Mir
Public Member Functions | List of all members
mir::graphics::offscreen::DisplayBuffer Class Reference

#include <display_buffer.h>

Inheritance diagram for mir::graphics::offscreen::DisplayBuffer:
[legend]

Public Member Functions

 DisplayBuffer (SurfacelessEGLContext egl_context, geometry::Rectangle const &area)
 
geometry::Rectangle view_area () const override
 The area the DisplayBuffer occupies in the virtual screen space. More...
 
void make_current () override
 Makes the DisplayBuffer the current GL rendering target. More...
 
void release_current () override
 Releases the current GL rendering target. More...
 
void gl_swap_buffers () override
 Swap buffers for OpenGL rendering. More...
 
void flip () override
 After gl_swap_buffers, flip the new front buffer to the screen This most likely involves a wait for vblank so can be very time consuming. More...
 
MirOrientation orientation () const override
 Returns the orientation of the display buffer relative to how the user should see it (the orientation of the output). More...
 
bool uses_alpha () const override
 Returns true if the display buffer has an alpha channel and the alpha channel will be read from at some point - in which case the renderer must produce valid alpha channel content. More...
 
bool post_renderables_if_optimizable (RenderableList const &renderlist) override
 This will render renderlist to the screen and post the result to the screen if there is a hardware optimization that can be done. More...
 
- Public Member Functions inherited from mir::graphics::DisplayBuffer
virtual ~DisplayBuffer ()
 
 __attribute__ ((__deprecated__("Use gl_swap_buffers() and flip(), remembering to release all compositor buffers in the middle."))) void post_update()
 

Additional Inherited Members

- Protected Member Functions inherited from mir::graphics::DisplayBuffer
 DisplayBuffer ()=default
 
 DisplayBuffer (DisplayBuffer const &c)=delete
 
DisplayBufferoperator= (DisplayBuffer const &c)=delete
 

Constructor & Destructor Documentation

mir::graphics::offscreen::DisplayBuffer::DisplayBuffer ( SurfacelessEGLContext  egl_context,
geometry::Rectangle const &  area 
)

Member Function Documentation

void mir::graphics::offscreen::DisplayBuffer::flip ( )
overridevirtual

After gl_swap_buffers, flip the new front buffer to the screen This most likely involves a wait for vblank so can be very time consuming.

This function is separate to gl_swap_buffers() because in real display systems the act of scanning out (or flipping) the front buffer is a very separate step to the GL buffer swapping. Not least because "flipping" is a hardware operation that is independent of the graphics library (OpenGL or other). Also, flip() can be a dramatically slower operation than gl_swap_buffers() and it would be an unacceptable performance hit to wait for both before freeing GL resources.

Implements mir::graphics::DisplayBuffer.

void mir::graphics::offscreen::DisplayBuffer::gl_swap_buffers ( )
overridevirtual

Swap buffers for OpenGL rendering.

After this method returns is the earliest time that it is safe to free GL-related resources such as textures and buffers.

Implements mir::graphics::DisplayBuffer.

void mir::graphics::offscreen::DisplayBuffer::make_current ( )
overridevirtual

Makes the DisplayBuffer the current GL rendering target.

Implements mir::graphics::DisplayBuffer.

MirOrientation mir::graphics::offscreen::DisplayBuffer::orientation ( ) const
overridevirtual

Returns the orientation of the display buffer relative to how the user should see it (the orientation of the output).

This tells us how much (if any) rotation the renderer needs to do. If your DisplayBuffer can do the rotation itself then this will always return mir_orientation_normal. If the DisplayBuffer does not implement the rotation itself then this function will return the amount of rotation the renderer must do to make things "look right".

Implements mir::graphics::DisplayBuffer.

bool mir::graphics::offscreen::DisplayBuffer::post_renderables_if_optimizable ( RenderableList const &  renderlist)
overridevirtual

This will render renderlist to the screen and post the result to the screen if there is a hardware optimization that can be done.

Parameters
[in]renderlistThe renderables that should appear on the screen if the hardware is capable of optmizing that list somehow. If what you want displayed on the screen cannot be represented by a RenderableList, then you should draw using OpenGL and use post_update()
Returns
true if the hardware can optimize the rendering of the list. When this call completes, the renderlist will have been posted to the screen. false if the hardware platform cannot optimize the list. The screen will not be updated. The caller should render the list another way, and post using post_update()

Implements mir::graphics::DisplayBuffer.

void mir::graphics::offscreen::DisplayBuffer::release_current ( )
overridevirtual

Releases the current GL rendering target.

Implements mir::graphics::DisplayBuffer.

bool mir::graphics::offscreen::DisplayBuffer::uses_alpha ( ) const
overridevirtual

Returns true if the display buffer has an alpha channel and the alpha channel will be read from at some point - in which case the renderer must produce valid alpha channel content.

Implements mir::graphics::DisplayBuffer.

geometry::Rectangle mir::graphics::offscreen::DisplayBuffer::view_area ( ) const
overridevirtual

The area the DisplayBuffer occupies in the virtual screen space.

Implements mir::graphics::DisplayBuffer.


The documentation for this class was generated from the following file:

Copyright © 2012,2013 Canonical Ltd.
Generated on Tue Mar 24 16:15:19 UTC 2015