chromium/ui/gl/gl_context.h

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef UI_GL_GL_CONTEXT_H_
#define UI_GL_GL_CONTEXT_H_

#include <map>
#include <memory>
#include <string>

#include "base/atomicops.h"
#include "base/cancelable_callback.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/observer_list.h"
#include "base/synchronization/atomic_flag.h"
#include "build/build_config.h"
#include "ui/gfx/extension_set.h"
#include "ui/gl/gl_export.h"
#include "ui/gl/gl_implementation_wrapper.h"
#include "ui/gl/gl_share_group.h"
#include "ui/gl/gl_state_restorer.h"
#include "ui/gl/gpu_preference.h"

namespace gl {
class GLContextEGL;
class GLDisplayEGL;
}  // namespace gl

namespace gpu {
class GLContextVirtual;

#if BUILDFLAG(IS_APPLE)
class GL_EXPORT BackpressureMetalSharedEvent {
 public:
  virtual ~BackpressureMetalSharedEvent() = default;
  virtual bool HasCompleted() const = 0;
};
#endif  // #if BUILDFLAG(IS_APPLE)

}  // namespace gpu

namespace gl {

struct CurrentGL;
class LogGLApi;
struct DriverGL;
class GLApi;
class GLFence;
class GLSurface;
class GPUTiming;
class GPUTimingClient;
struct GLVersionInfo;
class RealGLApi;
class TraceGLApi;

// Where available, choose a GL context priority for devices that support it.
// Currently this requires the EGL_IMG_context_priority extension that is
// present on Daydream ready Android devices. Default is Medium, and the
// attribute is ignored if the extension is missing.
//
// "High" priority must only be used for special cases with strong realtime
// requirements, it is incompatible with other critical system GL work such as
// the GVR library's asynchronous reprojection for VR viewing. Please avoid
// using it for any GL contexts that may be used during VR presentation,
// see crbug.com/727800.
//
// Instead, consider using "Low" priority for possibly-slow GL work such as
// user WebGL content.
enum ContextPriority { … };

// Angle allows selecting context virtualization group at context creation time.
// This enum is used to specify the group number to use for a given context.
// Currently all contexts which do not specify any group number are part of
// default angle context virtualization group. The below use cases in Chrome use
// become part of different virtualization groups via this enum.
enum class AngleContextVirtualizationGroup { … };

struct GL_EXPORT GLContextAttribs { … };

// Encapsulates an OpenGL context, hiding platform specific management.
// TODO(344606399): Consider folding GLContextEGL into this class.
class GL_EXPORT GLContext : public base::RefCounted<GLContext> { … };

class GL_EXPORT GLContextReal : public GLContext { … };

// Wraps GLContext in scoped_refptr and tries to initializes it. Returns a
// scoped_refptr containing the initialized GLContext or nullptr if
// initialization fails.
GL_EXPORT scoped_refptr<GLContext> InitializeGLContext(
    scoped_refptr<GLContext> context,
    GLSurface* compatible_surface,
    const GLContextAttribs& attribs);

}  // namespace gl

#endif  // UI_GL_GL_CONTEXT_H_