GitHub - richgel999/libsquish: Fixed fork of libsquish DXT1-5/BC1-5 texture encoding library, with improved solid-color tables

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Fixed fork of libsquish DXT1-5/BC1-5 texture encoding library, with improved solid-color tables

MIT license

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Name		Name	Last commit message	Last commit date
Latest commit History 57 Commits
CMakeModules		CMakeModules
extra		extra
images		images
test		test
vs7		vs7
vs8		vs8
vs9		vs9
CMakeLists.txt		CMakeLists.txt
ChangeLog		ChangeLog
Doxyfile		Doxyfile
GNUmakefile		GNUmakefile
LICENSE		LICENSE
README		README
alpha.cpp		alpha.cpp
alpha.h		alpha.h
clusterfit.cpp		clusterfit.cpp
clusterfit.h		clusterfit.h
colourblock.cpp		colourblock.cpp
colourblock.h		colourblock.h
colourfit.cpp		colourfit.cpp
colourfit.h		colourfit.h
colourset.cpp		colourset.cpp
colourset.h		colourset.h
config		config
config.h		config.h
libSquish.png		libSquish.png
libSquish.pri		libSquish.pri
libSquish.pro		libSquish.pro
libSquish.svg		libSquish.svg
maths.cpp		maths.cpp
maths.h		maths.h
rangefit.cpp		rangefit.cpp
rangefit.h		rangefit.h
simd.h		simd.h
simd_float.h		simd_float.h
simd_sse.h		simd_sse.h
simd_ve.h		simd_ve.h
singlecolourfit.cpp		singlecolourfit.cpp
singlecolourfit.h		singlecolourfit.h
singlecolourlookup.inl		singlecolourlookup.inl
squish.cpp		squish.cpp
squish.h		squish.h

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LICENSE
-------

The squish library is distributed under the terms and conditions of the MIT
license. This license is specified at the top of each source file and must be
preserved in its entirety.

FIXED TABLES
------------

This fork of the original library contains fixed solid color tables for 3 and
4 color blocks. The original tables did not factor in the up to 3% error allowed
by actual GPU BC1 decoding hardware, leading to noticeable artifacts on some textures.
More information is here:
http://www.ludicon.com/castano/blog/2009/03/gpu-dxt-decompression/

To use the original tables, set SQUISH_USE_ORIGINAL_TABLES to 1 in singlecolourfit.cpp.

Average across 101 test textures:

Original/bad tables:
Ideal BC1 PSNR: 36.504513 dB, std dev: 7.569236
NVidia BC1 PSNR: 36.391151 dB, std dev: 7.389989

Fixed (this fork):
Ideal BC1 PSNR: 36.498199 dB, std dev: 7.555960
NVidia BC1 PSNR: 36.462097 dB, std dev: 7.475064

This is across 101 textures. Some textures are impacted more than others. One example (a grayscale texture):

Original:
Ideal BC1 PSNR: 46.656 dB
NVidia BC1 PSNR: 43.203 dB

Fixed:
Ideal BC1 PSNR: 46.625 dB
NVidia BC1 PSNR: 45.410 dB

BUILDING AND INSTALLING THE LIBRARY
-----------------------------------

If you are using Visual Studio 2003 or above under Windows then load the Visual
Studio 2003 project in the vs7 folder. By default, the library is built using
SSE2 optimisations. To change this either change or remove the SQUISH_USE_SSE=2
from the preprocessor symbols.

If you are using a Mac then load the Xcode 2.2 project in the distribution. By
default, the library is built using Altivec optimisations. To change this
either change or remove SQUISH_USE_ALTIVEC=1 from the preprocessor symbols. I
guess I'll have to think about changing this for the new Intel Macs that are
rolling out...

If you are using unix then first edit the config file in the base directory of
the distribution, enabling Altivec or SSE with the USE_ALTIVEC or USE_SSE
variables, and editing the optimisation flags passed to the C++ compiler if
necessary. Then make can be used to build the library, and make install (from
the superuser account) can be used to install (into /usr/local by default).

REPORTING BUGS OR FEATURE REQUESTS
----------------------------------

Feedback can be sent to Simon Brown (the developer) at si@sjbrown.co.uk

New releases are announced on the squish library homepage at
http://sjbrown.co.uk/?code=squish