1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef UI_OZONE_PLATFORM_DRI_SCANOUT_SURFACE_H_ 6 #define UI_OZONE_PLATFORM_DRI_SCANOUT_SURFACE_H_ 7 8 #include <stdint.h> 9 10 namespace gfx { 11 class Size; 12 } 13 14 namespace ui { 15 16 // ScanoutSurface is an interface for a surface that can be scanned out to a 17 // monitor using the DRM/KMS API. Implementations will store the internal state 18 // associated with the drawing surface. Implementations are also required to 19 // performs all the needed operations to initialize and update the drawing 20 // surface. 21 // 22 // The typical usage pattern is: 23 // ----------------------------------------------------------------------------- 24 // HardwareDisplayController controller; 25 // // Initialize controller 26 // 27 // ScanoutSurface* surface = new ScanoutSurfaceImpl(size); 28 // surface.Initialize(); 29 // controller.BindSurfaceToController(surface); 30 // 31 // while (true) { 32 // DrawIntoSurface(surface); 33 // controller.SchedulePageFlip(); 34 // 35 // Wait for page flip event. The DRM page flip handler will call 36 // surface.SwapBuffers(); 37 // } 38 // 39 // delete surface; 40 // ----------------------------------------------------------------------------- 41 // In the above example the wait consists of reading a DRM pageflip event from 42 // the graphics card file descriptor. This is done by calling |drmHandleEvent|, 43 // which will read and process the event. |drmHandleEvent| will call a callback 44 // registered by |SchedulePageFlip| which will update the internal state. 45 // 46 // |SchedulePageFlip| can also be used to limit drawing to the screen's vsync 47 // since page flips only happen on vsync. In a threaded environment a message 48 // loop would listen on the graphics card file descriptor for an event and 49 // |drmHandleEvent| would be called from the message loop. The event handler 50 // would also be responsible for updating the renderer's state and signal that 51 // it is OK to start drawing the next frame. 52 class ScanoutSurface { 53 public: 54 virtual ~ScanoutSurface() {} 55 56 // Used to allocate all necessary buffers for this surface. If the 57 // initialization succeeds, the device is ready to be used for drawing 58 // operations. 59 // Returns true if the initialization is successful, false otherwise. 60 virtual bool Initialize() = 0; 61 62 // Swaps the back buffer with the front buffer. 63 virtual void SwapBuffers() = 0; 64 65 // Returns the ID of the current backbuffer. 66 virtual uint32_t GetFramebufferId() const = 0; 67 68 // Returns the handle of the current backbuffer. 69 virtual uint32_t GetHandle() const = 0; 70 71 // Returns the surface size. 72 virtual gfx::Size Size() const = 0; 73 }; 74 75 class ScanoutSurfaceGenerator { 76 public: 77 virtual ~ScanoutSurfaceGenerator() {} 78 79 virtual ScanoutSurface* Create(const gfx::Size& size) = 0; 80 }; 81 82 } // namespace ui 83 84 #endif // UI_OZONE_PLATFORM_DRI_SCANOUT_SURFACE_H_ 85