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diff --git a/thirdparty/etc2comp/README.md b/thirdparty/etc2comp/README.md new file mode 100644 index 0000000000..1c70ae9f4e --- /dev/null +++ b/thirdparty/etc2comp/README.md @@ -0,0 +1,197 @@ +# Etc2Comp - Texture to ETC2 compressor
+
+Etc2Comp is a command line tool that converts textures (e.g. bitmaps)
+into the [ETC2](https://en.wikipedia.org/wiki/Ericsson_Texture_Compression)
+format. The tool is built with a focus on encoding performance
+to reduce the amount of time required to compile asset heavy applications as
+well as reduce overall application size.
+
+This repo provides source code that can be compiled into a binary. The
+binary can then be used to convert textures to the ETC2 format.
+
+Important: This is not an official Google product. It is an experimental
+library published as-is. Please see the CONTRIBUTORS.md file for information
+about questions or issues.
+
+## Setup
+This project uses [CMake](https://cmake.org/) to generate platform-specific
+build files:
+ - Linux: make files
+ - OS X: Xcode workspace files
+ - Microsoft Windows: Visual Studio solution files
+ - Note: CMake supports other formats, but this doc only provides steps for
+ one of each platform for brevity.
+
+Refer to each platform's setup section to setup your environment and build
+an Etc2Comp binary. Then skip to the usage section of this page for examples
+of how to use the library.
+
+### Setup for OS X
+ build tested on this config:
+ OS X 10.9.5 i7 16GB RAM
+ Xcode 5.1.1
+ cmake 3.2.3
+
+Start by downloading and installing the following components if they are not
+already installed on your development machine.
+ - *Xcode* version 5.1.1, or greater
+ - [CMake](https://cmake.org/download/) version 3.2.3, or greater
+
+To build the Etc2Comp binary:
+ 1. Open a *Terminal* window and navigate to the project directory.
+ 1. Run `mkdir build_xcode`
+ 1. Run `cd build_xcode`
+ 1. Run `cmake -G Xcode ../`
+ 1. Open *Xcode* and import the `build_xcode/EtcTest.xcodeproj` file.
+ 1. Open the Product menu and choose Build For -> Running.
+ 1. Once the build succeeds the binary located at `build_xcode/EtcTool/Debug/EtcTool`
+can be executed.
+
+Optional
+Xcode EtcTool ‘Run’ preferences
+note: if the build_xcode/EtcTest.xcodeproj is manually deleted then some Xcode preferences
+will need to be set by hand after cmake is run (these prefs are retained across
+cmake updates if the .xcodeproj is not deleted/removed)
+
+1. Set the active scheme to ‘EtcTool’
+1. Edit the scheme
+1. Select option ‘Run EtcTool’, then tab ‘Arguments’.
+Add this launch argument: ‘-argfile ../../EtcTool/args.txt’
+1. Select tab ‘Options’ and set a custom working directory to: ‘$(SRCROOT)/Build_Xcode/EtcTool’
+
+### SetUp for Windows
+
+1. Open a *Terminal* window and navigate to the project directory.
+1. Run `mkdir build_vs`
+1. Run `cd build_vs`
+1. Run CMAKE, noting what build version you need, and pointing to the parent directory as the source root;
+ For VS 2013 : `cmake -G "Visual Studio 12 2013 Win64" ../`
+ For VS 2015 : `cmake -G "Visual Studio 14 2015 Win64" ../`
+ NOTE: To see what supported Visual Studio outputs there are, run `cmake -G`
+1. open the 'EtcTest' solution
+1. make the 'EtcTool' project the start up project
+1. (optional) in the project properties, under 'Debugging ->command arguments'
+add the argfile textfile thats included in the EtcTool directory.
+example: -argfile C:\etc2\EtcTool\Args.txt
+
+### Setup For Linux
+The Linux build was tested on this config:
+ Ubuntu desktop 14.04
+ gcc/g++ 4.8
+ cmake 2.8.12.2
+
+1. Verify linux has cmake and C++-11 capable g++ installed
+1. Open shell
+1. Run `mkdir build_linux`
+1. Run `cd build_linux`
+1. Run `cmake ../`
+1. Run `make`
+1. navigate to the newly created EtcTool directory `cd EtcTool`
+1. run the executable: `./EtcTool -argfile ../../EtcTool/args.txt`
+
+Skip to the <a href="#usage">Usage</a> section for more information about using the
+tool.
+
+## Usage
+
+### Command Line Usage
+EtcTool can be run from the command line with the following usage:
+ etctool.exe source_image [options ...] -output encoded_image
+
+The encoder will use an array of RGBA floats read from the source_image to create
+an ETC1 or ETC2 encoded image in encoded_image. The RGBA floats should be in the
+range [0:1].
+
+Options:
+
+ -analyze <analysis_folder>
+ -argfile <arg_file> additional command line arguments read from a file
+ -blockAtHV <H V> encodes a single block that contains the
+ pixel specified by the H V coordinates
+ -compare <comparison_image> compares source_image to comparison_image
+ -effort <amount> number between 0 and 100 to specify the encoding quality
+ (100 is the highest quality)
+ -errormetric <error_metric> specify the error metric, the options are
+ rgba, rgbx, rec709, numeric and normalxyz
+ -format <etc_format> ETC1, RGB8, SRGB8, RGBA8, SRGB8, RGB8A1,
+ SRGB8A1 or R11
+ -help prints this message
+ -jobs or -j <thread_count> specifies the number of threads (default=1)
+ -normalizexyz normalize RGB to have a length of 1
+ -verbose or -v shows status information during the encoding
+ process
+ -mipmaps or -m <mip_count> sets the maximum number of mipaps to generate (default=1)
+ -mipwrap or -w <x|y|xy> sets the mipmap filter wrap mode (default=clamp)
+
+* -analyze will run an analysis of the encoding and place it in folder
+"analysis_folder" (e.g. ../analysis/kodim05). within the analysis_folder, a folder
+will be created with a name of the current date/time (e.g. 20151204_153306). this
+date/time folder is used to compare encodings of the same texture over time.
+within the date/time folder is a text file with several encoding stats and a 2x png
+image showing the encoding mode for each 4x4 block.
+
+* -argfile allows additional command line arguments to be placed in a text file
+
+* -blockAtHV selects the 4x4 pixel subset of the source image at position (H,V).
+This is mainly used for debugging
+
+* -compare compares the source image to the created encoded image. The encoding
+will dictate what error analysis is used in the comparison.
+
+* -effort uses an "amount" between 0 and 100 to determine how much additional effort
+to apply during the encoding.
+
+* -errormetric selects the fitting algorithm used by the encoder. "rgba" calculates
+RMS error using RGB components that are weighted by A. "rgbx" calculates RMS error
+using RGBA components, where A is treated as an additional data channel, instead of
+as alpha. "rec709" is similar to "rgba", except the RGB components are also weighted
+according to Rec709. "numeric" calculates RMS error using unweighted RGBA components.
+"normalize" calculates error based on dot product and vector length for RGB and RMS
+error for A.
+
+* -help prints out the usage message
+
+* -jobs enables multi-threading to speed up image encoding
+
+* -normalizexyz normalizes the source RGB to have a length of 1.
+
+* -verbose shows information on the current encoding process. It will then display the
+PSNR and time time it took to encode the image.
+
+* -mipmaps takes an argument that specifies how many mipmaps to generate from the
+source image. The mipmaps are generated with a lanczos3 filter using edge clamping.
+If the mipmaps option is not specified no mipmaps are created.
+
+* -mipwrap takes an argument that specifies the mipmap filter wrap mode. The options
+are "x", "y" and "xy" which specify wrapping in x only, y only or x and y respectively.
+The default options are clamping in both x and y.
+
+Note: Path names can use slashes or backslashes. The tool will convert the
+slashes to the appropriate polarity for the current platform.
+
+
+## API
+
+The library supports two different APIs - a C-like API that is not heavily
+class-based and a class-based API.
+
+main() in EtcTool.cpp contains an example of both APIs.
+
+The Encode() method now returns an EncodingStatus that contains bit flags for
+reporting various warnings and flags encountered when encoding.
+
+
+## Copyright
+Copyright 2015 Etc2Comp Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
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