Replace JavaFX with SDL2 + OpenGL ES 2.0 via JNI

.gitignore

@@ -71,6 +71,9 @@ compile_commands.json
 todo/
 susuwu/*.class
 susuwu/FishSim_local.log
+susuwu/*.so
+susuwu/*.dll
+susuwu/*.dylib
 
 # `remark-cli` temp
 package.json

build.sh

@@ -6,37 +6,39 @@
 #  * If *this attribution* is shown, *this source code* allows all uses. *This attribution* constitutes the most permissive which is compatible with [*GPLv2*](https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html) + [*Apache 2*](https://www.apache.org/licenses/LICENSE-2.0.html), which is suitable for personal use (also suitable for school use).
 #  * If *this attribution* is not professional enough for business use: businesses can use *this source code* through included versions of [*GPLv2*](./LICENSE_GPLv2), [*Apache 2*](./LICENSE), or through both of those. */
 
-PATH_TO_FX="${PATH_TO_FX:-"/usr/share/openjfx/lib/"}" # /* Notice: prefix " "s in path with slashes, such as "\ ". */
 PATH_TO_CLASS="susuwu/FishSim"
 PATH_TO_SOURCE="${PATH_TO_CLASS}.java"
-JAVA_MODULES="${JAVA_MODULES} --module-path ${PATH_TO_FX} --add-modules javafx.controls,javafx.fxml" # /* Notice: quotes around `${PATH_TO_FX}` give errors, so ensure to escape the path in `PATH_TO_FX=...` */
-#JAVA_MODULES="${JAVA_MODULES} --module-path \"${PATH_TO_FX}\" --add-modules javafx.controls,javafx.fxml" # /* Notice: those quotes (around `${PATH_TO_FX}`) give "java.lang.module.FindException: Module javafx.controls not found" */
-JAVA_FLAGS="${JAVA_FLAGS} --enable-native-access=javafx.graphics"
-#JAVA_FLAGS="${JAVA_FLAGS} -XX:+HeapDumpOnOutOfMemoryError " # /* Notice: if "Exception java.lang.OutOfMemoryError occurred dispatching signal SIGINT to handler- the VM may need to be forcibly terminated" then uncomment this to use `jhat java_pid*.hprof` */
+PATH_TO_NATIVE="susuwu/sdl_gles2_jni.c"
+PATH_TO_NATIVE_LIB="susuwu/libsdl_gles2_jni.so" # /* `.so` on Linux/Android, `.dll` on Windows, `.dylib` on macOS */
 JAVA_FLAGS="${JAVA_FLAGS} -enableassertions" # /* Notice: remove `-enableassertions` so performance improves */
+JAVA_FLAGS="${JAVA_FLAGS} -Djava.library.path=susuwu" # /* Allows JNI to find `libsdl_gles2_jni.so` */
 export JAVA_BUILD_TEST_FLAGS="-verbose"
 export JAVA_TEST_FLAGS="-verbose:module"
 if command -v sudo >/dev/null; then
 	APTITUDE="sudo apt -y install "
 else
 	APTITUDE="apt -y install " # /* Fixes "The program sudo is not installed." on platforms such as smartphones */
 fi
-if ! test -d "${PATH_TO_FX}"; then # /* TODO: search for this if default (**Ubuntu**'s) path is not found */
-	${APTITUDE} openjfx || ${APTITUDE} libopenjfx-java
-	if ! test -d "${PATH_TO_FX}"; then
-		echo "$0: '${PATH_TO_FX}' dir not found. Use \`${APTITUDE} install openjfx\`, then set '\${PATH_TO_FX}' to the actual libs."
-	fi
-fi
 command -v java >/dev/null || ${APTITUDE} openjdk-21-jdk-headless || ${APTITUDE} default-jdk-headless
 
+if ! dpkg -l libsdl2-dev >/dev/null 2>&1; then # /* Install SDL2 + GLES2 dev headers (replaces `openjfx`) */
+	${APTITUDE} libsdl2-dev libgles2-mesa-dev || true
+fi
+
+# /* Compile the JNI native library: `libsdl_gles2_jni.so` (replaces `--module-path`/`--add-modules javafx.*`) */
+JAVA_HOME="${JAVA_HOME:-$(java -XshowSettings:properties -version 2>&1 | grep 'java.home' | sed 's/.*= //')}"
+JNI_INCLUDES="-I${JAVA_HOME}/include -I${JAVA_HOME}/include/linux" # /* Linux; macOS uses `include/darwin`, Android uses NDK paths */
+#shellcheck disable=SC2086 # /* Quotes cause errors with pkg-config output */
+cc -shared -fPIC "${PATH_TO_NATIVE}" -o "${PATH_TO_NATIVE_LIB}" ${JNI_INCLUDES} $(pkg-config --cflags --libs sdl2) -lGLESv2 || exit $?
+
 if [ -n "${GITHUB_ACTIONS}" ]; then
 #shellcheck disable=SC2086 # /* Quotes cause "Unrecognized option:" */
-	javac ${JAVA_BUILD_TEST_FLAGS} ${JAVA_MODULES} ${PATH_TO_SOURCE} # /* Gives "Missing JavaFX application class susuwu/FishSim" unless `cd $(dirname ${PATH_TO_CLASS})` is used. */
-#	java ${JAVA_TEST_FLAGS} ${JAVA_FLAGS} ${JAVA_MODULES} ${PATH_TO_CLASS} # /* Assumes `main()` will `return` (but, `FishSim.java`'s does not) */
-#	java ${JAVA_TEST_FLAGS} ${JAVA_FLAGS} --source 16 ${JAVA_MODULES} ${PATH_TO_SOURCE} # /* Assumes `main()` will `return` (but, `FishSim.java`'s does not) */
+	javac ${JAVA_BUILD_TEST_FLAGS} susuwu/SdlGles2.java susuwu/SimUsages.java ${PATH_TO_SOURCE} # /* Gives "Missing JavaFX application class susuwu/FishSim" unless `cd $(dirname ${PATH_TO_CLASS})` is used. */
+#	java ${JAVA_TEST_FLAGS} ${JAVA_FLAGS} ${PATH_TO_CLASS} # /* Assumes `main()` will `return` (but, `FishSim.java`'s does not) */
+#	java ${JAVA_TEST_FLAGS} ${JAVA_FLAGS} --source 16 ${PATH_TO_SOURCE} # /* Assumes `main()` will `return` (but, `FishSim.java`'s does not) */
 else
 #shellcheck disable=SC2086 # /* Quotes cause "Unrecognized option:" */
-	java ${JAVA_FLAGS} --source 16 ${JAVA_MODULES} ${PATH_TO_SOURCE} # /* `---source` is workaround for "Missing JavaFX application class susuwu/FishSim" */
+	java ${JAVA_FLAGS} --source 16 ${PATH_TO_SOURCE} # /* `--source` is workaround for "error: cannot find symbol\n...\n  symbol: {class Force, variable Utils}" when not compiling all sources together */
 fi
 
 exit $? #Status required so [*CodeQL*](https://docs.github.com/en/code-security/code-scanning/introduction-to-code-scanning/about-code-scanning-with-codeql) passes.