Method
CoglOnscreenswap_buffers_with_damage
Declaration [src]
void
cogl_onscreen_swap_buffers_with_damage (
CoglOnscreen* onscreen,
const int* rectangles,
int n_rectangles,
CoglFrameInfo* info,
gpointer user_data
)
Description [src]
Swaps the current back buffer being rendered too, to the front for display and provides information to any system compositor about what regions of the buffer have changed (damage) with respect to the last swapped buffer.
This function has the same semantics as
cogl_framebuffer_swap_buffers()
except that it additionally allows
applications to pass a list of damaged rectangles which may be
passed on to a compositor so that it can minimize how much of the
screen is redrawn in response to this applications newly swapped
front buffer.
For example if your application is only animating a small object in the corner of the screen and everything else is remaining static then it can help the compositor to know that only the bottom right corner of your newly swapped buffer has really changed with respect to your previously swapped front buffer.
If n_rectangles
is 0 then the whole buffer will implicitly be
reported as damaged as if cogl_onscreen_swap_buffers()
had been called.
This function also implicitly discards the contents of the color,
depth and stencil buffers as if cogl_framebuffer_discard_buffers()
were used. The significance of the discard is that you should not
expect to be able to start a new frame that incrementally builds on
the contents of the previous frame. If you want to perform
incremental updates to older back buffers then please refer to the
cogl_onscreen_get_buffer_age()
api.
Whenever possible it is recommended that applications use this
function instead of cogl_onscreen_swap_buffers()
to improve
performance when running under a compositor.
It is highly recommended to use this API in conjunction with
the cogl_onscreen_get_buffer_age()
api so that your application can
perform incremental rendering based on old back buffers.
Parameters
rectangles
-
Type: An array of
int
An array of integer 4-tuples representing damaged rectangles as (x, y, width, height) tuples.
The length of the array is specified in the n_rectangles
argument.The data is owned by the caller of the method. n_rectangles
-
Type:
int
The number of 4-tuples to be read from
rectangles
. info
-
Type:
CoglFrameInfo
No description available.
The data is owned by the caller of the method. user_data
-
Type:
gpointer
No description available.
The argument can be NULL
.The data is owned by the caller of the method.