[cairo] [patch] gl: do not force flush everytime uploading a glyph image to glyph cache

Eric Anholt eric at anholt.net
Tue Jan 29 18:51:07 PST 2013

"Henry (Yu) Song - SISA" <hsong at sisa.samsung.com> writes:

> Hi, Eric
> Thanks for review and comment.  I will reformat the message.
> Each glyph uploading causes a flush of previous glDrawXXX().  A single
> glyph uploading is done by _cairo_gl_surface_draw_image(), in which
> _cairo_gl_composite_flush() is called.
> If I understand correctly, the question is how to ensure all glyph
> drawings are flushed before we start draw something else.  correct me
> if I am wrong.
> _cairo_gl_composite_flush () is called in multiple points, for example
> when mask surface has changed.  In glyph rendering, we uses two
> particular mask surface - one is the glyph cache that stores
> alpha-only glyphs, the second one is the rgba-glyph cache that stores
> lcd/subpixel images.  It is ensured all glyphs will be glDraw() before
> we switch to draw something else in _cairo_gl_operand_needs_setup(),
> where it checks the new mask vs the ctx->mask.

From what I can see, add_glyph is inside of the loop rendering glyphs to
the temp mask.  I want to know how the rendering of former glyphs to the
into the temp mask gets flushed when a new glyph is being put into the
glyph cache that may overwrite a previous glyph.
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