As of 9/15/2020, the LZHAM and crunch data compression libraries are in the Public Domain. For jurisdictions that don't recognize releasing Public Domain software, there are unlicense-style fallback clauses:
Tuesday, September 15, 2020
Wednesday, August 26, 2020
As the owner of the "LZHAM" and "crunch" free open source software IP, I have decided to place these two works into the Public Domain in the United States, expressly waiving copyright protection. Once this is done this software will no longer by my or anyone's IP (i.e. it will NOT BE INTELLECTUAL PROPERTY, OR ANYONE'S PROPERTY). The upload placing these works into the Public Domain will occur on 9/15/2020 around noon EST.
1. FALLBACK CLAUSES
THIS SOFTWARE MAY BE FREELY USED, DERIVED FROM, EXECUTED, LINKED WITH, MODIFIED AND DISTRIBUTED FOR ANY PURPOSE, COMMERCIAL OR NON-COMMERCIAL, BY ANYONE, FOR ANY REASON, WITH NO ATTRIBUTION, IN PERPETUITY.
THE AUTHOR OR AUTHORS OF THIS WORK HEREBY OVERTLY, FULLY, PERMANENTLY, IRREVOCABLY AND UNCONDITIONALLY FORFEITS AND WAIVES ALL CLAIM OF COPYRIGHT (ECONOMIC AND MORAL), ANY AND ALL RIGHTS OF INTEGRITY, AND ANY AND ALL RIGHTS OF ATTRIBUTION. ANYONE IS FREE TO COPY, MODIFY, ENHANCE, OPTIMIZE, PUBLISH, USE, COMPILE, DECOMPILE, ASSEMBLE, DISASSEMBLE, DOWNLOAD, UPLOAD, TRANSMIT, RECEIVE, SELL, FORK, DERIVE FROM, LINK, LINK TO, CALL, REFERENCE, WRAP, THUNK, ENCODE, ENCRYPT, TRANSFORM, STORE, RETRIEVE, DISTORT, DESTROY, RENAME, DELETE, BROADCAST, OR DISTRIBUTE THIS SOFTWARE, EITHER IN SOURCE CODE FORM, IN A TRANSLATED FORM, AS A LIBRARY, AS TEXT, IN PRINT, OR AS A COMPILED BINARY OR EXECUTABLE PROGRAM, OR IN DIGITAL FORM, OR IN ANALOG FORM, OR IN PHYSICAL FORM, OR IN ANY OTHER REPRESENTATION, FOR ANY PURPOSE, COMMERCIAL OR NON-COMMERCIAL, AND BY ANY MEANS, WITH NO ATTRIBUTION, IN PERPETUITY.
IN JURISDICTIONS THAT RECOGNIZE COPYRIGHT LAWS, THE AUTHOR OR AUTHORS OF THIS SOFTWARE OVERTLY, FULLY, PERMANENTLY, IRREVOCABLY AND UNCONDITIONALLY DEDICATE, FORFEIT, AND WAIVE ANY AND ALL COPYRIGHT INTEREST IN THE SOFTWARE TO THE PUBLIC DOMAIN. WE MAKE THIS DEDICATION AND WAIVER FOR THE BENEFIT OF THE PUBLIC AT LARGE AND TO THE DETRIMENT OF OUR HEIRS AND SUCCESSORS. WE INTEND THIS DEDICATION AND WAIVER TO BE AN OVERT ACT OF RELINQUISHMENT IN PERPETUITY OF ALL PRESENT AND FUTURE RIGHTS TO THIS SOFTWARE UNDER COPYRIGHT LAW. WE INTEND THIS SOFTWARE TO BE FREELY USED, COMPILED, EXECUTED, MODIFIED, PUBLISHED, DERIVED FROM, OR DISTRIBUTED BY ANYONE, FOR ANY COMMERCIAL OR NON-COMMERCIAL USE, WITH NO ATTRIBUTION, IN PERPETUITY.
3. NO WARRANTY CLAUSE
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR OR AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE, OR DERIVING FROM THE SOFTWARE, OR LINKING WITH THE SOFTWARE, OR CALLING THE SOFTWARE, OR EXECUTING THE SOFTWARE, OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
4. FINAL ANTI-COPYRIGHT AND INTENT FALLBACK CLAUSE
SHOULD ANY PART OF THIS PUBLIC DOMAIN DECLARATION, OR THE FALLBACK CLAUSES, OR THE ANTI-COPYRIGHT WAIVER FOR ANY REASON BE JUDGED LEGALLY INVALID OR INEFFECTIVE UNDER APPLICABLE LAW, THEN THE PUBLIC DOMAIN DECLARATION, THE FALLBACK CLAUSES, AND ANTI-COPYRIGHT WAIVER SHALL BE PRESERVED TO THE MAXIMUM EXTENT PERMITTED BY LAW TAKING INTO ACCOUNT THE ABOVE STATEMENT OF INTENT.
Thursday, April 16, 2020
Same benchmark except this time with 3-color transparent texels used for black or dark texels in rgbcx (purple samples):
Here's an update, now with nvdxt.exe (black sample) and ispc_texcomp (brown sample). Note that the nvdxt.exe time is approximate because I had to spawn nvdxt.exe and it loads a .png and saves a .dds file. I did spawn it twice, once without timing it, then immediately again timing it.
nvdxt.exe command line:
nvdxt.exe -nomipmap -quality_highest -rms_threshold 50 -file image.png -output nvcompressed.dds -dxt1c -weight 1.0 1.0 1.0
Thursday, April 9, 2020
This is across 100 textures, so even small avg. improvements are significant. Amazingly, the inset method (a few lines of code) buys rgbcx.h PCA .131 dB! All encoders should be doing this. You *must* pay attention to every little detail in these texture encoders.
Quality is performance in competitive texture block encoding, so even small boosts in quality allow us to dial down the # of total orders to check for the same average quality. This leads to a more competitive encoder.
- bounds+inset+XY covar method is Castano's/van Waveren's.
Wednesday, April 8, 2020
For selectors 0 and 1, the 5->8 and 6->8 endpoint conversion just uses bitshifts/OR's (same as ideal BC1). For 4-color selector 2, use the tables. For selector 3, just invert the low/high endpoints. (I've verified you can do this.) For 3-color selector 2, use the tables.
To access the tables, use [color0_component*32+color1_component], or *64 for 6-bits:
Block Compression (Direct3D 10) - Win32 appsdocs.microsoft.com
Converting the tables to formulas sounds like an interesting puzzle.
Example showing exactly how to use the tables to decode AMD BC1:
Tuesday, April 7, 2020
I didn't include AMD Compressonator's encoder because in previous benchmarks (conducted by others) it was beaten by a weaker version of rgbcx.h for both perf. and quality.
The overall CPU BC1 Pareto frontier is defined by ispc_texcomp (at low quality: ~33.1 dB) and rgbcx for any higher quality level. We're going to need SIMD to compete against ispc_texcomp BC1 (a weak stb_dxt clone), which is my next major goal.
To get rgbcx to compete against icbc for max. quality I had to add prioritized cluster fit support for 3-color blocks (not just 4).
It's possible to permit rgbcx to go to even higher quality levels by enlarging the total ordering tables. They're currently limited to 32 entries per total ordering.
I think rgbcx.h's max quality is slightly higher than icbc's HQ mode because prioritized cluster fit can afford to do optimal rounding and evaluate accurate MSE errors in every trial. Regular cluster fit can't afford to do so because it has to evaluate so many total orderings.
Saturday, April 4, 2020
Here's my latest benchmark:
- h is cEncodeBC1HighQuality
- ut is cEncodeBC1UseLikelyTotalOrderings
- ub is cEncodeBC1Use3ColorBlocksForBlackPixels
- 3 is cEncodeBC1Use3ColorBlocks
From the benchmarks I've seen it appears NVidia Texture Tools BC1 is around the same perf. as libsquish at slightly higher quality:
I believe this was rgbcx using 10 total orderings (the default setting). The max is 32, and every additional total ordering increases average quality. So at higher settings rgbcx is likely competitive against nvtt while being faster.
I'm currently working on integrating NVTT into my test app.