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Neil Roberts 6d51a18e7c Add support for per-vertex point sizes
This adds a new function to enable per-vertex point size on a
pipeline. This can be set with
cogl_pipeline_set_per_vertex_point_size(). Once enabled the point size
can be set either by drawing with an attribute named
'cogl_point_size_in' or by writing to the 'cogl_point_size_out'
builtin from a snippet.

There is a feature flag which must be checked for before using
per-vertex point sizes. This will only be set on GL >= 2.0 or on GLES
2.0. GL will only let you set a per-vertex point size from GLSL by
writing to gl_PointSize. This is only available in GL2 and not in the
older GLSL extensions.

The per-vertex point size has its own pipeline state flag so that it
can be part of the state that affects vertex shader generation.

Having to enable the per vertex point size with a separate function is
a bit awkward. Ideally it would work like the color attribute where
you can just set it for every vertex in your primitive with
cogl_pipeline_set_color or set it per-vertex by just using the
attribute. This is harder to get working with the point size because
we need to generate a different vertex shader depending on what
attributes are bound. I think if we wanted to make this work
transparently we would still want to internally have a pipeline
property describing whether the shader was generated with per-vertex
support so that it would work with the shader cache correctly.
Potentially we could make the per-vertex property internal and
automatically make a weak pipeline whenever the attribute is bound.
However we would then also need to automatically detect when an
application is writing to cogl_point_size_out from a snippet.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 8495d9c1c15ce389885a9356d965eabd97758115)

Conflicts:
	cogl/cogl-context.c
	cogl/cogl-pipeline-private.h
	cogl/cogl-pipeline.c
	cogl/cogl-private.h
	cogl/driver/gl/cogl-pipeline-progend-fixed.c
	cogl/driver/gl/gl/cogl-pipeline-progend-fixed-arbfp.c
2013-06-07 16:53:29 +01:00
build Update Visual Studio Project Files 2013-03-07 11:37:32 +08:00
cogl Add support for per-vertex point sizes 2013-06-07 16:53:29 +01:00
cogl-gles2 build: update to build with automake 1.13 2013-01-22 18:00:05 +00:00
cogl-pango Add compiler deprecation warnings 2013-04-24 22:23:50 +01:00
deps build: fix make dist 2013-01-22 17:48:03 +00:00
doc Add support for per-vertex point sizes 2013-06-07 16:53:29 +01:00
examples Add support for per-vertex point sizes 2013-06-07 16:53:29 +01:00
po [l10n] Updated Italian translation. 2013-04-28 19:24:20 +02:00
test-fixtures Add support for per-vertex point sizes 2013-06-07 16:53:29 +01:00
tests Add support for per-vertex point sizes 2013-06-07 16:53:29 +01:00
.gitignore gitignore: Ignore the examples/cogl-gles2-gears executable 2013-04-23 18:30:54 +01:00
.vimrc misc: Add a .vimrc file 2011-05-17 15:24:54 +01:00
autogen.sh build: update to build with automake 1.13 2013-01-22 18:00:05 +00:00
ChangeLog dist: Don't use elaborate script to gen Changelogs 2011-07-20 16:58:46 +01:00
cogl.doap Adds an initial cogl.doap file 2011-05-06 12:12:13 +01:00
config-custom.h configure: Force #undef of 'near' and 'far' on Windows 2011-06-14 12:14:02 +01:00
config.h.win32.in Update config.h.win32.in 2013-03-15 00:26:35 +08:00
configure.ac tests: Adds our first white-box unit test 2013-06-06 21:27:16 +01:00
COPYING Update the COPYING file 2011-09-05 19:02:05 +01:00
Makefile.am tests: Adds our first white-box unit test 2013-06-06 21:27:16 +01:00
NEWS Updates NEWS for the 1.14.0 release 2013-03-25 13:26:05 +00:00
README.in configure: Add a minimum required version for the wayland package 2013-03-22 00:13:36 +00:00

README for Cogl @COGL_1_VERSION@
===============================================================================

Note: This file is delimited with -- markers so it is possible to split
sections out for other purposes, such as for release notes.

--
DESCRIPTION
-------------------------------------------------------------------------------

Cogl is a small open source library for using 3D graphics hardware for
rendering. The API departs from the flat state machine style of OpenGL and is
designed to make it easy to write orthogonal components that can render without
stepping on each others toes.

As well as aiming for a nice API, we think having a single library as opposed
to an API specification like OpenGL has a few advantages too; like being
able to paper over the inconsistencies/bugs of different OpenGL
implementations in a centralized place, not to mention the myriad of OpenGL
extensions. It also means we are in a better position to provide utility
APIs that help software developers since they only need to be implemented
once and there is no risk of inconsistency between implementations.

Having other backends, besides OpenGL, such as drm, Gallium or D3D are
options we are interested in for the future.

--
REQUIREMENTS
-------------------------------------------------------------------------------

Cogl currently only requires:

  • GLib ≥ @GLIB_REQ_VERSION@
  • OpenGL ≥ 1.3 (or 1.2 + multitexturing), or OpenGL ES 2.0 (or 1.1)
  • GLX, AGL, WGL or an EGL implementation

Cogl also has optional dependencies:

  • GDK-Pixbuf ≥ @GDK_PIXBUF_REQ_VERSION@
     - for image loading
  • Cairo ≥ @CAIRO_REQ_VERSION@
     - for debugging texture atlasing (debug builds only)

The optional Cogl Pango library requires:
  • Cairo ≥ @CAIRO_REQ_VERSION@
  • PangoCairo ≥ @PANGOCAIRO_REQ_VERSION@

On X11, Cogl depends on the following extensions

  • XComposite ≥ @XCOMPOSITE_REQ_VERSION@
  • XDamage
  • XExt
  • XFixes ≥ @XFIXES_REQ_VERSION@

For the Wayland backend, Cogl requires:
  • Wayland ≥ @WAYLAND_REQ_VERSION@

When running with OpenGL, Cogl requires at least version 1.3
or 1.2 with the multitexturing extension. However to build Cogl
you will need the latest GL headers which can be obtained from:

  http://www.khronos.org

If you are building the API reference you will also need:

  • GTK-Doc ≥ @GTK_DOC_REQ_VERSION@

If you are building the additional documentation you will also need:

  • xsltproc
  • jw (optional, for generating PDFs)

If you are building the Introspection data you will also need:

  • GObject-Introspection ≥ @GI_REQ_VERSION@

GObject-Introspection is available from:

  git://git.gnome.org/gobject-introspection

If you want support for profiling Cogl you will also need:

  • UProf ≥ @UPROF_REQ_VERSION@

UProf is available from:

  git://github.com/rib/UProf.git

--
DOCUMENTATION
-------------------------------------------------------------------------------

The 1.x stable API is documented here:

  http://developer.gnome.org/cogl/stable/

The 1.x development API is documented here:

  http://developer.gnome.org/cogl/1.$(COGL_1_MINOR_VERSION)

The experimental 2.0 API is currently not hosted online but can be built
by passing the --enable-gtk-doc option to ./configure when building
and the documentation can then be found under
doc/reference/cogl-2.0-experimental/html/index.html

--
LICENSE
-------------------------------------------------------------------------------

Most of Cogl is licensed under the terms of the GNU Lesser General Public
License, version 2.1 or (at your option) later. Some files are licensed under
more permissive licenses MIT or BSD style licenses though so please see
individual files for details.

--
BUILDING AND INSTALLATION
-------------------------------------------------------------------------------

Please refer to the INSTALL document.

--
BUGS
-------------------------------------------------------------------------------

Please report bugs here:

  http://bugzilla.gnome.org/enter_bug.cgi?product=cogl

You will need a Bugzilla account.

Please include the following in bug reports:

  • what system you're running Cogl on;
  • which version of Cogl you are using;
  • which version of GLib and OpenGL (or OpenGL ES) you are using;
  • which video card and which drivers you are using, including output of
    glxinfo and xdpyinfo (if applicable);
  • how to reproduce the bug.

If you cannot reproduce the bug with one of the tests that come with
Cogl's source code, it can help a lot to include a small test case
displaying the bad behaviour.

If the bug exposes a crash, the exact text printed out and a stack trace
obtained using gdb are greatly appreciated.

--
CONTRIBUTING
-------------------------------------------------------------------------------

The CODING_STYLE file describes the coding style we use throughout Cogl,
please try your best to conform to this style because the consistency
really helps keep the code maintainable.

We can accept contributions in several ways:
  • Either as patches attached to bugs on bugzilla
      - For this you may be interested in using git-bz.

        See http://git.fishsoup.net/man/git-bz.html for details
  • You can email us patches
      - For this we recommend using git-send-email

  • You can create a remote branch and ask us to pull from that for more
    substantial changes.
      - For this we recommend using github.

Ideally standalone patches should be created using git format-patch since
that makes it easiest to import the patch with a commit message into a
git repository.