| or |GL_BGRA_EXT|. |flipped| means that the
-  // texture is in the usual GL orientation (origin at lower-left). This object
-  // will create a surface (of initial size |initial_size|), and call the
-  // client's |OnSurfaceIdChanged()| when it has a surface ID for it (which the
-  // client can then provide to its |View|).
-  GlHelper(Client* client,
-           mojo::Shell* shell,
-           GLint texture_format,
-           bool flipped,
-           const mojo::Size& initial_size);
-  ~GlHelper() override;
-
-  // Sets the size of the surface. (The surface will only be created at this
-  // size lazily at the next |StartFrame()|.)
-  void SetSurfaceSize(const mojo::Size& surface_size);
-
-  // Ensures that a GL context is available and makes it current. (Note that
-  // this is automatically called by |StartFrame()|, so this is mostly useful
-  // for creating GL resources outside |StartFrame()|/|EndFrame()|.
-  void MakeCurrent();
-
-  // Starts a frame; makes an appropriate GL context current, and binds a
-  // texture of the current size (creating it if necessary), returning its ID.
-  // Between |StartFrame()| and |EndFrame()|, the run loop must not be run and
-  // no other methods of this object other than |MakeCurrent()| and
-  // |GetFrameTexture()| may be called. This object must not be destroyed after
-  // |StartFrame()| before calling |EndFrame()|.
-  void StartFrame();
-  // Completes the current frame (started using |StartFrame()|). Before calling
-  // this, the frame's texture must be bound and the GL context must be current.
-  // (This is the default state after |StartFrame()|, so nothing has to be done
-  // unless another texture is bound or another GL context is made current,
-  // respectively.) Returns an ID for this frame (which will be given to the
-  // client on |OnFrameDisplayed()|).
-  uint32_t EndFrame();
-
-  // Gets the texture that will be used for the current frame, e.g., so that it
-  // may be (re)bound. Only valid between |StartFrame()| and |EndFrame()|. (Note
-  // that this texture is automatically bound by |StartFrame()|, so this is
-  // typically only needed if another texture is bound.)
-  GLuint GetFrameTexture();
-
- private:
-  struct TextureInfo {
-    TextureInfo(uint32_t resource_id, GLuint texture, const mojo::Size& size)
-        : resource_id(resource_id), texture(texture), size(size) {}
-
-    // Only interesting if it's pending return.
-    uint32_t resource_id;
-    GLuint texture;
-    mojo::Size size;
-  };
-
-  // |mojo::ResourceReturner|:
-  void ReturnResources(
-      mojo::Array<mojo::ReturnedResourcePtr> resources) override;
-
-  // Ensures that we have a GL context and that it is current.
-  void EnsureContext();
-
-  // Ensures that we have a surface of the appropriate size. This should only be
-  // called with a valid GL context which is current (e.g., after calling
-  // |EnsureContext()|).
-  void EnsureSurface();
-
-  // Calls the client's |OnSurfaceIdChanged()| if appropriate (both
-  // |id_namespace_| and |local_id_| must be set).
-  void CallOnSurfaceIdChanged();
-
-  // Texture queue functions. (For all functions, |mgl_context_| should be
-  // current.)
-  // Gets and binds a texture of size |current_surface_size_|.
-  TextureInfo GetTexture();
-  // Returns a texture to the queue (or deletes it, if it's not of the right
-  // size or there are already enough textures in the queue).
-  void ReturnTexture(const TextureInfo& texture_info);
-  // Clears all textures (i.e., calls |glDeleteTextures()| on all textures in
-  // the texture queue).
-  void ClearTextures();
-
-  // Callbacks:
-
-  // Callback for |GetIdNamespace()|:
-  void GetIdNamespaceCallback(uint32_t id_namespace);
-
-  // "Callback" for |MojoGLES2CreateContext()|:
-  static void OnContextLostThunk(void* self);
-  void OnContextLost();
-
-  // Callback for |SubmitFrame()|:
-  void SubmitFrameCallback(uint32_t frame_id);
-
-  Client* const client_;
-  const GLint texture_format_;
-  const bool flipped_;
-
-  mojo::GpuPtr gpu_;
-  mojo::SurfacePtr surface_;
-  mojo::Binding<mojo::ResourceReturner> returner_binding_;
-
-  // The size for the surface at the next |StartFrame()|.
-  mojo::Size next_surface_size_;
-
-  MGLContext mgl_context_;
-
-  std::deque<TextureInfo> textures_;
-
-  uint32_t next_frame_id_;
-  // The texture that'll be used to draw the current frame. Only valid (nonzero)
-  // between |StartFrame()| and |EndFrame()|.
-  GLuint frame_texture_;
-
-  uint32_t id_namespace_;
-  uint32_t local_id_;
-  // If |local_id_| is nonzero, there's currently a surface, in which case this
-  // is its size.
-  mojo::Size current_surface_size_;
-
-  uint32_t next_resource_id_;
-  std::vector<TextureInfo> textures_pending_return_;
-
-  base::WeakPtrFactory<GlHelper> weak_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(GlHelper);
-};
-
-#endif  // APPS_MOTERM_GL_HELPER_H_