add scripts to build astcenc

.gitignore

@@ -8,6 +8,7 @@ htmlcov
 # scripts
 *.bat
 *.sh
+!external/build*.*
 
 # textures
 *.dds
@@ -30,4 +31,4 @@ htmlcov
 
 # doc
 *.txt
-!changelog.txt
+!changelog.txt

external/build_astcenc.bat

@@ -0,0 +1,25 @@
+@echo off
+
+REM Builds texconv.dll with CMake and Visual Studio.
+REM texconv.dll will be generated in ..\
+
+set VS_VERSION=Visual Studio 17 2022
+
+@pushd %~dp0\astc-encoder\
+mkdir build
+cd build
+
+cmake -G "%VS_VERSION%"^
+ -A x64^
+ -D CMAKE_CONFIGURATION_TYPES=Release^
+ -D CMAKE_MSVC_RUNTIME_LIBRARY=MultiThreadedDLL^
+ -D ASTCENC_CLI=OFF^
+ -D ASTCENC_ISA_SSE2=ON^
+ -D ASTCENC_SHAREDLIB=ON^
+ ../
+
+cmake --build . --config Release
+copy Source\Release\astcenc-sse2-shared.dll ..\
+@popd
+
+pause

external/build_astcenc_Linux.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+# Builds astc-encoder with cmake on Linux.
+# libastc-sse2-shared.so will be generated in ./astc-encoder/
+
+pushd $(dirname "$0")/astc-encoder/
+mkdir build
+cd build
+cmake \
+  -D CMAKE_BUILD_TYPE=Release\
+  -D CMAKE_POSITION_INDEPENDENT_CODE=ON\
+  -D ASTCENC_CLI=OFF\
+  -D ASTCENC_ISA_SSE2=ON\
+  -D ASTCENC_SHAREDLIB=ON\
+  ../
+cmake --build .
+cp Source/libastcenc-sse2-shared.so ../
+popd

external/build_astcenc_macOS.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+# Builds astc-encoder with cmake on macOS.
+# libastc-shared.dylib will be generated in ./astc-encoder/
+
+pushd $(dirname "$0")/astc-encoder/
+mkdir build
+cd build
+cmake -D CMAKE_BUILD_TYPE=Release -D CMAKE_POSITION_INDEPENDENT_CODE=ON -D CMAKE_OSX_DEPLOYMENT_TARGET=10.15 -D ASTCENC_CLI=OFF -D ASTCENC_SHAREDLIB=ON ../
+cmake --build .
+cd Source
+lipo -create -output libastcenc-shared.dylib -arch x86_64 libastcenc-sse4.1-shared.dylib -arch x86_64h libastcenc-avx2-shared.dylib -arch arm64 libastcenc-neon-shared.dylib
+cp libastcenc-shared.dylib ../../
+popd