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cogl_texture_get_data uses find_best_gl_get_data_format from the texture driver which returns the closest format to use for retrieving pixel data given an intended format. However this function doesn't know about the texture we are reading data from so it doesn't know that the data we will actually receive will have the same premult status as the texture's format. With the GL driver, this function ends up returning exactly the same format as passed in which means it will never do a premult conversion. Under GLES it always returns COGL_PIXEL_FORMAT_RGBA_8888 so it will always make the data unpremult even if the final requested format is premultiplied. This patch fixes it so that it copies the premult status of the closest_format from the format of the underlying texture. That way it will later convert or not depending on the requested target format. Note this patch breaks test-sub-texture with the GL driver because that is incorrectly trying to read the texture data back as RGBA_8888 even though it depends on it not doing a premult conversion. The test was already broken with GLES2 and remains broken. Reviewed-by: Robert Bragg <robert@linux.intel.com> |
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cogl | ||
cogl-pango | ||
doc | ||
examples | ||
po | ||
tests | ||
.gitignore | ||
.vimrc | ||
autogen.sh | ||
ChangeLog | ||
cogl.doap | ||
config-custom.h | ||
config.h.win32.in | ||
configure.ac | ||
COPYING | ||
Makefile.am | ||
NEWS | ||
README.in |
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@ 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 API references for the latest stable release are available at: http://docs.clutter-project.org/docs/cogl/stable/ The experimental 2.0 API can be found here: http://docs.clutter-project.org/docs/cogl-2.0-experimental/stable/ Note: The confusing "stable" at the end refers to the overall Cogl release status, not the documentation specifically. -- 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.