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// Copyright 2020 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_OZONE_PLATFORM_WAYLAND_GPU_GL_SURFACE_EGL_READBACK_WAYLAND_H_
#define UI_OZONE_PLATFORM_WAYLAND_GPU_GL_SURFACE_EGL_READBACK_WAYLAND_H_
#include "base/containers/circular_deque.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/shared_memory_mapping.h"
#include "ui/ozone/common/gl_surface_egl_readback.h"
#include "ui/ozone/platform/wayland/gpu/wayland_surface_gpu.h"
namespace ui {
class WaylandBufferManagerGpu;
// This is a GLSurface implementation that uses glReadPixels to populate a
// shared memory region with the contents of the surface, and then passes the
// shared memory region to Wayland for presentation.
//
// Basic control flow:
// 1. Resize() creates kMaxBuffers shared memory regions. These are added to
// available_buffers_ and registered with Wayland via CreateShmBasedBuffer().
// 2. SwapBuffersAsync() calls glReadPixels() to read the contents of the
// active GL context into the next available shared memory region. The shared
// memory region is immediately sent to Wayland via CommitBuffer().
// 3. The buffer is not available for reuse until OnSubmission() is called.
//
// Note: This class relies on the assumption that kMaxBuffers is necessary and
// sufficient. The behavior is undefined if SwapBuffersAsync() is called and no
// buffers are available.
class GLSurfaceEglReadbackWayland : public GLSurfaceEglReadback,
public WaylandSurfaceGpu {
public:
GLSurfaceEglReadbackWayland(gl::GLDisplayEGL* display,
gfx::AcceleratedWidget widget,
WaylandBufferManagerGpu* buffer_manager);
GLSurfaceEglReadbackWayland(const GLSurfaceEglReadbackWayland&) = delete;
GLSurfaceEglReadbackWayland& operator=(const GLSurfaceEglReadbackWayland&) =
delete;
// gl::GLSurface:
void Destroy() override;
bool Resize(const gfx::Size& size,
float scale_factor,
const gfx::ColorSpace& color_space,
bool has_alpha) override;
gfx::SwapResult SwapBuffers(PresentationCallback callback,
gfx::FrameData data) override;
bool SupportsAsyncSwap() override;
void SwapBuffersAsync(SwapCompletionCallback completion_callback,
PresentationCallback presentation_callback,
gfx::FrameData data) override;
gfx::SurfaceOrigin GetOrigin() const override;
private:
struct PixelBuffer {
PixelBuffer(base::WritableSharedMemoryMapping shm_mapping,
uint32_t buffer_id);
~PixelBuffer();
PixelBuffer(const PixelBuffer&) = delete;
PixelBuffer& operator=(const PixelBuffer&) = delete;
// Shared memory mapping that readback pixels are written to so that Wayland
// is able to turn them in light.
base::WritableSharedMemoryMapping shm_mapping_;
// The buffer id that corresponds to the |wl_buffer| created on the browser
// process side.
uint32_t buffer_id_ = 0;
};
~GLSurfaceEglReadbackWayland() override;
// WaylandSurfaceGpu:
void OnSubmission(uint32_t frame_id,
const gfx::SwapResult& swap_result,
gfx::GpuFenceHandle release_fence) override;
void OnPresentation(uint32_t frame_id,
const gfx::PresentationFeedback& feedback) override;
void DestroyBuffers();
// Widget of the window that this readback writes pixels to.
const gfx::AcceleratedWidget widget_;
const raw_ptr<WaylandBufferManagerGpu> buffer_manager_;
// Size of the buffer.
gfx::Size size_;
float surface_scale_factor_ = 1.f;
// Available pixel buffers based on shared memory.
std::vector<std::unique_ptr<PixelBuffer>> available_buffers_;
// Displayed buffer that will become available after another buffer is
// submitted.
std::unique_ptr<PixelBuffer> displayed_buffer_;
// Submitted buffers waiting to be displayed.
base::circular_deque<std::unique_ptr<PixelBuffer>> in_flight_pixel_buffers_;
std::vector<SwapCompletionCallback> completion_callbacks_;
std::vector<PresentationCallback> presentation_callbacks_;
size_t pending_frames_ = 0;
};
} // namespace ui
#endif // UI_OZONE_PLATFORM_WAYLAND_GPU_GL_SURFACE_EGL_READBACK_WAYLAND_H_
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