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Owen W. Taylor f0de41331a Default to a blend function that expects premultiplied colors
Many operations, like mixing two textures together or alpha-blending
onto a destination with alpha, are done most logically if texture data
is in premultiplied form. We also have many sources of premultiplied
texture data, like X pixmaps, FBOs, cairo surfaces. Rather than trying
to work with two different types of texture data, simplify things by
always premultiplying texture data before uploading to GL.

Because the default blend function is changed to accommodate this,
uses of pure-color CoglMaterial need to be adapted to add
premultiplication.

gl/cogl-texture.c gles/cogl-texture.c: Always premultiply
  non-premultiplied texture data before uploading to GL.

cogl-material.c cogl-material.h: Switch the default blend functions
  to ONE, ONE_MINUS_SRC_ALPHA so they work correctly with premultiplied
  data.

cogl.c: Make cogl_set_source_color() premultiply the color.

cogl.h.in color-material.h: Add some documentation about
  premultiplication and its interaction with color values.

cogl-pango-render.c clutter-texture.c tests/interactive/test-cogl-offscreen.c:
  Use premultiplied colors.

http://bugzilla.openedhand.com/show_bug.cgi?id=1406

Signed-off-by: Robert Bragg <robert@linux.intel.com>
2009-06-11 14:17:52 +01:00
common Default to a blend function that expects premultiplied colors 2009-06-11 14:17:52 +01:00
doc/reference/cogl [cogl] Move the texture filters to be a property of the material layer 2009-06-04 19:03:40 +01:00
gl Default to a blend function that expects premultiplied colors 2009-06-11 14:17:52 +01:00
gles Default to a blend function that expects premultiplied colors 2009-06-11 14:17:52 +01:00
cogl-bitmap.h Fix inclusion guards and headers 2009-05-06 17:59:25 +01:00
cogl-color.h Add cogl_color_premultiply() 2009-06-11 14:17:51 +01:00
cogl-debug.h [cogl-material] Support string based blending and layer combine descriptions 2009-05-28 02:43:28 +01:00
cogl-deprecated.h [cogl deprecated] Add backface culling deprecation 2009-05-28 14:14:50 +01:00
cogl-fixed.h [cogl] Updates all file headers and removes lots of trailing white space 2009-05-02 04:12:25 +01:00
cogl-material.h Default to a blend function that expects premultiplied colors 2009-06-11 14:17:52 +01:00
cogl-matrix.h Rename 'near' and 'far' variables to 'z_near' and 'z_far' 2009-06-04 11:48:51 +01:00
cogl-offscreen.h [cogl-offscreen] Cleans up the cogl offscreen API and adds documentation 2009-05-02 04:12:26 +01:00
cogl-path.h [cogl] Updates all file headers and removes lots of trailing white space 2009-05-02 04:12:25 +01:00
cogl-shader.h [cogl-shader] Make get_info_log() slightly nicer 2009-06-01 17:40:23 +01:00
cogl-texture.h [cogl] Move the texture filters to be a property of the material layer 2009-06-04 19:03:40 +01:00
cogl-types.h [cogl] Move the texture filters to be a property of the material layer 2009-06-04 19:03:40 +01:00
cogl-vertex-buffer.h [cogl-vertex-buffer] Add cogl_vertex_buffer_indices_get_for_quads 2009-06-01 14:50:52 +01:00
cogl.h.in Default to a blend function that expects premultiplied colors 2009-06-11 14:17:52 +01:00
cogl.pc.in [cogl] Fix hardcoded paths in the pc file 2009-03-10 12:38:04 +00:00
Makefile.am [introspection] Add --c-include to g-ir-scanner 2009-06-09 12:45:23 +01:00
TODO Merged clutter-ivan branch into trunk. 2008-04-25 13:37:36 +00:00